Energy flow (ecology)
In ecology, energy flow called the calorific flow, refers to the flow of energy through a food chain, is the focus of study in ecological energetics. In an ecosystem, ecologists seek to quantify the relative importance of different component species and feeding relationships. A general energy flow scenario follows: Solar energy is fixed by the photoautotrophs, called primary producers, like green plants. Primary consumers absorb most of the stored energy in the plant through digestion, transform it into the form of energy they need, such as adenosine triphosphate, through respiration. A part of the energy received by primary consumers, herbivores, is converted to body heat, radiated away and lost from the system; the loss of energy through body heat is far greater in warm-blooded animals, which must eat much more than those that are cold-blooded. Energy loss occurs in the expulsion of undigested food by excretion or regurgitation. Secondary consumers, carnivores consume the primary consumers, although omnivores consume primary producers.
Energy, used by the primary consumers for growth and storage is thus absorbed into the secondary consumers through the process of digestion. As with primary consumers, secondary consumers convert this energy into a more suitable form during respiration. Again, some energy is lost from the system, since energy which the primary consumers had used for respiration and regulation of body temperature cannot be utilized by the secondary consumers. Tertiary consumers, which may or may not be apex predators consume the secondary consumers, with some energy passed on and some lost, as with the lower levels of the food chain. A final link in the food chain are decomposers which break down the organic matter of the tertiary consumers and release nutrients into the soil, they break down plants and carnivores that were not eaten by organisms higher on the food chain, as well as the undigested food, excreted by herbivores and carnivores. Saprotrophic bacteria and fungi are decomposers, play a pivotal role in the nitrogen and carbon cycles.
The energy is passed on from trophic level to trophic level and each time about 90% of the energy is lost, with some being lost as heat into the environment and some being lost as incompletely digested food. Therefore, primary consumers get about 10% of the energy produced by autotrophs, while secondary consumers get 1% and tertiary consumers get 0.1%. This means the top consumer of a food chain receives the least energy, as a lot of the food chain's energy has been lost between trophic levels; this loss of energy at each level limits typical food chains to only four to six links. Ecological energetics appears to have grown out of the Age of Enlightenment and the concerns of the Physiocrats, it began in the works of Sergei Podolinsky in the late 1800s, subsequently was developed by the Soviet ecologist Vladmir Stanchinsky, the Austro-American Alfred J. Lotka, American limnologists, Raymond Lindeman and G. Evelyn Hutchinson, it underwent substantial development by Howard T. Odum and was applied by systems ecologists, radiation ecologists.
Ecological stoichiometry Energy S. Podolinsky. "Socialism and the Unity of Physical Forces". Organization & Environment. 17: 61–75. Doi:10.1177/1086026603262092. D. R. Weiner. Models of Nature: Ecology and Cultural Revolution in Soviet Russia. U. S.: University of Pittsburgh Press
In biology, homology is the existence of shared ancestry between a pair of structures, or genes, in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats, the arms of primates, the front flippers of whales and the forelegs of dogs and horses are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor; the term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matching primordia in successive segments of the same animal, are serially homologous.
Examples include the legs of a centipede, the maxillary palp and labial palp of an insect, the spinous processes of successive vertebrae in a vertebral column. Male and female reproductive organs are homologous if they develop from the same embryonic tissue, as do the ovaries and testicles of mammals including humans. Sequence homology between protein or DNA sequences is defined in terms of shared ancestry. Two segments of DNA can have shared ancestry because of either a speciation event or a duplication event. Homology among proteins or DNA is inferred from their sequence similarity. Significant similarity is strong evidence that two sequences are related by divergent evolution from a common ancestor. Alignments of multiple sequences are used to discover the homologous regions. Homology remains controversial in animal behaviour, but there is suggestive evidence that, for example, dominance hierarchies are homologous across the primates. Homology was noticed by Aristotle, was explicitly analysed by Pierre Belon in his 1555 Book of Birds, where he systematically compared the skeletons of birds and humans.
The pattern of similarity was interpreted as part of the static great chain of being through the mediaeval and early modern periods: it was not seen as implying evolutionary change. In the German Naturphilosophie tradition, homology was of special interest as demonstrating unity in nature. In 1790, Goethe stated his foliar theory in his essay "Metamorphosis of Plants", showing that flower part are derived from leaves; the serial homology of limbs was described late in the 18th century. The French zoologist Etienne Geoffroy Saint-Hilaire showed in 1818 in his theorie d'analogue that structures were shared between fishes, reptiles and mammals; when Geoffroy went further and sought homologies between Georges Cuvier's embranchements, such as vertebrates and molluscs, his claims triggered the 1830 Cuvier-Geoffroy debate. Geoffroy stated the principle of connections, namely that what is important is the relative position of different structures and their connections to each other; the Estonian embryologist Karl Ernst von Baer stated what are now called von Baer's laws in 1828, noting that related animals begin their development as similar embryos and diverge: thus, animals in the same family are more related and diverge than animals which are only in the same order and have fewer homologies.
Von Baer's theory recognises that each taxon has distinctive shared features, that embryonic development parallels the taxonomic hierarchy: not the same as recapitulation theory. The term "homology" was first used in biology by the anatomist Richard Owen in 1843 when studying the similarities of vertebrate fins and limbs, defining it as the "same organ in different animals under every variety of form and function", contrasting it with the matching term "analogy" which he used to describe different structures with the same function. Owen codified 3 main criteria for determining if features were homologous: position and composition. In 1859, Charles Darwin explained homologous structures as meaning that the organisms concerned shared a body plan from a common ancestor, that taxa were branches of a single tree of life; the word homology, coined in about 1656, is derived from the Greek ὁμόλογος homologos from ὁμός homos "same" and λόγος logos "relation". Biological structures or sequences in different taxa are homologous if they are derived from a common ancestor.
Homology thus implies divergent evolution. For example, many insects possess two pairs of flying wings. In beetles, the first pair of wings has evolved into a pair of hard wing covers, while in Dipteran flies the second pair of wings has evolved into small halteres used for balance; the forelimbs of ancestral vertebrates have evolved into the front flippers of whales, the wings of birds, the running forelegs of dogs and horses, the short forelegs of frogs and lizards, the grasping hands of primates including humans. The same major forearm bones are found in fossils of lobe-finned fish such as Eusthenopteron; the opposite of homologous organs are analogous organs which do similar jobs in two taxa that were not present in their most recent common ancestor but rather evolved separately. For example, the wings of insects and birds evolved independently in separated groups, converged functionally to support powered flight, so they are analogous; the wings of a sycamore maple seed and the wings of a bird are analogous but not homologous, as they develop from quite different structures.
A structure can be only analogous at another. Pterosaur and bat wings are analogous as wings
Habitat destruction is the process by which natural habitat becomes incapable of supporting its native species. In this process, the organisms that used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity is for the purpose of harvesting natural resources for industrial production and urbanization. Clearing habitats for agriculture is the principal cause of habitat destruction. Other important causes of habitat destruction include mining, logging and urban sprawl. Habitat destruction is ranked as the primary cause of species extinction worldwide, it is a process of natural environmental change that may be caused by habitat fragmentation, geological processes, climate change or by human activities such as the introduction of invasive species, ecosystem nutrient depletion, other human activities. The terms habitat loss and habitat reduction are used in a wider sense, including loss of habitat from other factors, such as water and noise pollution. In the simplest term, when a habitat is destroyed, the plants and other organisms that occupied the habitat have a reduced carrying capacity so that populations decline and extinction becomes more likely.
The greatest threat to organisms and biodiversity is the process of habitat loss. Temple found that 82% of endangered bird species were threatened by habitat loss. Most amphibian species are threatened by habitat loss, some species are now only breeding in modified habitat. Endemic organisms with limited ranges are most affected by habitat destruction because these organisms are not found anywhere else within the world, thus have less chance of recovering. Many endemic organisms have specific requirements for their survival that can only be found within a certain ecosystem, resulting in their extinction. Extinction may take place long after the destruction of habitat, a phenomenon known as extinction debt. Habitat destruction can decrease the range of certain organism populations; this can result in the reduction of genetic diversity and the production of infertile youths, as these organisms would have a higher possibility of mating with related organisms within their population, or different species.
One of the most famous examples is the impact upon China's giant panda, once found across the nation. Now it is only found in fragmented and isolated regions in the southwest of the country, as a result of widespread deforestation in the 20th century. Biodiversity hotspots are chiefly tropical regions that feature high concentrations of endemic species and, when all hotspots are combined, may contain over half of the world’s terrestrial species; these hotspots are suffering from habitat destruction. Most of the natural habitat on islands and in areas of high human population density has been destroyed. Islands suffering extreme habitat destruction include New Zealand, the Philippines, Japan. South and East Asia — China, Malaysia and Japan — and many areas in West Africa have dense human populations that allow little room for natural habitat. Marine areas close to populated coastal cities face degradation of their coral reefs or other marine habitat; these areas include the eastern coasts of Asia and Africa, northern coasts of South America, the Caribbean Sea and its associated islands.
Regions of unsustainable agriculture or unstable governments, which may go hand-in-hand experience high rates of habitat destruction. Central America, Sub-Saharan Africa, the Amazonian tropical rainforest areas of South America are the main regions with unsustainable agricultural practices and/or government mismanagement. Areas of high agricultural output tend to have the highest extent of habitat destruction. In the U. S. less than 25 % of native vegetation remains in many parts of the Midwest. Only 15% of land area remains unmodified by human activities in all of Europe. Tropical rainforests have received most of the attention concerning the destruction of habitat. From the 16 million square kilometers of tropical rainforest habitat that existed worldwide, less than 9 million square kilometers remain today; the current rate of deforestation is 160,000 square kilometers per year, which equates to a loss of 1% of original forest habitat each year. Other forest ecosystems have suffered as more destruction as tropical rainforests.
Farming and logging have disturbed at least 94% of temperate broadleaf forests. Tropical deciduous dry forests are easier to clear and burn and are more suitable for agriculture and cattle ranching than tropical rainforests. Plains and desert areas have been degraded to a lesser extent. Only 10-20% of the world's drylands, which include temperate grasslands and shrublands, deciduous forests, have been somewhat degraded, but included in that 10-20% of land is the 9 million square kilometers of seasonally dry-lands that humans have converted to deserts through the process of desertification. The tallgrass prairies of North America, on the other hand, have less than 3% of natural habitat remaining that has not been converted to farmland. Wetlands and marine areas have endured high levels of habitat destruction. More than 50% of wetlands in the U. S. have been destroyed in just the last 200 years. Between 60% and 70% of European wetlands have been destroyed. In the United Kingdom, there has been an i
The biomass is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, the mass of one or more species, or to community biomass, the mass of all species in the community, it can include plants or animals. The mass can be expressed as the total mass in the community. How biomass is measured depends on why it is being measured. Sometimes, the biomass is regarded as the natural mass of organisms in situ. For example, in a salmon fishery, the salmon biomass might be regarded as the total wet weight the salmon would have if they were taken out of the water. In other contexts, biomass can be measured in terms of the dried organic mass, so only 30% of the actual weight might count, the rest being water. For other purposes, only biological tissues count, teeth and shells are excluded. In some applications, biomass is measured as the mass of organically bound carbon, present; the total live biomass on Earth is about 550–560 billion tonnes C, the total annual primary production of biomass is just over 100 billion tonnes C/yr.
The total live biomass of bacteria may be much less. The total number of DNA base pairs on Earth, as a possible approximation of global biodiversity, is estimated at ×1037, weighs 50 billion tonnes. In comparison, the total mass of the biosphere has been estimated to be as much as 4×1012 tonnes of carbon. An ecological pyramid is a graphical representation that shows, for a given ecosystem, the relationship between biomass or biological productivity and trophic levels. A biomass pyramid shows the amount of biomass at each trophic level. A productivity pyramid shows the turn-over in biomass at each trophic level. An ecological pyramid provides a snapshot in time of an ecological community; the bottom of the pyramid represents the primary producers. The primary producers take energy from the environment in the form of sunlight or inorganic chemicals and use it to create energy-rich molecules such as carbohydrates; this mechanism is called primary production. The pyramid proceeds through the various trophic levels to the apex predators at the top.
When energy is transferred from one trophic level to the next only ten percent is used to build new biomass. The remaining ninety percent is dissipated as heat; this energy loss means that productivity pyramids are never inverted, limits food chains to about six levels. However, in oceans, biomass pyramids can be wholly or inverted, with more biomass at higher levels. Terrestrial biomass decreases markedly at each higher trophic level. Examples of terrestrial producers are grasses and shrubs; these have a much higher biomass than the animals that consume them, such as deer and insects. The level with the least biomass are the highest predators in the food chain, such as foxes and eagles. In a temperate grassland and other plants are the primary producers at the bottom of the pyramid. Come the primary consumers, such as grasshoppers and bison, followed by the secondary consumers, shrews and small cats; the tertiary consumers, large cats and wolves. The biomass pyramid decreases markedly at each higher level.
Ocean or marine biomass, in a reversal of terrestrial biomass, can increase at higher trophic levels. In the ocean, the food chain starts with phytoplankton, follows the course: Phytoplankton → zooplankton → predatory zooplankton → filter feeders → predatory fish Phytoplankton are the main primary producers at the bottom of the marine food chain. Phytoplankton use photosynthesis to convert inorganic carbon into protoplasm, they are consumed by microscopic animals called zooplankton. Zooplankton comprise the second level in the food chain, includes small crustaceans, such as copepods and krill, the larva of fish, squid and crabs. In turn, small zooplankton are consumed by both larger predatory zooplankters, such as krill, by forage fish, which are small, filter-feeding fish; this makes up the third level in the food chain. The fourth trophic level consists of predatory fish, marine mammals and seabirds that consume forage fish. Examples are swordfish and gannets. Apex predators, such as orcas, which can consume seals, shortfin mako sharks, which can consume swordfish, make up the fifth trophic level.
Baleen whales can consume zooplankton and krill directly, leading to a food chain with only three or four trophic levels. Marine environments can have inverted biomass pyramids. In particular, the biomass of consumers is larger than the biomass of primary producers; this happens because the ocean's primary producers are tiny phytoplankton that grow and reproduce so a small mass can have a fast rate of primary production. In contrast, terrestrial primary producers reproduce slowly. There is an exception with cyanobacteria. Marine cyanobacteria are the smallest known photosynthetic organisms. Prochlorococcus is the most plentiful species on Earth: a single millilitre of surface seawater may contain 100,000 cells or more. Worldwide, there are estimated to be several octillion individuals. Prochlorococcus is ubiquitous between 40°N and 40°S and dominates in the oligotrophic regions of the oceans; the bacterium accounts for an estimated 20% of the oxygen in the Earth's atmosphere, forms part of the base of the ocean food chain.
There are 50 million bacterial cells in
Biodiversity refers to the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic and ecosystem level. Terrestrial biodiversity is greater near the equator, the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth, is richest in the tropics; these tropical forest ecosystems cover less than 10 percent of earth's surface, contain about 90 percent of the world's species. Marine biodiversity is highest along coasts in the Western Pacific, where sea surface temperature is highest, in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity. Biodiversity tends to cluster in hotspots, has been increasing through time, but will be to slow in the future. Rapid environmental changes cause mass extinctions. More than 99.9 percent of all species that lived on Earth, amounting to over five billion species, are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described.
More in May 2016, scientists reported that 1 trillion species are estimated to be on Earth with only one-thousandth of one percent described. The total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes. In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC. In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor of all organisms living on Earth; the age of the Earth is about 4.54 billion years. The earliest undisputed evidence of life on Earth dates at least from 3.5 billion years ago, during the Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean Eon. There are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old meta-sedimentary rocks discovered in Western Greenland. More in 2015, "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia.
According to one of the researchers, "If life arose quickly on Earth.. it could be common in the universe."Since life began on Earth, five major mass extinctions and several minor events have led to large and sudden drops in biodiversity. The Phanerozoic eon marked a rapid growth in biodiversity via the Cambrian explosion—a period during which the majority of multicellular phyla first appeared; the next 400 million years included repeated, massive biodiversity losses classified as mass extinction events. In the Carboniferous, rainforest collapse led to a great loss of animal life; the Permian–Triassic extinction event, 251 million years ago, was the worst. The most recent, the Cretaceous–Paleogene extinction event, occurred 65 million years ago and has attracted more attention than others because it resulted in the extinction of the dinosaurs; the period since the emergence of humans has displayed an ongoing biodiversity reduction and an accompanying loss of genetic diversity. Named the Holocene extinction, the reduction is caused by human impacts habitat destruction.
Conversely, biodiversity positively impacts human health in a number of ways, although a few negative effects are studied. The United Nations designated 2011–2020 as the United Nations Decade on Biodiversity. 1916 - The term biological diversity was used first by J. Arthur Harris in "The Variable Desert," Scientific American, JSTOR 6182: "The bare statement that the region contains a flora rich in genera and species and of diverse geographic origin or affinity is inadequate as a description of its real biological diversity." 1975 - The term natural diversity was introduced 1980 - Thomas Lovejoy introduced the term biological diversity to the scientific community in a book.. It became used. 1985 -The contracted form biodiversity was coined by W. G. Rosen 1985 - The term "biodiversity" appears in the article, "A New Plan to Conserve the Earth's Biota" by Laura Tangley. 1988 - The term biodiversity first appeared in a publication. The present - the term has achieved widespread use. "Biodiversity" is most used to replace the more defined and long established terms, species diversity and species richness.
Biologists most define biodiversity as the "totality of genes and ecosystems of a region". An advantage of this definition is that it seems to describe most circumstances and presents a unified view of the traditional types of biological variety identified: taxonomic diversity ecological diversity morphological diversity functional diversity This multilevel construct is consistent with Datman and Lovejoy. An explicit definition consistent with this interpretation was first given in a paper by Bruce A. Wilcox commissioned by the International Union for the Conservation of Nature and Natural Resources for the 1982 World National Parks Conference. Wilcox's definition was "Biological diversity is the variety of life forms...at all levels of biologi
A food chain is a linear network of links in a food web starting from producer organisms and ending at apex predator species, detritivores, or decomposer species. A food chain shows how the organisms are related with each other by the food they eat; each level of a food chain represents a different trophic level. A food chain differs from a food web, because the complex network of different animals' feeding relations are aggregated and the chain only follows a direct, linear pathway of one animal at a time. Natural interconnections between food chains make it a food web. A common metric used to the quantify food web trophic structure is food chain length. In its simplest form, the length of a chain is the number of links between a trophic consumer and the base of the web and the mean chain length of an entire web is the arithmetic average of the lengths of all chains in a food web. Food chains were first introduced by the Arab scientist and philosopher Al-Jahiz in the 9th century and popularized in a book published in 1927 by Charles Elton, which introduced the food web concept.
The food chain's length is a continuous variable that provides a measure of the passage of energy and an index of ecological structure that increases in value counting progressively through the linkages in a linear fashion from the lowest to the highest trophic levels. Food chains are used in ecological modeling, they are simplified abstractions of real food webs, but complex in their dynamics and mathematical implications. Ecologists have formulated and tested hypotheses regarding the nature of ecological patterns associated with food chain length, such as increasing length increasing with ecosystem size, reduction of energy at each successive level, or the proposition that long food chain lengths are unstable. Food chain studies have an important role in ecotoxicology studies tracing the pathways and biomagnification of environmental contaminants. Producers, such as plants, are organisms. All food chains must start with a producer. In the deep sea, food chains centered on hydrothermal vents and cold seeps exist in the absence of sunlight.
Chemosynthetic bacteria and archaea use hydrogen sulfide and methane from hydrothermal vents and cold seeps as an energy source to produce carbohydrates. Consumers are organisms. All organisms in a food chain, except the first organism, are consumers. In a food chain, there is reliable energy transfer through each stage. However, all the energy at one stage of the chain is not absorbed by the organism at the next stage; the amount of energy from one stage to another decreases. Heterotroph Lithotroph Trophic pyramid Predator-prey interaction
An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy is incorporated into plant tissue. By feeding on plants and on one-another, animals play an important role in the movement of matter and energy through the system, they influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be used by plants and other microbes. Ecosystems are controlled by internal factors. External factors such as climate, the parent material which forms the soil and topography, control the overall structure of an ecosystem, but are not themselves influenced by the ecosystem. Ecosystems are dynamic entities—they are subject to periodic disturbances and are in the process of recovering from some past disturbance.
Ecosystems in similar environments that are located in different parts of the world can end up doing things differently because they have different pools of species present. Internal factors not only control ecosystem processes but are controlled by them and are subject to feedback loops. Resource inputs are controlled by external processes like climate and parent material. Resource availability within the ecosystem is controlled by internal factors like decomposition, root competition or shading. Although humans operate within ecosystems, their cumulative effects are large enough to influence external factors like climate. Biodiversity affects ecosystem functioning, as do the processes of disturbance and succession. Ecosystems provide a variety of services upon which people depend; the term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley. Tansley devised the concept to draw attention to the importance of transfers of materials between organisms and their environment.
He refined the term, describing it as "The whole system... including not only the organism-complex, but the whole complex of physical factors forming what we call the environment". Tansley regarded ecosystems not as natural units, but as "mental isolates". Tansley defined the spatial extent of ecosystems using the term ecotope. G. Evelyn Hutchinson, a limnologist, a contemporary of Tansley's, combined Charles Elton's ideas about trophic ecology with those of Russian geochemist Vladimir Vernadsky; as a result, he suggested. This would, in turn, limit the abundance of animals. Raymond Lindeman took these ideas further to suggest that the flow of energy through a lake was the primary driver of the ecosystem. Hutchinson's students, brothers Howard T. Odum and Eugene P. Odum, further developed a "systems approach" to the study of ecosystems; this allowed them to study the flow of material through ecological systems. Ecosystems are controlled both by internal factors. External factors called state factors, control the overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem.
The most important of these is climate. Climate determines the biome. Rainfall patterns and seasonal temperatures influence photosynthesis and thereby determine the amount of water and energy available to the ecosystem. Parent material determines the nature of the soil in an ecosystem, influences the supply of mineral nutrients. Topography controls ecosystem processes by affecting things like microclimate, soil development and the movement of water through a system. For example, ecosystems can be quite different if situated in a small depression on the landscape, versus one present on an adjacent steep hillside. Other external factors that play an important role in ecosystem functioning include time and potential biota; the set of organisms that can be present in an area can significantly affect ecosystems. Ecosystems in similar environments that are located in different parts of the world can end up doing things differently because they have different pools of species present; the introduction of non-native species can cause substantial shifts in ecosystem function.
Unlike external factors, internal factors in ecosystems not only control ecosystem processes but are controlled by them. They are subject to feedback loops. While the resource inputs are controlled by external processes like climate and parent material, the availability of these resources within the ecosystem is controlled by internal factors like decomposition, root competition or shading. Other factors like disturbance, succession or the types of species present are internal factors. Primary production is the production of organic matter from inorganic carbon sources; this occurs through photosynthesis. The energy incorporated through this process supports life on earth, while the carbon makes up much of the organic matter in living and dead biomass, soil carbon and fossil fuels, it drives the carbon cycle, which influences global climate via the greenhouse effect. Through the process of photosynthesis, plants capture energy from light and use it to combine carbon dioxide and water to produce carbohydrates and oxygen.
The photosynthesis carried out by all the plants in an ecosystem is called the gross primary production. About half of the GPP is consumed in plant respiration; the remainder, that portion of GPP, not used up by respirati