1.
Goldie's bird-of-paradise
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The Goldies bird-of-paradise is a species of bird-of-paradise. Endemic to Papua New Guinea, the Goldies bird-of-paradise is distributed in the forests of Fergusson and Normanby Island of the DEntrecasteaux Archipelago. The diet consists mainly of fruits, the name commemorates the Scottish collector Andrew Goldie, who discovered the bird in 1882. Due to ongoing habitat loss, limited range and overhunting in some areas and it is listed on Appendix II of CITES. Goldies bird-of-paradise is large, approximately 33 cm long, and olive-brown, the male has a yellow and dark green plumage with a lavender grey breast, yellow iris and grey colored bill, mouth and feet. It is adorned with large crimson ornamental flank plumes and two long tail wires, the male is distinguished from other Paradisaea species by its lavender grey breast plumage. Unadorned female has a plumage with cinnamon-brown below
2.
John Gerrard Keulemans
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Johannes Gerardus Keulemans was a Dutch bird illustrator. For most of his life he lived and worked in England, in 1869, he was persuaded by Richard Bowdler Sharpe to illustrate his Monograph of the Alcedinidae, or Family of Kingfishers and to move to England, where he lived for the rest of his life. He was married twice, and had eight children by his first wife, only nine of his children reached adulthood. He also wrote topics on spirituality, and claimed he had a premonition at the moment of death of one of his sons and he died in Ilford, Essex and is buried in Buckingham Road cemetery, Ilford, in an unmarked grave. Keulemans regularly provided illustrations for The Ibis and The Proceedings of the Zoological Society, one of his last great achievements was his contribution of over one hundred plates for Frederick Du Cane Godmans Monograph of the Petrels. He also spent some time collecting birds in Cape Verde and West Africa, Keulemans is credited with describing the Cape Verde swamp-warbler, Calamodyta brevipennis. This is a bird about 14–16 cm. light brown above and on its flanks. He did not publish an illustration of it, but his plate for Acrocephalus brunnescens in George Hendersons Lahore to Yarkand is similar, also of note is a contemporary obituary of Keulemans in the journal British Birds. Tony Keulemans later wrote Beyond the grave, which tells the story of a discovery of a painting John Gerrard had made of his own grave stone. And finally Tony Keulemans wrote an errata list to Feathers to Brush, keulemanss work is characterised by its consistency, showing little change over the course of his career, and focused to an extraordinary degree on the rendering of fine detail. These generalisations have also proven to be the basis for unjustified criticism of his work, aside from this, a number of critics have rightly placed Keulemans above his contemporaries, his ability to create accurate and vivid representations of birds gave him prominence in his field. Keulemans was prodigious in his output - he was commissioned to paint pictures of birds throughout his career. Keulemans first prints appeared in two books by Francois Pollen, Contributions a lhistoire naturelle des Lemuriens and Een blik in Madagascar, some appeared after his death until 1915, he had rendered the images on stone well before publication of these works. A calculation of his output gives about 4, 000-5,000 published illustrations. The vast majority of these were published within octavo-size books and publications. While the subject of his illustrations was almost entirely avian, he was commissioned to create portraits of mammals, insects. Most of the illustrations by Keulemans were produced through traditional lithography, allowing for a product that depicts a vivid, lifelike figure through depth. Printing was carried out by the two firms of Mintern and Hanhart, and early in his career, some were printed by P. M. W. Trap, often, the published lithographs were not coloured, and perhaps some were not intended to be coloured
3.
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
4.
Mate choice
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Mate choice, also known as intersexual selection, is an evolutionary process in which selection is dependent on the attractiveness of an individuals phenotypic traits. Evolutionary change is possible because the qualities that are desired in a mate are more frequently passed on to each generation over time, mate choice is one of two components of sexual selection, the other being intrasexual selection. Ideas on sexual selection were first introduced in 1871, by Charles Darwin, at present, there are five mechanisms that explain how mate choice has evolved over time. These are direct phenotypic benefits, sensory bias, the Fisherian runaway hypothesis, indicator traits, in systems where mate choice exists, one sex is competitive with same-sex members and the other sex is choosy. There are direct and indirect benefits of being the selective individual, in most species, females are the choosy sex which discriminates among competitive males, but there are several examples of reversed roles. It is preferable for an individual to choose a mate of the same species. Other factors that can have an impact on mate choice include pathogen stress, Charles Darwin first expressed his ideas on sexual selection and mate choice in his book The Descent of Man, and Selection in Relation to Sex in 1871. Darwin proposed two explanations for the existence of such traits, these traits are useful in combat or they are preferred by females. This article focuses on the latter, Darwin treated natural selection and sexual selection as two different topics, although in the 1930s biologists defined sexual selection as being a part of natural selection. In 1915, Ronald Fisher wrote a paper on the evolution of female preference, fifteen years later, he expanded this theory in a book called The Genetical Theory of Natural Selection. There he described a scenario where feedback between mate preference and a results in elaborate characters such as the long tail of the male peacock. Thus a female must be selective when choosing a mate because the quality of her offspring depends on it, males must fight, in the form of intra-sexual competition, for the opportunity to mate because not all males will be chosen by females. In 1972, soon after Williams revival of the subject, Robert L. Trivers presented his parental investment theory, Trivers defined parental investment as any investment made by the parent that benefits his or her current offspring at the cost of investment in future offspring. These investments include the costs of producing gametes as well as any other care or efforts that parents provide after birth or hatching, reformulating Batemans ideas, Trivers argued that the sex which exhibits less parental investment will have to compete for mating opportunities with the sex that invests more. The differences in levels of parental investment create the condition that favours mating biases, being choosy must incur a fitness advantage in order for this behaviour to evolve. Two types of benefits are thought to drive the evolutionary mechanisms of mate choice. These benefits include but are not limited to increased quality, increased parental care. There is much support for maintenance of mate choice by direct benefits, indirect benefits increase genetic fitness for the offspring, and thereby increase the parents inclusive fitness
5.
Reproductive success
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Reproductive success is defined as the passing of genes onto the next generation in a way that they too can pass on those genes. Factors like nutrition contribute to factors that influence reproductive success and these include different amounts of consumption and more specific carbohydrate to protein ratios. In some cases, the amounts or ratios of intake are more influential during certain stages of the lifespan, for example, in the Mexican fruit fly, male protein intake is critical only at eclosion. Intake at this time provides longer lasting reproductive ability, after this developmental stage, protein intake will have no effect and is not necessary for reproductive success. In addition, Ceratitis capitata males were experimented on to see how protein influence during the larval stage affects mating success, males were fed either a high protein diet, which consisted of 6. 5g/100mL, or a no protein diet during the larval stage. Males that were fed protein had more copulations than those that weren’t fed protein, protein-deprived black blow fly males have been seen to exhibit lower numbers of oriented mounts and inseminate fewer females than more lively fed males. In still other instances, prey deprivation or a diet has been shown to lead to a partial or complete halt in male mating activity. Copulation time lasted longer for sugar-fed males than protein-fed flies, showing that carbohydrates were more necessary for a longer copulation duration, in mammals, amounts of protein, carbohydrates, and fats are seen to influence reproductive success. This was evaluated among 28 female black bears evaluated by measuring the number of cubs born. Using different foods during the fall including corn, herbaceous, red oak, beech, and cherry, nutritional facts of protein, carbohydrate, seventy-percent of the bears who had high fat and high carbohydrate diets produced cubs. Conversely, all 10 females who had low carbohydrate diets did not reproduce cubs, adequate nutrition at pre-mating time periods showed to have the most effect on various reproductive processes in mammals. Increased nutrition, in general, during time was most beneficial for oocyte. As a result, offspring number and viability was also improved, thus, proper nutrition timing during the pre-mating time is key for development and long-term benefit of the offspring. Two different diets were fed to Florida scrub-jays and breeding performance was noted to have different effects, one diet consisted of high protein and high fat, and the other consisting of just high fat. The significant result was that the birds with the high protein, there was a difference in the amount of water inside the eggs, which accounted for the different weights. It’s hypothesized that the water resulting from the adequate protein-rich and fat-rich diet may contribute to development and survival of the chick. Dietary intake also improves egg production, which can also be considered to create viable offspring. Post-mating changes are seen in organisms in response to conditions for development
6.
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
7.
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
8.
Mating call
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A mating call is the auditory signal used by animals to attract mates. It can occur in males or females, but literature is abundantly favored toward researching mating calls in males. In addition, mating calls are often the subject of mate choice and this can result in sympatric speciation of some animals, where two species diverge from each other while living in the same environment. There are many different mechanisms to produce mating calls, which can be categorized into vocalizations. Vocalizations are considered as sounds produced by the larynx and are seen in species of birds, mammals, amphibians. Mechanical calls refer to any type of sound that the animal produces using unique body parts and/or tools for communication with potential mates. Examples include crickets that vibrate their wings, birds that flap their feathers, the use of vocalizations is widespread in avian species and are often used to attract mates. Different aspects and features of bird such as structure, amplitude. Large song repertoires are preferred by females of many avian species, one hypothesis for this is that song repertoire is positively correlated with the size of the brain’s song control nucleus. A large HVC would indicate developmental success, in song sparrows, males with large repertoires had larger HVCs, better body condition and lower heterophil-to-lymphocyte ratios indicating better immune health. This supports the idea that song sparrows with large song repertoires have better lifetime fitness, possible explanations for this adaptation include direct benefits to the female, such as superior parental care or territory defense, and indirect benefits, such as good genes for their offspring. Japanese bush warbler songs from island populations have a simple structure when compared to mainland populations. Another example is in purple-crowned fairywrens, larger males of this species sing advertising songs at a lower frequency than smaller rival males, since body size is a characteristic of good health, lower frequency calls are a form of honest signaling. Negative correlation between size and call frequency is supported across multiple species within the taxa. In the rock sparrow, song frequency is positively associated with reproductive success, slower song rate is associated with age and is preferred by females. Reproductive status of the individual is communicated through higher maximum frequency, there was also positive correlation between age and extra pair copulation frequency. Bird calls are known to continue after pair formation in several socially monogamous bird species. In one experimental population of finches, there was increased singing activity by the male after breeding
9.
Charles Darwin
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Charles Robert Darwin, FRS FRGS FLS FZS was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution. Darwin published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species, by the 1870s, the scientific community and much of the general public had accepted evolution as a fact. In modified form, Darwins scientific discovery is the theory of the life sciences. Darwins early interest in nature led him to neglect his education at the University of Edinburgh, instead. Studies at the University of Cambridge encouraged his passion for natural science, puzzled by the geographical distribution of wildlife and fossils he collected on the voyage, Darwin began detailed investigations and in 1838 conceived his theory of natural selection. Although he discussed his ideas with several naturalists, he needed time for extensive research and he was writing up his theory in 1858 when Alfred Russel Wallace sent him an essay that described the same idea, prompting immediate joint publication of both of their theories. Darwins work established evolutionary descent with modification as the dominant scientific explanation of diversification in nature, in 1871 he examined human evolution and sexual selection in The Descent of Man, and Selection in Relation to Sex, followed by The Expression of the Emotions in Man and Animals. His research on plants was published in a series of books, Darwin has been described as one of the most influential figures in human history, and he was honoured by burial in Westminster Abbey. Charles Robert Darwin was born in Shrewsbury, Shropshire, on 12 February 1809, at his familys home and he was the fifth of six children of wealthy society doctor and financier Robert Darwin and Susannah Darwin. He was the grandson of two prominent abolitionists, Erasmus Darwin on his fathers side, and Josiah Wedgwood on his mothers side, both families were largely Unitarian, though the Wedgwoods were adopting Anglicanism. The eight-year-old Charles already had a taste for history and collecting when he joined the day school run by its preacher in 1817. From September 1818, he joined his older brother Erasmus attending the nearby Anglican Shrewsbury School as a boarder and he found lectures dull and surgery distressing, so neglected his studies. He learned taxidermy in around 40 daily hour-long sessions from John Edmonstone, one day, Grant praised Lamarcks evolutionary ideas. Darwin was astonished by Grants audacity, but had recently read similar ideas in his grandfather Erasmus journals, Darwin was rather bored by Robert Jamesons natural-history course, which covered geology - including the debate between Neptunism and Plutonism. He learned the classification of plants, and assisted with work on the collections of the University Museum, as Darwin was unqualified for the Tripos, he joined the ordinary degree course in January 1828. He preferred riding and shooting to studying, when his own exams drew near, Darwin focused on his studies and was delighted by the language and logic of William Paleys Evidences of Christianity. In his final examination in January 1831 Darwin did well, coming out of 178 candidates for the ordinary degree. Darwin had to stay at Cambridge until June 1831, inspired with a burning zeal to contribute, Darwin planned to visit Tenerife with some classmates after graduation to study natural history in the tropics
10.
Alfred Russel Wallace
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Alfred Russel Wallace OM FRS was a British naturalist, explorer, geographer, anthropologist, and biologist. He is best known for conceiving the theory of evolution through natural selection. This prompted Darwin to publish his own ideas in On the Origin of Species and he was considered the 19th centurys leading expert on the geographical distribution of animal species and is sometimes called the father of biogeography. Wallace was one of the leading thinkers of the 19th century. Wallace was strongly attracted to unconventional ideas and his advocacy of spiritualism and his belief in a non-material origin for the higher mental faculties of humans strained his relationship with some members of the scientific establishment. Aside from scientific work, he was a social activist who was critical of what he considered to be an unjust social and his interest in natural history resulted in his being one of the first prominent scientists to raise concerns over the environmental impact of human activity. Since its publication in 1869 it has never been out of print, Wallace had financial difficulties throughout much of his life. Alfred Wallace was born in the Welsh village of Llanbadoc, near Usk and he was the seventh of nine children of Thomas Vere Wallace and Mary Anne Greenell. Mary Anne was English, Thomas Wallace was probably of Scottish ancestry and his family, like many Wallaces, claimed a connection to William Wallace, a leader of Scottish forces during the Wars of Scottish Independence in the 13th century. Thomas Wallace graduated in law, but never practised law and he owned some income-generating property, but bad investments and failed business ventures resulted in a steady deterioration of the familys financial position. His mother was from a middle-class English family from Hertford, north of London, when Wallace was five years old, his family moved to Hertford. There he attended Hertford Grammar School until financial difficulties forced his family to him in 1836. Wallace then moved to London to board with his older brother John and this was a stopgap measure until William, his oldest brother, was ready to take him on as an apprentice surveyor. While in London, Alfred attended lectures and read books at the London Mechanics Institute, here he was exposed to the radical political ideas of the Welsh social reformer Robert Owen and of Thomas Paine. He left London in 1837 to live with William and work as his apprentice for six years, at the end of 1839, they moved to Kington, Hereford, near the Welsh border, before eventually settling at Neath in Glamorgan in Wales. Between 1840 and 1843, Wallace did land surveying work in the countryside of the west of England, by the end of 1843, Williams business had declined due to difficult economic conditions, and Wallace, at the age of 20, left in January. One result of Wallaces early travels is a controversy about his nationality. Since Wallace was born in Monmouthshire, some sources have considered him to be Welsh, one Wallace scholar has stated that the most reasonable interpretation is therefore that he was an Englishman born in Wales
11.
Ronald Fisher
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Sir Ronald Aylmer Fisher FRS, who published as R. A. Fisher, was an English statistician and biologist who used mathematics to combine Mendelian genetics and natural selection. This helped to create the new Darwinist synthesis of evolution known as the evolutionary synthesis. He was also a prominent eugenicist in the part of his life. He is known as one of the three founders of population genetics. He outlined Fishers principle as well as the Fisherian runaway and sexy son hypothesis theories of sexual selection and he also made important contributions to statistics, including the maximum likelihood, fiducial inference, the derivation of various sampling distributions among many others. Anders Hald called him a genius who almost single-handedly created the foundations for modern statistical science, not only was he the most original and constructive of the architects of the neo-Darwinian synthesis, Fisher also was the father of modern statistics and experimental design. He therefore could be said to have provided researchers in biology and medicine with their most important research tools, geoffrey Miller said of him To biologists, he was an architect of the modern synthesis that used mathematical models to integrate Mendelian genetics with Darwins selection theories. To psychologists, Fisher was the inventor of various tests that are still supposed to be used whenever possible in psychology journals. To farmers, Fisher was the founder of agricultural research. Fisher was born in East Finchley in London, England, one of twins with the other being still-born, from 1896 until 1904 they lived at Inverforth House in London, where English Heritage installed a blue plaque in 2002, before moving to Streatham. He entered Harrow School age 14 and won the schools Neeld Medal in mathematics, in 1909, he won a scholarship to Gonville and Caius College, Cambridge. In 1919 he began working at Rothamsted Research and his fame grew and he began to travel and lecture widely. In 1937, he visited the Indian Statistical Institute in Calcutta, mahalanobis, often returning to encourage its development, being the guest of honour at its 25th anniversary in 1957 when it had 2000 employees. His marriage disintegrated during World War II and his oldest son George and his daughter and one of his biographers, Joan, married the noted statistician George E. P. Box. Fisher gained a scholarship to study Mathematics at the University of Cambridge in 1909, in 1915 he published a paper The evolution of sexual preference on sexual selection and mate choice. He published The Correlation Between Relatives on the Supposition of Mendelian Inheritance in 1918, in which he introduced the term variance, Joan Box, Fishers biographer and daughter says that Fisher had resolved this problem in 1911. Between 1912 and 1922 Fisher recommended, analyzed and vastly popularized Maximum likelihood, in 1928 Joseph Oscar Irwin began a three-year stint at Rothamsted and became one of the first people to master Fishers innovations. His first application of the analysis of variance was published in 1921 and he pioneered the principles of the design of experiments and the statistics of small samples and the analysis of real data
12.
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
13.
Plumage
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Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies, and may vary with age classes, within species there can be different colour morphs. The placement of feathers on a bird are not haphazzard, but rather emerge in organized, overlapping rows and groups, most birds moult, usually before and after breeding, resulting in a breeding or nuptial plumage and a basic plumage. Many ducks and some species such as the red junglefowl have males wearing a bright nuptial plumage while breeding. The painted buntings juveniles have two inserted moults in their first autumn, each yielding plumage like an adult females, the first starts a few days after fledging replacing the juvenile plumage with an auxiliary formative plumage, the second a month or so later giving the formative plumage. Abnormal plumages include a variety of conditions, albinism, total loss of colour, is rare, but partial loss of colours is more common. Some species are polymorphic, having two or more colour variants. A few species have special types of polymorphism, as in the male ruff which has an assortment of different colours around the head, hen feathering is an inherited plumage character in domestic fowl controlled by a single gene. Plumology is the name for the science that is associated with the study of feathers, almost all species of birds moult at least annually, usually after the breeding season, known as the pre-basic moult. This resulting covering of feathers, which will last either until the breeding season or until the next annual moult, is known as the basic plumage. Many species undertake another moult prior to the season known as the pre-alternate moult. The alternate plumage is brighter than the basic plumage, for the purposes of sexual display. The Humphrey-Parkes terminology requires some attention to detail to name moults, many ducks have bright, colourful plumage, exhibiting strong sexual dimorphism. However, they moult into a dull plumage after breeding in mid-summer and this drab, female-like appearance is called eclipse plumage. When they shed feathers to go into eclipse, the ducks become flightless for a period of time. Although mainly found in the Anatidae, a few species, including related red junglefowl, most fairywrens. There are hereditary as well as variations in plumage that are rare. Melanism refers to an excess of black or dark colours, erythromelanism or erythrism is the result of excessive reddish brown erythromelanin deposition in feathers that normally lack melanin
14.
Bird
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Birds, a subgroup of Reptiles, are the last living examples of Dinosaurs. Birds live worldwide and range in size from the 5 cm bee hummingbird to the 2.75 m ostrich. They rank as the class of tetrapods with the most living species, at ten thousand. Birds are the closest living relatives of crocodilians, the fossil record indicates that birds evolved from feathered ancestors within the theropod group of saurischian dinosaurs. True birds first appeared during the Cretaceous period, around 100 million years ago, Birds, especially those in the southern continents, survived this event and then migrated to other parts of the world while diversifying during periods of global cooling. Primitive bird-like dinosaurs that lie outside class Aves proper, in the broader group Avialae, have been found dating back to the mid-Jurassic period, around 170 million years ago. Birds have wings which are more or less developed depending on the species, the digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have evolved for swimming. Many species annually migrate great distances, Birds are social, communicating with visual signals, calls, and bird songs, and participating in such social behaviours as cooperative breeding and hunting, flocking, and mobbing of predators. The vast majority of species are socially monogamous, usually for one breeding season at a time, sometimes for years. Other species have breeding systems that are polygynous or, rarely, Birds produce offspring by laying eggs which are fertilised through sexual reproduction. They are usually laid in a nest and incubated by the parents, most birds have an extended period of parental care after hatching. Some birds, such as hens, lay eggs even when not fertilised, songbirds, parrots, and other species are popular as pets. Guano is harvested for use as a fertiliser, Birds prominently figure throughout human culture. About 120–130 species have become extinct due to human activity since the 17th century, human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry, the first classification of birds was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae. Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system currently in use, Birds are categorised as the biological class Aves in Linnaean taxonomy. Phylogenetic taxonomy places Aves in the dinosaur clade Theropoda, Aves and a sister group, the clade Crocodilia, contain the only living representatives of the reptile clade Archosauria
15.
Bird-of-paradise
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The birds-of-paradise are members of the family Paradisaeidae of the order Passeriformes. The majority of species are found in eastern Indonesia, Papua New Guinea, the family has 42 species in 15 genera. For the most part they are confined to dense rainforest habitat, the diet of all species is dominated by fruit and to a lesser extent arthropods. The birds-of-paradise have a variety of breeding systems, ranging from monogamy to lek-type polygamy, a number of species are threatened by hunting and habitat loss. For many years the birds-of-paradise were treated as being related to the bowerbirds. Today while both are treated as being part of the Australasian lineage Corvida, the two are now thought to be distantly related. The closest evolutionary relatives of the birds-of-paradise are the crow and jay family Corvidae, the monarch flycatchers Monarchidae, the second clade includes the parotias and the King of Saxony bird-of-paradise. The third clade provisionally contains a number of genera, Seleucidis, the Drepanornis sicklebills, Semioptera, Ptiloris and Lophorina, the fourth clade includes the Epimachus sicklebills, Paradigalla and the astrapias. The final clade includes the Cicinnurus and the Paradisaea birds-of-paradise, the exact limits of the family have been the subject of revision as well. The three species of satinbird were treated as a subfamily of the birds-of-paradise, Cnemophilinae, in spite of differences in the mouth, foot morphology and nesting habits they remained in the family until a 2000 study moved them to a separate family closer to the berrypeckers and longbills. The same study found that the Macgregors bird-of-paradise was actually a member of the large Australasian honeyeater family, in addition to these three species, a number of systematically enigmatic species and genera have been considered potential members of this family. The silktail of Fiji has been linked with the many times since its discovery. Recent molecular evidence now places the species with the fantails, hybrid birds-of-paradise may occur when individuals of different species, that look similar and have overlapping ranges, confuse each other for their own species and crossbreed. Birds-of-paradise are closely related to the corvids, birds-of-paradise range in size from the king bird-of-paradise at 50 g and 15 cm to the curl-crested manucode at 44 cm and 430 g. The male black sicklebill, with its tail, is the longest species at 110 cm. In most species, the tails of the males are larger and longer than the female, the wings are rounded and in some species structurally modified on the males in order to make sound. There is considerable variation in the family with regard to bill shape, bills may be long and decurved, as in the sicklebills and riflebirds, or small and slim like the Astrapias. As with body size bill size varies between the sexes, although species where the females have larger bills than the male are more common, plumage variation between the sexes is closely related to breeding system
16.
Peafowl
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The peafowl include three species of birds in the genera Pavo and Afropavo of the Phasianidae family, the pheasants and their allies. There are two Asiatic species and one African species, male peafowl are known for their piercing call and their extravagant plumage. The latter is especially prominent in the Asiatic species, who have a tail or train of covert feathers which they display as part of a courtship ritual. The term peacock is properly reserved for the male, the female is known as a peahen, the functions of the elaborate iridescent coloration and large train of peacocks have been the subject of extensive scientific debate. Charles Darwin suggested they served to attract females, and the features of the males had evolved by sexual selection. The Indian peacock has iridescent blue and green plumage, the peacock tail, known as a train, consists not of tail quill feathers, but highly elongated upper tail coverts. These feathers are marked with eyespots, best seen when a peacock fans his tail, both sexes of all species have a crest atop the head. The Indian peahen has a mixture of grey, brown. The female also displays her plumage to ward off female competition or signal danger to her young, the green peafowl differs from the Indian peafowl in that the male has green and gold plumage with black wings with a sheen of blue. Unlike the Indian peafowl, the green peahen is similar to the male, only having shorter upper tail coverts, a more coppery neck, the Congo peacock male does not display his covert feathers, but uses his actual tail feathers during courtship displays. These feathers are shorter than those of the Indian and green species. Females of the Indian and African species are dull grey and/or brown, chicks of both sexes in all the species are cryptically coloured. They vary between yellow and tawny, usually with patches of brown or light tan and dirty white ivory. Occasionally, peafowl appear with white plumage and this can result in the complete lack of coloration of their plumage, while preserving normal eye colour. By contrast, true albino peafowl have a lack of melanin. Leucistic peachicks are born yellow and become white as they mature. As with many birds, vibrant iridescent plumage colours are not primarily pigments, optical interference Bragg reflections based on regular, periodic nanostructures of the barbules of the feathers produce the peacocks colours. Slight changes to the spacing of these result in different colours
17.
Deer
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Deer are the ruminant mammals forming the family Cervidae. The two main groups are the Cervinae, including the muntjac, the deer and the chital, and the Capreolinae, including the elk, reindeer, the Western roe deer. Female reindeer, and male deer of all species, grow, in this they differ from permanently horned antelope, which are in the same order, Artiodactyla. The musk deer of Asia and water chevrotain of tropical African and Asian forests are not usually regarded as true deer and form their own families, Moschidae and Tragulidae, respectively. Deer appear in art from Palaeolithic cave paintings onwards, and they have played a role in mythology, religion and their economic importance includes the use of their meat as venison, their skins as soft, strong buckskin, and their antlers as handles for knives. Deer hunting has been a sport since at least the Middle Ages. Deer live in a variety of biomes, ranging from tundra to the tropical rainforest, while often associated with forests, many deer are ecotone species that live in transitional areas between forests and thickets and prairie and savanna. The majority of deer species inhabit temperate mixed deciduous forest, mountain mixed coniferous forest, tropical seasonal/dry forest. Clearing open areas within forests to some extent may actually benefit deer populations by exposing the understory and allowing the types of grasses, weeds, additionally, access to adjacent croplands may also benefit deer. However, adequate forest or brush cover must still be provided for populations to grow, however, fallow deer have been introduced to South Africa. There are also species of deer that are highly specialized, and live almost exclusively in mountains, grasslands, swamps. Some deer have a distribution in both North America and Eurasia. Examples include the caribou that live in Arctic tundra and taiga and moose that inhabit taiga, huemul deer of South Americas Andes fill the ecological niches of the ibex and wild goat, with the fawns behaving more like goat kids. Mountain slope habitats vary from moist coniferous/mixed forested habitats to dry forests with alpine meadows higher up. The foothills and river valleys between the mountain provide a mosaic of cropland and deciduous parklands. The rare woodland caribou have the most restricted range living at altitudes in the subalpine meadows. Elk and mule deer both migrate between the alpine meadows and lower coniferous forests and tend to be most common in this region, elk also inhabit river valley bottomlands, which they share with White-tailed deer. They also live in the aspen parklands north of Calgary and Edmonton, the adjacent Great Plains grassland habitats are left to herds of elk, American bison, and pronghorn antelope
18.
Lion
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The lion is one of the big cats in the genus Panthera and a member of the family Felidae. The commonly used term African lion collectively denotes the several subspecies in Africa, with some males exceeding 250 kg in weight, it is the second-largest living cat after the tiger. Wild lions currently exist in sub-Saharan Africa and in India, in ancient historic times, their range was in most of Africa, including North Africa, and across Eurasia from Greece and southeastern Europe to India. Lion populations are untenable outside designated reserves and national parks, although the cause of the decline is not fully understood, habitat loss and conflicts with humans are the greatest causes of concern. Within Africa, the West African lion population is particularly endangered, in the wild, males seldom live longer than 10 to 14 years, as injuries sustained from continual fighting with rival males greatly reduce their longevity. In captivity they can more than 20 years. They typically inhabit savanna and grassland, although they may take to bush, Lions are unusually social compared to other cats. A pride of lions consists of related females and offspring and a number of adult males. Groups of female lions typically hunt together, preying mostly on large ungulates, Lions are apex and keystone predators, although they are also expert scavengers obtaining over 50 percent of their food by scavenging as opportunity allows. While lions do not typically hunt humans, some have, sleeping mainly during the day, lions are active primarily at night, although sometimes at twilight. Highly distinctive, the lion is easily recognised by its mane. It has been depicted in sculptures, in paintings, on national flags. Lions have been kept in menageries since the time of the Roman Empire, Zoos are cooperating worldwide in breeding programs for the endangered Asiatic subspecies. The lions name, similar in many Romance languages, is derived from the Latin leo, the Hebrew word לָבִיא may also be related. It was one of the originally described by Linnaeus, who gave it the name Felis leo, in his eighteenth-century work. The lions closest relatives are the species of the genus Panthera, the tiger, the snow leopard, the jaguar. P. leo evolved in Africa between 1 million and 800,000 years ago, before spreading throughout the Holarctic region and it appeared in the fossil record in Europe for the first time 700,000 years ago with the subspecies Panthera leo fossilis at Isernia in Italy. From this lion derived the later cave lion, which appeared about 300,000 years ago, Lions died out in northern Eurasia at the end of the last glaciation, about 10,000 years ago, this may have been secondary to the extinction of Pleistocene megafauna
19.
Positive feedback
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Positive feedback is a process that occurs in a feedback loop in which the effects of a small disturbance on a system include an increase in the magnitude of the perturbation. That is, A produces more of B which in turn more of A. In contrast, a system in which the results of an act to reduce or counteract it has negative feedback. Both concepts play an important role in science and engineering, including biology, chemistry, mathematically, positive feedback is defined as a positive loop gain around a closed loop of cause and effect. That is, positive feedback is in phase with the input, Positive feedback tends to cause system instability. When the loop gain is positive and above 1, there will typically be exponential growth, increasing oscillations, system parameters will typically accelerate towards extreme values, which may damage or destroy the system, or may end with the system latched into a new stable state. Positive feedback may be controlled by signals in the system being filtered, damped, or limited, Positive feedback is used in digital electronics to force voltages away from intermediate voltages into 0 and 1 states. On the other hand, thermal runaway is a positive feedback that can destroy semiconductor junctions, Positive feedback in chemical reactions can increase the rate of reactions, and in some cases can lead to explosions. Positive feedback in mechanical design causes tipping-point, or over-centre, mechanisms to snap into position, for example in switches, out of control, it can cause bridges to collapse. Positive feedback in systems can cause boom-then-bust cycles. Positive feedback enhances or amplifies an effect by it having an influence on the process gave rise to it. For example, when part of an output signal returns to the input, and is in phase with it. The feedback from the outcome to the process can be direct. Such systems can give rich qualitative behaviors, but whether the feedback is positive or negative in sign has an extremely important influence on the results. Positive feedback reinforces and negative feedback moderates the original process, Positive and negative in this sense refer to loop gains greater than or less than zero, and do not imply any value judgements as to the desirability of the outcomes or effects. A key feature of positive feedback is thus that small disturbances get bigger, when a change occurs in a system, positive feedback causes further change, in the same direction. A simple feedback loop is shown in the diagram, if the loop gain AB is positive, then a condition of positive or regenerative feedback exists. If the functions A and B are linear and AB is smaller than unity, then the system gain from the input to output is finite
20.
Fisherian runaway
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Fisherian runaway can be postulated to include sexually dimorphic phenotypic traits such as behaviour expressed by either sex. Extreme and apparently maladaptive sexual dimorphism represented a paradox for evolutionary biologists from Charles Darwins time up to the evolutionary synthesis. Subsequently, if strong enough, female preference for exaggerated ornamentation in mate selection could be enough to undermine natural selection even when the ornament has become non-adaptive. Over subsequent generations this could lead to selection by positive feedback, and the speed with which the trait. Fisherian runaway has been difficult to demonstrate empirically, because it has been difficult to both an underlying genetic mechanism and a process by which it is initiated. Alfred Russel Wallace disagreed with Darwin, particularly after Darwins death, the plumage dimorphism of the peacock and peahen of the species within the Pavo genus is a prime example of the ornamentation paradox that has long puzzled evolutionary biologists. The peacocks colorful and elaborate tail requires a great deal of energy to grow and it also reduces the birds agility, and may increase the animals visibility to predators. The tail appears to lower the overall fitness of the individuals who possess it, yet, it has evolved, indicating that peacocks with longer and more colorfully elaborate tails have some advantage over peacocks who don’t. Fisherian runaway posits that the evolution of the tail is made possible if peahens have a preference to mate with peacocks that possess a longer. Peahens that select males with these tails in turn have male offspring that are likely to have long and colourful tails. Equally importantly, the offspring of these peahens are more likely to produce peahen offspring that have a preference for peacocks with longer. This suggestion is compatible with his theory, and indicates that the choice of feature is essentially arbitrary, such arbitrariness is borne out by mathematical modelling, and by observation of isolated populations of sandgrouse, where the males can differ markedly from those in other populations. Fisherian runaway assumes that sexual preference in females and ornamentation in males are both genetically variable, fisher argued that the selection for exaggerated male ornamentation is driven by the coupled exaggeration of female sexual preference for the ornament. Several alternative hypotheses use the same genetic runaway mechanism but differ in the mechanisms of the initiation, indicator hypotheses suggest that females choose desirably ornamented males because the cost of producing the desirable ornaments is indicative of good genes by way of the individuals vigour. Other hypotheses for the evolution of male ornamentation include the sensory bias hypothesis, the compatibility hypothesis, secondary sex characteristic Sexy sons hypothesis Handicap principle Good genes hypothesis
21.
Fisher's principle
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Fishers principle is an evolutionary model that explains why the sex ratio of most species that produce offspring through sexual reproduction is approximately 1,1 between males and females. It was famously outlined by Ronald Fisher in his 1930 book The Genetical Theory of Natural Selection, nevertheless, A. W. F. Edwards has remarked that it is probably the most celebrated argument in evolutionary biology. Specifically, Fisher couched his argument in terms of parental expenditure, Sex ratios that are 1,1 are hence known as Fisherian, and those that are not 1,1 are non-Fisherian or extraordinary and occur because they break the assumptions made in Fishers model. Many eusocial wasps, such as the Polistes fuscatus and the Polistes exclamans seem to exhibit such a ratio at times, a newborn male then has better mating prospects than a newborn female, and therefore can expect to have more offspring. Therefore parents genetically disposed to produce males tend to have more than numbers of grandchildren born to them. Therefore the genes for male-producing tendencies spread, and male births become more common, as the 1,1 sex ratio is approached, the advantage associated with producing males dies away. The same reasoning holds if females are substituted for males throughout, therefore 1,1 is the equilibrium ratio. In modern language, the 1,1 ratio is the evolutionarily stable strategy, let us consider the reproductive value of these offspring at the moment when this parental expenditure on their behalf has just ceased. Selection would thus raise the sex-ratio until the expenditure upon males became equal to that upon females, Fishers principle is rooted in the concept of frequency-dependent selection, though Fishers principle is not frequency-dependent selection per se. Frequency-dependent selection, in scenario, is the logic that the probability of an individual being able to breed is dependent on the frequency of the opposite sex in relation to its own sex. It was first described by Darwin in 1871, Fisher predicted that parents will invest their resources equally between each sex of offspring, because each sex supplies exactly half the genes of all future generations. As a result, those genes that cause parents to invest unequally in the sexes tend to be selected against. Fisher was aware that in humans, more boys are born, Fishers principle is also the precursor to evolutionary game theory. R. H. MacArthur first suggested applying to sex ratios the language of game theory, and this was subsequently picked up by W. D. Hamilton who termed the equilibrium point the unbeatable strategy. Hamiltons unbeatable strategy was refined by John Maynard Smith and George R. Price into their concept of the evolutionarily stable strategy, Fishers concept of parental expenditure, developed particularly by Robert Trivers is now an important concept in ecology. Edwards has shown that the argument is attributed to Fisher. Specifically, Carl Düsing of the University of Jena published this in three works between 1883–84, and this is identical to Shaw and Mohlers later model. As probably the most celebrated argument in evolutionary biology, Fishers principle is a staple of science books on evolution
22.
Plant
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Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
23.
Fungus
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A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from the other eukaryotic life kingdoms of plants, a characteristic that places fungi in a different kingdom from plants, bacteria and some protists, is chitin in their cell walls. Similar to animals, fungi are heterotrophs, they acquire their food by absorbing dissolved molecules, growth is their means of mobility, except for spores, which may travel through the air or water. Fungi are the principal decomposers in ecological systems and this fungal group is distinct from the structurally similar myxomycetes and oomycetes. The discipline of biology devoted to the study of fungi is known as mycology, in the past, mycology was regarded as a branch of botany, although it is now known fungi are genetically more closely related to animals than to plants. Abundant worldwide, most fungi are inconspicuous because of the size of their structures. Fungi include symbionts of plants, animals, or other fungi and they may become noticeable when fruiting, either as mushrooms or as molds. Fungi perform a role in the decomposition of organic matter and have fundamental roles in nutrient cycling. Since the 1940s, fungi have been used for the production of antibiotics, Fungi are also used as biological pesticides to control weeds, plant diseases and insect pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, the fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings, and become significant pathogens of humans, losses of crops due to fungal diseases or food spoilage can have a large impact on human food supplies and local economies. The fungus kingdom encompasses a diversity of taxa with varied ecologies, life cycle strategies. However, little is known of the biodiversity of Kingdom Fungi. Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, phylogenetic studies published in the last decade have helped reshape the classification within Kingdom Fungi, which is divided into one subkingdom, seven phyla, and ten subphyla. The English word fungus is directly adopted from the Latin fungus, used in the writings of Horace, a group of all the fungi present in a particular area or geographic region is known as mycobiota, e. g. the mycobiota of Ireland. Like plants, fungi grow in soil and, in the case of mushrooms, form conspicuous fruit bodies. The fungi are now considered a kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago. Fungi have membrane-bound cytoplasmic organelles such as mitochondria, sterol-containing membranes and they have a characteristic range of soluble carbohydrates and storage compounds, including sugar alcohols, disaccharides, and polysaccharides
24.
Asexual reproduction
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Asexual reproduction is the primary form of reproduction for single-celled organisms such as the Archaea and bacteria. Many plants and fungi reproduce asexually as well, a complete lack of sexual reproduction is relatively rare among multicellular organisms, particularly animals. It is not entirely understood why the ability to reproduce sexually is so common among them, developmental constraints may underlie why few animals have relinquished sexual reproduction completely in their life-cycles. An important form of fission is binary fission, in binary fission, the parent organism is replaced by two daughter organisms, because it literally divides in two. Only prokaryotes reproduce asexually through binary fission, eukaryotes may reproduce in a functionally similar manner by mitosis, most of these are also capable of sexual reproduction. Another type of fission is multiple fission, multiple fission at the cellular level occurs in many protists, e. g. sporozoans and algae. The nucleus of the parent cell divides several times by mitosis, the cytoplasm then separates, creating multiple daughter cells. In apicomplexans, multiple fission, or schizogony, is manifested either as merogony, sporogony or gametogony, merogony results in merozoites, which are multiple daughter cells, that originate within the same cell membrane, sporogony results in sporozoites, and gametogony results in microgametes. Some cells split via budding, resulting in a mother and daughter cell, the offspring organism is smaller than the parent. Budding is also known on a level, an animal example is the hydra. The buds grow into fully matured individuals which break away from the parent organism. Internal budding is a process of reproduction, favoured by parasites such as Toxoplasma gondii. It involves a process in which two or more daughter cells are produced inside a mother cell, which is then consumed by the offspring prior to their separation. Also, budding is present in some worm like Taenia or Echinococci, vegetative propagation is a type of asexual reproduction found in plants where new individuals are formed without the production of seeds or spores by meiosis or syngamy. Examples of vegetative reproduction include the formation of miniaturized plants called plantlets on specialized leaves, other plants reproduce by forming bulbs or tubers. Some plants produce adventitious shoots and omay form a colony, where all the individuals are clones. Many multicellular organisms form spores during their life cycle in a process called sporogenesis. Exceptions are animals and some protists, who undergo meiosis immediately followed by fertilization, plants and many algae on the other hand undergo sporic meiosis where meiosis leads to the formation of haploid spores rather than gametes
25.
On the Origin of Species
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On the Origin of Species, published on 24 November 1859, is a work of scientific literature by Charles Darwin which is considered to be the foundation of evolutionary biology. Darwins book introduced the theory that populations evolve over the course of generations through a process of natural selection. It presented a body of evidence that the diversity of life arose by common descent through a pattern of evolution. Darwin included evidence that he had gathered on the Beagle expedition in the 1830s and his subsequent findings from research, correspondence, various evolutionary ideas had already been proposed to explain new findings in biology. The political and theological implications were intensely debated, but transmutation was not accepted by the scientific mainstream, the book was written for non-specialist readers and attracted widespread interest upon its publication. As Darwin was an eminent scientist, his findings were taken seriously and the evidence he presented generated scientific, philosophical, and religious discussion. The debate over the book contributed to the campaign by T. H. Huxley, during the eclipse of Darwinism from the 1880s to the 1930s, various other mechanisms of evolution were given more credit. Despite periodic fluctuations, populations remain roughly the same size, resources such as food are limited and are relatively stable over time. Individuals in a population significantly from one another. Much of this variation is heritable and this slowly effected process results in populations changing to adapt to their environments, and ultimately, these variations accumulate over time to form new species. In later editions of the book, Darwin traced evolutionary ideas as far back as Aristotle, Nature was widely believed to be unstable and capricious, with monstrous births from union between species, and spontaneous generation of life. After the turmoil of the English Civil War, the Royal Society wanted to show that science did not threaten religious, in Gods benevolent design, carnivores caused mercifully swift death, but the suffering caused by parasitism was a puzzling problem. The biological classification introduced by Carl Linnaeus in 1735 also viewed species as fixed according to the divine plan. In 1766, Georges Buffon suggested that some species, such as horses and asses, or lions, tigers. The Ussher chronology of the 1650s had calculated creation at 4004 BC, wernerians thought strata were deposits from shrinking seas, but James Hutton proposed a self-maintaining infinite cycle, anticipating uniformitarianism. Charles Darwins grandfather Erasmus Darwin outlined a hypothesis of transmutation of species in the 1790s and this process was later called Lamarckism. Lamarck thought there was an inherent progressive tendency driving organisms continuously towards greater complexity, in parallel, Georges Cuvier strongly disputed such ideas, holding that unrelated, fixed species showed similarities that reflected a design for functional needs. His palæontological work in the 1790s had established the reality of extinction, in Britain, William Paleys Natural Theology saw adaptation as evidence of beneficial design by the Creator acting through natural laws
26.
Camouflage
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Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the spotted coat, the battledress of a modern soldier. A third approach, motion dazzle, confuses the observer with a pattern, making the object visible. The majority of camouflage methods aim for crypsis, often through a general resemblance to the background, high contrast disruptive coloration, eliminating shadow, and countershading. Some animals, such as chameleons and octopuses, are capable of changing their skin pattern and colours. Military camouflage was spurred by the range and accuracy of firearms in the 19th century. In particular the replacement of the inaccurate musket with the rifle made personal concealment in battle a survival skill, in the 20th century, military camouflage developed rapidly, especially during the First World War. On land, artists such as André Mare designed camouflage schemes, at sea, merchant ships and troop carriers were painted in dazzle patterns that were highly visible, but designed to confuse enemy submarines as to the targets speed, range, and heading. During and after the Second World War, a variety of schemes were used for aircraft. The use of radar since the century has largely made camouflage for fixed-wing military aircraft obsolete. Non-military use of camouflage includes making cell telephone towers less obtrusive, patterns derived from military camouflage are frequently used in fashion clothing, exploiting their strong designs and sometimes their symbolism. Camouflage themes recur in modern art, and both figuratively and literally in science fiction and works of literature, in ancient Greece, Aristotle commented on the colour-changing abilities, both for camouflage and for signalling, of cephalopods including the octopus, in his Historia animalium, The octopus. Seeks its prey by so changing its colour as to render it like the colour of the adjacent to it, it does so also when alarmed. Camouflage has been a topic of interest and research in zoology for well over a century, the English zoologist Edward Bagnall Poulton studied animal coloration, especially camouflage. In his 1890 book The Colours of Animals, he classified different types such as special protective resemblance and his experiments showed that swallowtailed moth pupae were camouflaged to match the backgrounds on which they were reared as larvae. Among vertebrates numerous species of parrots, iguanas, tree-frogs, beddard did however briefly mention other methods, including the alluring coloration of the flower mantis and the possibility of a different mechanism in the orange tip butterfly. He wrote that the scattered green spots upon the surface of the wings might have been intended for a rough sketch of the small flowerets of the plant. The artist Abbott Handerson Thayer formulated what is sometimes called Thayers Law, Thayer was roundly mocked for these views by critics including Teddy Roosevelt
27.
Beetle
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Beetles are a group of insects that form the order Coleoptera, in the superorder Endopterygota. Their front pair of wings is hardened into wing-cases, elytra, the Coleoptera, with about 400,000 species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal life-forms, new species are discovered frequently. The largest of all families, the Curculionidae with some 70,000 member species and they are found in almost every habitat except the sea and the polar regions. They interact with their ecosystems in several ways, beetles often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Beetles typically have a hard exoskeleton including the elytra, though some such as the rove beetles have very short elytra while blister beetles have softer elytra. Some, such as, stag beetles have a sexual dimorphism. Many beetles are aposematic, with colours and patterns warning of their toxicity. Many beetles, including those that live in places, have effective camouflage. Beetles are prominent in human culture, from the sacred scarabs of ancient Egypt to beetlewing art and use as pets or fighting insects for entertainment, many beetle groups are brightly and attractively coloured making them objects of collection and decorative displays. Over 300 species are used as food, mostly as larvae, species widely consumed include mealworms, however, the major impact of beetles on human life is as agricultural, forestry, and horticultural pests. Serious pests include the boll weevil of cotton, the Colorado potato beetle, the coconut hispine beetle, most beetles, however, do not cause economic damage and many, such as the lady beetles and dung beetles are beneficial by helping to control insect pests. The name of the order, Coleoptera, comes from the Greek koleopteros, given to the group by Aristotle for their elytra, hardened shield-like forewings, from koleos, sheath. The English name beetle comes from the Old English word bitela, little biter, related to bītan, another Old English name for beetle is ceafor, chafer, used in names such as cockchafer, from the Proto-Germanic *kabraz-. Beetles are by far the largest order of insects, the roughly 400,000 species make up about 40% of all species so far described. The four estimates made use of host-specificity relationships, ratios with other taxa, plant, beetle ratios, and extrapolations based on body size by year of description. The heaviest beetle, indeed the heaviest insect stage, is the larva of the beetle, Goliathus goliatus, which can attain a mass of at least 115 g. Adult male goliath beetles are the heaviest beetle in its stage, weighing 70–100 g. Adult elephant beetles, Megasoma elephas and Megasoma actaeon often reach 50 g and 10 cm, the longest beetle is the Hercules beetle Dynastes hercules, with a maximum overall length of at least 16.7 cm including the very long pronotal horn
28.
Aesthetics
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Aesthetics is a branch of philosophy that explores the nature of art, beauty, and taste, with the creation and appreciation of beauty. It is more defined as the study of sensory or sensori-emotional values, sometimes called judgements of sentiment. More broadly, scholars in the field define aesthetics as critical reflection on art, in modern English, the term aesthetic can also refer to a set of principles underlying the works of a particular art movement or theory, one speaks, for example, of the Cubist aesthetic. The word aesthetic is derived from the Greek αἰσθητικός, which in turn was derived from αἰσθάνομαι, for some, aesthetics is considered a synonym for the philosophy of art since Hegel, while others insist that there is a significant distinction between these closely related fields. In practice, aesthetic judgement refers to the sensory contemplation or appreciation of an object, philosophical aesthetics has not only to speak about art and to produce judgments about art works, but has also to give a definition of what art is. Art is an entity for philosophy, because art deals with the senses. Hence, there are two different conceptions of art in aesthetics, art as knowledge or art as action, any aesthetic doctrines that guided the production and interpretation of prehistoric art are mostly unknown. Western aesthetics usually refers to Greek philosophers as the earliest source of aesthetic considerations. Plato believed in beauty as a form in which beautiful objects partake and he felt that beautiful objects incorporated proportion, harmony, and unity among their parts. Similarly, in the Metaphysics, Aristotle found that the elements of beauty were order, symmetry. From the late 17th to the early 20th century Western aesthetics underwent a revolution into what is often called modernism. German and British thinkers emphasized beauty as the key component of art and of the aesthetic experience, and saw art as necessarily aiming at absolute beauty. For Alexander Gottlieb Baumgarten aesthetics is the science of the experiences, a younger sister of logic. For Immanuel Kant the aesthetic experience of beauty is a judgment of a subjective but similar human truth, however, beauty cannot be reduced to any more basic set of features. For Friedrich Schiller aesthetic appreciation of beauty is the most perfect reconciliation of the sensual and rational parts of human nature, for Friedrich Wilhelm Joseph Schelling, the philosophy of art is the organon of philosophy concerning the relation between man and nature. So aesthetics began now to be the name for the philosophy of art, Friedrich von Schlegel, August Wilhelm Schlegel, Friedrich Schleiermacher and Georg Wilhelm Friedrich Hegel also gave lectures on aesthetics as philosophy of art after 1800. For Hegel, all culture is a matter of absolute spirit coming to be manifest to itself, stage by stage, Art is the first stage in which the absolute spirit is manifest immediately to sense-perception, and is thus an objective rather than subjective revelation of beauty. It is thus for Schopenhauer one way to fight the suffering, the British were largely divided into intuitionist and analytic camps
29.
England
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England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west, the Irish Sea lies northwest of England and the Celtic Sea lies to the southwest. England is separated from continental Europe by the North Sea to the east, the country covers five-eighths of the island of Great Britain in its centre and south, and includes over 100 smaller islands such as the Isles of Scilly, and the Isle of Wight. England became a state in the 10th century, and since the Age of Discovery. The Industrial Revolution began in 18th-century England, transforming its society into the worlds first industrialised nation, Englands terrain mostly comprises low hills and plains, especially in central and southern England. However, there are uplands in the north and in the southwest, the capital is London, which is the largest metropolitan area in both the United Kingdom and the European Union. In 1801, Great Britain was united with the Kingdom of Ireland through another Act of Union to become the United Kingdom of Great Britain and Ireland. In 1922 the Irish Free State seceded from the United Kingdom, leading to the latter being renamed the United Kingdom of Great Britain, the name England is derived from the Old English name Englaland, which means land of the Angles. The Angles were one of the Germanic tribes that settled in Great Britain during the Early Middle Ages, the Angles came from the Angeln peninsula in the Bay of Kiel area of the Baltic Sea. The earliest recorded use of the term, as Engla londe, is in the ninth century translation into Old English of Bedes Ecclesiastical History of the English People. According to the Oxford English Dictionary, its spelling was first used in 1538. The earliest attested reference to the Angles occurs in the 1st-century work by Tacitus, Germania, the etymology of the tribal name itself is disputed by scholars, it has been suggested that it derives from the shape of the Angeln peninsula, an angular shape. An alternative name for England is Albion, the name Albion originally referred to the entire island of Great Britain. The nominally earliest record of the name appears in the Aristotelian Corpus, specifically the 4th century BC De Mundo, in it are two very large islands called Britannia, these are Albion and Ierne. But modern scholarly consensus ascribes De Mundo not to Aristotle but to Pseudo-Aristotle, the word Albion or insula Albionum has two possible origins. Albion is now applied to England in a poetic capacity. Another romantic name for England is Loegria, related to the Welsh word for England, Lloegr, the earliest known evidence of human presence in the area now known as England was that of Homo antecessor, dating to approximately 780,000 years ago. The oldest proto-human bones discovered in England date from 500,000 years ago, Modern humans are known to have inhabited the area during the Upper Paleolithic period, though permanent settlements were only established within the last 6,000 years
30.
Statistician
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A statistician is someone who works with theoretical or applied statistics. The profession exists in both the private and public sectors and it is common to combine statistical knowledge with expertise in other subjects, and statisticians may work as employees or as statistical consultants. According to the United States Bureau of Labor Statistics, as of 2014,26,970 jobs were classified as statistician in the United States, of these people, approximately 30 percent worked for governments. Statisticians are included with the professions in various national and international occupational classifications, in the United States most employment in the field requires either a masters degree in statistics or a related field or a PhD. List of statisticians Statistician entry, Occupational Outlook Handbook, U. S
31.
Evolutionary biology
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Evolutionary biology is the subfield of biology that studies the evolutionary processes that produced the diversity of life on Earth, starting from a single origin of life. These processes include natural selection, common descent, and speciation, the study of evolution is the central unifying concept in biology. Biology can be divided in various ways, one way is by the level of biological organisation, from molecular to cell, organism to population. Another way is by taxonomic group, with such as zoology, ornithology. A third way is by approach, such as biology, theoretical biology, experimental evolution. These alternative ways of dividing up the subject can be combined with evolutionary biology to create subfields like evolutionary ecology, Evolutionary biology, as an academic discipline in its own right, emerged during the period of the modern evolutionary synthesis in the 1930s and 1940s. It was not until the 1980s that many universities had departments of evolutionary biology, in the United States, many universities have created departments of molecular and cell biology or ecology and evolutionary biology, in place of the older departments of botany and zoology. Palaeontology is often grouped with earth science, microbiology too is becoming an evolutionary discipline, now that microbial physiology and genomics are better understood. The quick generation time of bacteria and viruses such as makes it possible to explore evolutionary questions. Many biologists have contributed to our current understanding of evolution, ford established an empirical research programme. Ronald Fisher, Sewall Wright and J. S. Haldane created a theoretical framework. Ernst Mayr in systematics, George Gaylord Simpson in palaeontology and G. Ledyard Stebbins in botany helped to form the modern synthesis, james Crow, Richard Lewontin, Dan Hartl, Marcus Feldman, and Brian Charlesworth trained a generation of evolutionary biologists. Current research in evolutionary biology covers diverse topics and incorporates ideas from diverse areas, such as molecular genetics, first, some fields of evolutionary research try to explain phenomena that were poorly accounted for in the modern evolutionary synthesis. These include speciation, the evolution of reproduction, the evolution of cooperation, the evolution of ageing. Second, biologists ask the most straightforward evolutionary question, what happened and this includes fields such as palaeobiology, as well as systematics and phylogenetics. Third, the evolutionary synthesis was devised at a time when nobody understood the molecular basis of genes. Today, evolutionary biologists try to determine the architecture of interesting evolutionary phenomena such as adaptation and speciation. They try to reconcile the high heritability seen in studies with the difficulty in finding which genes are responsible for this heritability using genome-wide association studies
32.
The Genetical Theory of Natural Selection
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First published in 1930 by The Clarendon Press, it is one of the most important books of the modern evolutionary synthesis, and helped define population genetics. It was dictated to his wife in the evenings as he worked at Rothamsted Research in the day, in the first chapter, Fisher considers the nature of inheritance, rejecting blending inheritance, because it would eliminate genetic variance, in favour of particulate inheritance. The second chapter introduces Fishers fundamental theorem of natural selection, the third considers the evolution of dominance, which Fisher believed was strongly influenced by modifiers. Using his knowledge of statistics, the Fisherian runaway, which explores how sexual selection can lead to a positive feedback runaway loop and he also wrote about the evolution of dominance, which explores genetic dominance. The last five chapters include Fishers more idiosyncratic views on eugenics, a second, slightly revised edition was republished in 1958. Reviewed by Charles Galton Darwin, who sent Fisher his copy of the book, with notes in the margin and this book also had a major influence on W. D. Hamiltons theories on the genetic basis of kin selection. John Henry Bennett gave an account of the writing and reception of the book, sewall Wright, who had many disagreements with Fisher, reviewed the book and wrote that it was certain to take rank as one of the major contributions to the theory of evolution. J. B. S. Haldane described it as brilliant, the book was largely overlooked for 40 years, and in particular Fishers fundamental theorem of natural selection was misunderstood. The work had an effect on W. D. Unlike in 1958, natural selection has become part of the syllabus of our intellectual life, by the time of my ultimate graduation, will I have understood all that is true in this book and will I get a First. In some ways some of us have overtaken Fisher, in many, however, this brilliant, daring man is still far in front. The publication of the edition in 1999 led to renewed interest in the work and reviews by Laurence Cook, Brian Charlesworth, James F. Crow. The Genetical Theory Of Natural Selection on the Internet Archive
33.
Exponential growth
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Exponential decay occurs in the same way when the growth rate is negative. In the case of a domain of definition with equal intervals, it is also called geometric growth or geometric decay. In either exponential growth or exponential decay, the ratio of the rate of change of the quantity to its current size remains constant over time. The formula for growth of a variable x at the growth rate r. This formula is transparent when the exponents are converted to multiplication, in this way, each increase in the exponent by a full interval can be seen to increase the previous total by another five percent. Since the time variable, which is the input to function, occurs as the exponent. Biology The number of microorganisms in a culture will increase exponentially until an essential nutrient is exhausted, typically the first organism splits into two daughter organisms, who then each split to form four, who split to form eight, and so on. Because exponential growth indicates constant growth rate, it is assumed that exponentially growing cells are at a steady-state. However, cells can grow exponentially at a constant rate while remodelling their metabolism, a virus typically will spread exponentially at first, if no artificial immunization is available. Each infected person can infect multiple new people, human population, if the number of births and deaths per person per year were to remain at current levels. This means that the time of the American population is approximately 50 years. Physics Avalanche breakdown within a dielectric material, a free electron becomes sufficiently accelerated by an externally applied electrical field that it frees up additional electrons as it collides with atoms or molecules of the dielectric media. These secondary electrons also are accelerated, creating larger numbers of free electrons, the resulting exponential growth of electrons and ions may rapidly lead to complete dielectric breakdown of the material. Each uranium nucleus that undergoes fission produces multiple neutrons, each of which can be absorbed by adjacent uranium atoms, due to the exponential rate of increase, at any point in the chain reaction 99% of the energy will have been released in the last 4.6 generations. It is an approximation to think of the first 53 generations as a latency period leading up to the actual explosion. Economics Economic growth is expressed in terms, implying exponential growth. For example, U. S. GDP per capita has grown at a rate of approximately two percent since World War 2. Finance Compound interest at a constant interest rate provides exponential growth of the capital, pyramid schemes or Ponzi schemes also show this type of growth resulting in high profits for a few initial investors and losses among great numbers of investors
34.
Geometric progression
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For example, the sequence 2,6,18,54. is a geometric progression with common ratio 3. Similarly 10,5,2.5,1.25. is a sequence with common ratio 1/2. Examples of a sequence are powers rk of a fixed number r, such as 2k. The general form of a sequence is a, a r, a r 2, a r 3, a r 4, … where r ≠0 is the common ratio. The n-th term of a sequence with initial value a. Such a geometric sequence also follows the relation a n = r a n −1 for every integer n ≥1. Generally, to whether a given sequence is geometric, one simply checks whether successive entries in the sequence all have the same ratio. The common ratio of a sequence may be negative, resulting in an alternating sequence, with numbers switching from positive to negative. For instance 1, −3,9, −27,81, the behaviour of a geometric sequence depends on the value of the common ratio. If the common ratio is, Positive, the terms will all be the sign as the initial term. Negative, the terms will alternate between positive and negative, greater than 1, there will be exponential growth towards positive or negative infinity. 1, the progression is a constant sequence, between −1 and 1 but not zero, there will be exponential decay towards zero. −1, the progression is an alternating sequence Less than −1, for the absolute values there is exponential growth towards infinity, due to the alternating sign. Geometric sequences show exponential growth or exponential decay, as opposed to the growth of an arithmetic progression such as 4,15,26,37,48. This result was taken by T. R. Malthus as the foundation of his Principle of Population. A geometric series is the sum of the numbers in a geometric progression, for example,2 +10 +50 +250 =2 +2 ×5 +2 ×52 +2 ×53. The formula works for any real numbers a and r. For example, −2 π +4 π2 −8 π3 = −2 π +2 +3 = −2 π1 − = −2 π1 +2 π ≈ −214.855
35.
Long-tailed widowbird
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The long-tailed widowbird, also known as the “Sakabula, ” is a species of bird in the family Ploceidae. The species are found in Angola, Botswana, the Democratic Republic of the Congo, Kenya, Lesotho, South Africa, Swaziland, Zambia, the long-tailed widowbird is a medium-sized bird and one of the most common in the territories it inhabits. Adult breeding males are almost entirely black with orange and white shoulders, long, wide tails, females are rather inconspicuous, their feathers streaked tawny and black with pale patches on the chest, breast and back, narrow tail feathers, and horn-color bills. When flying, male long-tailed widowbirds are readily visible due to their long tails. Between six and eight of their tail feathers are approximately half a metre long. The tail during flight display is expanded vertically into a deep, because of the seemingly large cost to such male ornaments, the long-tailed widowbird has been the subject of extensive research into the function and evolution of sexually selected traits. The long-tailed widowbird was first described by Pieter Boddaert, a Dutch physician and naturalist, the long-tailed widowbird is a member of the genus Euplectes, and therefore closely related to other species of widowbirds and bishops. The long-tailed widowbird is classified as a bird in the weaver family, Ploceidae. The long-tailed widowbird has several of the morphological traits and dietary preferences of this family, including its rounded conical bill. The long-tailed widowbird has three geographically differentiated subspecies and these include delamerei, found in the highlands of Kenya, delacouri, found in the Congo, Angola and Zambia, and progne, found in Botswana, South Africa, Swaziland and Lesotho. Some researchers have suggested the existence of long-tailed widowbird superspecies based on similarity in male nuptial plumage such as tail length, there are three known isolated populations of long-tailed widowbirds. The first is found in the Kenyan highlands, the second in Angola, southern Zaire and Zambia, and it is unknown when these populations were last in contact, however, the central population differs most in morphology relative to the other two populations. The Southern African population extends from the Eastern Cape Providence through the Free State, Lesotho, Transkei, KwaZulu Natal, the species just enters southeastern Botswana, but is most commonly found in the central highveld of South Africa. The long-tailed widowbird can be found at elevations up to 2750 metres in the Drakensberg Mountains, long-tailed widowbirds are generally found in swampy grassland in flocks consisting of one or two males and a number of females. The males fly with their tails drooping and somewhat spread, in wet weather, they are unable to fly due to their elongated tails. During the non-breeding season, long-tailed widowbirds congregate into flocks, which can be found roosting in reed beds, the long-tailed widowbirds diet generally consists of seeds, supplemented occasionally by arthropods. The birds do most of their foraging in flocks on the ground and they also feed upon both insects, including species of beetles, cicadas and aphids, and spiders. Long-tailed widowbirds exhibit distinct sexual dimorphism, males and females exhibit differences in behavior and morphological traits
36.
Gene expression
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Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are proteins, but in non-protein coding genes such as transfer RNA or small nuclear RNA genes. The process of gene expression is used by all known life—eukaryotes, prokaryotes, several steps in the gene expression process may be modulated, including the transcription, RNA splicing, translation, and post-translational modification of a protein. Gene regulation gives the cell control over structure and function, and is the basis for differentiation, morphogenesis. In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype, the genetic code stored in DNA is interpreted by gene expression, and the properties of the expression give rise to the organisms phenotype. Such phenotypes are expressed by the synthesis of proteins that control the organisms shape. Regulation of gene expression is critical to an organisms development. A gene is a stretch of DNA that encodes information, genomic DNA consists of two antiparallel and reverse complementary strands, each having 5 and 3 ends. This RNA is complementary to the template 3 →5 DNA strand, therefore, the resulting 5 →3 RNA strand is identical to the coding DNA strand with the exception that thymines are replaced with uracils in the RNA. A coding DNA strand reading ATG is indirectly transcribed through the non-coding strand as AUG in RNA, in prokaryotes, transcription is carried out by a single type of RNA polymerase, which needs a DNA sequence called a Pribnow box as well as a sigma factor to start transcription. RNA polymerase I is responsible for transcription of ribosomal RNA genes, RNA polymerase II transcribes all protein-coding genes but also some non-coding RNAs. Pol II includes a C-terminal domain that is rich in serine residues, when these residues are phosphorylated, the CTD binds to various protein factors that promote transcript maturation and modification. RNA polymerase III transcribes 5S rRNA, transfer RNA genes, transcription ends when the polymerase encounters a sequence called the terminator. These include 5 capping, which is set of reactions that add 7-methylguanosine to the 5 end of pre-mRNA. The m7G cap is then bound by cap binding complex heterodimer, another modification is 3 cleavage and polyadenylation. They occur if polyadenylation signal sequence is present in pre-mRNA, which is usually between protein-coding sequence and terminator, the pre-mRNA is first cleaved and then a series of ~200 adenines are added to form poly tail, which protects the RNA from degradation. Poly tail is bound by multiple poly-binding proteins necessary for mRNA export, a very important modification of eukaryotic pre-mRNA is RNA splicing. The majority of eukaryotic pre-mRNAs consist of alternating segments called exons and introns, in certain cases, some introns or exons can be either removed or retained in mature mRNA
37.
Richard Dawkins
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Clinton Richard Dawkins FRS FRSL is an English ethologist, evolutionary biologist and author. He is a fellow of New College, Oxford, and was the University of Oxfords Professor for Public Understanding of Science from 1995 until 2008. Dawkins first came to prominence with his 1976 book The Selfish Gene, in 2006, he founded the Richard Dawkins Foundation for Reason and Science. Dawkins is an atheist, and is known for his criticism of creationism. In The Blind Watchmaker, he argues against the watchmaker analogy, instead, he describes evolutionary processes as analogous to a blind watchmaker in that reproduction, mutation, and selection are unguided by any designer. In The God Delusion, Dawkins contends that a supernatural creator almost certainly does not exist and he opposes the teaching of creationism in schools. Dawkins was born in Nairobi, then in British Kenya, on 26 March 1941 and he is the son of Jean Mary Vyvyan and Clinton John Dawkins, who was an agricultural civil servant in the British Colonial Service in Nyasaland. His father was called up into the Kings African Rifles during World War II and returned to England in 1949 and his father had inherited a country estate, Over Norton Park in Oxfordshire, which he farmed commercially. Dawkins considers himself English and lives in Oxford, England, both his parents were interested in natural sciences, and they answered Dawkinss questions in scientific terms. Dawkins describes his childhood as a normal Anglican upbringing, and that left me with nothing. From 1954 to 1959 Dawkins attended Oundle School in Northamptonshire, an English public school with a distinct Church of England flavour, while at Oundle Dawkins read Bertrand Russells Why I Am Not a Christian for the first time. He studied zoology at Balliol College, Oxford, graduating in 1962, while there and he continued as a research student under Tinbergens supervision, receiving his MA and DPhil degrees by 1966, and remained a research assistant for another year. Tinbergen was a pioneer in the study of behaviour, particularly in the areas of instinct, learning and choice. From 1967 to 1969, he was an assistant professor of zoology at the University of California, during this period, the students and faculty at UC Berkeley were largely opposed to the ongoing Vietnam War, and Dawkins became involved in the anti-war demonstrations and activities. He returned to the University of Oxford in 1970 as a lecturer, in 1990, he became a reader in zoology. He held that professorship from 1995 until 2008, since 1970, he has been a fellow of New College, Oxford and he is now an emeritus fellow. In 1991, he gave the Royal Institution Christmas Lectures for Children on Growing Up in the Universe and he has also edited several journals, and has acted as editorial advisor to the Encarta Encyclopedia and the Encyclopedia of Evolution. He is listed as an editor and a columnist of the Council for Secular Humanisms Free Inquiry magazine
38.
The Blind Watchmaker
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He also presents arguments to refute certain criticisms made on his first book, The Selfish Gene. An unabridged audiobook edition was released in 2011, narrated by Richard Dawkins, in his choice of the title for this book, Dawkins refers to the watchmaker analogy made famous by William Paley in his 1802 book Natural Theology. To dispel the idea that complexity cannot arise without the intervention of a creator, in making this journey, he points to several creatures whose various seeing apparatus are, whilst still useful, living examples of intermediate levels of complexity. He demonstrates this by the example of the weasel program, the program displayed a two dimensional shape made up of straight black lines, the length, position, and angle of which were defined by a simple set of rules and instructions. Adding new lines based on these rules offered a set of possible new shapes. The chosen mutation would then be the basis for generation of biomorph mutants to be chosen from. Thus, the user, by selection, could steer the evolution of biomorphs and this process often produced images which were reminiscent of real organisms for instance beetles, bats, or trees. He dubbed this insight the evolution of evolvability, must already have been vastly complex in the first place. He calls this postulating organized complexity without offering an explanation and he notes that analogies with computer programs have their limitations, but are still useful. Ghiselin observes that Dawkins is NOT content with rebutting creationists but goes on to press home his arguments against alternative theories to neo-Darwinism and he thinks the book fills the need to know more about evolution that others would conceal from them. He concludes that Readers who are not outraged will be delighted and he notes that Dawkins demolishes several weak arguments, such as the argument from personal incredulity. He denies that Dawkinss computer exercises and arguments from gradual change show that forms of life could have evolved. Willard concludes by arguing that in writing this book, Dawkins is not functioning as a scientist in the line of Darwin, the engineer Theo Jansen read the book in 1986 and became fascinated by evolution and natural selection. Since 1990 he has been building kinetic sculptures, the Strandbeest, the journalist Dick Pountain described Sean B. Carrolls 2005 account of developmental biology, Endless Forms Most Beautiful, as the most important popular science book since The Blind Watchmaker. New York, W. W. Norton & Company, Inc, evolution for those that have ears. We Are All Contraptions – review by Michael Ghiselin
39.
Irish elk
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The irish elk also called the giant deer or Irish giant deer, is an extinct species of deer in the genus Megaloceros and is one of the largest deer that ever lived. Its range extended across Eurasia during the Pleistocene, from Ireland to Siberia to China, a related form is recorded in China during the Late Pleistocene. The most recent remains of the species have been dated to about 7,700 years ago in Siberia. For this reason, the name Giant deer is used in some publications, a study has suggested that the Irish elk was closely related to the Red deer. However, other phylogenetic analyses support the idea of a relationship between fallow deer and the Irish elk. In the seventeenth and eighteenth centuries it began to be apparent to scientists that many fossilized specimens being discovered did not represent any organisms that were living on earth. The Irish elk was among these specimens, neither exclusive to Ireland nor an elk, it was named so because the most well-known and most preserved fossil specimens have been found in lake sediments and peat bogs in Ireland. The Irish elk had a range, being located throughout Europe, northern Africa. The first scientists’ descriptions of the elk erroneously confused the animal with the American moose and these scientists did not have the current conception of evolutionary biology that we have now. They did not consider extinction, believing instead that the fossils had living descendants in undiscovered parts of the globe. French scientist Georges Cuvier was the first to challenge that notion and his study of the Irish elk was a key moment in the history of the study of extinction. The Irish elk evolved throughout the last few years during the Glacial Periods and Ice Age. Once established, the elk spread throughout Europe, northern Asia and Africa, most remains of Irish elk date from between 11,750 BP -with the first Megaloceros giganteus appearing about 400,000 years ago-and 10,950 BP. Studies have shown they possibly evolved from M. antecedens, the earlier taxon — sometimes considered a paleosubspecies M. giganteus antecedens — is similar but had more complex and compact antlers. The Irish elk stood about 2.1 metres tall at the shoulders carrying the largest antlers of any known cervid. In body size, the Irish Elk tied with the extant moose subspecies of Alaska as the third largest known deer, second and first belonging to the Cervalces genus. The Irish elk is estimated to have attained a mass of 540–600 kg, with large specimens having weighed 700 kg or more. A significant collection of M. giganteus skeletons can be found at the Natural History Museum in Dublin, the size of Irish elk antlers are distinctive
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