1.
Caddisfly
–
The caddisflies are an order, Trichoptera, of insects with approximately 7,000 described species. Also called sedge-flies or rail-flies, they are small moth-like insects having two pairs of membranous wings. They are closely related to Lepidoptera which have scales on their wings, caddisflies have aquatic larvae and are found in a wide variety of habitats such as streams, rivers, lakes, ponds, spring seeps and temporary waters. The larvae of species use silk to make protective cases of gravel, sand. The name Trichoptera comes from Greek, θρίξ + πτερόν, although caddisflies may be found in waterbodies of varying qualities, species-rich caddisfly assemblages are generally thought to indicate clean water. The caddisfly can be found in lakes, ponds, and marshes, together with stoneflies and mayflies, caddisflies feature importantly in bioassessment surveys of streams and other water bodies. Most caddisfly larvae are underwater architects and use silk, excreted from salivary glands near their mouths, for building. Net-making caddisflies usually live in running water, and their nets, often made amongst aquatic vegetation, caddisfly cases are open at both ends, the larva drawing oxygenated water through the posterior end, over their gills, and out of the wider anterior end. The anterior end is wider and it is to this end that they add material as they grow. Their abdomens are soft, but their front ends project from their larval tubes. Caddisfly cases resemble bagworm cases, which are constructed by various terrestrial moth species, free-living caddisflies do not build retreats or carry portable cases until they are ready to pupate, and their bodies tend to be tougher than caddisflies that build. Many species of caddisfly larvae enter a stage of inactivity called the stage for weeks or months after they mature. Their emergence is then triggered by cooling temperatures in the fall. In the Northwestern US, caddisfly larvae within their gravel cases are called periwinkles, caddisfly pupation occurs much like pupation of Lepidoptera. That is, caddisflies pupate in a cocoon spun from silk, caddisflies that build the portable cases attach their case to some underwater object, seal the front and back apertures against predation though still allowing water flow, and pupate within it. In a minority of species, the swim to shore—either below the water or across the surface—and crawl out to emerge. Many of them are able to fly immediately after breaking from their pupal skin, the adult stage of caddisflies, in most cases, is very short-lived, usually only 1–2 weeks, but can sometimes last for 2 months. Most adults are non-feeding and are equipped mainly to mate, once mated, the female caddisfly will often lay eggs by attaching them above or below the water surface
2.
Invertebrate
–
Invertebrates are animals that neither possess nor develop a vertebral column, derived from the notochord. This includes all animals apart from the subphylum Vertebrata, familiar examples of invertebrates include insects, crabs, lobsters and their kin, snails, clams, octopuses and their kin, starfish, sea-urchins and their kin, jellyfish, and worms. The majority of species are invertebrates, one estimate puts the figure at 97%. Many invertebrate taxa have a number and variety of species than the entire subphylum of Vertebrata. Some of the invertebrates, such as the Tunicata and Cephalochordata are more closely related to the vertebrates than to other invertebrates. This makes the term invertebrate paraphyletic and hence almost meaningless for taxonomic purposes, the word invertebrate comes from the form of the Latin word vertebra, which means a joint in general, and sometimes specifically a joint from the spinal column of a vertebrate. In turn the jointed aspect of vertebra derived from the concept of turning, coupled with the prefix in-, meaning not or without. The term invertebrates is not always precise among non-biologists since it does not accurately describe a taxon in the way that Arthropoda. Each of these describes an valid taxon, phylum, subphylum or family. Invertebrata is a term of convenience, not a taxon, it has very little circumscriptional significance except within the Chordata, the Vertebrata as a subphylum comprises such a small proportion of the Metazoa that to speak of the kingdom Animalia in terms of Vertebrata and Invertebrata has limited practicality. That would at least circumscribe the Chordata, however, even the notochord would be a less fundamental criterion than aspects of embryological development and symmetry or perhaps bauplan. The following text reflects earlier scientific understanding of the term and of animals which have constituted it. According to this understanding, invertebrates do not possess a skeleton of bone and they include hugely varied body plans. Many have fluid-filled, hydrostatic skeletons, like jellyfish or worms, others have hard exoskeletons, outer shells like those of insects and crustaceans. The most familiar invertebrates include the Protozoa, Porifera, Coelenterata, Platyhelminthes, Nematoda, Annelida, Echinodermata, Mollusca, Arthropoda include insects, crustaceans and arachnids. By far the largest number of described species are insects. The following table lists the number of described extant species for major invertebrate groups as estimated in the IUCN Red List of Threatened Species,2014.3. The IUCN estimates that 66,178 extant vertebrate species have been described, the trait that is common to all invertebrates is the absence of a vertebral column, this creates a distinction between invertebrates and vertebrates
3.
Water quality
–
Water quality refers to the chemical, physical, biological, and radiological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and it is most frequently used by reference to a set of standards against which compliance can be assessed. The most common used to assess water quality relate to health of ecosystems, safety of human contact. In the setting of standards, agencies make political and technical/scientific decisions about how the water will be used, in the case of natural water bodies, they also make some reasonable estimate of pristine conditions. Natural water bodies will vary in response to environmental conditions, Environmental scientists work to understand how these systems function, which in turn helps to identify the sources and fates of contaminants. Environmental lawyers and policymakers work to define legislation with the intention that water is maintained at a quality for its identified use. The vast majority of water on the Earth is neither potable nor toxic. This remains true when seawater in the oceans is not counted, another general perception of water quality is that of a simple property that tells whether water is polluted or not. In fact, water quality is a subject, in part because water is a complex medium intrinsically tied to the ecology of the Earth. Industrial and commercial activities are a cause of water pollution as are runoff from agricultural areas, urban runoff. The parameters for water quality are determined by the intended use, work in the area of water quality tends to be focused on water that is treated for human consumption, industrial use, or in the environment. Water quality depends on the geology and ecosystem, as well as human uses such as sewage dispersion, industrial pollution, use of water bodies as a heat sink. The United States Environmental Protection Agency limits the amounts of contaminants in tap water provided by US public water systems. The U. S. Food and Drug Administration regulations establish limits for contaminants in bottled water that must provide the protection for public health. Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants, the presence of these contaminants does not necessarily indicate that the water poses a health risk. Water drawn directly from a stream, lake, or aquifer, dissolved minerals may affect suitability of water for a range of industrial and domestic purposes. Hard water may be softened to remove these ions, the softening process often substitutes sodium cations. Hard water may be preferable to soft water for consumption, since health problems have been associated with excess sodium
4.
Species
–
In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
5.
Copepod
–
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Many live underground in marine and freshwater caves, sinkholes, or stream beds, copepods are sometimes used as biodiversity indicators. As with other crustaceans, copepods have a larval form, for copepods, the egg hatches into a nauplius form, with a head and a tail but no true thorax or abdomen. The larva molts several times until it resembles the adult and then, after more molts, the nauplius form is so different from the adult form that it was once thought to be a separate species. Copepods form a subclass belonging to the subphylum Crustacea, they are divided into ten orders, some 13,000 species of copepods are known, and 2,800 of them live in fresh water. Copepods vary considerably, but can typically be 1 to 2 mm long, with a teardrop-shaped body, like other crustaceans, they have an armoured exoskeleton but they are so small that in most species this thin armour and the entire body, is almost totally transparent. Some polar copepods reach 1 cm, most copepods have a single median compound eye, usually bright red and in the centre of the transparent head, subterranean species may be eyeless. Like other crustaceans copepods possess two pairs of antennae, the first pair is long and conspicuous. Copepods typically have a short, cylindrical body, with a rounded or beaked head, the head is fused with the first one or two thoracic segments, while the remainder of the thorax has three to five segments, each with limbs. The first pair of appendages is modified to form maxillipeds. The abdomen is narrower than the thorax, and contains five segments without any appendages. Because of their size, copepods have no need of any heart or circulatory system. Instead, they absorb oxygen directly into their bodies and their excretory system consists of maxillary glands. The second pair of appendages in free-living copepods is usually the main time-averaged source of propulsion. Many species have neurons surrounded by myelin, which is rare among invertebrates. Even rarer, the myelin is highly organized, resembling the well-organized wrapping found in vertebrates, finding a mate in the three-dimensional space of open water is challenging. Some copepod females solve the problem by emitting pheromones, which leave a trail in the water that the male can follow, copepods feed directly on phytoplankton, catching cells singly. Some of the species are predators of their smaller relatives
6.
Crustacean
–
Crustaceans form a large, diverse arthropod taxon which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill, woodlice and barnacles. In other words, some crustaceans are more related to insects. The 67,000 described species range in size from Stygotantulus stocki at 0.1 mm, to the Japanese spider crab with a leg span of up to 3.8 m, like other arthropods, crustaceans have an exoskeleton, which they moult to grow. Most crustaceans are free-living aquatic animals, but some are terrestrial, some are parasitic, the group has an extensive fossil record, reaching back to the Cambrian, and includes living fossils such as Triops cancriformis, which has existed apparently unchanged since the Triassic period. More than 10 million tons of crustaceans are produced by fishery or farming for human consumption, krill and copepods are not as widely fished, but may be the animals with the greatest biomass on the planet, and form a vital part of the food chain. The scientific study of crustaceans is known as carcinology, and a scientist who works in carcinology is a carcinologist, the body of a crustacean is composed of segments, which are grouped into three regions, the cephalon or head, the thorax, and the pleon or abdomen. The head and thorax may be fused together to form a cephalothorax, the crustacean body is protected by the hard exoskeleton, which must be moulted for the animal to grow. The shell around each somite can be divided into a dorsal tergum, ventral sternum, various parts of the exoskeleton may be fused together. The abdomen bears pleopods, and ends in a telson, which bears the anus, the number and variety of appendages in different crustaceans may be partly responsible for the groups success. It is unclear whether the condition is a derived state which evolved in crustaceans. Trilobites, for instance, also possessed biramous appendages, the main body cavity is an open circulatory system, where blood is pumped into the haemocoel by a heart located near the dorsum. Malacostraca have haemocyanin as the pigment, while copepods, ostracods, barnacles. The alimentary canal consists of a tube that often has a gizzard-like gastric mill for grinding food and a pair of digestive glands that absorb food. Structures that function as kidneys are located near the antennae, a brain exists in the form of ganglia close to the antennae, and a collection of major ganglia is found below the gut. In many decapods, the first pair of pleopods are specialised in the male for sperm transfer, many terrestrial crustaceans mate seasonally and return to the sea to release the eggs. Others, such as woodlice, lay their eggs on land, in most decapods, the females retain the eggs until they hatch into free-swimming larvae. Marine crustaceans are as ubiquitous in the oceans as insects are on land, some branchiurans are able to withstand rapid changes of salinity and will also switch hosts from marine to non-marine species. Krill are the layer and the most important part of the food chain in Antarctic animal communities
7.
Water body
–
A body of water or waterbody is any significant accumulation of water, generally on a planets surface. The term most often refers to oceans, seas, and lakes, a body of water does not have to be still or contained, Rivers, streams, canals, and other geographical features where water moves from one place to another are also considered bodies of water. Most are naturally occurring geographical features, but some are artificial, there are types that can be either. For example, most reservoirs are created by engineering dams, similarly, most harbors are naturally occurring bays, but some harbors have been created through construction. Bodies of water that are navigable are known as waterways, some bodies of water collect and move water, such as rivers and streams, and others primarily hold water, such as lakes and oceans. The term body of water can also refer to a reservoir of water held by a plant, note that there are some geographical features involving water that are not bodies of water, for example waterfalls, geysers and rapids. Arm of the sea - also sea arm, used to describe a sea loch, arroyo - a usually dry creek bed or gulch that temporarily fills with water after a heavy rain, or seasonally. Artificial lake or artificial pond - see reservoir or impoundment, barachois - a lagoon separated from the ocean by a sand bar. Bay - an area of water bordered by land on three sides, similar to, but smaller than a gulf, bayou - a slow-moving stream or a marshy lake. Bight - a large and often only slightly receding bay, or a bend in any geographical feature, billabong - see Oxbow lake, a pond or still body of water created when a river changes course and some water becomes trapped. Boil - see Seep Brook - a small stream, canal - an artificial waterway, usually connected to existing lakes, rivers, or oceans. Channel - the physical confine of a river, slough or ocean consisting of a bed. See also stream bed and strait, earth scientists generally use the term to describe a circular or round inlet with a narrow entrance, though colloquially the term is sometimes used to describe any sheltered bay. Basin - a region of land where water from rain or snowmelt drains downhill into another body of water, such as a river, lake, creek - an inlet of the sea, narrower than a cove. Delta - the location where a river flows into an ocean, sea, estuary, lake, distributary or distributary channel - a stream that branches off and flows away from a main stream channel. Draw - a usually dry creek bed or gulch that temporarily fills with water after a heavy rain, fjord - a submergent landform which has occurred due to glacial activity. Glacier - a large collection of ice or a river that moves slowly down a mountain. Glacial Pothole - see Kettle Gulf - a part of a lake or ocean that extends so that it is surrounded by land on three sides, similar to, but larger than a bay, headland - an area of water bordered by land on three sides
8.
Physiology
–
Physiology is the scientific study of normal mechanisms, and their interactions, which operate within a living system. A sub-discipline of biology, its focus is in how organisms, organ systems, organs, cells, and biomolecules carry out the chemical or physical functions that exist in a living system. Given the size of the field, it is divided into, among others, animal physiology, plant physiology, cellular physiology, microbial physiology, bacterial physiology, and viral physiology. The Nobel Prize in Physiology or Medicine is awarded to those who make significant achievements in this discipline by the Royal Swedish Academy of Sciences. In medicine, a state is one occurring from normal body function, rather than pathologically. Physiological studies date back to the ancient civilizations of India and Egypt alongside anatomical studies, the study of human physiology as a medical field dates back to at least 420 BC to the time of Hippocrates, also known as the father of medicine. Hippocrates incorporated his belief called the theory of humours, which consisted of four basic substance, earth, water, air. Each substance is known for having a corresponding humour, black bile, phlegm, blood and yellow bile, Hippocrates also noted some emotional connections to the four humours, which Claudis Galenus would later expand on. The critical thinking of Aristotle and his emphasis on the relationship between structure and function marked the beginning of physiology in Ancient Greece. Like Hippocrates, Aristotle took to the theory of disease. Claudius Galenus, known as Galen of Pergamum, was the first to use experiments to probe the functions of the body, unlike Hippocrates though, Galen argued that humoral imbalances can be located in specific organs, including the entire body. His modification of this theory better equipped doctors to more precise diagnoses. Galen was also the founder of experimental physiology, and for the next 1,400 years, Galenic physiology was a powerful and influential tool in medicine. Jean Fernel, a French physician, introduced the term physiology, inspired in the work of Adam Smith, Milne-Edwards wrote that the body of all living beings, whether animal or plant, resembles a factory. Where the organs, comparable to workers, work incessantly to produce the phenomena that constitute the life of the individual, in more differentiated organisms, the functional labor could be apportioned between different instruments or systems. In 1858, Joseph Lister studied the cause of blood coagulation and inflammation that resulted after previous injuries and he later discovered and implemented antiseptics in the operating room, and as a result decreases death rate from surgery by a substantial amount. The Physiological Society was founded in London in 1876 as a dining club, the American Physiological Society is a nonprofit organization that was founded in 1887. The Society is, devoted to fostering education, scientific research, in 1891, Ivan Pavlov performed research on conditional reflexes that involved dogs saliva production in response to a plethora of sounds and visual stimuli
9.
Pollution
–
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution, Air pollution has always accompanied civilizations. Pollution started from prehistoric times when man created the first fires, metal forging appears to be a key turning point in the creation of significant air pollution levels outside the home. The burning of coal and wood, and the presence of horses in concentrated areas made the cities the cesspools of pollution. The Industrial Revolution brought an infusion of untreated chemicals and wastes into local streams that served as the water supply, king Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke became a problem. But the fuel was so common in England that this earliest of names for it was acquired because it could be carted away from some shores by the wheelbarrow and it was the industrial revolution that gave birth to environmental pollution as we know it today. London also recorded one of the extreme cases of water quality problems with the Great Stink on the Thames of 1858. Pollution issues escalated as population growth far exceeded view ability of neighborhoods to handle their waste problem, reformers began to demand sewer systems, and clean water. In 1870, the conditions in Berlin were among the worst in Europe. There were no toilets in the streets or squares. Visitors, especially women, often became desperate when nature called, in the public buildings the sanitary facilities were unbelievably primitive. As a metropolis, Berlin did not emerge from a state of barbarism into civilization until after 1870. Chicago and Cincinnati were the first two American cities to enact laws ensuring cleaner air in 1881, as historian Martin Melosi notes, The generation that first saw automobiles replacing the horses saw cars as miracles of cleanliness. By the 1940s, however, automobile-caused smog was an issue in Los Angeles. Other cities followed around the country early in the 20th century. Extreme smog events were experienced by the cities of Los Angeles and Donora, Pennsylvania in the late 1940s, Air pollution would continue to be a problem in England, especially later during the industrial revolution, and extending into the recent past with the Great Smog of 1952. Awareness of atmospheric pollution spread widely after World War II, with fears triggered by reports of fallout from atomic warfare. Then a non-nuclear event, The Great Smog of 1952 in London and this prompted some of the first major modern environmental legislation, The Clean Air Act of 1956
10.
Water pollution
–
Water pollution is the contamination of water bodies. This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds, Water pollution affects the entire biosphere – plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and population, Water pollution is a major global problem which requires ongoing evaluation and revision of water resource policy at all levels. It has been suggested that pollution is the leading worldwide cause of deaths and diseases. An estimated 580 people in India die of water related illness every day. About 90 percent of the water in the cities of China is polluted, as of 2007, half a billion Chinese had no access to safe drinking water. In addition to the problems of water pollution in developing countries. The head of Chinas national development agency said in 2007 that one quarter the length of Chinas seven main rivers were so poisoned the water harmed the skin. Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause changes in water quality. Although interrelated, surface water and groundwater have often studied and managed as separate resources. Surface water seeps through the soil and becomes groundwater, conversely, groundwater can also feed surface water sources. Sources of surface water pollution are generally grouped into two based on their origin. Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain. The U. S. Clean Water Act defines point source for regulatory enforcement purposes, the CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites. Nonpoint source pollution refers to contamination that does not originate from a single discrete source. NPS pollution is often the cumulative effect of small amounts of contaminants gathered from a large area, a common example is the leaching out of nitrogen compounds from fertilized agricultural lands. Nutrient runoff in storm water from sheet flow over a field or a forest are also cited as examples of NPS pollution. Contaminated storm water washed off of parking lots, roads and highways, however, because this runoff is typically channeled into storm drain systems and discharged through pipes to local surface waters, it becomes a point source
11.
Organism
–
In biology, an organism is any contiguous living system, such as an animal, plant, fungus, protist, archaeon, or bacterium. All known types of organisms are capable of some degree of response to stimuli, reproduction, growth and development and homeostasis. An organism consists of one or more cells, when it has one cell it is known as an organism. Most unicellular organisms are of microscopic scale and are thus described as microorganisms. Humans are multicellular organisms composed of trillions of cells grouped into specialized tissues. An organism may be either a prokaryote or a eukaryote, prokaryotes are represented by two separate domains—bacteria and archaea. Eukaryotic organisms are characterized by the presence of a cell nucleus. Fungi, animals and plants are examples of kingdoms of organisms within the eukaryotes, estimates on the number of Earths current species range from 10 million to 14 million, of which only about 1.2 million have been documented. More than 99% of all species, amounting to five billion species. In 2016, a set of 355 genes from the last universal ancestor of all living organisms living was identified. The term organism first appeared in the English language in 1703 and it is directly related to the term organization. There is a tradition of defining organisms as self-organizing beings. An organism may be defined as an assembly of molecules functioning as a more or less stable whole that exhibits the properties of life. Dictionary definitions can be broad, using such as any living structure, such as a plant, animal, fungus or bacterium, capable of growth. Many definitions exclude viruses and possible man-made non-organic life forms, as viruses are dependent on the machinery of a host cell for reproduction. A superorganism is an organism consisting of individuals working together as a single functional or social unit. There has been controversy about the best way to define the organism, several contributions are responses to the suggestion that the category of organism may well not be adequate in biology. Viruses are not typically considered to be organisms because they are incapable of autonomous reproduction and this controversy is problematic because some cellular organisms are also incapable of independent survival and live as obligatory intracellular parasites
12.
Environment (biophysical)
–
The biophysical environment can vary in scale from microscopic to global in extent. It can also be subdivided according to its attributes, examples include the marine environment, the atmospheric environment and the terrestrial environment. The number of environments is countless, given that each living organism has its own environment. The term environment is used as a short form for the biophysical environment. The expression the environment often refers to a global environment in relation to humanity. All life that has survived must have adapted to conditions of its environment, temperature, light, humidity, soil nutrients, etc. all influence any species, within any environment. However life in turn modifies, in forms, its conditions. Some long term modifications along the history of our planet have been significant and this process consisted in the breakdown of carbon dioxide by anaerobic microorganisms that used the carbon in their metabolism and released the oxygen to the atmosphere. This led to the existence of oxygen-based plant and animal life, other interactions are more immediate and simple, such as the smoothing effect that forests have on the temperature cycle, compared to neighboring unforested areas. Environmental science is the study of the interactions within the biophysical environment, part of this scientific discipline is the investigation of the effect of human activity on the environment. Ecology, a sub-discipline of biology and a part of environmental sciences, is mistaken as a study of human induced effects on the environment. Environmental studies is an academic discipline that is the systematic study of interaction of humans with their environment. It is a field of study that includes the natural environment, built environments. Environmentalism is a social and philosophical movement that, in a large part, seeks to minimise. The issues of concern for environmentalists usually relate to the environment with the more important ones being climate change, species extinction, pollution. One of the studies related include employing Geographic Information Science to study the biophysical environment, biophysics subject to the context List of conservation topics List of environmental issues Lists of environmental topics Miller, G. Tyler. McCallum, Malcolm L. Gwendolynn W. Bury, google search patterns suggest declining interest in the environment
13.
Bacillus
–
Bacillus is a genus of gram-positive, rod-shaped bacteria and a member of the phylum Firmicutes. Bacillus species can be obligate aerobes, or facultative anaerobes and they will test positive for the enzyme catalase when there has been oxygen used or present. Ubiquitous in nature, Bacillus includes both free-living and parasitic pathogenic species and these characteristics originally defined the genus, but not all such species are closely related, and many have been moved to other genera of the Firmicutes. Many species of Bacillus can produce copious amounts of enzymes which are use of in different industries. B. subtilis has proved a model for research. Other species of Bacillus are important pathogens, causing anthrax and food poisoning, many Bacillus species are able to secrete large quantities of enzymes. A portion of the Bacillus thuringiensis genome was incorporated into corn crops, the resulting GMOs are therefore resistant to some insect pests. Bacillus subtilis is one of the best understood prokaryotes, in terms of molecular and cellular biology and its superb genetic amenability and relatively large size have provided the powerful tools required to investigate a bacterium from all possible aspects. Recent improvements in fluorescent microscopy techniques have provided insight into the dynamic structure of a single cell organism. Bacillus species are almost ubiquitous in nature, e. g. in soil, B. thuringiensis produces a toxin that can kill insects and thus has been used as insecticide. Two Bacillus species are considered significant, B. anthracis, which causes anthrax, and B. cereus. A third species, B. thuringiensis, is an important insect pathogen, the type species is B. subtilis, an important model organism. It is also a notable food spoiler, causing ropiness in bread, some environmental and commercial strains of B. coagulans may play a role in food spoilage of highly acidic, tomato-based products. An easy way to isolate Bacillus species is by placing nonsterile soil in a test tube with water, shaking, placing in melted mannitol salt agar, colonies are usually large, spreading, and irregularly shaped. Under the microscope, the Bacillus cells appear as rods, the cell wall is composed of teichoic and teichuronic acids. The role of the cytoskeleton in shape generation and maintenance is important The genus Bacillus was named in 1835 by Christian Gottfried Ehrenberg and he had seven years earlier named the genus Bacterium. Bacillus was later amended by Ferdinand Cohn to further describe them as spore-forming, Gram-positive, like other genera associated with the early history of microbiology, such as Pseudomonas and Vibrio, the 266 species of Bacillus are ubiquitous. The genus has a very large ribosomal 16S diversity and is environmentally diverse, several studies have tried to reconstruct the phylogeny of the genus
14.
Sterilization (microbiology)
–
Sterilization can be achieved through various means, including, heat, chemicals, irradiation, high pressure, and filtration. Sterilization is distinct from disinfection, sanitization, and pasteurization in that kills, deactivates, or eliminates all forms of life. Canning of foods is an extension of the principle, and has helped to reduce food borne illness. Other methods of sterilizing foods include food irradiation and high pressure, in general, surgical instruments and medications that enter an already aseptic part of the body must be sterile. Examples of such instruments include scalpels, hypodermic needles and artificial pacemakers and this is also essential in the manufacture of parenteral pharmaceuticals. Most medical and surgical devices used in healthcare facilities are made of materials that are able to go under steam sterilization, however, since 1950, there has been an increase in medical devices and instruments made of materials that require low-temperature sterilization. Ethylene oxide gas has been used since the 1950s for heat-, within the past 15 years, a number of new, low-temperature sterilization systems have been developed and are being used to sterilize medical devices. ]Steam sterilization is the most widely used and the most dependable. Steam sterilization is nontoxic, inexpensive, rapidly microbicidal, sporicidal, there are strict international rules to protect the contamination of Solar System bodies from biological material from Earth. Standards vary depending on both the type of mission and its destination, the more likely a planet is considered to be habitable, the aim of sterilization is the reduction of initially present microorganisms or other potential pathogens. The degree of sterilization is commonly expressed by multiples of the decimal reduction time, or D-value, then the number of microorganisms N after sterilization time t is given by, N N0 =10. The D-value is a function of sterilization conditions and varies with the type of microorganism, temperature, water activity, for steam sterilization typically the temperature is given as index. Theoretically, the likelihood of survival of an individual microorganism is never zero, to compensate for this, the overkill method is often used. Using the overkill method, sterilization is performed by sterilizing for longer than is required to kill the present on or in the item being sterilized. This provides a sterility assurance level equal to the probability of a non-sterile unit, for high-risk applications such as medical devices and injections, a sterility assurance level of at least 10−6 is required by the United States Food and Drug Administration. A widely used method for heat sterilization is the autoclave, sometimes called a converter or steam sterilizer, autoclaves use steam heated to 121-134 °C under pressure. To achieve sterility, the article is heated in a chamber by injected steam until the article reaches a time, meantime almost all the air is removed from the chamber, because air is undesired in the moist heat sterilization process. The article is then held at that setpoint for a period of time varies depending on the bioburden present on the article being sterilized. Following sterilization, liquids in a pressurized autoclave must be cooled slowly to avoid boiling over when the pressure is released and this may be achieved by gradually depressurizing the sterilization chamber and allowing liquids to evaporate under a negative pressure, while cooling the contents
15.
Microorganism
–
A microorganism or microbe is a microscopic organism, which may be single-celled or multicellular. The study of microorganisms is called microbiology, a subject that began with the discovery of microorganisms in 1674 by Antonie van Leeuwenhoek, microorganisms are very diverse and include all bacteria, archaea and most protozoa. This group also contains some fungi, algae, and some such as rotifers. Many macroscopic animals and plants have microscopic juvenile stages, some microbiologists classify viruses and viroids as microorganisms, but others consider these as nonliving. In July 2016, scientists identified a set of 355 genes from the last universal ancestor of all life, including microorganisms. Microorganisms, under certain test conditions, have observed to thrive in the vacuum of outer space. Microorganisms likely far outweigh all other living things combined, the mass of prokaryote microorganisms including the bacteria and archaea may be as much as 0.8 trillion tons of carbon, out of the total biomass of between 1 and 4 trillion tons. Microorganisms appear to thrive in the Mariana Trench, the deepest spot in the Earths oceans, in August 2014, scientists confirmed the existence of microorganisms living 800 m below the ice of Antarctica. According to one researcher, You can find microbes everywhere — theyre extremely adaptable to conditions, microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a part of the nitrogen cycle. Microorganisms are also exploited in biotechnology, both in food and beverage preparation, and in modern technologies based on genetic engineering. A small proportion of microorganisms are pathogenic, causing disease and even death in plants, Robert Hooke coined the term cell after viewing plant cells under his microscope. Antonie Van Leeuwenhoek was one of the first people to observe microorganisms in 1673, later, in the 19th century, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In 1876 Robert Koch discovered that microorganisms cause diseases, single-celled microorganisms were the first forms of life to develop on Earth, approximately 3–4 billion years ago. Further evolution was slow, and for about 3 billion years in the Precambrian eon, so, for most of the history of life on Earth, the only forms of life were microorganisms. Bacteria, algae and fungi have been identified in amber that is 220 million years old, microorganisms tend to have a relatively fast rate of evolution. Most microorganisms can reproduce rapidly, and bacteria are able to freely exchange genes through conjugation, transformation and transduction. This rapid evolution is important in medicine, as it has led to the development of multidrug resistant pathogenic bacteria, superbugs, the possible existence of microorganisms was discussed for many centuries before their discovery in the 17th century
16.
Pollutant
–
A pollutant is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. A pollutant may cause long- or short-term damage by changing the rate of plant or animal species, or by interfering with human amenities, comfort, health. Some pollutants are biodegradable and therefore will not persist in the environment in the long term, however the degradation products of some pollutants are themselves polluting such as the products DDE and DDD produced from degradation of DDT. Pollutants, towards which the environment has little or no absorptive capacity are called stock pollutants, stock pollutants accumulate in the environment over time. The damage they cause increases as more pollutant is emitted, stock pollutants can create a burden for future generations, by passing on damage that persists well after the ‘benefits received from incurring that damage, have been forgotten. Fund pollutants are those for which the environment has some absorptive capacity, fund pollutants do not cause damage to the environment unless the emission rate exceeds the receiving environments absorptive capacity. Fund pollutants are not destroyed, but rather converted into less harmful substances and it also encompasses ecological light pollution which describes the effect of artificial light on individual organisms and on the structure of ecosystems as a whole. Pollutants can also be defined by their zones of influence, both horizontally and vertically, the horizontal zone refers to the area that is damaged by a pollutant. Local pollutants cause damage near the emission source, regional pollutants cause damage further from the emission source. The vertical zone is referred to whether the damage is ground-level or atmospheric, surface pollutants cause damage by concentrations of the pollutant accumulating near the Earths surface Global pollutants cause damage by concentrations in the atmosphere. Pollutants can cross borders and therefore international regulations are needed for their control. The Stockholm Convention on Persistent Organic Pollutants, which entered force in 2004, is an international legally binding agreement for the control of persistent organic pollutants. Pollutant Release and Transfer Registers are systems to collect and disseminate information on releases and transfers of toxic chemicals from industrial. The National Emissions Standards for Hazardous Air Pollutants are additional emission standards that are set by EPA for toxic air pollutants, under the Clean Water Act, EPA promulgated national standards for municipal sewage treatment plants, also called publicly owned treatment works, in the Secondary Treatment Regulation. National standards for industrial dischargers are called Effluent guidelines and New Source Performance Standards, in addition, the Act requires states to publish water quality standards for individual water bodies to provide additional protection where the national standards are insufficient. The Resource Conservation and Recovery Act regulates the management, transport and disposal of solid waste, hazardous waste. A tank or piping network that has at least 10 percent of its volume underground is known as a storage tank. They often store substances such as petroleum, that are harmful to the environment should it become contaminated
17.
Chemical substance
–
A chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical methods, i. e. without breaking chemical bonds. Chemical substances can be chemical elements, chemical compounds, ions or alloys, Chemical substances are often called pure to set them apart from mixtures. A common example of a substance is pure water, it has the same properties. Other chemical substances commonly encountered in pure form are diamond, gold, table salt, however, in practice, no substance is entirely pure, and chemical purity is specified according to the intended use of the chemical. Chemical substances exist as solids, liquids, gases, or plasma, Chemical substances may be combined or converted to others by means of chemical reactions. Forms of energy, such as light and heat, are not matter, a chemical substance may well be defined as any material with a definite chemical composition in an introductory general chemistry textbook. According to this definition a chemical substance can either be a chemical element or a pure chemical compound. But, there are exceptions to this definition, a substance can also be defined as a form of matter that has both definite composition and distinct properties. The chemical substance index published by CAS also includes several alloys of uncertain composition, in geology, substances of uniform composition are called minerals, while physical mixtures of several minerals are defined as rocks. Many minerals, however, mutually dissolve into solid solutions, such that a rock is a uniform substance despite being a mixture in stoichiometric terms. Feldspars are an example, anorthoclase is an alkali aluminium silicate. In law, chemical substances may include both pure substances and mixtures with a composition or manufacturing process. For example, the EU regulation REACH defines monoconstituent substances, multiconstituent substances and substances of unknown or variable composition, the latter two consist of multiple chemical substances, however, their identity can be established either by direct chemical analysis or reference to a single manufacturing process. For example, charcoal is a complex, partially polymeric mixture that can be defined by its manufacturing process. Therefore, although the chemical identity is unknown, identification can be made to a sufficient accuracy. The CAS index also includes mixtures, polymers almost always appear as mixtures of molecules of multiple molar masses, each of which could be considered a separate chemical substance. However, the polymer may be defined by a precursor or reaction
18.
Chemical element
–
A chemical element or element is a species of atoms having the same number of protons in their atomic nuclei. There are 118 elements that have identified, of which the first 94 occur naturally on Earth with the remaining 24 being synthetic elements. There are 80 elements that have at least one stable isotope and 38 that have exclusively radioactive isotopes, iron is the most abundant element making up Earth, while oxygen is the most common element in the Earths crust. Chemical elements constitute all of the matter of the universe. The two lightest elements, hydrogen and helium, were formed in the Big Bang and are the most common elements in the universe. The next three elements were formed mostly by cosmic ray spallation, and are rarer than those that follow. Formation of elements with from 6 to 26 protons occurred and continues to occur in main sequence stars via stellar nucleosynthesis, the high abundance of oxygen, silicon, and iron on Earth reflects their common production in such stars. The term element is used for atoms with a number of protons as well as for a pure chemical substance consisting of a single element. A single element can form multiple substances differing in their structure, when different elements are chemically combined, with the atoms held together by chemical bonds, they form chemical compounds. Only a minority of elements are found uncombined as relatively pure minerals, among the more common of such native elements are copper, silver, gold, carbon, and sulfur. All but a few of the most inert elements, such as gases and noble metals, are usually found on Earth in chemically combined form. While about 32 of the elements occur on Earth in native uncombined forms. For example, atmospheric air is primarily a mixture of nitrogen, oxygen, and argon, the history of the discovery and use of the elements began with primitive human societies that found native elements like carbon, sulfur, copper and gold. Later civilizations extracted elemental copper, tin, lead and iron from their ores by smelting, using charcoal, alchemists and chemists subsequently identified many more, almost all of the naturally occurring elements were known by 1900. Save for unstable radioactive elements with short half-lives, all of the elements are available industrially, almost all other elements found in nature were made by various natural methods of nucleosynthesis. On Earth, small amounts of new atoms are produced in nucleogenic reactions, or in cosmogenic processes. Of the 94 naturally occurring elements, those with atomic numbers 1 through 82 each have at least one stable isotope, Isotopes considered stable are those for which no radioactive decay has yet been observed. Elements with atomic numbers 83 through 94 are unstable to the point that radioactive decay of all isotopes can be detected, the very heaviest elements undergo radioactive decay with half-lives so short that they are not found in nature and must be synthesized
19.
Chemical compound
–
A chemical compound is an entity consisting of two or more atoms, at least two from different elements, which associate via chemical bonds. Many chemical compounds have a numerical identifier assigned by the Chemical Abstracts Service. For example, water is composed of two atoms bonded to one oxygen atom, the chemical formula is H2O. A compound can be converted to a different chemical composition by interaction with a chemical compound via a chemical reaction. In this process, bonds between atoms are broken in both of the compounds, and then bonds are reformed so that new associations are made between atoms. Schematically, this reaction could be described as AB + CD → AC + BD, where A, B, C, and D are each unique atoms, and AB, CD, AC, and BD are each unique compounds. A chemical element bonded to a chemical element is not a chemical compound since only one element. Examples are the diatomic hydrogen and the polyatomic molecule sulfur. Chemical compounds have a unique and defined chemical structure held together in a spatial arrangement by chemical bonds. Pure chemical elements are not considered chemical compounds, failing the two or more atom requirement, though they often consist of molecules composed of multiple atoms. There is varying and sometimes inconsistent nomenclature differentiating substances, which include truly non-stoichiometric examples, from chemical compounds, other compounds regarded as chemically identical may have varying amounts of heavy or light isotopes of the constituent elements, which changes the ratio of elements by mass slightly. Characteristic properties of compounds include that elements in a compound are present in a definite proportion, for example, the molecule of the compound water is composed of hydrogen and oxygen in a ratio of 2,1. In addition, compounds have a set of properties. The physical and chemical properties of compounds differ from those of their constituent elements, however, mixtures can be created by mechanical means alone, but a compound can be created only by a chemical reaction. Some mixtures are so combined that they have some properties similar to compounds. Other examples of compound-like mixtures include intermetallic compounds and solutions of metals in a liquid form of ammonia. Compounds may be described using formulas in various formats, for compounds that exist as molecules, the formula for the molecular unit is shown. For polymeric materials, such as minerals and many metal oxides, the elements in a chemical formula are normally listed in a specific order, called the Hill system
20.
Morphology (biology)
–
Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features. This includes aspects of the appearance, i. e. external morphology, as well as the form and structure of the internal parts like bones and organs. This is in contrast to physiology, which deals primarily with function, Morphology is a branch of life science dealing with the study of gross structure of an organism or taxon and its component parts. The word morphology is from the Ancient Greek don, morphé, meaning form, among other important theorists of morphology are Lorenz Oken, Georges Cuvier, Étienne Geoffroy Saint-Hilaire, Richard Owen, Karl Gegenbaur and Ernst Haeckel. In English-speaking countries, the term molecular morphology has been used for time for describing the structure of compound molecules, such as polymers. Comparative Morphology is analysis of the patterns of the locus of structures within the plan of an organism. Functional Morphology is the study of the relationship between the structure and function of morphological features, experimental Morphology is the study of the effects of external factors upon the morphology of organisms under experimental conditions, such as the effect of genetic mutation. Anatomy is a branch of morphology that deals with the structure of organisms, most taxa differ morphologically from other taxa. Typically, closely related taxa differ much less than more distantly related ones, cryptic species are species which look very similar, or perhaps even outwardly identical, but are reproductively isolated. Conversely, sometimes unrelated taxa acquire a similar appearance as a result of convergent evolution or even mimicry, in addition, there can be morphological differences within a species, such as in Apoica flavissima where queens are significantly smaller than workers. A further problem with relying on morphological data is that what may appear, morphologically speaking, the significance of these differences can be examined through the use of allometric engineering in which one or both species are manipulated to phenocopy the other species. Invention and development of microscopy enable the observation of 3-D cell morphology with both spatial and temporal resolution. The dynamic processes of cell morphology which are controlled by a complex system play an important role in varied important biological process, such as immune. Comparative anatomy Insect morphology Morphometrics Neuromorphology Phenetics Phenotype Phenotypic plasticity Plant morphology
21.
Cell (biology)
–
The cell is the basic structural, functional, and biological unit of all known living organisms. A cell is the smallest unit of life that can replicate independently, the study of cells is called cell biology. Cells consist of cytoplasm enclosed within a membrane, which contains many such as proteins. Organisms can be classified as unicellular or multicellular, while the number of cells in plants and animals varies from species to species, humans contain more than 10 trillion cells. Most plant and animal cells are only under a microscope. The cell was discovered by Robert Hooke in 1665, who named the unit for its resemblance to cells inhabited by Christian monks in a monastery. Cells emerged on Earth at least 3.5 billion years ago, Cells are of two types, eukaryotic, which contain a nucleus, and prokaryotic, which do not. Prokaryotes are single-celled organisms, while eukaryotes can be either single-celled or multicellular, prokaryotic cells were the first form of life on Earth, characterised by having vital biological processes including cell signaling and being self-sustaining. They are simpler and smaller than eukaryotic cells, and lack membrane-bound organelles such as the nucleus, prokaryotes include two of the domains of life, bacteria and archaea. The DNA of a prokaryotic cell consists of a chromosome that is in direct contact with the cytoplasm. The nuclear region in the cytoplasm is called the nucleoid, most prokaryotes are the smallest of all organisms ranging from 0.5 to 2.0 µm in diameter. Though most prokaryotes have both a cell membrane and a wall, there are exceptions such as Mycoplasma and Thermoplasma which only possess the cell membrane layer. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, the cell wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and bursting from osmotic pressure due to a hypotonic environment, some eukaryotic cells also have a cell wall. Inside the cell is the region that contains the genome, ribosomes. The genetic material is found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular, linear bacterial plasmids have been identified in several species of spirochete bacteria, including members of the genus Borrelia notably Borrelia burgdorferi, which causes Lyme disease. Though not forming a nucleus, the DNA is condensed in a nucleoid, plasmids encode additional genes, such as antibiotic resistance genes
22.
Metabolism
–
Metabolism is the set of life-sustaining chemical transformations within the cells of living organisms. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, usually, breaking down releases energy and building up consumes energy. The chemical reactions of metabolism are organized into metabolic pathways, in one chemical is transformed through a series of steps into another chemical. Enzymes act as catalysts that allow the reactions to proceed more rapidly, enzymes also allow the regulation of metabolic pathways in response to changes in the cells environment or to signals from other cells. The metabolic system of a particular organism determines which substances it will find nutritious, for example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals. The speed of metabolism, the rate, influences how much food an organism will require. A striking feature of metabolism is the similarity of the metabolic pathways. These striking similarities in metabolic pathways are likely due to their appearance in evolutionary history. Most of the structures that make up animals, plants and microbes are made from three classes of molecule, amino acids, carbohydrates and lipids. These biochemicals can be joined together to make such as DNA and proteins. Proteins are made of amino acids arranged in a linear chain joined together by peptide bonds, many proteins are enzymes that catalyze the chemical reactions in metabolism. Other proteins have structural or mechanical functions, such as those that form the cytoskeleton, Proteins are also important in cell signaling, immune responses, cell adhesion, active transport across membranes, and the cell cycle. Lipids are the most diverse group of biochemicals and their main structural uses are as part of biological membranes both internal and external, such as the cell membrane, or as a source of energy. Lipids are usually defined as hydrophobic or amphipathic biological molecules but will dissolve in organic solvents such as benzene or chloroform, the fats are a large group of compounds that contain fatty acids and glycerol, a glycerol molecule attached to three fatty acid esters is called a triacylglyceride. Several variations on this structure exist, including alternate backbones such as sphingosine in the sphingolipids. Steroids such as cholesterol are another class of lipids. Carbohydrates are aldehydes or ketones, with hydroxyl groups attached. Carbohydrates are the most abundant biological molecules, and fill numerous roles, such as the storage and transport of energy, the basic carbohydrate units are called monosaccharides and include galactose, fructose, and most importantly glucose
23.
Biochemistry
–
Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to living organisms. By controlling information flow through biochemical signaling and the flow of energy through metabolism. Biochemistry is closely related to biology, the study of the molecular mechanisms by which genetic information encoded in DNA is able to result in the processes of life. Depending on the definition of the terms used, molecular biology can be thought of as a branch of biochemistry, or biochemistry as a tool with which to investigate. The chemistry of the cell depends on the reactions of smaller molecules. These can be inorganic, for water and metal ions, or organic, for example the amino acids. The mechanisms by which cells harness energy from their environment via chemical reactions are known as metabolism, the findings of biochemistry are applied primarily in medicine, nutrition, and agriculture. In medicine, biochemists investigate the causes and cures of diseases, in nutrition, they study how to maintain health and study the effects of nutritional deficiencies. In agriculture, biochemists investigate soil and fertilizers, and try to discover ways to improve crop cultivation, crop storage and pest control. However, biochemistry as a scientific discipline has its beginning sometime in the 19th century, or a little earlier. Gowland Hopkins on enzymes and the nature of biochemistry. The term biochemistry itself is derived from a combination of biology, the German chemist Carl Neuberg however is often cited to have coined the word in 1903, while some credited it to Franz Hofmeister. Then, in 1828, Friedrich Wöhler published a paper on the synthesis of urea and these techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle. Another significant historic event in biochemistry is the discovery of the gene and this part of biochemistry is often called molecular biology. In the 1950s, James D. Watson, Francis Crick, Rosalind Franklin, in 1958, George Beadle and Edward Tatum received the Nobel Prize for work in fungi showing that one gene produces one enzyme. In 1988, Colin Pitchfork was the first person convicted of murder with DNA evidence, mello received the 2006 Nobel Prize for discovering the role of RNA interference, in the silencing of gene expression. Around two dozen of the 92 naturally occurring elements are essential to various kinds of biological life. Most rare elements on Earth are not needed by life, while a few common ones are not used, most organisms share element needs, but there are a few differences between plants and animals
24.
Genotype
–
The genotype is the part of the genetic makeup of a cell, and therefore of an organism or individual, which determines a specific characteristic of that cell/organism/individual. Genotype is one of three factors that determine phenotype, the two being inherited epigenetic factors, and non-inherited environmental factors. An example of how genotype determines a characteristic is petal color in a pea plant, the genotype of an organism is the inherited map it carries within its genetic code. Not all organisms with the same genotype look or act the way because appearance. Likewise, not all organisms that look alike necessarily have the same genotype, ones genotype differs subtly from ones genomic sequence. So typically, one refers to a genotype with regard to a particular gene of interest and, in polyploid individuals. The genetic constitution of an organism is referred to as its genotype, any given gene will usually cause an observable change in an organism, known as the phenotype. The terms genotype and phenotype are distinct for at least two reasons, To distinguish the source of an observers knowledge, genotype and phenotype are not always directly correlated. Some genes only express a phenotype in certain environmental conditions. Conversely, some phenotypes could be the result of multiple genotypes, the genotype is commonly mixed up with the phenotype which describes the end result of both the genetic and the environmental factors giving the observed expression. A simple example to illustrate genotype as distinct from phenotype is the colour in pea plants. There are three available genotypes, PP, Pp, and pp, all three have different genotypes but the first two have the same phenotype as distinct from the third. A more technical example to illustrate genotype is the single nucleotide polymorphism or SNP, a SNP occurs when corresponding sequences of DNA from different individuals differ at one DNA base, for example where the sequence AAGCCTA changes to AAGCTTA. This contains two alleles, C and T. SNPs typically have three genotypes, denoted generically AA Aa and aa, in the example above, the three genotypes would be CC, CT and TT. Other types of marker, such as microsatellites, can have more than two alleles, and thus many different genotypes. The distinction between genotype and phenotype is commonly experienced when studying family patterns for certain diseases or conditions, for example. Due to the diploidy of humans, there are two alleles for any given gene and these alleles can be the same or different, depending on the individual. With a dominant allele, the offspring is guaranteed to inherit the trait in question irrespective of the second allele, in the case of an albino with a recessive allele, the phenotype depends upon the other allele
25.
Bioaccumulation
–
Bioaccumulation refers to the accumulation of substances, such as pesticides, or other chemicals in an organism. Bioaccumulation occurs when an organism absorbs a possibly toxic - substance at a faster than that at which the substance is lost by catabolism. Thus, the longer the biological half-life of a substance the greater the risk of chronic poisoning. Bioaccumulation, for example in fish, can be predicted by models, hypotheses for molecular size cutoff criteria for use as bioaccumulation potential indicators are not supported by data. Biotransformation can strongly modify bioaccumulation of chemicals in an organism, bioconcentration is a related but more specific term, referring to uptake and accumulation of a substance from water alone. By contrast, bioaccumulation refers to uptake from all sources combined An example of poisoning in the workplace can be seen from the phrase as mad as a hatter, other lipid-soluble poisons include tetraethyllead compounds, and DDT. These compounds are stored in the fat, and when the fatty tissues are used for energy. Strontium-90, part of the fallout from atomic bombs, is similar enough to calcium that it is utilized in osteogenesis. Naturally produced toxins can also bioaccumulate, one example is the tobacco hornworm, which concentrates nicotine to a toxic level in its body as it consumes tobacco plants. Poisoning of small consumers can be passed along the chain to affect the consumers later on. Other compounds that are not normally considered toxic can be accumulated to toxic levels in organisms and it was known by the native peoples of the Arctic that the livers of carnivores should not be eaten, but Arctic explorers have suffered Hypervitaminosis A from eating the bear livers. One notable example of this is the expedition of Sir Douglas Mawson, coastal fish and seabirds are often monitored for heavy metal bioaccumulation. In some eutrophic aquatic systems, biodilution can occur and this trend is a decrease in a contaminant with an increase in trophic level and is due to higher concentrations of algae and bacteria to dilute the concentration of the pollutant
26.
Lobaria pulmonaria
–
Its population has declined across Europe and L. pulmonaria is considered endangered in many lowland areas. The species has a history of use in medicines. It is a foliose lichen and its leaf-like thallus is green, leathery and lobed with a pattern of ridges, bright green under moist conditions, it becomes brownish and papery when dry. This species often has a fine layers of hairs, a tomentum, the cortex, the outer protective layer on the thallus surface, is roughly comparable to the epidermis of a green plant. The thallus is typically 5–15 centimetres in diameter, with individual lobes 1–3 centimetres wide, the asexual reproductive structures soredia and isidia are present on the thallus surface. Minute cephalodia—pockets of cyanobacteria—are often present on the surface of the thallus. Like other foliose lichens, the thallus is only attached to the surface on which it grows. The thallus contains internal structures known as cephalodia, characteristic of three-membered lichen symbioses involving two photobionts and these internal cephalodia, found between the ribs of the thallus surface, arise when blue-green algae on the thallus surface are enveloped during mycobiont growth. Blue-green cyanobacteria can fix nitrogen, enhancing nutrient availability for the lichen. The other photobiont of L. pulmonaria is the green algae Dictyochloropsis reticulata, L. pulmonaria has the ability to form both vegetative propagation and sexual propagules at an age of about 25 years. In sexual reproduction, the species produces small reddish-brown discs known as apothecia containing asci, based on studies of ascospore germination, it has been suggested that L. Dispersal by vegetative propagules has been determined as the predominant mode of reproduction in L. pulmonaria. In this method, the protruding propagules become dry and brittle during the regular wet/dry cycles of the lichen and these fragments may develop into new thalli, either at the same locale or at a new site after dispersal by wind or rain. This steps lead to an increase in pressure which eventually breaks through the cortex. Continued growth leads to these granules being pushed upwards and out of the thallus surface and it has a wide distribution in Europe, Asia, North America and Africa, preferring damp habitats with high rainfall, especially coastal areas. It is the most widely distributed and most common Lobaria species in North America, associated with old-growth forests, its presence and abundance may be used as an indicator of forest age, at least in the Interior Cedar-Hemlock biogeoclimatic zone in eastern British Columbia. It is also found in pasture-woodlands and it usually grows on the bark of broad-leaved trees such as oak, beech and maple but will also grow on rocks. In the laboratory, L. pulmonaria has been grown on nylon microfilaments, various environmental factors are thought to affect the distribution of L. pulmonaria, such as temperature, moisture, sunlight exposure, and levels of air pollution. Due to declining population, L. pulmonaria is considered to be rare or threatened in parts of the world
27.
Environmentalism
–
While environmentalism focuses more on the environmental and nature-related aspects of green ideology and politics, ecologism combines the ideology of social ecology and environmentalism. ‘Ecologism’ is more used in continental European languages while ‘environmentalism’ is more commonly used in English. For this reason, concepts such as an ethic, environmental ethics, biodiversity, ecology. The exact measures and outcomes of this balance is controversial and there are different ways for environmental concerns to be expressed in practice. Environmentalism and environmental concerns are represented by the color green. Environmentalism denotes a movement that seeks to influence the political process by lobbying, activism. The word was first coined in 1922, an environmentalist is a person who may speak out about our natural environment and the sustainable management of its resources through changes in public policy or individual behavior. In various ways, environmentalists and environmental organizations seek to give the world a stronger voice in human affairs. In general terms, environmentalists advocate the sustainable management of resources, in its recognition of humanity as a participant in ecosystems, the movement is centered around ecology, health, and human rights. A concern for environmental protection has recurred in diverse forms, in different parts of the world, for example, in Europe, King Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke had become a problem. The fuel was so common in England that this earliest of names for it was acquired because it could be carted away from some shores by the wheelbarrow. Earlier in the Middle East, the Caliph Abu Bakr in the 630s commanded his army to Bring no harm to the trees, nor burn them with fire, at the advent of steam and electricity the muse of history holds her nose and shuts her eyes. The origins of the movement lay in the response to increasing levels of smoke pollution in the atmosphere during the Industrial Revolution. An Alkali inspector and four sub-inspectors were appointed to curb this pollution, typically the highest priority went to water and air pollution. The Coal Smoke Abatement Society was formed in 1898 making it one of the oldest environmental NGOs and it was founded by artist Sir William Blake Richmond, frustrated with the pall cast by coal smoke. Although there were pieces of legislation, the Public Health Act 1875 required all furnaces and fireplaces to consume their own smoke. It also provided for sanctions against factories that emitted large amounts of black smoke, financial incentives were offered to householders to replace open coal fires with alternatives, or for those who preferred, to burn coke instead which produces minimal smoke. Smoke control areas were introduced in some towns and cities in which only smokeless fuels could be burnt, the act formed an important impetus to modern environmentalism, and caused a rethinking of the dangers of environmental degradation to peoples quality of life
28.
Moss
–
Mosses are small flowerless plants that typically grow in dense green clumps or mats, often in damp or shady locations. Although some species have conducting tissues, these are poorly developed. Mosses do not have seeds and after fertilisation develop sporophytes with unbranched stalks topped with single capsules containing spores and they are typically 0. 2–10 cm tall, though some species are much larger. Dawsonia, the tallest moss in the world, can grow to 50 cm in height, mosses are commonly confused with lichens, hornworts, and liverworts. Lichens may superficially look like mosses, and have names that include the word moss. This contrasts with the pattern in all plants, where the diploid sporophyte generation is dominant. Mosses are now classified on their own as the division Bryophyta, the main commercial significance of mosses is as the main constituent of peat, although they are also used for decorative purposes, such as in gardens and in the florist trade. Traditional uses of mosses included as insulation and for the ability to absorb liquids up to 20 times their weight, botanically, mosses are non-vascular plants in the land plant division Bryophyta. They are small plants that absorb water and nutrients mainly through their leaves and harvest carbon dioxide. They differ from plants in lacking water-bearing xylem tracheids or vessels. As in liverworts and hornworts, the gametophyte generation is the dominant phase of the life cycle. This contrasts with the pattern in all plants, where the diploid sporophyte generation is dominant. Mosses reproduce using spores, not seeds, and have no flowers, Moss gametophytes have stems which may be simple or branched and upright or prostrate. Their leaves are simple, usually only a layer of cells with no internal air spaces. They do not have roots, but have threadlike rhizoids that anchor them to their substrate. Mosses do not absorb water or nutrients from their substrate through their rhizoids and they can be distinguished from liverworts by their multi-cellular rhizoids. Spore-bearing capsules or sporangia of mosses are borne singly on long, unbranched stems, thereby distinguishing them from the polysporangiophytes, the spore-bearing sporophytes are short-lived and dependent on the gametophyte for water supply and nutrition. Also, in most mosses, the capsule enlarges and matures after its stalk elongates
29.
Lichen
–
A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi in a symbiotic relationship. The combined lichen has properties different from those of its component organisms, Lichens come in many colours, sizes, and forms. The properties are sometimes plant-like, but lichens are not plants, Lichens may have tiny, leafless branches, flat leaf-like structures, flakes that lie on the surface like peeling paint, or other growth forms. A macrolichen is a lichen that is either bush-like or leafy, here, macro and micro do not refer to size, but to the growth form. Common names for lichens may contain the word moss, and lichens may superficially look like and grow with mosses, Lichens do not have roots that absorb water and nutrients as plants do, but like plants, they produce their own food by photosynthesis. When they grow on plants, they do not live as parasites, Lichens occur from sea level to high alpine elevations, in many environmental conditions, and can grow on almost any surface. Lichens are abundant growing on bark, leaves, mosses, on other lichens and they grow on rock, walls, gravestones, roofs, exposed soil surfaces, and in the soil as part of a biological soil crust. Different kinds of lichens have adapted to survive in some of the most extreme environments on Earth, arctic tundra, hot dry deserts, rocky coasts and they can even live inside solid rock, growing between the grains. It is estimated that 6% of Earths land surface is covered by lichen, there are about 20,000 known species of lichens. Some lichens have lost the ability to reproduce sexually, yet continue to speciate, Lichens may be long-lived, with some considered to be among the oldest living things. They are among the first living things to grow on fresh rock exposed after an event such as a landslide, the long life-span and slow and regular growth rate of some lichens can be used to date events. In American English, lichen is pronounced the same as the verb liken, in British English, both this pronunciation and one rhyming with kitchen /ˈlɪtʃən/) are used. Lichens grow in a range of shapes and forms. The shape of a lichen is determined by the organization of the fungal filaments. The nonreproductive tissues, or vegetative body parts, is called the thallus, Lichens are grouped by thallus type, since the thallus is usually the most visually prominent part of the lichen. Thallus growth forms typically correspond to a few basic internal structure types, Common names for lichens often come from a growth form or color that is typical of a lichen genus. When a crustose lichen gets old, the center may start to crack up like old-dried paint, old-broken asphalt paving and this is called being rimose or areolate, and the island pieces separated by the cracks are called areolas. The areolas appear separated, but are connected by an underlying prothallus or hypothallus, when a crustose lichen grows from a center and appears to radiate out, it is called crustose placodioid
30.
Bark (botany)
–
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines, and shrubs, Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the bark and the outer bark. The inner bark, which in older stems is living tissue, the outer bark in older stems includes the dead tissue on the surface of the stems, along with parts of the innermost periderm and all the tissues on the outer side of the periderm. The outer bark on trees which lies external to the last formed periderm is also called the rhytidome, Bark has been used to make cloth, canoes, and ropes and used as a surface for paintings and map making. A number of plants are grown for their attractive or interesting bark colorations. What is commonly called bark includes a number of different tissues, Cork is an external, secondary tissue that is impermeable to water and gases, and is also called the phellem. The cork is produced by the cork cambium which is a layer of active cells which serve as a lateral meristem for the periderm. The cork cambium, which is called the phellogen, is normally only one cell layer thick. The phelloderm, which is not always present in all barks, is a layer of cells formed by, together, the phellem, phellogen and phelloderm constitute the periderm. Cork cell walls contain suberin, a substance which protects the stem against water loss, the invasion of insects into the stem. The cambium tissues, i. e. Phloem is a nutrient-conducting tissue composed of sieve tubes or sieve cells mixed with parenchyma, the cortex is the primary tissue of stems and roots. In stems the cortex is between the layer and the phloem, in roots the inner layer is not phloem. From the outside to the inside of a woody stem. The bark includes through, and is composed of periderm and phloem, as the stem ages and grows, changes occur that transform the surface of the stem into the bark. The epidermis is a layer of cells that cover the plant body, including the stems, leaves, flowers and fruits, in old stems the epidermal layer, cortex, and primary phloem become separated from the inner tissues by thicker formations of cork. Due to the cork layer these cells die because they do not receive water. This dead layer is the rough corky bark that forms around tree trunks, often a secondary covering called the periderm forms on small woody stems and many non woody plants, which is composed of cork, the cork cambium, and the phelloderm
31.
Dendrochronology
–
Dendrochronology is the scientific method of dating tree rings to the exact year they were formed in order to analyze atmospheric conditions during different periods in history. Dendrochronology is useful for determining the timing of events and rates of change in the environment and also in works of art and architecture, such as old panel paintings on wood, buildings and it is also used in radiocarbon dating to calibrate radiocarbon ages. New growth in trees occurs in a layer of cells near the bark, a trees growth rate changes in a predictable pattern throughout the year in response to seasonal climate changes, resulting in visible growth rings. Each ring marks a complete cycle of seasons, or one year, as of 2013, the oldest tree-ring measurements in the Northern Hemisphere extend back 13,900 years. Dendrochronology derives from Ancient Greek, δένδρον, meaning tree limb, χρόνος, meaning time, and -λογία, the Greek botanist Theophrastus first mentioned that the wood of trees has rings. In his Trattato della Pittura, Leonardo da Vinci was the first person to mention that trees form rings annually, in 1737, French investigators Henri-Louis Duhamel du Monceau and Georges-Louis Leclerc de Buffon examined the effect of growing conditions on the shape of tree rings. They found that in 1709, a severe winter produced a distinctly dark tree ring, the English polymath Charles Babbage proposed using dendrochronology to date the remains of trees in peat bogs or even in geological strata. During the latter half of the century, the scientific study of tree rings. In 1859, the German-American Jacob Kuechler used crossdating to examine oaks in order to study the record of climate in western Texas, in 1866, the German botanist, entomologist, and forester Julius Ratzeburg observed the effects on tree rings of defoliation caused by insect infestations. By 1882, this observation was already appearing in forestry textbooks, in the 1870s, the Dutch astronomer Jacobus C. Kapteyn was using crossdating to reconstruct the climates of the Netherlands, in 1881, the Swiss-Austrian forester Arthur von Seckendorff-Gudent was using crossdating. From 1869 to 1901, Robert Hartig, a German professor of forest pathology, wrote a series of papers on the anatomy, in 1892, the Russian physicist Fedor Nikiforovich Shvedov wrote that he had used patterns found in tree rings to predict droughts in 1882 and 1891. During the first half of the 20th century, the astronomer A. E. Douglass founded the Laboratory of Tree-Ring Research at the University of Arizona. Growth rings, also referred to as tree rings or annual rings, growth rings are the result of new growth in the vascular cambium, a layer of cells near the bark that is classified as a lateral meristem, this growth in diameter is known as secondary growth. Visible rings result from the change in speed through the seasons of the year, thus, critical for the title method. If the bark of the tree has been removed in a particular area, the rings are more visible in temperate zones, where the seasons differ more markedly. The inner portion of a ring is formed early in the growing season, when growth is comparatively rapid and is known as early wood. Many trees in temperate zones make one growth ring each year, hence, for the entire period of a trees life, a year-by-year record or ring pattern is formed that reflects the age of the tree and the climatic conditions in which the tree grew
32.
Leaf
–
A leaf is an organ of a vascular plant and is the principal lateral appendage of the stem. The leaves and stem together form the shoot, Leaves are collectively referred to as foliage, as in autumn foliage. Although leaves can be seen in different shapes, sizes and textures, typically a leaf is a thin, dorsiventrally flattened organ, borne above ground. Most leaves have distinctive upper surface and lower surface that differ in colour, hairiness, broad, flat leaves with complex venation are known as megaphylls and the species that bear them, the majority, as broad-leaved or megaphyllous plants. In others, such as the clubmosses, with different evolutionary origins, some leaves, such as bulb scales are not above ground, and in many aquatic species the leaves are submerged in water. Succulent plants often have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls, furthermore, several kinds of leaf-like structures found in vascular plants are not totally homologous with them. Examples include flattened plant stems called phylloclades and cladodes, and flattened leaf stems called phyllodes which differ from both in their structure and origin. Many structures of plants, such as the phyllids of mosses and liverworts and even of some foliose lichens. Leaves are the most important organs of most vascular plants and these are then further processed by chemical synthesis into more complex organic molecules such as cellulose, the basic structural material in plant cell walls. The plant must therefore bring these three together in the leaf for photosynthesis to take place. Once sugar has been synthesized, it needs to be transported to areas of growth such as the plant shoots and roots. Vascular plants transport sucrose in a tissue called the phloem. The phloem and xylem are parallel to each other but the transport of materials is usually in opposite directions. Within the leaf these vascular systems branch to form veins which supply as much as the leaf as possible and they are arranged on the plant so as to expose their surfaces to light as efficiently as possible without shading each other, but there are many exceptions and complications. For instance plants adapted to windy conditions may have pendent leaves, such as in many willows, the flat, or laminar, shape also maximises thermal contact with the surrounding air, promoting cooling. Functionally, in addition to photosynthesis the leaf is the site of transpiration and guttation. Many gymnosperms have thin needle-like or scale-like leaves that can be advantageous in cold climates with frequent snow and these are interpreted as reduced from megaphyllous leaves of their Devonian ancestors. For xerophytes the major constraint is not light flux or intensity, some window plants such as Fenestraria species and some Haworthia species such as Haworthia tesselata and Haworthia truncata are examples of xerophytes. and Bulbine mesembryanthemoides
33.
Algae
–
Algae is an informal term for a large, diverse group of photosynthetic organisms which are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular genera, such as Chlorella and the diatoms, to forms, such as the giant kelp. Most are aquatic and autotrophic and lack many of the cell and tissue types, such as stomata, xylem, and phloem. No definition of algae is generally accepted, one definition is that algae have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells. Some authors exclude all prokaryotes thus do not consider cyanobacteria as algae, Algae constitute a polyphyletic group since they do not include a common ancestor, and although their plastids seem to have a single origin, from cyanobacteria, they were acquired in different ways. Green algae are examples of algae that have primary chloroplasts derived from endosymbiotic cyanobacteria, diatoms and brown algae are examples of algae with secondary chloroplasts derived from an endosymbiotic red alga. Algae exhibit a range of reproductive strategies, from simple asexual cell division to complex forms of sexual reproduction. Algae lack the various structures that characterize land plants, such as the phyllids of bryophytes, rhizoids in nonvascular plants, and the roots, leaves, and other organs found in tracheophytes. Most are phototrophic, although some are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some other heterotrophic organisms, such as the apicomplexans, are derived from cells whose ancestors possessed plastids. Fossilized filamentous algae from the Vindhya basin have been dated back to 1.6 to 1.7 billion years ago, the singular alga is the Latin word for seaweed and retains that meaning in English. Although some speculate that it is related to Latin algēre, be cold, a more likely source is alliga, binding, entwining. The Ancient Greek word for seaweed was φῦκος, which could mean either the seaweed or a red dye derived from it, the Latinization, fūcus, meant primarily the cosmetic rouge. It could be any color, black, red, green, accordingly, the modern study of marine and freshwater algae is called either phycology or algology, depending on whether the Greek or Latin root is used. The name Fucus appears in a number of taxa, most algae contain chloroplasts that are similar in structure to cyanobacteria. Chloroplasts contain circular DNA like that in cyanobacteria and presumably represent reduced endosymbiotic cyanobacteria, however, the exact origin of the chloroplasts is different among separate lineages of algae, reflecting their acquisition during different endosymbiotic events. The table below describes the composition of the three groups of algae. Their lineage relationships are shown in the figure in the upper right, many of these groups contain some members that are no longer photosynthetic
34.
Conservation biology
–
It is an interdisciplinary subject drawing on natural and social sciences, and the practice of natural resource management. The conservation ethic is based on the findings of conservation biology, wilcox and Michael E. Soulé with a group of leading university and zoo researchers and conservationists including Kurt Benirschke, Sir Otto Frankel, Thomas E. Lovejoy, and Jared M. Diamond. The meeting was prompted by the concern over deforestation, disappearing species. Conservation biology and the concept of biological diversity emerged together, helping crystallize the modern era of conservation science, the inherent multidisciplinary basis for conservation biology has led to new subdisciplines including conservation social science, conservation behavior and conservation physiology. It stimulated further development of genetics which Otto Frankel had originated first but is now often considered a subdiscipline as well. The rapid decline of established biological systems around the means that conservation biology is often referred to as a Discipline with a deadline. Conservation biology is tied closely to ecology in researching the ecology of rare or endangered species. Conservation biologists work in the field and office, in government, universities, non-profit organizations, the topics of their research are diverse, because this is an interdisciplinary network with professional alliances in the biological as well as social sciences. Those dedicated to the cause and profession advocate for a response to the current biodiversity crisis based on morals, ethics. Conscious efforts to conserve and protect global biodiversity are a recent phenomenon, natural resource conservation, however, has a history that extends prior to the age of conservation. Resource ethics grew out of necessity through direct relations with nature and this social dilemma with respect to natural resource management is often called the Tragedy of the Commons. From this principle, conservation biologists can trace communal resource based ethics throughout cultures as a solution to communal resource conflict. For example, the Alaskan Tlingit peoples and the Haida of the Pacific Northwest had resource boundaries, rules and these rules were guided by clan elders who knew lifelong details of each river and stream they managed. There are numerous examples in history where cultures have followed rules, rituals, Conservation ethics are also found in early religious and philosophical writings. There are examples in the Tao, Shinto, Hindu, Islamic, in the bible, through Moses, God commanded to let the land rest from cultivation every seventh year. Before the 18th century, however, much of European culture considered it a view to admire nature. Wilderness was denigrated while agricultural development was praised, however, as early as AD680 a wildlife sanctuary was founded on the Farne Islands by St Cuthbert in response to his religious beliefs. Natural history was a preoccupation in the 18th century, with grand expeditions
35.
Air pollution
–
Air pollution occurs when harmful substances including particulates and biological molecules are introduced into Earths atmosphere. It may cause diseases, allergies or death in humans, it may cause harm to other living organisms such as animals and food crops. Human activity and natural processes can both generate air pollution, indoor air pollution and poor urban air quality are listed as two of the worlds worst toxic pollution problems in the 2008 Blacksmith Institute Worlds Worst Polluted Places report. According to the 2014 WHO report, air pollution in 2012 caused the deaths of around 7 million people worldwide, an air pollutant is a substance in the air that can have adverse effects on humans and the ecosystem. The substance can be particles, liquid droplets, or gases. A pollutant can be of natural origin or man-made, pollutants are classified as primary or secondary. Primary pollutants are usually produced from a process, such as ash from a volcanic eruption, other examples include carbon monoxide gas from motor vehicle exhaust, or the sulfur dioxide released from factories. Secondary pollutants are not emitted directly, rather, they form in the air when primary pollutants react or interact. Ground level ozone is a prominent example of a secondary pollutant, some pollutants may be both primary and secondary, they are both emitted directly and formed from other primary pollutants. Substances emitted into the atmosphere by human activity include, Carbon dioxide - Debate continues over whether carbon dioxide should be classified as an atmospheric pollutant, because of its role as a greenhouse gas it has been described as the leading pollutant and the worst climate pollution. Against this it is argued that carbon dioxide is a component of the atmosphere, essential for plant life. This question of terminology has practical effects, for example as determining whether the U. S. Clean Air Act is deemed to regulate CO2 emissions, CO2 increase in earths atmosphere has been accelerating. Sulfur oxides - particularly sulfur dioxide, a compound with the formula SO2. SO2 is produced by volcanoes and in industrial processes. Coal and petroleum often contain sulfur compounds, and their combustion generates sulfur dioxide, further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain. This is one of the causes for concern over the impact of the use of these fuels as power sources. Nitrogen oxides - Nitrogen oxides, particularly nitrogen dioxide, are expelled from high temperature combustion and they can be seen as a brown haze dome above or a plume downwind of cities. Nitrogen dioxide is a compound with the formula NO2
36.
Nitrogen oxide
–
In addition, there are several anions of nitrogen oxides. The most stable of these is the anion, Nitrate, trioxonitrate ion but other nitrogen oxoanions include hyponitrite, nitrite, peroxonitrite, trioxodinitrate. In atmospheric chemistry, air pollution, and related fields, nitrogen oxides refers specifically to NOx, only the first three of these compounds can be isolated at room temperature. N2O3, N2O4, and N2O5 all decompose rapidly at room temperature, nO3, N4O, and N3 are very reactive. N2O is stable and rather unreactive at room temperature, while NO and NO2 are quite reactive, NOx refers to NO and NO2. They are produced during combustion, especially at high temperature and these two chemicals are important trace species in Earths atmosphere. CH3O2 is just one example of many partly oxidised organic molecules that can react with NO to form NO2 and these reactions are rather fast, so NO and NO2 tend to cycle, but the sum of their concentration tends to remain fairly constant. Because of this cycling, it is convenient to think of the two chemicals as a group, hence the term NOx, in addition to acting as a main precursor for tropospheric ozone, NOx is also harmful to human health in its own right. NOx may react with water to make nitric acid, which may end up in the soil, where it makes nitrate, nitrogen oxide sensor Sulfur nitrides, which are valence isoelectronic with nitrogen oxides
37.
Genetic engineering
–
Genetic engineering, also called genetic modification, is the direct manipulation of an organisms genome using biotechnology. It is a set of used to change the genetic makeup of cells, including the transfer of genes within. Genes may be removed, or knocked out, using a nuclease, gene targeting is a different technique that uses homologous recombination to change an endogenous gene, and can be used to delete a gene, remove exons, add a gene, or introduce point mutations. An organism that is generated through genetic engineering is considered to be a modified organism. The first GMOs were bacteria generated in 1973 and GM mice in 1974, insulin-producing bacteria were commercialized in 1982 and genetically modified food has been sold since 1994. GloFish, the first GMO designed as a pet, was first sold in the United States in December 2003, Genetic engineering techniques have been applied in numerous fields including research, agriculture, industrial biotechnology, and medicine. However the European Commission has also defined genetic engineering broadly as including selective breeding, cloning and stem cell research, although not considered genetic engineering, are closely related and genetic engineering can be used within them. Synthetic biology is a discipline that takes genetic engineering a step further by introducing artificially synthesized material from raw materials into an organism. If genetic material from another species is added to the host, if genetic material from the same species or a species that can naturally breed with the host is used the resulting organism is called cisgenic. Genetic engineering can also be used to remove material from the target organism. In Europe genetic modification is synonymous with genetic engineering while within the United States of America it can refer to conventional breeding methods. The Canadian regulatory system is based on whether a product has novel features regardless of method of origin, within the scientific community, the term genetic engineering is not commonly used, more specific terms such as transgenic are preferred. Plants, animals or micro organisms that have changed through genetic engineering are termed genetically modified organisms or GMOs, bacteria were the first organisms to be genetically modified. Plasmid DNA containing new genes can be inserted into the bacterial cell and these genes can code for medicines or enzymes that process food and other substrates. Plants have been modified for insect protection, herbicide resistance, virus resistance, enhanced nutrition, tolerance to environmental pressures, most commercialised GMOs are insect resistant and/or herbicide tolerant crop plants. Genetically modified animals have used for research, model animals. The genetically modified animals include animals with genes knocked out, increased susceptibility to disease, hormones for extra growth, humans have altered the genomes of species for thousands of years through selective breeding, or artificial selection as contrasted with natural selection, and more recently through mutagenesis. Genetic engineering as the manipulation of DNA by humans outside breeding
38.
Toxicity
–
Toxicity is the degree to which a substance can damage an organism. Toxicity can refer to the effect on an organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism. By extension, the word may be used to describe toxic effects on larger and more complex groups. Sometimes the word is more or less synonymous with poisoning in everyday usage, toxicity is species-specific, making cross-species analysis problematic. Newer paradigms and metrics are evolving to bypass animal testing, while maintaining the concept of toxicity endpoints, disease-causing microorganisms and parasites are toxic in a broad sense, but are generally called pathogens rather than toxicants. The biological toxicity of pathogens can be difficult to measure because the dose may be a single organism. Theoretically one virus, bacterium or worm can reproduce to cause a serious infection, in some cases, e. g. cholera, the disease is chiefly caused by a nonliving substance secreted by the organism, rather than the organism itself. Such nonliving biological toxicants are generally called toxins if produced by a microorganism, plant, or fungus, Physical toxicants are substances that, due to their physical nature, interfere with biological processes. Examples include coal dust, asbestos fibers or finely divided silicon dioxide, corrosive chemicals possess physical toxicity because they destroy tissues, but theyre not directly poisonous unless they interfere directly with biological activity. Water can act as a physical toxicant if taken in high doses because the concentration of vital ions decreases dramatically if theres too much water in the body. Asphyxiant gases can be considered physical toxicants because they act by displacing oxygen in the environment but they are inert, as already mentioned, radiation can have a toxic effect on organisms. Toxicity can be measured by its effects on the target, one such measure is the LD50. When such data does not exist, estimates are made by comparison to known similar toxic things, then, safety factors are added to account for uncertainties in data and evaluation processes. Similarly, an extra protection factor may be used for individuals believed to be susceptible to toxic effects such as in pregnancy or with certain diseases. Obviously, this approach is approximate, but such protection factors are deliberately very conservative. In addition, it is possible that a single cell transformed into a cell is all it takes to develop the full effect. Common mixtures include gasoline, cigarette smoke, and industrial waste, even more complex are situations with more than one type of toxic entity, such as the discharge from a malfunctioning sewage treatment plant, with both chemical and biological agents. The preclinical toxicity testing on various biological systems reveals the species-, organ-, the toxicity of substances can be observed by studying the accidental exposures to a substance in vitro studies using cells/ cell lines in vivo exposure on experimental animals
39.
Population genetics
–
Julian Huxley invented the term in his 1942 book, Evolution, The Modern Synthesis. The modern synthesis solved difficulties and confusions caused by the specialisation, at its heart was the question of whether Mendelian genetics could be reconciled with gradual evolution by means of natural selection. A second issue was whether the changes of macroevolution seen by palaeontologists could be explained by changes seen in the microevolution of local populations. The synthesis included evidence from geneticists who studied populations in the field and these studies were crucial to evolutionary theory. The synthesis drew together ideas from several branches of biology which had separated, particularly genetics, cytology, systematics, botany. The modern synthesis of the early 20th century bridged the gap between the work of geneticists and naturalists, and paleontologists. It states that, All evolutionary phenomena can be explained in a way consistent with known genetic mechanisms, Evolution is gradual, small genetic changes regulated by natural selection accumulate over long periods. Discontinuities amongst species are explained as originating gradually through geographical separation and extinction and this theory contrasts with the saltation theory of William Bateson. Natural selection is by far the main mechanism of change, even slight advantages are important when continued, the object of selection is the phenotype in its surrounding environment. The role of genetic drift is equivocal, though strongly supported initially by Dobzhansky, it was downgraded later as results from ecological genetics were obtained. Thinking in terms of populations, rather than individuals, is primary, in palaeontology, the ability to explain historical observations by extrapolation from microevolution to macroevolution is proposed. Historical contingency means explanations at different levels may exist, gradualism does not mean constant rate of change. The idea that speciation occurs after populations are reproductively isolated has been much debated, in plants, polyploidy must be included in any view of speciation. Formulations such as evolution consists primarily of changes in the frequencies of alleles between one generation and another were proposed rather later. The traditional view is that biology played little part in the synthesis. In the 19th and early 20th centuries, variations of Lamarckism, orthogenesis, also, Darwin did not offer a precise explanation of how new species arise. Weismann and Wallace rejected the Lamarckian idea of inheritance of acquired characteristics, weismann was translated into English, and though he was influential, it took many years for the full significance of his work to be appreciated. Gregor Mendels work was re-discovered by Hugo de Vries and Carl Correns in 1900, news of this reached William Bateson in England, who reported on the paper during a presentation to the Royal Horticultural Society in May 1900
40.
Population decline
–
Population decline can refer to the decline in population of any organism, but this article refers to population decline in humans. It is a term used to describe any great reduction in a human population. Sometimes known as depopulation, population decline is the reduction over time in a regions population, the decline can be caused by several factors including sub-replacement fertility, heavy emigration, disease, famine, and war. History is replete with examples of large-scale depopulations, many wars, for example, have been accompanied by significant depopulations. Before the 20th century, population decline was observed due to disease. In modern times, the AIDS epidemic caused declines in the population of some African countries, less frequently, population declines are caused by genocide or mass execution, for example, in the 1970s, the population of Cambodia declined because of wide-scale executions by the Khmer Rouge. Sometimes the term underpopulation is applied to an economic system. Underpopulation is usually defined as a state in which a population has declined too much to support its current economic system. An example would be if retirees were supported through a security system which does not invest savings. In this case, the younger generation may not be able to support the older generation, since the dire predictions of coming population overshoot in the 1960s and 70s, more couples have tended to choose to have fewer children. Today, emigration, sub-replacement fertility and high rates in the former Soviet Union. However, governments can influence the speed of the decline, including measures to halt, such measures include pro-birth policies and subsidies, media influence, immigration, bolstering healthcare and laws aimed at reducing death rates. Such is the case in Russia, Armenia, and many Western European nations who have used immigration, therefore, although the long-term trend may be for greater population decline, short term trends may slow the decline or even reverse it, creating seemingly conflicting statistical data. A great example of changing trends occurring over a century is Ireland, statistical data, especially comparing only two sets of figures, can show an incorrect population trend. A nations population could be increasing, but an event could have resulted in decline. Political instability can render an area within a nations count unreliable for comparison, a common misreading is due to time. Therefore, numerous sets of statistics should be interpreted to get an idea of a trend, a number of nations today face population decline. Countries rapidly approaching long-term population declines include Spain, Cuba, Uruguay, Denmark, Finland, Russia also faces long-term population decline, although the trend has been stalled through a reversal of stagnant birth rates
41.
Overpopulation (biology)
–
Overpopulation occurs when a species population exceeds the carrying capacity of its ecological niche. It can result from an increase in births, a decline in the mortality rate, overpopulation can also be very devastating to a population once the death rates increase and the population growth declines and comes back to around the carrying capacity. An example is the human population, in the wilderness, the problem of overpopulation is often solved by a growth in the population of predators. Predators tend to look for signs of weakness in their prey and this has the effect of controlling the prey population and ensuring its evolution in favor of genetic characteristics that render it less vulnerable to predation. In the absence of predators, species are bound by the resources they can find in their environment, an abundant supply of resources can produce a population boom that ends up with more individuals than the environment can support. In this case, starvation, thirst and sometimes violent competition for scarce resources may affect a sharp reduction in population in a short lapse. Lemmings, as well as species of rodents, are known to have such cycles of rapid population growth. Some species seem to have a measure of self-control, by which individuals refrain from mating when they find themselves in a crowded environment and this voluntary abstinence may be induced by stress or by pheromones. In an ideal situation, when animal populations grow, so do the number of predators feed on that particular animal. Animals that have birth defects or weak genes are unable to compete for food with stronger, healthier animals, in reality, an animal that is not native to an environment may have advantages over the native ones, such being unsuitable for the local predators. If left uncontrolled, such an animal can quickly overpopulate and ultimately destroy its environment, in Australia, when rabbits were introduced by European immigrants, they bred out of control and ate the farm crops and food that both native and farm animals needed. Farmers hunted the rabbits, and also brought cats into guard against rabbits and rats and these introduced cats created another problem, becoming predators of local species. Examples of locust overpopulation caused by natural cyclic variations include, the 2004 Locust Outbreak in West, the rate of population growth has been declining since the 1980s. As of 2011, the United Nations Population Division projected that global growth will nearly halt by 2050. However, some contend that this projection is off. Most contemporary estimates for the capacity of the Earth under existing conditions are between 4 billion and 16 billion. In 2013 the human population was 7 billion, by 2025 the world population is expected to grow an additional 1 billion, depending on which estimate of overpopulation is used, human overpopulation may or may not have already occurred. However, some believe that waste and over-consumption, especially by wealthy nations, is putting more strain on the environment than overpopulation, animal population control Culling Cascade effect Overexploitation
42.
Stress (biology)
–
Physiological or biological stress is an organisms response to a stressor such as an environmental condition. Stress is the method of reacting to a challenge. Stimuli that alter an organisms environment are responded to by multiple systems in the body, the autonomic nervous system and hypothalamic-pituitary-adrenal axis are two major systems that respond to stress. The second major physiological stress, the HPA axis regulates the release of cortisol, the SAM and HPA axes are regulated by a wide variety of brain regions, including the limbic system, prefrontal cortex, amygdala, hypothalamus, and stria terminalis. Through these mechanisms, stress can alter memory functions, reward, immune function, metabolism, definitions of stress differ, however, one system proposed by Elliot and Eisdorfer suggests five types of stress. The five types of stress are labeled acute time limited stressors, brief naturalistic stressors, stressful event sequence, chronic stressors, acute time limited stressors involve a short term challenge, while brief naturalistic stressors involve an event that is normal but nevertheless challenging. Stressful event sequences are a stressor that occur, and continue to yield stress into the immediate future, chronic stressors are stressors that involve exposure to a long-term stressor. A distant stressor is a stressor that isnt immediate, there is likely a connection between stress and illness. Theories of the stress–illness link suggest that both acute and chronic stress can cause illness, and several studies have suggested such a link, according to these studies, both acute and chronic stress can lead to changes in behavior and in physiology. Behavioral changes can include smoking, changes in eating habits and physical activity, physiological changes can include changes in sympathetic activation or HPA activity, and immunological function. However, there is variability in the link between stress and illness. The HPA axis regulates many bodily functions, both behavioral and physiological, through the release of glucocorticoid hormones, the HPA axis activity varies according to the circadian rhythm, with a spike in the morning. The axis involves the release of corticotropin releasing hormone and vasopressin from the hypothalamus which stimulates the pituitary to secrete ACTH, ACTH may then stimulate the adrenal glands to secrete cortisol. The HPA axis is subject to feedback regulation as well. The release of CRH and VP are regulated by descending glutaminergic and GABAergic pathways from the amygdala, increased cortisol usually acts to increase blood glucose, blood pressure, and surpasses lysosomal, and immunological activity. Under other circumstances, however, the activity may differ, increased cortisol also favors habit based learning, by favoring memory consolidation of emotional memories. Selye demonstrated that stress decreases adaptability of an organism and proposed to describe the adaptability as a special resource, in recent works, it is considered as an internal coordinate on the dominant path in the model of adaptation. Stress can make the more susceptible to physical illnesses like the common cold
. PMID 24621307.