1.
Population
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A population is the number of all the organisms of the same group or species, which live in a particular geographical area, and have the capability of interbreeding. In sociology, population refers to a collection of humans, Demography is a social science which entails the statistical study of human populations. This article refers mainly to human population, in population genetics a sexual population is a set of organisms in which any pair of members can breed together. This means that they can regularly exchange gametes to produce normally-fertile offspring and this also implies that all members belong to the same species. If the gamodeme is very large, and all gene alleles are uniformly distributed by the gametes within it, however, there may be low frequencies of exchange with these neighbours. This may be viewed as the breaking up of a sexual population into smaller overlapping sexual populations. The overall rise in homozygosity is quantified by the inbreeding coefficient, note that all homozygotes are increased in frequency – both the deleterious and the desirable. The mean phenotype of the collection is lower than that of the panmictic original – which is known as inbreeding depression. It is most important to note, however, that some lines will be superior to the panmictic original, while some will be about the same. The probabilities of each can be estimated from those binomial equations, in plant and animal breeding, procedures have been developed which deliberately utilise the effects of dispersion. It can be shown that dispersion-assisted selection leads to the greatest genetic advance and this is so for both allogamous and autogamous gamodemes. In ecology, the population of a species in a certain area can be estimated using the Lincoln Index. As of todays date, the population is estimated by the United States Census Bureau to be 7.496 billion. The US Census Bureau estimates the 7 billion number was surpassed on 12 March 2012, according to papers published by the United States Census Bureau, the world population hit 6.5 billion on 24 February 2006. The United Nations Population Fund designated 12 October 1999 as the day on which world population reached 6 billion. This was about 12 years after world population reached 5 billion in 1987, the population of countries such as Nigeria, is not even known to the nearest million, so there is a considerable margin of error in such estimates. Researcher Carl Haub calculated that a total of over 100 billion people have probably been born in the last 2000 years, Population growth increased significantly as the Industrial Revolution gathered pace from 1700 onwards. In 2007 the United Nations Population Division projected that the population will likely surpass 10 billion in 2055
2.
Genocide
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Genocide is intentional action to destroy a people in whole or in part. The hybrid word genocide is a combination of the Greek word génos, the United Nations Genocide Convention, which was established in 1948, defines genocide as acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group. The term genocide was coined in a 1943 book responding to mass murder of populations in the 20th century, in 1943, Raphael Lemkin created the term genocide in his book Axis Rule in Occupied Europe. The book describes the implementation of Nazi policies in occupied Europe, the term described the systematic destruction of a nation or people, and the word was quickly adopted by many in the international community. The word genocide is the combination of the Greek prefix geno-, Lemkin defined genocide as follows, Generally speaking, genocide does not necessarily mean the immediate destruction of a nation, except when accomplished by mass killings of all members of a nation. The preamble to the 1948 Genocide Convention notes that instances of genocide have taken place throughout history. Lemkins lifelong interest in the murder of populations in the 20th century was initially in response to the killing of Armenians in 1915. He dedicated his life to mobilizing the international community, to together to prevent the occurrence of such events. In a 1949 interview, Lemkin said I became interested in genocide because it happened so many times and it happened to the Armenians, then after the Armenians, Hitler took action. In 1948, the UN General Assembly adopted the Convention on the Prevention, the CPPCG was adopted by the UN General Assembly on 9 December 1948 and came into effect on 12 January 1951. The USSR argued that the Conventions definition should follow the etymology of the term, and may have feared greater international scrutiny of its own Great Purge. Other nations feared that including political groups in the definition would invite international intervention in domestic politics. ”The conventions purpose and scope was later described by the United Nations Security Council as follows, In 2007 the European Court of Human Rights, noted in its judgement on Jorgic v. In the same judgement the ECHR reviewed the judgements of several international and municipal courts judgements, in the case of Onesphore Rwabukombe the German Supreme Court adhered to its previous judgement and didnt follow the narrow interpretation of the ICTY and the ICJ. The phrase in whole or in part has been subject to discussion by scholars of international humanitarian law. The International Criminal Tribunal for the Former Yugoslavia found in Prosecutor v. Radislav Krstic – Trial Chamber I – Judgment – IT-98-33 ICTY8 that Genocide had been committed. The aim of the Genocide Convention is to prevent the destruction of entire human groups. The Appeals Chamber goes into details of other cases and the opinions of respected commentators on the Genocide Convention to explain how they came to this conclusion. The judges continue in paragraph 12, The determination of when the part is substantial enough to meet this requirement may involve a number of considerations
3.
Genetic diversity
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Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary, genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals, the academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral substitutions, diversifying selection is the hypothesis that two subpopulations of a species live in different environments that select for different alleles at a particular locus. This may occur, for instance, if a species has a large relative to the mobility of individuals within it. Frequency-dependent selection is the hypothesis that as alleles become more common and this occurs in host–pathogen interactions, where a high frequency of a defensive allele among the host means that it is more likely that a pathogen will spread if it is able to overcome that allele. According to the researcher in the study, Dr. Richard Lankau, If any one type is removed from the system, the cycle can break down. The interdependence between genetic and species diversity is delicate, changes in species diversity lead to changes in the environment, leading to adaptation of the remaining species. Changes in genetic diversity, such as in loss of species, loss of genetic diversity in domestic animal populations has also been studied and attributed to the extension of markets and economic globalization. Genetic diversity plays an important role in the survival and adaptability of a species, variation in the populations gene pool provides variable traits among the individuals of that population. These variable traits can be selected for, via natural selection, ultimately leading to a change in the population. Genetic diversity is essential for a species to evolve, with very little gene variation within the species, healthy reproduction becomes increasingly difficult, and offspring are more likely to have problems resulting from inbreeding. The vulnerability of a population to certain types of diseases can also increase with reduction in genetic diversity, concerns about genetic diversity are especially important with large mammals due to their small population size and high levels of human-caused population effects. When humans initially started farming, they used selective breeding to pass on traits of the crops while omitting the undesirable ones. Selective breeding leads to monocultures, entire farms of nearly genetically identical plants, If the genetic variation that the bacterium is best at attacking happens to be that which humans have selectively bred to use for harvest, the entire crop will be wiped out. A very similar occurrence is the cause of the infamous Potato Famine in Ireland, in the 1840s, much of Irelands population depended on potatoes for food
4.
Offspring
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In biology, offspring are the young born of living organisms, produced either by a single organism or, in the case of sexual reproduction, two organisms. Collective offspring may be known as a brood or progeny in a general way. This can refer to a set of offspring, such as the chicks hatched from one clutch of eggs, or to all the offspring. Human offspring are referred to as children, male children are sons, offspring can occur after mating or after artificial insemination. Offspring contains many parts and properties that are precise and accurate in what they consist of, and what they define. As the offspring of a new species, also known as a child or f1 generation, consist of genes of the father and the mother, each of these offspring contains numerous genes which have coding for specific tasks and properties. Males and females contribute equally to the genotypes of their offspring, in which gametes fuse and form. An important aspect of the formation of the parent offspring is the chromosome, depending on which genes are dominantly expressed in the gene will result in the sex of the offspring. The female will give an X chromosome, whereas the male, depending on the situation. If a male offspring is produced, the gene will consist of an X, if two X chromosomes are expressed and produced, it produces a female offspring. Cloning is the production of an offspring which represents the identical genes as its parent, reproductive cloning begins with the removal of the nucleus from an egg, which holds the genetic material. In order to clone an organ, a cell is to be produced. A common misconception of cloning is that it produces a copy of the parent being cloned. Cloning copies the DNA/genes of the parent and then creates a genetic duplicate, the clone will not be a similar copy as he or she will grow up in different surroundings from the clone and may encounter different opportunities and experiences. Although mostly positive, cloning also faces some setbacks in terms of ethics, though cell division and DNA replication is a vital part of survival, there are many steps involved and mutations can occur with permanent change in an organisms and their offsprings DNA. Lineal descendant kinship and descent Clutch size Infanticide Litter Parent-offspring conflict Parental investment
5.
Mutation
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In biology, a mutation is the permanent alteration of the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA or other genetic elements. Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements, mutations may or may not produce discernible changes in the observable characteristics of an organism. Mutations play a part in normal and abnormal biological processes including, evolution, cancer, and the development of the immune system. The genomes of RNA viruses are based on RNA rather than DNA, the RNA viral genome can be double stranded or single stranded. In some of these viruses replication occurs quickly and there are no mechanisms to check the genome for accuracy and this error-prone process often results in mutations. Mutation can result in different types of change in sequences. Mutations in genes can either have no effect, alter the product of a gene, mutations can also occur in nongenic regions. Mutations can involve the duplication of large sections of DNA, usually through genetic recombination and these duplications are a major source of raw material for evolving new genes, with tens to hundreds of genes duplicated in animal genomes every million years. Most genes belong to larger families of shared ancestry, known as homology. Here, protein domains act as modules, each with a particular and independent function, that can be mixed together to produce genes encoding new proteins with novel properties. For example, the eye uses four genes to make structures that sense light. Another advantage of duplicating a gene is that this increases engineering redundancy, other types of mutation occasionally create new genes from previously noncoding DNA. Changes in chromosome number may involve even larger mutations, where segments of the DNA within chromosomes break and then rearrange. For example, in the Homininae, two fused to produce human chromosome 2, this fusion did not occur in the lineage of the other apes. Sequences of DNA that can move about the genome, such as transposons, make up a fraction of the genetic material of plants and animals. For example, more than a million copies of the Alu sequence are present in the genome. Another effect of these mobile DNA sequences is that when they move within a genome, they can mutate or delete existing genes, nonlethal mutations accumulate within the gene pool and increase the amount of genetic variation. The abundance of some changes within the gene pool can be reduced by natural selection, while other more favorable mutations may accumulate
6.
Natural selection
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Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in heritable traits of a population over time, Charles Darwin popularised the term natural selection, and compared it with artificial selection. Variation exists within all populations of organisms and this occurs partly because random mutations arise in the genome of an individual organism, and offspring can inherit such mutations. Throughout the lives of the individuals, their genomes interact with their environments to cause variations in traits, the environment of a genome includes the molecular biology in the cell, other cells, other individuals, populations, species, as well as the abiotic environment. Individuals with certain variants of the trait may survive and reproduce more than individuals with other, less successful, variants, therefore, factors that affect reproductive success are also important, including sexual selection and fecundity selection. Over time, this process can result in populations that specialise for particular ecological niches, in other words, natural selection is a key process in the evolution of a population. Natural selection can be contrasted with artificial selection, in which humans intentionally choose specific traits, Natural selection is one of the cornerstones of modern biology. The concept of natural selection originally developed in the absence of a theory of heredity, at the time of Darwins writing. The union of traditional Darwinian evolution with subsequent discoveries in classical genetics formed the synthesis of the mid-20th century. The addition of molecular genetics has led to developmental biology. While genotypes can slowly change by random genetic drift, natural selection remains the primary explanation for adaptive evolution, empedocles idea that organisms arose entirely by the incidental workings of causes such as heat and cold was criticised by Aristotle in Book II of Physics. He posited natural teleology in its place, and believed that form was achieved for a purpose, nevertheless, he accepted in his biology that new types of animals, monstrosities, can occur in very rare instances. And in like manner as to the parts in which there appears to exist an adaptation to an end. Yet it is impossible that this should be the true view, for teeth and all other natural things either invariably or normally come about in a given way, but of not one of the results of chance or spontaneity is this true. We do not ascribe to chance or mere coincidence the frequency of rain in winter, but frequent rain in summer we do, nor heat in the dog-days, therefore action for an end is present in things which come to be and are by nature. The struggle for existence was later described by the Islamic writer Al-Jahiz in the 9th century, the classical arguments were reintroduced in the 18th century by Pierre Louis Maupertuis and others, including Darwins grandfather, Erasmus Darwin. Until the early 19th century, the view in Western societies was that differences between individuals of a species were uninteresting departures from their Platonic ideals of created kinds. However, the theory of uniformitarianism in geology promoted the idea that simple and this theory, Lamarckism, was an influence on the Soviet biologist Trofim Lysenkos antagonism to mainstream genetic theory as late as the mid 20th century
7.
Climate change
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Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time. Climate change may refer to a change in weather conditions. Climate change is caused by such as biotic processes, variations in solar radiation received by Earth, plate tectonics. Certain human activities have also identified as significant causes of recent climate change. Scientists actively work to understand past and future climate by using observations, more recent data are provided by the instrumental record. The most general definition of change is a change in the statistical properties of the climate system when considered over long periods of time. Accordingly, fluctuations over periods shorter than a few decades, such as El Niño, the term climate change is often used to refer specifically to anthropogenic climate change. Anthropogenic climate change is caused by activity, as opposed to changes in climate that may have resulted as part of Earths natural processes. In this sense, especially in the context of environmental policy, within scientific journals, global warming refers to surface temperature increases while climate change includes global warming and everything else that increasing greenhouse gas levels affect. A related term is climatic change, in 1966, the World Meteorological Organization proposed the term climatic change to encompass all forms of climatic variability on time-scales longer than 10 years, regardless of cause. Change was a given and climatic was used as an adjective to describe this kind of change, when it was realized that human activities had a potential to drastically alter the climate, the term climate change replaced climatic change as the dominant term to reflect an anthropogenic cause. Climate change was incorporated in the title of the Intergovernmental Panel on Climate Change, Climate change, used as a noun, became an issue rather than the technical description of changing weather. On the broadest scale, the rate at which energy is received from the Sun and this energy is distributed around the globe by winds, ocean currents, and other mechanisms to affect the climates of different regions. Factors that can shape climate are called climate forcings or forcing mechanisms, there are a variety of climate change feedbacks that can either amplify or diminish the initial forcing. Some parts of the system, such as the oceans and ice caps, respond more slowly in reaction to climate forcings. There are also key factors which when exceeded can produce rapid change. Forcing mechanisms can be internal or external. Internal forcing mechanisms are natural processes within the system itself
8.
Fitness (biology)
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Fitness is the quantitative representation of natural and sexual selection within evolutionary biology. It can be defined either with respect to a genotype or to a phenotype in a given environment, the fitness of a genotype is manifested through its phenotype, which is also affected by the developmental environment. The fitness of a phenotype can also be different in different selective environments. With asexual reproduction, it is sufficient to assign fitnesses to genotypes, with sexual reproduction, genotypes are scrambled every generation. In this case, fitness values can be assigned to alleles by averaging over possible genetic backgrounds, Natural selection tends to make alleles with higher fitness more common over time, resulting in Darwinian evolution. The term Darwinian fitness can be used to clear the distinction with physical fitness. One mechanism of inclusive fitness is kin selection, Fitness is often defined as a propensity or probability, rather than the actual number of offspring. For example, according to Maynard Smith, Fitness is a property, not of an individual, thus the phrase ’expected number of offspring’ means the average number, not the number produced by some one individual. If the first human infant with a gene for levitation were struck by lightning in its pram, this would not prove the new genotype to have low fitness, but only that the particular child was unlucky. Equivalently, the fitness of the individual - having an array x of phenotypes — is the probability, s, to avoid the complications of sex and recombination, we initially restrict our attention to an asexual population without genetic recombination. Then fitnesses can be assigned directly to genotypes rather than having to worry about individual alleles, there are two commonly used measures of fitness, absolute fitness and relative fitness. The absolute fitness of a genotype is defined as the change in the abundance of that genotype over one generation attributable to selection. For example, if n is the abundance of a genotype in generation t in a large population. An absolute fitness larger than 1 indicates growth in that genotypes abundance, whereas absolute fitness determines changes in genotype abundance, relative fitness determines changes in genotype frequency. If N is the population size in generation t, and the relevant genotypes frequency is p = n / N, then p = w w ¯ p. It is often convenient to one genotype as a reference. Relative fitness is used in the standard Wright-Fisher and Moran models of population genetics, absolute fitnesses can be used to calculate relative fitness, since p = n / N = p. This implies that w / w ¯ = W / W ¯, or in other words and it is not possible to calculate absolute fitnesses from relative fitnesses alone, since relative fitnesses contain no information about changes in overall population abundance N
9.
Genetic drift
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Genetic drift is the change in the frequency of a gene variant in a population due to random sampling of organisms. The alleles in the offspring are a sample of those in the parents, a populations allele frequency is the fraction of the copies of one gene that share a particular form. Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation, when there are few copies of an allele, the effect of genetic drift is larger, and when there are many copies the effect is smaller. In the early 20th century, vigorous debates occurred over the importance of natural selection versus neutral processes. The process of genetic drift can be illustrated using 20 marbles in a jar to represent 20 organisms in a population, consider this jar of marbles as the starting population. Half of the marbles in the jar are red and half blue, in each new generation the organisms reproduce at random. To represent this reproduction, randomly select a marble from the original jar, repeat this process until there are 20 new marbles in the second jar. The second jar then contains a second generation of offspring, consisting of 20 marbles of various colours, unless the second jar contains exactly 10 red marbles and 10 blue marbles, a random shift occurred in the allele frequencies. Repeat this process a number of times, randomly reproducing each generation of marbles to form the next, the numbers of red and blue marbles picked each generation fluctuates, sometimes more red and sometimes more blue. This fluctuation is analogous to genetic drift – a change in the allele frequency resulting from a random variation in the distribution of alleles from one generation to the next. It is even possible that in any one generation no marbles of a particular colour are chosen, in this example, if no red marbles are selected, the jar representing the new generation contains only blue offspring. If this happens, the red allele has been lost permanently in the population, while the remaining blue allele has become fixed, in small populations, fixation can occur in just a few generations. The mechanisms of genetic drift can be illustrated with a simplified example, consider a very large colony of bacteria isolated in a drop of solution. The bacteria are genetically identical except for a gene with two alleles labeled A and B. A and B are neutral alleles meaning that they do not affect the ability to survive and reproduce, all bacteria in this colony are equally likely to survive. Suppose that half the bacteria have allele A and the other half have allele B, thus A and B each have allele frequency 1/2. The drop of solution then shrinks until it has enough food to sustain four bacteria. All other bacteria die without reproducing, among the four who survive, there are sixteen possible combinations for the A and B alleles
10.
Allele
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An allele is the variant form of a given gene. Sometimes, different alleles can result in different observable phenotypic traits, however, most genetic variations result in little or no observable variation. The word allele is a form of allelomorph, which was used in the early days of genetics to describe variant forms of a gene detected as different phenotypes. It derives from the Greek prefix ἀλλήλ, allel, meaning reciprocal or each other, most multicellular organisms have two sets of chromosomes, that is, they are diploid. These chromosomes are referred to as homologous chromosomes, if both alleles at a gene on the homologous chromosomes are the same, they and the organism are homozygous with respect to that gene. If the alleles are different, they and the organism are heterozygous with respect to that gene, where the heterozygote is indistinguishable from one of the homozygotes, the allele involved is said to be dominant to the other, which is said to be recessive to the former. The degree and pattern of dominance varies among loci and this type of interaction was first formally described by Gregor Mendel. However, many traits defy this simple categorization and the phenotypes are modeled by co-dominance, the term wild type allele is sometimes used to describe an allele that is thought to contribute to the typical phenotypic character as seen in wild populations of organisms, such as fruit flies. Such a wild type allele was historically regarded as dominant, common, and normal, in contrast to mutant alleles regarded as recessive, rare, a population or species of organisms typically includes multiple alleles at each locus among various individuals. Allelic variation at a locus is measurable as the number of alleles present, a null allele is a gene variant that lacks the genes normal function because it either is not expressed, or the expressed protein is inactive. For example, at the locus for the ABO blood type carbohydrate antigens in humans. The frequency of alleles in a population can be used to predict the frequencies of the corresponding genotypes. Then, p2 is the fraction of the population homozygous for the first allele, 2pq is the fraction of heterozygotes, and q2 is the fraction homozygous for the alternative allele. If the first allele is dominant to the then the fraction of the population that will show the dominant phenotype is p2 + 2pq. With three alleles, p + q + r =1 and p 2 + q 2 + r 2 +2 p q +2 p r +2 q r =1. In the case of multiple alleles at a locus, the number of possible genotypes with a number of alleles is given by the expression. A number of disorders are caused when an individual inherits two recessive alleles for a single-gene trait. Recessive genetic disorders include albinism, cystic fibrosis, galactosemia, phenylketonuria, other disorders are also due to recessive alleles, but because the gene locus is located on the X chromosome, so that males have only one copy, they are more frequent in males than in females
11.
Homogeneity
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Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the uniformity in a substance or organism. A material or image that is homogeneous is uniform in composition or character, the alternate spellings homogenous and heterogenous are commonly, but incorrectly, used. Heterogenous meanwhile is a term primarily confined to pathology which refers to the property of an object in the body having its origin outside the body, the concepts are the same to every level of complexity, from atoms to populations of animals or people, and galaxies. Hence, an element may be homogeneous on a larger scale and this is known as an effective medium approach, or effective medium approximations. Various disciplines understand heterogeneity, or being heterogeneous, in different ways, heterogeneous solids, liquids, and gases may be made homogeneous by melting, stirring, or by allowing time to pass for diffusion to distribute the molecules evenly. For example, adding dye to water will create a solution at first. Entropy allows for heterogeneous substances to become homogeneous over time, a heterogeneous mixture is a mixture of two or more compounds. Examples are, mixtures of sand and water or sand and iron filings, a rock, water and oil, a salad, trail mix. A mixture can be determined to be homogeneous when everything is settled and equal, various models have been proposed to model the concentrations in different phases. The phenomena to be considered are mass rates and reaction, homogeneous reactions are chemical reactions in which the reactants and products are in the same phase, while heterogeneous reactions have reactants in two or more phases. Reactions that take place on the surface of a catalyst of a different phase are also heterogeneous, a reaction between two gases or two miscible liquids is homogeneous. A reaction between a gas and a liquid, a gas and a solid or a liquid and a solid is heterogeneous, earth is a heterogeneous substance in many aspects. E. g. rocks are inherently heterogeneous, usually occurring at the micro-scale and mini-scale, in algebra, homogeneous polynomials have the same number of factors of a given kind. This can cause problems in attempts to summarize the meaning of the studies, in medicine and genetics, a genetic or allelic heterogeneous condition is one where the same disease or condition can be caused, or contributed to, by several factors. In the case of genetics, varying different genes or alleles, in cancer research, cancer cell heterogeneity is thought to be one of the underlying reasons that make treatment of cancer difficult. In physics, heterogeneous is understood to mean having physical properties that vary within the medium, in sociology, heterogeneous may refer to a society or group that includes individuals of differing ethnicities, cultural backgrounds, sexes, or ages. Academic Press Dictionary of Science and Technology
12.
Inbreeding depression
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Inbreeding depression is the reduced biological fitness in a given population as a result of inbreeding, or breeding of related individuals. Population biological fitness refers to an ability to survive and perpetuate its genetic material. Inbreeding depression is often the result of a population bottleneck, in general, the higher the genetic variation or gene pool within a breeding population, the less likely it is to suffer from inbreeding depression. Inbreeding depression seems to be present in most groups of organisms, hermaphroditic species often exhibit lower degrees of inbreeding depression than outcrossing species, as repeated generations of selfing is thought to purge deleterious alleles from populations. Inbreeding results in more recessive, deleterious traits manifesting themselves, because the genomes of pair-mates are more similar, recessive traits can only occur in an offspring if present in both parents genomes. The more genetically similar the parents are, the more often recessive traits appear in their offspring, consequently, the more closely related the breeding pair is, the more homozygous, deleterious genes the offspring may have, resulting in very unfit individuals. For alleles that confer an advantage in the heterozygous and/or homozygous-dominant state, an example of inbreeding depression is shown to the right. In this case, a is the allele which has negative effects. In order for the a phenotype to become active, the gene must end up as homozygous aa because in the geneotype Aa, the A takes dominance over the a, another mechanism responsible for inbreeding depression is the fitness advantage of heterozygosity, which is known as overdominance. This can lead to reduced fitness of a population with many homozygous genotypes, here, even the dominant alleles result in reduced fitness if present homozygously. Currently, it is not known which of the two mechanisms is more prevalent in nature, Natural selection cannot effectively remove all deleterious recessive genes from a population for several reasons. First, deleterious genes arise constantly through mutation within a population, second, in a population where inbreeding occurs frequently, most offspring will have some deleterious traits, so few will be more fit for survival than the others. Third, recessive deleterious alleles will be masked by heterozygosity, and so in a dominant-recessive trait, in general, sexual reproduction in eukaryotes has two fundamental aspects, recombination during meiosis, and outcrossing. It has been proposed that two aspects have two natural selective advantages respectively. A proposed adaptive advantage of meiosis is that it facilitates repair of DNA damages that are otherwise difficult to repair. A proposed adaptive advantage of outcrossing is complementation, which is the masking of deleterious recessive alleles, the selective advantage of complementation may largely account for the general avoidance of inbreeding. Introducing alleles from a different population can reverse inbreeding depression, different populations of the same species have different deleterious traits, and therefore their cross breeding will not result in homozygosity at most loci in the offspring. This is known as outbreeding enhancement, practiced by conservation managers, however, intermixing two different populations can give rise to unfit polygenic traits in outbreeding depression
13.
Founder effect
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In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942, using existing work by those such as Sewall Wright. As a result of the loss of genetic variation, the new population may be distinctively different, in extreme cases, the founder effect is thought to lead to the speciation and subsequent evolution of new species. In the figure shown, the population has nearly equal numbers of blue. The three smaller founder populations show that one or the color may predominate, due to random sampling of the original population. A population bottleneck may also cause an effect, though it is not strictly a new population. The founder effect occurs when a group of migrants that is not genetically representative of the population from which they came establish in a new area. In addition to effects, the new population is often a very small population, so shows increased sensitivity to genetic drift, an increase in inbreeding. This can be observed in the gene pools of Icelanders, Parsis, Ashkenazi Jews, Faroe Islanders, Easter Islanders. Another example is the remarkably high deaf population of Marthas Vineyard, in genetics, a founder mutation is a mutation that appears in the DNA of one or more individuals which are founders of a distinct population. Founder mutations initiate with changes that occur in the DNA and can be passed down to other generations, the mutation may occur in any organism that becomes a founder of the line of descendants containing that mutation, which could be a virus, a goat, or a human. Founder mutations originate in long stretches of DNA on a chromosome, indeed. As the generations progress, the proportion of the haplotype that is common to all carriers of the mutation is shortened and this shortening allows scientists to roughly estimate the age of the mutation. The founder effect is a case of genetic drift, occurring when a small group in a population splinters off from the original population. This consequence of inbreeding makes the colony more vulnerable to extinction, when a newly formed colony is small, its founders can strongly affect the populations genetic makeup far into the future. Alleles which were present but relatively rare in the population can move to one of two extremes. The new colony can experience an increase in the frequency of alleles, as well, and as a result. The variation in frequency between the original population and colony may also trigger the two groups to diverge significantly over the course of many generations
14.
Invasive species
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One study pointed out widely divergent perceptions of the criteria for invasive species among researchers and concerns with the subjectivity of the term invasive. Such invasive species may be either plants or animals and may disrupt by dominating a region, wilderness areas, particular habitats and this includes non-native invasive plant species labeled as exotic pest plants and invasive exotics growing in native plant communities. It has been used in this sense by government organizations as well as groups such as the International Union for Conservation of Nature. The European Union defines Invasive Alien Species as those that are, firstly, outside their natural distribution area and it is also used by land managers, botanists, researchers, horticulturalists, conservationists, and the public for noxious weeds. The kudzu vine, Andean Pampas grass, and yellow starthistle are examples, an alternate usage broadens the term to include indigenous or native species along with non-native species, that have colonized natural areas. Deer are an example, considered to be overpopulating their native zones and adjacent suburban gardens, by some in the Northeastern, sometimes the term is used to describe a non-native or introduced species that has become widespread. However, not every introduced species has adverse effects on the environment, a nonadverse example is the common goldfish, which is found throughout the United States, but rarely achieves high densities. Scientists include species and ecosystem factors among the mechanisms that when combined, while all species compete to survive, invasive species appear to have specific traits or specific combinations of traits that allow them to outcompete native species. In some cases, the competition is about rates of growth, in other cases, species interact with each other more directly. Researchers disagree about the usefulness of traits as invasiveness markers, one study found that of a list of invasive and noninvasive species, 86% of the invasive species could be identified from the traits alone. Another study found invasive species tended to have only a subset of the presumed traits. Repeated patterns of movement, such as ships sailing to and from ports or cars driving up. An introduced species might become if it can outcompete native species for resources such as nutrients, light, physical space, water. If these species evolved under great competition or predation, then the new environment may host fewer able competitors, allowing the invader to proliferate quickly. Ecosystems in which are being used to their fullest capacity by native species can be modeled as zero-sum systems in which any gain for the invader is a loss for the native, however, such unilateral competitive superiority is not the rule. For example, barbed goatgrass was introduced to California on serpentine soils, which have low water-retention, low nutrient levels, a high magnesium/calcium ratio, and possible heavy metal toxicity. Plant populations on these soils tend to low density, but goatgrass can form dense stands on these soils. Some species, like Kalanchoe daigremontana, produce allelopathic compounds, that might have an effect on competing species
15.
Conservation biology
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It is an interdisciplinary subject drawing on natural and social sciences, and the practice of natural resource management. The conservation ethic is based on the findings of conservation biology, wilcox and Michael E. Soulé with a group of leading university and zoo researchers and conservationists including Kurt Benirschke, Sir Otto Frankel, Thomas E. Lovejoy, and Jared M. Diamond. The meeting was prompted by the concern over deforestation, disappearing species. Conservation biology and the concept of biological diversity emerged together, helping crystallize the modern era of conservation science, the inherent multidisciplinary basis for conservation biology has led to new subdisciplines including conservation social science, conservation behavior and conservation physiology. It stimulated further development of genetics which Otto Frankel had originated first but is now often considered a subdiscipline as well. The rapid decline of established biological systems around the means that conservation biology is often referred to as a Discipline with a deadline. Conservation biology is tied closely to ecology in researching the ecology of rare or endangered species. Conservation biologists work in the field and office, in government, universities, non-profit organizations, the topics of their research are diverse, because this is an interdisciplinary network with professional alliances in the biological as well as social sciences. Those dedicated to the cause and profession advocate for a response to the current biodiversity crisis based on morals, ethics. Conscious efforts to conserve and protect global biodiversity are a recent phenomenon, natural resource conservation, however, has a history that extends prior to the age of conservation. Resource ethics grew out of necessity through direct relations with nature and this social dilemma with respect to natural resource management is often called the Tragedy of the Commons. From this principle, conservation biologists can trace communal resource based ethics throughout cultures as a solution to communal resource conflict. For example, the Alaskan Tlingit peoples and the Haida of the Pacific Northwest had resource boundaries, rules and these rules were guided by clan elders who knew lifelong details of each river and stream they managed. There are numerous examples in history where cultures have followed rules, rituals, Conservation ethics are also found in early religious and philosophical writings. There are examples in the Tao, Shinto, Hindu, Islamic, in the bible, through Moses, God commanded to let the land rest from cultivation every seventh year. Before the 18th century, however, much of European culture considered it a view to admire nature. Wilderness was denigrated while agricultural development was praised, however, as early as AD680 a wildlife sanctuary was founded on the Farne Islands by St Cuthbert in response to his religious beliefs. Natural history was a preoccupation in the 18th century, with grand expeditions
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Minimum viable population
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Minimum viable population is a lower bound on the population of a species, such that it can survive in the wild. This term is used in the fields of biology, ecology, the term population rarely refers to an entire species. For example, the dromedary camel is extinct in its natural wild habitat, but there is a domestic population in captivity. Two groups of cats in separate houses which are not allowed outdoors are also technically distinct populations. Typically, however, MVP is used to refer solely to a wild population, minimum viable population is usually estimated as the population size necessary to ensure between 90 and 95 percent probability of survival between 100 and 1,000 years into the future. The MVP can be estimated using computer simulations for population viability analyses, PVA models populations using demographic and environmental information to project future population dynamics. The probability assigned to a PVA is arrived at after repeating the environmental simulation thousands of times, causes of extinction in the simulation may include inbreeding depression, natural disaster, or climate change. Extinction occurring in 30 out of 100 runs would give a probability of 70%. In contrast, in the simulation with a starting population of 60 pandas. In this case the minimum viable population that satisfies the 90- to 95% probability for survival is between 50 and 60 pandas, MVP does not take human intervention into account. There is a trend for insularity, surviving genetic bottlenecks. Conversely, taxa easily affected by inbreeding depression – having high MVPs – are often decidedly K-strategists, an MVP of 500 to 1,000 has often been given as an average for terrestrial vertebrates when inbreeding or genetic variability is ignored. When inbreeding effects are included, estimates of MVP for many species are in the thousands, based on a meta-analysis of reported values in the literature for many species, Traill et al. reported a median MVP of 4,169 individuals. Population uncertainty may be divided into four sources, Demographic stochasticity Environmental stochasticity Natural catastrophes Genetic stochasticity Effective population size Nurgalievs law
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Pest control
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Pest control refers to the regulation or management of a species defined as a pest, and can be perceived to be detrimental to a persons health, the ecology or the economy. A practitioner of pest control is called an exterminator, Pest control is at least as old as agriculture, as there has always been a need to keep crops free from pests. In order to maximize production, it is advantageous to protect crops from competing species of plants. Techniques such as rotation, companion planting, and the selective breeding of pest-resistant cultivars have a long history. In the UK, following concern about animal welfare, humane pest control, for instance, with the urban red fox which territorial behaviour is used against the animal, usually in conjunction with non-injurious chemical repellents. In rural areas of Britain, the use of firearms for pest control is quite common, chemical pesticides date back 4,500 years, when the Sumerians used sulfur compounds as insecticides. The Rig Veda, which is about 4,000 years old, in the 20th century, the discovery of several synthetic insecticides, such as DDT, and herbicides boosted this development. Many pests have only become a problem as a result of the actions by humans. Modifying these actions can often reduce the pest problem. In the United States, raccoons caused a nuisance by tearing open refuse sacks, many householders introduced bins with locking lids, which deterred the raccoons from visiting. House flies tend to accumulate wherever there is activity and live in close association with people all over the world especially where food or food waste is exposed. Similarly, seagulls have become pests at many seaside resorts, tourists would often feed the birds with scraps of fish and chips, and before long, the birds would rely on this food source and act aggressively towards humans. Living organisms evolve and increase their resistance to biological, chemical, physical or any form of control. Perhaps as far ago as 3000BC in Egypt, cats were being used to control pests of grain such as rodents. In 1939/40 a survey discovered that cats could keep a population of rats down to a low level. However, if the rats were cleared by trapping or poisoning, ferrets were domesticated at least by 500 AD in Europe, being used as mousers. Mongooses have been introduced into homes to control rodents and snakes, biological pest control is the control of one through the control and management of natural predators and parasites. For example, mosquitoes are often controlled by putting Bt Bacillus thuringiensis ssp. israelensis, the treatment has no known negative consequences on the remaining ecology and is safe for humans to drink
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Speciation
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Speciation is the evolutionary process by which biological populations evolve to become distinct species. The biologist Orator F. Cook coined the term speciation in 1906 for the splitting of lineages or cladogenesis, Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book The Origin of Species. He also identified sexual selection as a mechanism, but found it problematic. There are four modes of speciation in nature, based on the extent to which speciating populations are isolated from one another, allopatric, peripatric, parapatric. Speciation may also be induced artificially, through animal husbandry, agriculture, whether genetic drift is a minor or major contributor to speciation is the subject matter of much ongoing discussion. All forms of speciation have taken place over the course of evolution, however. During allopatric speciation, a population splits into two isolated populations. When the populations come back into contact, they have evolved such that they are isolated and are no longer capable of exchanging genes. Island genetics is the associated with the tendency of small. Examples include insular dwarfism and the changes among certain famous island chains. The Galápagos Islands are particularly famous for their influence on Charles Darwin, though the finches were less important for Darwin, more recent research has shown the birds now known as Darwins finches to be a classic case of adaptive evolutionary radiation. In peripatric speciation, a subform of allopatric speciation, new species are formed in isolated and it is related to the concept of a founder effect, since small populations often undergo bottlenecks. Genetic drift is often proposed to play a significant role in peripatric speciation, parapatric speciation may be associated with differential landscape-dependent selection. Even if there is a gene flow between two populations, strong differential selection may impede assimilation and different species may eventually develop, habitat differences may be more important in the development of reproductive isolation than the isolation time. Ecologists refer to parapatric and peripatric speciation in terms of ecological niches, a niche must be available in order for a new species to be successful. Ring species such as Larus gulls have been claimed to illustrate speciation in progress, the grass Anthoxanthum odoratum may be starting parapatric speciation in areas of mine contamination. Sympatric speciation refers to the formation of two or more descendant species from an ancestral species all occupying the same geographic location. Often-cited examples of sympatric speciation are found in insects that become dependent on different host plants in the same area, however, the existence of sympatric speciation as a mechanism of speciation remains highly debated
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Australopithecine
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Australopithecines are generally all species in the related Australopithecus and Paranthropus genera, and it typically includes Kenyanthropus, Ardipithecus, and Praeanthropus. All these related species are now sometimes collectively classified as a subtribe of the Hominini tribe called Australopithecina and they are the extinct, close relatives of humans and, with the extant genus Homo, comprise the human clade. Members of the clade, i. e. the Hominini after the split from the chimpanzees, are now called homonina. The terms australopithecine, et al. come from a classification as members of a distinct subfamily. Members of Australopithecus are sometimes referred to as the gracile australopithecines, humans may have descended from australopithecine ancestors and the genus Ardipithecus is a possible ancestor of the australopithecines. Phylogeny of subtribe Australopithecina according to Briggs & Crowther 2008, p.124 and they have a high brachial index when compared to other hominins, and they exhibit greater sexual dimorphism than members of Homo or Pan but less so than Gorilla or Pongo. It is thought that they averaged heights of 1. 2–1.5 metres, the brain size may have been 350 cc to 600 cc. Most scientists maintain that one of the species evolved into the Homo genus in Africa around two million years ago. Nearly every possible species has been suggested as a likely candidate, presently, it appears that A. garhi has the potential to occupy this coveted place in paleoanthropology, but the lack of fossil evidence is a serious problem. Another problem presents itself in the fact that it has very difficult to assess which hominid represents the first member of the genus Homo. Without knowing this, it is not possible to determine which species of australopithecine may have been ancestral to Homo, marc Verhaegen has argued that an australopithecine species could have also been ancestral to the Pan genus. A minority held viewpoint among palaeoanthropologists is that australopithecines moved outside of Africa, a notable proponent of this theory is Jens Lorenz Franzen, formerly Head of Paleoanthropology at the Research Institute Senckenberg. In 1957, an Early Pleistocene Chinese fossil tooth of unknown province was described as resembling P. robustus, three fossilized molars from Jianshi, China were later identified as belonging to an Australopithecus species. However further examination questioned this interpretation, Zhang argued the Jianshi teeth, but, Wolpoff notes that in China persistent claims of australopithecine or australopithecine-like remains continue. Dawn of Humanity Human taxonomy Informative lecture on Australopithecines
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Homo erectus
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Homo erectus is an extinct species of hominid that lived throughout most of the Pleistocene geological epoch. Its earliest fossil evidence dates to 1.9 million years ago and extends to 70,000 years ago, or, possibly, as recently as 35,000 years ago. It is generally thought that H. erectus originated in Africa and spread from there, migrating throughout Eurasia as far as Georgia, India, Sri Lanka, China, a new debate appeared in 2013, with the documentation of the Dmanisi skulls.58 million years ago. From there it migrated, in part, by 2, the fossil record shows that its development from about 1.8 mya to one mya was widely distributed, in Africa, the Transcaucasus, Indonesia, and in Vietnam, China, and India. The second hypothesis is that H. erectus evolved in Eurasia and they occupied the Dmanisi site from 1.85 million to 1.77 million years ago, which was about the same time or slightly before their earliest evidence in Africa. There are several proposed explanations of the dispersal of H. erectus georgicus—including whether or not Africa is the source), the Dutch anatomist Eugène Dubois was fascinated by Darwins theory of evolution especially as it applied to humankind. In 1886, he set out for Asia—which then was the region accepted as the cradle of evolution despite Darwins theory of African origin. In 1891, his team discovered a human fossil on the island of Java, the Java fossil from Indonesia aroused much public interest. It was dubbed by the press as Java Man, but few scientists accepted Dubois argument that his fossil was the transitional form—the so-called missing link—between apes. Java Man is now classified as Homo erectus, most of the spectacular discoveries of H. erectus next took place at the Zhoukoudian Project, now known as the Peking Man Site, in Zhoukoudian, China. This site was first discovered by Johan Gunnar Andersson in 1921 and was first excavated in 1921, canadian anatomist Davidson Blacks initial description of a lower molar as belonging to a previously unknown species prompted widely publicized interest. Extensive excavations followed, which altogether uncovered 200 human fossils from more than 40 individuals including five nearly complete skullcaps, german anatomist Franz Weidenreich provided much of the detailed description of this material in several monographs published in the journal Palaeontologica Sinica. Throughout much of the 20th century, anthropologists debated the role of H. erectus in human evolution, early in the century, due in part to the discoveries at Java and Zhoukoudian, it was widely accepted that modern humans first evolved in Asia. From the 1950s forward, numerous finds in East Africa confirmed the hypothesis of an African genesis and it is now generally accepted that H. erectus descended from either, 1) the earliest hominin genera, or 2) the earliest Homo-species. East Africa provided sympatric coexistence for H. erectus and H, in the 1950s, archaeologists John T. Robinson and Robert Broom named Telanthropus capensis, Robinson had discovered a jaw fragment in 1949 in Swartkrans, South Africa. Later, Simonetta proposed to re-designate it to Homo erectus, in 1961, Yves Coppens discovered a skull of Tchadanthropus uxoris, then the earliest fossil human discovered in north Africa. It was reported that the fossil had been so eroded by sand that it mimicked the appearance of an australopith. Although at first considered to be a specimen of H. habilis, T. uxoris is no longer considered a valid taxon, and has been subsumed into H. erectus
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Christopher Columbus
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Christopher Columbus was an Italian explorer, navigator, colonizer, and citizen of the Republic of Genoa. Under the auspices of the Catholic Monarchs of Spain, he completed four voyages across the Atlantic Ocean and those voyages and his efforts to establish permanent settlements on the island of Hispaniola initiated the European colonization of the New World. Western imperialism and economic competition were emerging among European kingdoms through the establishment of routes and colonies. During his first voyage in 1492, he reached the New World instead of arriving at Japan as he had intended, landing on an island in the Bahamas archipelago that he named San Salvador. Over the course of three voyages, he visited the Greater and Lesser Antilles, as well as the Caribbean coast of Venezuela and Central America. These voyages had, therefore, an impact in the historical development of the modern Western world. He spearheaded the transatlantic trade and has been accused by several historians of initiating the genocide of the Hispaniola natives. Columbus himself saw his accomplishments primarily in the light of spreading the Christian religion, Columbus never admitted that he had reached a continent previously unknown to Europeans, rather than the East Indies for which he had set course. He called the inhabitants of the lands that he visited indios, the name Christopher Columbus is the Anglicisation of the Latin Christophorus Columbus. His name in Italian is Cristoforo Colombo and, in Spanish and he was born before 31 October 1451 in the territory of the Republic of Genoa, though the exact location remains disputed. His father was Domenico Colombo, a wool weaver who worked both in Genoa and Savona and who also owned a cheese stand at which young Christopher worked as a helper. Bartolomeo, Giovanni Pellegrino, and Giacomo were his brothers, Bartolomeo worked in a cartography workshop in Lisbon for at least part of his adulthood. He also had a sister named Bianchinetta, Columbus never wrote in his native language, which is presumed to have been a Genoese variety of Ligurian. In one of his writings, he says he went to sea at the age of 10, in 1470, the Columbus family moved to Savona, where Domenico took over a tavern. In the same year, Christopher was on a Genoese ship hired in the service of René of Anjou to support his attempt to conquer the Kingdom of Naples. Some modern historians have argued that he was not from Genoa but, instead and these competing hypotheses have generally been discounted by mainstream scholars. In 1473, Columbus began his apprenticeship as business agent for the important Centurione, Di Negro, later, he allegedly made a trip to Chios, an Aegean island then ruled by Genoa. In May 1476, he took part in a convoy sent by Genoa to carry valuable cargo to northern Europe
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Indigenous peoples of the Americas
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The indigenous peoples of the Americas are the pre-Columbian peoples of the Americas and their descendants. The term Amerindian is used in Quebec, the Guianas, Indigenous peoples of the United States are commonly known as Native Americans or American Indians, and Alaska Natives. Application of the term Indian originated with Christopher Columbus, who, in his search for Asia, eventually, the Americas came to be known as the West Indies, a name still used to refer to the islands of the Caribbean Sea. This led to the blanket term Indies and Indians for the indigenous inhabitants, although some indigenous peoples of the Americas were traditionally hunter-gatherers—and many, especially in the Amazon basin, still are—many groups practiced aquaculture and agriculture. The impact of their agricultural endowment to the world is a testament to their time, although some societies depended heavily on agriculture, others practiced a mix of farming, hunting, and gathering. In some regions the indigenous peoples created monumental architecture, large-scale organized cities, chiefdoms, states, and empires. Many parts of the Americas are still populated by peoples, some countries have sizable populations, especially Belize, Bolivia, Chile, Ecuador, Greenland, Guatemala, Mexico. At least a different indigenous languages are spoken in the Americas. Some, such as the Quechuan languages, Aymara, Guaraní, Mayan languages, many also maintain aspects of indigenous cultural practices to varying degrees, including religion, social organization, and subsistence practices. Like most cultures, over time, cultures specific to many indigenous peoples have evolved to incorporate traditional aspects, some indigenous peoples still live in relative isolation from Western culture and a few are still counted as uncontacted peoples. The specifics of Paleo-Indian migration to and throughout the Americas, including the dates and routes traveled, are the subject of ongoing research. According to archaeological and genetic evidence, North and South America were the last continents in the world with human habitation. During the Wisconsin glaciation, 50–17,000 years ago, falling sea levels allowed people to move across the bridge of Beringia that joined Siberia to northwest North America. Alaska was a glacial refugium because it had low snowfall, allowing a small population to exist, the Laurentide Ice Sheet covered most of North America, blocking nomadic inhabitants and confining them to Alaska for thousands of years. Indigenous genetic studies suggest that the first inhabitants of the Americas share a single population, one that developed in isolation. The isolation of these peoples in Beringia might have lasted 10–20,000 years, around 16,500 years ago, the glaciers began melting, allowing people to move south and east into Canada and beyond. These people are believed to have followed herds of now-extinct Pleistocene megafauna along ice-free corridors that stretched between the Laurentide and Cordilleran Ice Sheets. Another route proposed involves migration - either on foot or using primitive boats - along the Pacific Northwest coast to the south, archeological evidence of the latter would have been covered by the sea level rise of more than 120 meters since the last ice age
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Americas
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The Americas, also collectively called America, encompass the totality of the continents of North America and South America. Together they make up most of the land in Earths western hemisphere, along with their associated islands, they cover 8% of Earths total surface area and 28. 4% of its land area. The topography is dominated by the American Cordillera, a chain of mountains that runs the length of the west coast. The flatter eastern side of the Americas is dominated by river basins, such as the Amazon, St. Lawrence River / Great Lakes basin, Mississippi. Humans first settled the Americas from Asia between 42,000 and 17,000 years ago, a second migration of Na-Dene speakers followed later from Asia. The subsequent migration of the Inuit into the neoarctic around 3500 BCE completed what is regarded as the settlement by the indigenous peoples of the Americas. The first known European settlement in the Americas was by the Norse explorer Leif Ericson, however, the colonization never became permanent and was later abandoned. The voyages of Christopher Columbus from 1492 to 1502 resulted in permanent contact with European powers, diseases introduced from Europe and Africa devastated the indigenous peoples, and the European powers colonized the Americas. Mass emigration from Europe, including numbers of indentured servants. Decolonization of the Americas began with the American Revolution in 1776, the population is over 1 billion, with over 65% of them living in one of the three most populous countries. As of the beginning of the 2010s, the most populous urban agglomerations are Mexico City, New York, Sao Paulo, Los Angeles, Buenos Aires and Rio de Janeiro, all of them megacities. The name America was first recorded in 1507 in the Cosmographiae Introductio, apparently written by Matthias Ringmann and it first applied to both North and South America by Gerardus Mercator in 1538. Amerigen means land of Amerigo and derives from Amerigo and gen, America accorded with the feminine names of Asia, Africa, and Europa. When conceived as a continent, the form is generally the continent of America in the singular. However, without a context, singular America in English commonly refers to the United States of America. In some countries of the world, America is considered a continent encompassing the North America and South America subcontinents, the first inhabitants migrated into the Americas from Asia. Habitation sites are known in Alaska and the Yukon from at least 20,000 years ago, beyond that, the specifics of the Paleo-Indian migration to and throughout the Americas, including the dates and routes traveled, are subject to ongoing research and discussion. Widespread habitation of the Americas occurred during the glacial maximum
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Settlement of the Americas
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Available scientific evidence indicates that humanity emerged from Africa over 100,000 years ago, yet did not arrive in the Americas until less than 20,000 years ago. Current understanding of the settlement of the Americas derives from advances in four interrelated disciplines, archaeology, Pleistocene geology, physical anthropology, in the 2000s, researchers sought to use familiar tools to validate or reject established theories, such as Clovis first. The settlement of the Americas is of intense interest to archaeologists and anthropologists, for an introduction to the radiocarbon dating techniques used by archaeologists and geologists, see radiocarbon dating. During the Wisconsin Glaciation, varying portions of the Earths water were stored as glacier ice, as water accumulated in glaciers, the volume of water in the oceans correspondingly decreased, resulting in lowering of the eustatic sea level. With the rise of sea level after the Last Glacial Maximum, estimates of the final re-submergence of the Beringian land bridge based purely on present bathymetry of the Bering Strait and eustatic sea level curve place the event around 11,000 years BP. The onset of the Last Glacial Maximum after 30,000 years BP saw the expansion of alpine glaciers, alpine glaciers in the coastal ranges and the Alaskan Peninsula isolated the interior of Beringia from the Pacific coast. As deglaciation occurred, refugia expanded until the coast became ice-free by 15,000 cal years BP, the retreat of glaciers on the Alaskan Peninsula provided access from Beringia to the Pacific coast by around 17,000 cal years BP. The ice barrier between interior Alaska and the Pacific coast broke up starting around 13,500 14C years BP, the ice-free corridor to the interior of North America opened between 13,000 and 12,000 cal years BP. Glaciation in eastern Siberia during the LGM was limited to alpine and valley glaciers in mountain ranges, the paleoclimates and vegetation of eastern Siberia and Alaska during the Wisconsin glaciation have been deduced from high resolution oxygen isotope data and pollen stratigraphy. Prior to the Last Glacial Maximum, climates in eastern Siberia fluctuated between conditions approximating present day conditions and colder periods, the pre-LGM warm cycles in Arctic Siberia saw flourishes of megafaunas. A similar record of pollen being replaced with herb pollen as the LGM approached was recovered near the Kolyma River in Arctic Siberia. Diverse, though not necessarily plentiful, megafaunas were present in those environments, herb tundra dominated during the LGM, due to cold and dry conditions. Coastal environments during the Last Glacial Maximum were complex, the lowered sea level, and an isostatic bulge equilibrated with the depression beneath the Cordilleran Ice Sheet, exposed the continental shelf to form a coastal plain. The now-submerged coastal plain has potential for more refugia, pollen data indicate mostly herb/shrub tundra vegetation in unglaciated areas, with some boreal forest towards the southern end of the range of Cordilleran ice. The coastal marine environment remained productive, as indicated by fossils of pinnipeds, the highly productive kelp forests over rocky marine shallows may have been a lure for coastal migration. Reconstruction of the southern Beringian coastline also suggests potential for a highly productive coastal marine environment, pollen data indicate a warm period culminating between 14k and 11k 14C years BP followed by cooling between 11k-10k 14C years BP. Coastal areas deglaciated rapidly as coastal alpine glaciers, then lobes of Cordilleran ice, the retreat was accelerated as sea levels rose and floated glacial termini. Estimates of a fully ice-free coast range between 16k and 15k cal years BP, littoral marine organisms colonized shorelines as ocean water replaced glacial meltwater
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Toba catastrophe theory
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The Toba supereruption was a supervolcanic eruption that occurred about 75,000 years ago at the site of present-day Lake Toba. It is one of the Earths largest known eruptions, the Toba catastrophe theory holds that this event caused a global volcanic winter of 6–10 years and possibly a 1, 000-year-long cooling episode. In 1998, the theory was further developed by Stanley H. Ambrose of the University of Illinois at Urbana-Champaign. Both the link and global winter theories are highly controversial, the Toba event is the most closely studied supereruption. The Toba eruption or Toba event occurred at the present location of Lake Toba, in Indonesia and this eruption was the last and largest of four eruptions of Toba during the Quaternary period, and is also recognized from its diagnostic horizon of ashfall, the youngest Toba tuff. It had a volcanic explosivity index of 8, it made a sizable contribution to the 100×30 km caldera complex. Tobas erupted mass deposited an ash layer about 15 centimetres thick over the whole of South Asia, a blanket of volcanic ash was also deposited over the Indian Ocean, and the Arabian Sea and South China Sea. The Toba eruption apparently coincided with the onset of the last glacial period, evidence from Greenland ice cores indicates a 1, 000-year period of low δ18O and increased dust deposition immediately following the eruption. The eruption may have caused this 1, 000-year period of cooler temperatures, according to Alan Robock, who has also published nuclear winter papers, the Toba eruption did not precipitate the last glacial period. Because the saturated adiabatic lapse rate is 4.9 °C/1,000 m for temperatures above freezing, the tree line and the snow line were around 3,000 m lower at this time. The climate recovered over a few decades, and Robock found no evidence that the 1, in contrast, Oppenheimer believes that estimates of a drop in surface temperature by 3–5 °C are probably too high, and he suggests that temperatures dropped only by 1 °C. Robock has criticized Oppenheimers analysis, arguing that it is based on simplistic T-forcing relationships and they concluded that the largest known volcanic eruption in the history of the human species did not significantly alter the climate of East Africa, attracting criticism from Richard Roberts. Lane explained, We examined smear slides at a 2-mm interval, corresponding to subdecadal resolution and we observed no obvious change in sediment composition or Fe/Ti ratio, suggesting that no thermally driven overturn of the water column occurred following the Toba supereruption. In 2015, a new study of climate of East Africa supported Lanes conclusion, according to the genetic bottleneck theory, between 50,000 and 100,000 years ago, human populations sharply decreased to 3, 000–10,000 surviving individuals. It is supported by genetic evidence suggesting that humans are descended from a very small population of between 1,000 and 10,000 breeding pairs that existed about 70,000 years ago. For example, a 10-year volcanic winter triggered by the eruption could have destroyed the food sources of humans. Τhese environmental changes may have generated population bottlenecks in many species, including hominids, therefore, the genetic differences among modern humans may reflect changes within the last 70,000 years, rather than gradual differentiation over hundreds of thousands of years. Other research has cast doubt on a link between Toba and a genetic bottleneck and this has been challenged by evidence for the presence of Neanderthals in Europe and Homo floresiensis in Southeastern Asia who survived the eruption by 50,000 and 60,000 years, respectively
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Human
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Modern humans are the only extant members of Hominina tribe, a branch of the tribe Hominini belonging to the family of great apes. Several of these hominins used fire, occupied much of Eurasia and they began to exhibit evidence of behavioral modernity around 50,000 years ago. In several waves of migration, anatomically modern humans ventured out of Africa, the spread of humans and their large and increasing population has had a profound impact on large areas of the environment and millions of native species worldwide. Humans are uniquely adept at utilizing systems of communication for self-expression and the exchange of ideas. Humans create complex structures composed of many cooperating and competing groups, from families. Social interactions between humans have established a wide variety of values, social norms, and rituals. These human societies subsequently expanded in size, establishing various forms of government, religion, today the global human population is estimated by the United Nations to be near 7.5 billion. In common usage, the word generally refers to the only extant species of the genus Homo—anatomically and behaviorally modern Homo sapiens. In scientific terms, the meanings of hominid and hominin have changed during the recent decades with advances in the discovery, there is also a distinction between anatomically modern humans and Archaic Homo sapiens, the earliest fossil members of the species. The English adjective human is a Middle English loanword from Old French humain, ultimately from Latin hūmānus, the words use as a noun dates to the 16th century. The native English term man can refer to the species generally, the species binomial Homo sapiens was coined by Carl Linnaeus in his 18th century work Systema Naturae. The generic name Homo is a learned 18th century derivation from Latin homō man, the species-name sapiens means wise or sapient. Note that the Latin word homo refers to humans of either gender, the genus Homo evolved and diverged from other hominins in Africa, after the human clade split from the chimpanzee lineage of the hominids branch of the primates. The closest living relatives of humans are chimpanzees and gorillas, with the sequencing of both the human and chimpanzee genome, current estimates of similarity between human and chimpanzee DNA sequences range between 95% and 99%. The gibbons and orangutans were the first groups to split from the leading to the humans. The splitting date between human and chimpanzee lineages is placed around 4–8 million years ago during the late Miocene epoch, during this split, chromosome 2 was formed from two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. There is little evidence for the divergence of the gorilla, chimpanzee. Each of these species has been argued to be an ancestor of later hominins
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Supervolcano
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A supervolcano is a volcano capable of producing a volcanic eruption with an ejecta mass greater than 1015 kg. This can occur at hotspots or at subduction zones, the Oruanui eruption of New Zealands Taupo Volcano, the worlds most recent supereruption, had a Volcanic Explosivity Index of 8. The origin of the term supervolcano is linked to an early 20th-century scientific debate about the geological history, in 1925, Edwin T. Hodge suggested that a very large volcano, which he named Mount Multnomah, had existed in that region. He believed that several peaks in the Three Sisters area are the left after Mount Multnomah had been largely destroyed by violent volcanic explosions. In 1948, the existence of Mount Multnomah was ignored by volcanologist Howel Williams in his book The Ancient Volcanoes of Oregon. The book was reviewed in 1949 by another volcanologist, F. M. Byers Jr, in the review, Byers refers to Mount Multnomah as a supervolcano. Volcanologists and geologists do not refer to supervolcanoes in their scientific work, since about 2000, however, the term has been used by professionals for communicating science to the public. The term megacaldera is sometimes used for caldera supervolcanoes, such as the Blake River Megacaldera Complex in the Abitibi greenstone belt of Ontario and Quebec, eruptions that rate VEI8 are termed super eruptions. Large igneous provinces such as Iceland, the Siberian Traps, Deccan Traps, when created, these regions often occupy several thousand square kilometres and have volumes on the order of millions of cubic kilometers. In most cases, the lavas are laid down over several million years. They release large amounts of gases, the Réunion hotspot produced the Deccan Traps about 66 million years ago, coincident with the Cretaceous–Paleogene extinction event. Such outpourings are not explosive, though lava fountains may occur, many volcanologists consider that Iceland may be a LIP that is currently being formed. The last major outpouring occurred in 1783–84 from the Laki fissure which is approximately 40 km long, an estimated 14 km3 of basaltic lava was poured out during the eruption. The Ontong Java Plateau now has an area of about 2,000,000 km2, Volcanic eruptions are classified using the Volcanic Explosivity Index, or VEI. It is a scale, which means that an increase of one in VEI number is equivalent to a tenfold increase in volume of erupted material. VEI8 eruptions are colossal events that throw out at least 1,000 km3 bulk volume, VEI7 events eject bulk volume at least 100 km3. VEI6 eruptions occurred at Krakatoa in 1883 and Mount Pinatubo in 1991 and these eruptions ejected ~10 and 25 km3 bulk volume, respectively. At Krakatoa, the Dutch colonial authorities claimed that the toll was 36,417
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Chimpanzee
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Chimpanzees are one of the two species of the genus Pan, the other being the bonobo. Together with gorillas, they are the only exclusively African species of ape that are currently extant. Native to sub-Saharan Africa, both chimpanzees and bonobos are found in the Congo jungle. In addition, P. troglodytes is divided into four subspecies, based on genome sequencing, the two extant Pan species diverged around one million years ago. The most obvious differences are that chimpanzees are somewhat larger, more aggressive and male-dominated, while the bonobos are more gracile, peaceful and their hair is typically black or brown. Males and females differ in size and appearance, both chimps and bonobos are some of the most social great apes, with social bonds occurring among individuals in large communities. Fruit is the most important component of a diet, however, they will also eat vegetation, bark, honey, insects. They can live over 30 years in both the wild and captivity, Chimpanzees and bonobos are equally humanitys closest living relatives. As such, they are among the largest-brained, and most intelligent of primates, they use a variety of sophisticated tools and construct elaborate sleeping nests each night from branches and they have both been extensively studied for their learning abilities. There may even be distinctive cultures within populations, field studies of Pan troglodytes were pioneered by primatologist Jane Goodall. Both Pan species are considered to be endangered as human activities have caused declines in the populations. Threats to wild populations include poaching, habitat destruction. Several conservation and rehabilitation organisations are dedicated to the survival of Pan species in the wild, the first use of the name chimpanze is recorded in The London Magazine in 1738, glossed as meaning mockman in a language of the Angolans. The spelling chimpanzee is found in a 1758 supplement to Chambers Cyclopædia, the colloquialism chimp was most likely coined some time in the late 1870s. The common chimpanzee was named Simia troglodytes by Johann Friedrich Blumenbach in 1776, the species name troglodytes is a reference to the Troglodytae, an African people described by Greco-Roman geographers. Blumenbach first used it in his De generis humani varietate nativa liber in 1776, the genus name Pan was first introduced by Lorenz Oken in 1816. An alternative Theranthropus was suggested by Brookes 1828 and Chimpansee by Voigt 1831, troglodytes was not available, as it had been given as the name of a genus of wren in 1809. The International Commission on Zoological Nomenclature adopted Pan as the official name of the genus in 1895
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Gorilla
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Gorillas are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. The eponymous genus Gorilla is divided into two species, the gorillas and the western gorillas, and either four or five subspecies. They are the largest living primates, the DNA of gorillas is highly similar to that of humans, from 95–99% depending on what is counted, and they are the next closest living relatives to humans after the chimpanzees and bonobos. Gorillas natural habitats cover tropical or subtropical forests in Africa, although their range covers a small percentage of Africa, gorillas cover a wide range of elevations. The mountain gorilla inhabits the Albertine Rift montane cloud forests of the Virunga Volcanoes, ranging in altitude from 2, 200–4,300 metres. The word gorilla comes from the history of Hanno the Navigator, members of the expedition encountered a savage people, the greater part of whom were women, whose bodies were hairy, and who our interpreters called Gorillae. The word was later used as the species name, though it is unknown whether what these ancient Carthaginians encountered were truly gorillas, another species of ape or monkeys. The American physician and missionary Thomas Staughton Savage and naturalist Jeffries Wyman first described the gorilla in 1847 from specimens obtained in Liberia. The name was derived from Ancient Greek Γόριλλαι, meaning tribe of hairy women, the closest relatives of gorillas are the other two Homininae species, chimpanzees and humans, all of them having diverged from a common ancestor about 7 million years ago. Human gene sequences differ only 1. 6% on average from the sequences of corresponding gorilla genes, until recently, gorillas were considered to be a single species, with three subspecies, the western lowland gorilla, the eastern lowland gorilla and the mountain gorilla. There is now agreement that there are two species, each with two subspecies, more recently, a third subspecies has been claimed to exist in one of the species. The separate species and subspecies developed from a type of gorilla during the Ice Age. Primatologists continue to explore the relationships between various gorilla populations, the species and subspecies listed here are the ones upon which most scientists agree. The proposed third subspecies of Gorilla beringei, which has not yet received a trinomen, is the Bwindi population of the mountain gorilla, some variations that distinguish the classifications of gorilla include varying density, size, hair colour, length, culture, and facial widths. Now, over 100,000 western lowland gorillas are thought to exist in the wild, with 4,000 in zoos, mountain gorillas are the most severely endangered, with an estimated population of about 880 left in the wild and none in zoos. Population genetics of the lowland gorillas suggest that the western and eastern lowland populations diverged ~261 thousand years ago, gorillas move around by knuckle-walking, although they sometimes walk bipedally for short distances while carrying food or in defensive situations. Wild male gorillas weigh 135 to 180 kg while females usually weigh half as much as adult males at 70–115 kg. Adult males are 1.7 to 1.8 m tall, female gorillas are shorter, with smaller arm spans
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Rhesus macaque
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The rhesus macaque is one of the best-known species of Old World monkeys. It is listed as Least Concern in the IUCN Red List of Threatened Species in view of its distribution, presumed large population. Native to South, Central, and Southeast Asia, troops of M. mulatta inhabit a variety of habitats, from grasslands to arid and forested areas. The rhesus macaque is brown or grey in color and has a pink face and its tail is of medium length and averages between 20.7 and 22.9 cm. Adult males measure about 53 cm on average and weigh about 7.7 kg, females are smaller, averaging 47 cm in length and 5.3 kg in weight. Rhesus macaques have, on average,50 vertebrae and their ratio of arm length to leg length is 89%. They have dorsal scapulae and a rib cage. The rhesus macaque has 32 teeth with a formula of 2.1.2. 3/2.1.2.3. The upper molars have four cusps, paracone, metacone, protocone, the lower molars also have four cusps, metaconid, protoconid, hypoconid, and entoconid. Rhesus macaques are native to The caucus mountains / Europe, Bangladesh, Pakistan, Nepal, Burma, Thailand, Afghanistan, Vietnam, southern China, and some neighboring areas. They have the widest geographic ranges of any primate, occupying a great diversity of altitudes throughout Central, South. Inhabiting arid, open areas, rhesus macaques may be found in grasslands, woodlands, and in mountainous regions up to 2,500 m in elevation. Babies as young as a few days old can swim, Rhesus macaques are noted for their tendency to move from rural to urban areas, coming to rely on handouts or refuse from humans. They adapt well to human presence, and form larger troops in human-dominated landscapes than in forests and this overlap region is characterized by the presence of mixed-species troops, with pure troops of both species sometimes occurring even in close proximity to one another. The name rhesus is reminiscent of the Greek mythological king, Rhesus, however, the French naturalist Jean-Baptiste Audebert, who applied the name to the species, stated, it has no meaning. Several Chinese subspecies of rhesus macaques were described between 1867 and 1917, the molecular differences identified among populations, however, are alone not consistent enough to conclusively define any subspecies. M. m. tcheliensis, the north Chinese rhesus macaque, lives in the north of Henan, south of Shanxi, some consider it as the most endangered subspecies. Others consider it synonymous with M. m. sanctijohannis
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Orangutan
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The orangutans are the two exclusively Asian species of extant great apes. Native to Indonesia and Malaysia, orangutans are found in only the rainforests of Borneo. Classified in the genus Pongo, orangutans were considered to be one species, since 1996, they have been divided into two species, the Bornean orangutan and the Sumatran orangutan. In addition, the Bornean species is divided three subspecies. Based on genome sequencing, the two extant orangutan species evidently diverged around 400,000 years ago, the ancestors of the Ponginae subfamily split from the main ape line in Africa 16 to 19 million years ago and spread into Asia. Orangutans are the most arboreal of the apes and spend most of their time in trees. Their hair is typically reddish-brown, instead of the brown or black hair typical of chimpanzees, males and females differ in size and appearance. Dominant adult males have distinctive cheek pads and produce long calls that attract females, younger males do not have these characteristics and resemble adult females. Orangutans are the most solitary of the apes, with social bonds occurring primarily between mothers and their dependent offspring, who stay together for the first two years. Fruit is the most important component of a diet, however. They can live over 30 years in both the wild and captivity, orangutans are among the most intelligent primates, they use a variety of sophisticated tools and construct elaborate sleeping nests each night from branches and foliage. The apes have been studied for their learning abilities. There may even be distinctive cultures within populations, field studies of the apes were pioneered by primatologist Birutė Galdikas. Both orangutan species are considered to be critically endangered, human activities have caused severe declines in the populations and ranges of both species. Threats to wild populations include poaching, habitat destruction. Several conservation and rehabilitation organisations are dedicated to the survival of orangutans in the wild, the name orangutan is derived from the Malay and Indonesian words orang meaning person and hutan meaning forest, thus person of the forest. Orang Hutan was originally not used to refer to apes, the Malay words used to refer specifically to the ape are maias and mawas, but it is unclear if those words refer to just orangutans, or to all apes in general. The word appeared in several German-language descriptions of Indonesian zoology in the 17th century, the likely origin of the word comes specifically from the Banjarese variety of Malay
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Tiger
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The tiger is the largest cat species, most recognisable for their pattern of dark vertical stripes on reddish-orange fur with a lighter underside. The species is classified in the genus Panthera with the lion, leopard, jaguar, Tigers are apex predators, primarily preying on ungulates such as deer and bovids. They are territorial and generally solitary but social animals, often requiring large contiguous areas of habitat that support their prey requirements and this, coupled with the fact that they are indigenous to some of the more densely populated places on Earth, has caused significant conflicts with humans. Tigers once ranged widely across eastern Eurasia, from the Black Sea in the west, to the Indian Ocean in the south, today, they range from the Siberian taiga to open grasslands and tropical mangrove swamps. The remaining six tiger subspecies have been classified as endangered by the International Union for Conservation of Nature, a 2016 global census estimated the population of wild tigers at approximately 3,890 individuals. Major reasons for decline include habitat destruction, habitat fragmentation. The extent of area occupied by tigers is estimated at less than 1,184,911 km2, in 2016, wildlife conservation group at WWF declared that worlds count of wild tigers has risen for the first time in a century. Tigers are among the most recognisable and popular of the charismatic megafauna. They have featured prominently in ancient mythology and folklore, and continue to be depicted in modern films and they appear on many flags, coats of arms, and as mascots for sporting teams. The tiger is the animal of Bangladesh, India, Malaysia. In 1758, Linnaeus described the tiger in his work Systema Naturae, in 1929, the British taxonomist Reginald Innes Pocock subordinated the species under the genus Panthera using the scientific name Panthera tigris. The derivation from Greek pan- and ther may be folk etymology, the specific epithet, tigris, as well as the common name, tiger, come from the Middle English tigre and the Old English tigras, both used for the animal. These derive from the Old French tigre, itself a derivative of the Latin word tigris and the Greek word tigris. The original source may have been the Persian tigra meaning pointed or sharp, the tigers closest living relatives were previously thought to be the lion, leopard and jaguar, all of which are classified under the genus Panthera. The oldest remains of an extinct relative, called Panthera zdanskyi or the Longdan tiger, have been found in the Gansu province of northwestern China. This species is considered to be a taxon to the extant tiger and lived about 2 million years ago. It was smaller than the tiger, being the size of a jaguar. Despite being considered more primitive, the Longdan tiger was functionally and possibly ecologically similar to its modern cousin, as Panthera zdanskyi lived in northwestern China, that may have been where the tiger lineage originated
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Mitochondrial DNA
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Mitochondrial DNA is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, adenosine triphosphate. Mitochondrial DNA is only a portion of the DNA in a eukaryotic cell, most of the DNA can be found in the cell nucleus and, in plants and algae. In humans, the 16,569 base pairs of mitochondrial DNA encode for only 37 genes, human mitochondrial DNA was the first significant part of the human genome to be sequenced. In most species, including humans, mtDNA is inherited solely from the mother, since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It also permits an examination of the relatedness of populations, and so has become important in anthropology and this theory is called the endosymbiotic theory. Each mitochondrion is estimated to contain 2–10 mtDNA copies, the reasons why mitochondria have retained some genes are debated. Recent analysis of a range of mtDNA genomes suggests that both these features may dictate mitochondrial gene retention. In most multicellular organisms, mtDNA is inherited from the mother, mechanisms for this include simple dilution, degradation of sperm mtDNA in the male genital tract, in the fertilized egg, and, at least in a few organisms, failure of sperm mtDNA to enter the egg. Whatever the mechanism, this single parent pattern of inheritance is found in most animals, most plants. In sexual reproduction, mitochondria are inherited exclusively from the mother. Also, most mitochondria are present at the base of the sperms tail, in 1999 it was reported that paternal sperm mitochondria are marked with ubiquitin to select them for later destruction inside the embryo. Some in vitro techniques, particularly injecting a sperm into an oocyte. The fact that mitochondrial DNA is maternally inherited enables researchers to trace maternal lineage far back in time. This is usually accomplished on human mitochondrial DNA by sequencing the hypervariable control regions, hVR1, for example, consists of about 440 base pairs. These 440 base pairs are then compared to the regions of other individuals to determine maternal lineage. Most often, the comparison is made to the revised Cambridge Reference Sequence, vilà et al. have published studies tracing the matrilineal descent of domestic dogs to wolves. The concept of the Mitochondrial Eve is based on the type of analysis. MtDNA is highly conserved, and its relatively slow mutation rates make it useful for studying the evolutionary relationships—phylogeny—of organisms, biologists can determine and then compare mtDNA sequences among different species and use the comparisons to build an evolutionary tree for the species examined
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Human Y-chromosome DNA haplogroup
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In human genetics, a human Y-chromosome DNA haplogroup is a haplogroup defined by differences in the non-recombining portions of DNA from the Y chromosome. It represents human genetic diversity based on single-nucleotide polymorphisms on the Y chromosome, Y-DNA haplogroups represent major branches of the Y-chromosome phylogenetic tree. Y-chromosomal Adam is the name given by researchers to the patrilineal most recent common ancestor of all living humans at the root of this tree, estimates of the date when Y-chromosomal Adam lived have varied significantly in different studies. Y-DNA haplogroups are defined by the presence of a series of Y-DNA SNP markers, subclades are defined by a terminal SNP, the SNP furthest down in the Y-chromosome phylogenetic tree. The Y Chromosome Consortium developed a system of naming major Y-DNA haplogroups with the capital letters A through T, with further subclades named using numbers and lower case letters. YCC shorthand nomenclature names Y-DNA haplogroups and their subclades with the first letter of the major Y-DNA haplogroup followed by a dash, Y-DNA haplogroup nomenclature is changing over time to accommodate the increasing number of SNPs being discovered and tested, and the resulting expansion of the Y-chromosome phylogenetic tree. This change in nomenclature has resulted in inconsistent nomenclature being used in different sources and this inconsistency, and increasingly cumbersome longhand nomenclature, has prompted a move towards using the simpler shorthand nomenclature. It is sparsely distributed in Africa and these mutations predate the Out of Africa migration. The defining mutations of DE probably occurred in Northeastern Africa some 65,000 years ago, the P143 mutation that defines Haplogroup CF may have occurred at that time, bringing modern humans to the southern coast of Asia. Subclades, Haplogroup CF Found outside of Africa, throughout Eurasia, Oceania, F xG, H, I, J, K is rare in modern populations and peaks in South Asia, especially Sri Lanka. It also appears to have long been present in South East Asia, has been reported at rates of 4-5% in Sulawesi and Lembata. F* has been reported among 10% of males in Sri Lanka and South India, 5% in Pakistan, as well as lower levels among the Tamang people and it spread to Europe with the Neolithic Revolution. It is found in ethnic groups in Eurasia, most common in the Caucasus, Iran, Anatolia. G-M201 is also found in numbers in northwestern China and India, Pakistan, Sri Lanka, Malaysia. However, H2 has been present in Europe since the Neolithic, Haplogroup I is found mainly in Europe and the Caucasus. Haplogroup I1 Found mainly in northern Europe Haplogroup I2 Found mainly in southeast Europe and Sardinia save for I2B1 which is found in Western, Central. Haplogroup J is found mainly in the Middle East and South-East Europe, Haplogroup J* is rare outside the island of Socotra. Haplogroup J1 is associated with Northeast Caucasian peoples in Dagestan and Semitic peoples in the Middle East, Ethiopia, Haplogroup J2 is found mainly in Semitic peoples, Anatolia, Greece, the Balkans, Italy, Iran, South/Central Asia and the Caucasus
35.
Sub-Saharan Africa
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Sub-Saharan Africa is, geographically, the area of the continent of Africa that lies south of the Sahara. According to the UN, it consists of all African countries that are fully or partially located south of the Sahara and it contrasts with North Africa, whose territories are part of the League of Arab states within the Arab world. Somalia, Djibouti, Comoros and Mauritania are geographically in Sub-Saharan Africa, the Sahel is the transitional zone between the Sahara and the tropical savanna and forest-savanna mosaic to the south. The Sahara pump theory explains how flora and fauna left Africa to penetrate the Middle East, African pluvial periods are associated with a wet Sahara phase during which larger lakes and more rivers existed. Geographers historically divided the region into several distinct ethnographic sections based on each areas respective inhabitants, commentators in Arabic in the medieval period used the general term bilâd as-sûdân for the vast Sudan region, or sometimes extending from the coast of West Africa to Western Sudan. Its equivalent in Southeast Africa was Zanj, which was situated in the vicinity of the Great Lakes region. The geographers drew an explicit distinction between the Sudan region and its analogue Zanj, from the area to their extreme east on the Red Sea coast in the Horn of Africa. In modern-day Ethiopia and Eritrea was Al-Habash or Abyssinia, which was inhabited by the Habash or Abyssinians, Sub-Saharan Africa has a wide variety of climate zones or biomes. South Africa and the Democratic Republic of the Congo in particular are considered Megadiverse countries, the Sahel shoots across all of Africa at a latitude of about 10° to 15° N. Countries that include parts of the Sahara Desert proper in their territories and parts of the Sahel in their southern region include Mauritania, Mali, Niger, Chad. The Sahel has a hot semi-arid climate, South of the Sahel, there is a belt of savanna, widening to include most of South Sudan and Ethiopia in the east. The Serengeti ecosystem is located in northwestern Tanzania and extends to southwestern Kenya, the Kalahari Basin includes the Kalahari Desert surrounded by a belt of semi-desert. The Bushveld is a tropical ecoregion of Southern Africa. The Karoo is a semi-desert in western South Africa and this occurred 10 million to 5 million years ago. By 3 million years ago several australopithecine hominid species had developed throughout southern, eastern and they were tool users rather than tool manufacturers. The tools were classed as Oldowan, roughly 1.8 million years ago, Homo ergaster first appeared in the fossil record in Africa. From Homo ergaster, Homo erectus evolved 1.5 million years ago, some of the earlier representatives of this species were small-brained and used primitive stone tools, much like H. habilis. The brain later grew in size, and H. erectus eventually developed a complex stone tool technology called the Acheulean
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Upper Paleolithic
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The Upper Paleolithic is the third and last subdivision of the Paleolithic or Old Stone Age. Very broadly, it dates to between 50,000 and 10,000 years ago, roughly coinciding with the appearance of behavioral modernity, modern humans are believed to have emerged about 195,000 years ago in Africa. Although these humans were modern in anatomy, their lifestyle changed very little from their contemporaries, such as Homo erectus, about 50,000 years ago, there was a marked increase in the diversity of artifacts. In Africa, bone artifacts and the first art appear in the archeological record, between 45,000 and 43,000 years ago, this new tool technology spread with human migration to Europe. The new technology generated an explosion of modern humans which is believed to have contributed to the extinction of the Neanderthals. The Upper Paleolithic has the earliest known evidence of organized settlements, in the form of campsites, artistic work blossomed, with cave painting, petroglyphs, carvings and engravings on bone or ivory. The first evidence of fishing is also noted, from artifacts in places such as Blombos cave in South Africa. More complex social groupings emerged, supported by more varied and reliable food sources and this probably contributed to increasing group identification or ethnicity. By 50, 000–40,000 BP, the first humans set foot in Australia, by 45,000 BP, humans lived at 61° north latitude in Europe. By 30,000 BP, Japan was reached, and by 27,000 BP humans were present in Siberia above the Arctic Circle, at the end of the Upper Paleolithic, a group of humans crossed the Bering land bridge and quickly expanded throughout North and South America. Both Homo erectus and Neanderthals used the same crude stone tools, archaeologist Richard G. Klein, who has worked extensively on ancient stone tools, describes the stone tool kit of archaic hominids as impossible to categorize. It was as if the Neanderthals made stone tools, and were not much concerned about their final forms and he argues that almost everywhere, whether Asia, Africa or Europe, before 50,000 years ago all the stone tools are much alike and unsophisticated. These new stone-tool types have been described as being distinctly differentiated from each other, the invaders, commonly referred to as the Cro-Magnons, left many sophisticated stone tools, carved and engraved pieces on bone, ivory and antler, cave paintings and Venus figurines. The Neanderthals continued to use Mousterian stone tool technology and possibly Chatelperronian technology and these tools disappeared from the archeological record at around the same time the Neanderthals themselves disappeared from the fossil record, about 40,000 years ago. Settlements were often located in valley bottoms, possibly associated with hunting of passing herds of animals. Hunting was important, and caribou/wild reindeer may well be the species of single greatest importance in the anthropological literature on hunting. Technological advances included significant developments in flint tool manufacturing, with industries based on fine blades rather than simpler and shorter flakes, burins and racloirs were used to work bone, antler and hides. Advanced darts and harpoons also appear in period, along with the fish hook, the oil lamp, rope
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European bison
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The European bison, also known as wisent or the European wood bison, is a Eurasian species of bison. It is one of two extant species of bison, alongside the American bison, three subspecies existed in the recent past, but only one survives today. B. b. hungarorum was hunted to extinction in the mid-1800s, the Białowieża or lowland European bison was kept alive in captivity, and has since been reintroduced into several countries in Europe. The species has had few recent predators besides humans, with only scattered reports from the 19th century of wolf, European bison were first scientifically described by Carl Linnaeus in 1758. Some later descriptions treat the European bison as conspecific with the American bison and it is not to be confused with the aurochs, the extinct ancestor of domestic cattle. In 1996, the International Union for Conservation of Nature classified the European bison as an endangered species and its status has since been changed to being a vulnerable species. In the past, especially during the Middle Ages, it was killed for its hide. The European bison is the heaviest surviving land animal in Europe, a typical European bison is about 2.1 to 3.5 m long, not counting a tail of 30 to 80 cm long. At birth, calves are quite small, weighing between 15 and 35 kg, an occasional big bull European bison can weigh up to 1,000 kg or more. On average, it is lighter in body mass and yet taller at the shoulder than the American bison. Compared to the American species, the wisent has shorter hair on the neck, head, and forequarters, but longer tail and horns. The modern English word wisent was borrowed in the 19th century from modern German Wisent, itself from Old High German wisunt, wisant, related to Old English wesend, weosend, and Old Norse vísundr. The Old English cognate disappeared as the bisons range shrank away from English-speaking areas by the Late Middle Ages, the English word bison was borrowed around 1611 from Latin bisōn, itself from Germanic. The root *wis-, also found in weasel, originally referred to the animals musk, the word bonasus was first mentioned by Aristotle in the fourth century BC when he precisely described the animal, calling it βόνασος in Greek. He also noted that the Paeonians called it μόναπος, historically, the lowland European bisons range encompassed most of the lowlands of northern Europe, extending from the Massif Central to the Volga River and the Caucasus. It may have lived in the Asiatic part of what is now the Russian Federation. The European bison is known in southern Sweden only between 9500 and 8700 BP, and in Denmark similarly is documented only from the Pre-Boreal and it is not recorded from Britain or Ireland nor from Italy or the Iberian Peninsula. Cave paintings appear to distinguish between B. bonasus and B. priscus, within mainland Europe, its range decreased as human populations expanded and cut down forests
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American bison
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The American bison, also commonly known as the American buffalo or simply buffalo, is a North American species of bison that once roamed the grasslands of North America in massive herds. Bison were seen in North Carolina near Buffalo Ford on the Catawba River as late as 1750. Two subspecies or ecotypes have been described, the bison, smaller in size and with a more rounded hump. Furthermore, the bison has been suggested to consist of a northern. However, this is not supported. The wood bison is one of the largest wild species of bovid in the world, surpassed by only the Asian gaur and it is the largest extant land animal in the Americas. The American bison is the mammal of the United States. The term buffalo is considered to be a misnomer for this animal, and could be confused with true buffalos, the Asian water buffalo. The name buffalo is listed in dictionaries as an acceptable name for American buffalo or bison. In reference to animal, the term buffalo dates to 1625 in North American usage when the term was first recorded for the American mammal. It thus has a longer history than the term bison. The American bison is very related to the wisent or European bison. In Plains Indian languages in general, male and female buffaloes are distinguished, a bison has a shaggy, long, dark-brown winter coat, and a lighter-weight, lighter-brown summer coat. As is typical in ungulates, the bison is slightly larger than the female and, in some cases. Plains bison are often in the range of sizes. Head-and-body lengths range from 2 to 3.5 m long, shoulder heights in the species can range from 152 to 186 cm. Weights can range from 318 to 1,000 kg Mature bulls tend to be larger than cows. Cow weights have had reported medians of 450 to 495 kg, with one small sample averaging 479 kg, the heaviest wild bull ever recorded weighed 1,270 kg
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Northern elephant seal
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The northern elephant seal is one of two species of elephant seal. It is a member of the family Phocidae, Elephant seals derive their name from their great size and from the males large proboscis, which is used in making extraordinarily loud roaring noises, especially during the mating competition. The huge male northern elephant seal typically weighs 1, 500–2,300 kg and measures 4–5 m, although some males can weigh up to 3,700 kg. Females are much smaller and can range from 400 to 900 kg in weight, or roughly a third of the males bulk, both adult and juvenile elephant seals are bar-skinned and black before molting. After molting, they generally have a silver to gray coat that fades to brownish-yellow. Adult males have hairless necks and chests speckled with pink, white, pups are mostly black at birth and molt to a silver gray after weaning. The eyes are large, round and black, the width of the eyes and a high concentration of low light pigments suggest sight plays an important role in the capture of prey. Like all seals, elephant seals have atrophied hind limbs whose underdeveloped ends form the tail and tail fin, each of the feet can deploy five long, webbed fingers. This agile, dual palm is used to propel water, the pectoral fins are used little while swimming. While their hind limbs are unfit for locomotion on land, elephant seals use their fins as support to propel their bodies and they are able to propel themselves quickly in this way for short-distance travel, to return to water, catch up with a female or chase an intruder. Like other seals, elephant seals bloodstreams are adapted to the cold in which a mixture of small veins surrounds arteries capturing heat from them and this structure is present in extremities such as the hind legs. A unique characteristic of the elephant seal is that it has developed the ability to store oxygenated red blood cells within its spleen. In a 2004 study researchers used MRI to observe physiological changes of the spleen of 5 seal pups during simulated dives, by 3 minutes, the spleens on average contracted to a fifth of their original size, indicating a dive-related sympathetic contraction of the spleen. Also, a delay was observed between contraction of the spleen and increased hematocrit within the blood, and attributed to the hepatic sinus. This ability to slowly introduce RBC into the stream is likely to prevent any harmful effects caused by a rapid increase in hematocrit. The northern elephant seal lives in the eastern Pacific Ocean and they spend most of their time at sea, and usually only come to land to give birth, breed, and molt. These activities occur at rookeries that are located on islands or remote mainland beaches. The majority of these rookeries are in California and northern Baja California, ranging from Point Reyes National Seashore, California to Isla Natividad, in recent decades the breeding range has extended northwards
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Golden hamster
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The golden hamster, or Syrian hamster is a member of the subfamily Cricetinae, the hamsters. In the wild, they are now considered vulnerable and their natural geographical range is limited to the north of Syria and the south of Turkey, in arid habitats. Their numbers have been declining due to loss of habitat caused by agriculture, however, captive-breeding programs are well established, and captive-bred Syrian hamsters are often kept as pets. They are also used as research animals throughout the world. The size of adult animals ranges from 5 to 7 in long, body mass is in the range of 120-125 g. Like most members of the subfamily, the Syrian hamster has cheek pouches. In the wild, hamsters are larder hoarders, they use their cheek pouches to transport food to their burrows and their name in the local Arabic dialect where they were found roughly translates to mister saddlebags due to the amount of storage space in their cheek pouches. If food is plentiful, the stores it in large amounts. Sexually mature female hamsters come into season every four days, Syrian hamsters have the shortest gestation period in any known placental mammal at only 16 days. Gestation has been known to last up to 21 days, but this is rare and they can produce large litters of 20 or more young, although the average litter size is between eight and 10 pups. If a mother hamster is inexperienced or feels threatened, she may abandon or eat her pups, a female hamster enters estrus almost immediately after giving birth, and can become pregnant despite already having a litter. This act puts stress on the body and often results in very weak. Hamsters are very territorial and intolerant of other, attacks against each other are ubiquitous. Exceptions do occur, usually when a female and male meet when the female is in heat, but even so, even siblings, once mature, may attack one another. In captivity, babies are separated from their mother and by gender after four weeks, same-sex groups of siblings can stay with each other until they are about eight weeks old, at which point they will become territorial and fight with one another, sometimes to the death. Infanticide is not uncommon among female Syrian hamsters, in captivity, they may kill and eat healthy young as a result of the pups interacting with humans, for any foreign scent is treated as a threat. Females also eat their young in the wild to prevent predators detecting them. Syrian hamsters mark their burrows with secretions from scent glands on their hips
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Syria
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Syrias capital and largest city is Damascus. Religious groups include Sunnis, Christians, Alawites, Druze, Mandeans, Shiites, Salafis, Sunni Arabs make up the largest religious group in Syria. Its capital Damascus and largest city Aleppo are among the oldest continuously inhabited cities in the world, in the Islamic era, Damascus was the seat of the Umayyad Caliphate and a provincial capital of the Mamluk Sultanate in Egypt. The post-independence period was tumultuous, and a number of military coups. In 1958, Syria entered a union with Egypt called the United Arab Republic. Syria was under Emergency Law from 1963 to 2011, effectively suspending most constitutional protections for citizens, Bashar al-Assad has been president since 2000 and was preceded by his father Hafez al-Assad, who was in office from 1970 to 2000. Mainstream modern academic opinion strongly favours the argument that the Greek word is related to the cognate Ἀσσυρία, Assyria, in the past, others believed that it was derived from Siryon, the name that the Sidonians gave to Mount Hermon. However, the discovery of the inscription in 2000 seems to support the theory that the term Syria derives from Assyria. The area designated by the word has changed over time, since approximately 10,000 BC, Syria was one of centers of Neolithic culture where agriculture and cattle breeding appeared for the first time in the world. The following Neolithic period is represented by houses of Mureybet culture. At the time of the pre-pottery Neolithic, people used vessels made of stone, gyps, finds of obsidian tools from Anatolia are evidences of early trade relations. Cities of Hamoukar and Emar played an important role during the late Neolithic, archaeologists have demonstrated that civilization in Syria was one of the most ancient on earth, perhaps preceded by only those of Mesopotamia. The earliest recorded indigenous civilisation in the region was the Kingdom of Ebla near present-day Idlib, gifts from Pharaohs, found during excavations, confirm Eblas contact with Egypt. One of the earliest written texts from Syria is an agreement between Vizier Ibrium of Ebla and an ambiguous kingdom called Abarsal c.2300 BC. The Northwest Semitic language of the Amorites is the earliest attested of the Canaanite languages, Mari reemerged during this period, and saw renewed prosperity until conquered by Hammurabi of Babylon. Ugarit also arose during this time, circa 1800 BC, close to modern Latakia, Ugaritic was a Semitic language loosely related to the Canaanite languages, and developed the Ugaritic alphabet. The Ugarites kingdom survived until its destruction at the hands of the marauding Indo-European Sea Peoples in the 12th century BC, Yamhad was described in the tablets of Mari as the mightiest state in the near east and as having more vassals than Hammurabi of Babylon. Yamhad imposed its authority over Alalakh, Qatna, the Hurrians states, the army of Yamhad campaigned as far away as Dēr on the border of Elam
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Genome
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In modern molecular biology and genetics, a genome is the genetic material of an organism. The genome includes both the genes, the noncoding DNA and the material of the mitochondria and chloroplasts. The term genome was created in 1920 by Hans Winkler, professor of botany at the University of Hamburg, the Oxford Dictionary suggests the name is a blend of the words gene and chromosome. However, see omics for a thorough discussion. A few related -ome words already existed—such as biome, rhizome, Some organisms have multiple copies of chromosomes, diploid, triploid, tetraploid and so on. In classical genetics, in a sexually reproducing organism the gamete has half the number of chromosomes of the somatic cell, the halving of the genetic material in gametes is accomplished by the segregation of homologous chromosomes during meiosis. Additionally, the genome can comprise non-chromosomal genetic elements such as viruses, plasmids, even in species that exist in only one sex, what is described as a genome sequence may be a composite read from the chromosomes of various individuals. Colloquially, the genetic makeup is sometimes used to signify the genome of a particular individual or organism. Both the number of pairs and the number of genes vary widely from one species to another. The only exception in humans is found in red blood cells which become enucleated during development. In 1976, Walter Fiers at the University of Ghent was the first to establish the complete sequence of a viral RNA-genome. The next year Fred Sanger completed the first DNA-genome sequence, Phage Φ-X174, the first genome sequence for an archaeon, Methanococcus jannaschii, was completed in 1996, again by The Institute for Genomic Research. The development of new technologies has made it easier and cheaper to do sequencing. The US National Institutes of Health maintains one of several databases of genomic information. Among the thousands of completed genome sequencing projects include those for rice, a mouse, the plant Arabidopsis thaliana, the fish. In December 2013, scientists first sequenced the genome of a Neanderthal. The genome was extracted from the toe bone of a 130, new sequencing technologies, such as massive parallel sequencing have also opened up the prospect of personal genome sequencing as a diagnostic tool, as pioneered by Manteia Predictive Medicine. A major step toward that goal was the completion in 2007 of the genome of James D. Watson
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Giant panda
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The giant panda, also known as panda bear or simply panda, is a bear native to south central China. It is easily recognized by the large, distinctive black patches around its eyes, over the ears, the name giant panda is sometimes used to distinguish it from the unrelated red panda. Though it belongs to the order Carnivora, the giant pandas diet is over 99% bamboo, Giant pandas in the wild will occasionally eat other grasses, wild tubers, or even meat in the form of birds, rodents or carrion. In captivity, they may receive honey, eggs, fish, yams, shrub leaves, oranges, the giant panda lives in a few mountain ranges in central China, mainly in Sichuan province, but also in neighbouring Shaanxi and Gansu. As a result of farming, deforestation, and other development, the giant panda is a conservation reliant vulnerable species. A2007 report showed 239 pandas living in captivity inside China, as of December 2014,49 giant pandas lived in captivity outside China, living in 18 zoos in 13 different countries. Some reports also show that the number of giant pandas in the wild is on the rise, in March 2015, Mongabay stated that the wild giant panda population had increased by 268, or 16. 8%, to 1,864 individuals. In 2016, the IUCN reclassified the species from endangered to vulnerable, while the dragon has often served as Chinas national symbol, internationally the giant panda appears at least as commonly. As such, it is becoming widely used within China in international contexts, for many decades, the precise taxonomic classification of the giant panda was under debate because it shares characteristics with both bears and raccoons. However, molecular studies suggest the giant panda is a bear and part of the family Ursidae. The giant pandas closest extant relative is the bear of South America. The giant panda has been referred to as a living fossil, despite the shared name, habitat type, and diet, as well as a unique enlarged bone called the pseudo thumb the giant panda and red panda are only distantly related. The word panda was borrowed into English from French, but no explanation of the origin of the French word panda has been found. The closest candidate is the Nepali word ponya, possibly referring to the adapted wrist bone of the red panda, the Western world originally applied this name to the red panda. Until 1901, when it was stated to be related to the red panda. Even in 2013, the Encyclopædia Britannica still used giant panda or panda bear for the bear, since the earliest collection of Chinese writings, the Chinese language has given the bear 20 different names, such as huāxióng and zhúxióng. The most popular names in China today is dàxióngmāo, or simply xióngmāo, the name xióngmāo was originally used to describe the red panda, but since giant panda was thought to be closely related to red panda, dàxióngmāo was named relatively. In Taiwan, another name for panda is the inverted dàmāoxióng, though many encyclopediae
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Golden snub-nosed monkey
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The golden snub-nosed monkey is an Old World monkey in the Colobinae subfamily. It is endemic to an area in temperate, mountainous forests of central. They inhabit these forests of Southwestern China at elevations of 1. The Chinese name is Sichuan golden hair monkey and it is also widely referred to as the Sichuan snub-nosed monkey. Of the three species of snub-nosed monkeys in China, the golden snub-nosed monkey is the most widely distributed throughout China, snow occurs frequently within its range and it can withstand colder average temperatures than any other non-human primates. Its diet varies markedly with the seasons, but it is primarily an herbivore with lichens being its food source. It is diurnal and largely arboreal, spending some 97% of its time in the canopy, population estimates range from 8,000 to 15,000 and it is threatened by habitat loss. Biologists presently identify three subspecies of monkey, which can be distinguished primarily by the length of their tails. The dense human settlement of much of eastern Sichuan and the Han River valley of southern Shaanxi creates geographical separation between the three subspecies, moupin golden snub-nosed monkey, Rhinopithecus roxellana roxellana. This subspecies is found in the mountainous areas flanking the Sichuan Basin from the west, according to the estimates made between 1995 and 2006, the population includes some 10,000 individuals, living mostly in Sichuan. Of them, some 6,000 lived in the Min Mountains of northern Sichuan,3,500 in the Qionglai Mountains further west, smaller groups are also found just north of Sichuan border, in the border counties of Gansu and Shaanxi. Qinling golden snub-nosed monkey, Rhinopithecus roxellana qinlingensis, according to an estimate published in 2001, this subspecies included some 3, 800-4,000 individuals in 39 in Qinling Mountains of southern Shaanxi. The Qinling Mountains are separated from the more southern Min - Daba Mountains belt by the wide, Hubei golden snub-nosed monkey, Rhinopithecus roxellana hubeiensis. Members of this subspecies reside in the Daba Mountains of the westernmost Hubei, according to a 1998 estimate, the population included 600-1,000 individuals in 5-6 troops. In 2005, the management of the Shennongjia Nature Reserve reported that the population had grown between 1990 and 2005 from 500 to over 1200, the adult and subadult golden snub-nosed monkey is sexually dimorphic. Adult males have bodies covered with very long, golden guard hairs on their backs. The crest is medium brown while the back, crown to nape, arms, the brown crest also contains physically upright hairs, which the shape are useful for individual identification. Also, when their mouths are open, researchers can observe long canines, subadult males have a similar sized body as the fully developed male adult, but have a more slender body
. PMID 18439549. Lay summary – BBC News (April 24, 2008).
