ENERGY-PHOTOSYNTHESIS in photosynthesis process, organisms utilize luminous energy (sun radiation) to produce organic compounds (from carbon dioxide and inorganic molecules).
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ENERGY-BIOGEOCHEMICAL CYCLE in biogeochemical cycles , chemical reaction are powered by energy from different sources, such as solar radiation and energy of chemical bonds.
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NUTRIENTS-BIOGEOCHEMICAL CYCLE every nutrient, being a chemical molecule or compounds, follows a biogeochemical cycle in which it usually passes from a chemical inorganic form to an organic one, often in a living organism.
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NUTRIENTS-AUTOTROPH autotrophs uses nutrients (simple inorganic molecules)to produce complex organic compounds (carbohydrates, fats, proteins) using chemical or luminous energy.
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NUTRIENTS-DECOMPOSITION nutrients (simple inorganic compounds) came from natural decomposition of organic matter by decomposer.
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ABIOTIC FACTOR-NUTRIENTS nutrients and their concentration in the environment belong to abiotic factors .
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ABIOTIC FACTOR-ENVIROMENTAL CONDITION(PH. T, S) environmental conditions are considered to be important abiotic factor influencing living organisms.
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ABIOTIC FACTOR- COMMUNITY habitat in which a biologic community live in is expecially characterized by abiotic factors (Temperature, salinity, chemical composition , nutrient availability). Organisms forming a community has to be physiologically able to live there.
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COMMUNITY-SPECIES an ecologic community is an assemblage of populations of different species, interacting in the same habitat.
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COMMUNITY-SUCCESSION an Ecological succession is a changes in the composition or structure of an ecological community.
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SUCCESSION- CLIMAX Climax is a term which refer to a stable biological community, developed through a process of ecological succession.
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COMMUNITY-ECOSYSTEM an ecosystem is defined by a biotope and the ecological community living there. They interact each-other and function as a unit.
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ECOSYSTEM-COMMUNITY an ecosystem is defined by a biotope and the ecological community living there. They interact each-other and function as a unit.
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ECOSYSTEM-FUNCTIONING there are links between ecosystem structure (environment and species composition) and ecosystem functioning, as cycle of matter and energy.
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ECOSYSTEM-TROPHIC LEVEL usually an ecosystem is composed by organisms of different trophic levels, which interact each other giving rise to an indefinite recycle of resources.
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ECOSYSTEM-BIODIVERSITY increase in number of existing ecosystems or diversification mean increase of biodiversity.
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FUNCTIONING-BIOGEOCHEMICAL CYCLE extraspecific component of ecosystem functioning is rapresented by biogeochemical cycle, a correct cycle of energy and resource is essential for a correct functioning of the ecosystem.
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FUNCTIONING-BIODIVERSITY increase in biodiversity means increase in complexity of ecosystem functioning, with different function performed. Change in biodiversity lead to a change also in functioning.
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BIODIVERSITY- SPECIATION Speciation is the evolutionary process by which new biological species arise, increasing biodiversity.
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SPECIES-BIODIVERSITY increase of species diversity (number of different species) means increase of biodiversity.
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SPECIES-KEYSTONE a Keystone Specie is a specie with a high influential role in ecosystem in relation to his biomass contribution.
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SPECIES-CHARISMATIC Charismatic species are animal species with widespread popular appeal.
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POPULATION-SPECIES a population is composed by organism of the same specie sharing an ecosystem.
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POPULATION-BIOTIC FACTORS a population and its dynamics are usually influenced by biotic factors as deseas, predation, competition, symbiosis.
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ORGANISM-POPULATION population in described as a group of organisms of the same species living in the same ecosystem.
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ORGANISM-HABITAT physical, physiologycal, metabolic characteristic of an organism are in close relation with his habitat, as a result of his biological adaptation.
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ORGANISM-NICHE the concept of ecological niche describe how an organism respond to the environmental condition , especially to the resources and competitors distribution.
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ALIEN SPECIES-ORGANISM Alien species are usually migrating organisms able to survive in an habitat which is different from the original one.
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HABITAT-NICHE the habitat of a certain organism or biological specie is part of his ecological niche, both are connected with physiological and ecological feature of the rogansims.
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ANTROPHIC IMPACT-HABITAT anthropic use of natural environment and its colonization causes fragmentation and degradation of habitats.
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ANTROPHIC IMPACT-POLLUTION Pollution is introduction of contaminants into a natural environment by human activities.
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ANTROPHIC IMPACT-USES OF RESOURCE resources are used for human activities. An wrong way to use natural resources led to a relevant impact on the environment.
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ANTROPHIC IMPACT-CONSERVATION Conservation is the study of Earth's biodiversity, species, habitats, ecosystems status, , and of how antrophic impact influence them.
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ANTROPHIC IMPACT-ALIEN SPECIES Spread of alien species in actual ecosystems is mainly due to human factors, expecially activities implying direct use of environment and its inhabitat.
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ANTROPHIC IMPACT-GLOBAL WARMING global warming is caused by increase of atmospheric concentration of greenhouse gasses, especially carbon dioxide, due to antrophic activities.
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GLOBAL WARMING-TROPICALIZATION tropicalization, settlement of Mediterranean species by tropical one, is a consequence of sea water warming.
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GLOBAL WARMING-MERIDIONALIZATION meridionalization is the northward shift of species distribution area typical of the south Mediterranean, a consequence of the warmer climate in these areas.
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GLOBAL WARMING-ALIEN SPECIES increase of global temperature cause changes in ecosystems distributions and features, allowing a facilitate adaptation of alien species in their migration habitats.
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ALIEN SPECIES-FOUNDERS EFFECT establishment of a new alien species in a new habitat lead a loss of genetic variation in the specie and in the native species of the habitat.
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CONSERVATION-EXTINCTION Conservation’s studies try to prevent species extinction.
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DYNAMICS-EXTINCTION a strong and effective alteration of population dynamics (caused by external or internal factors) can lead to the extinction of a species.
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CARRING CAPACITY-DYNAMICS carring capacity influence population dynamics, in particular population size in time.
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CARRING CAPACITY- POPULATION the carring capacity of a species in a physical area , refer to the population size, of that specie, which can be indefinitely sustained in this area.
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R/K STRATEGY- DYNAMICS reproduction rate is a key concept in population dynamics, especially in size and age composition, birth and death rates.
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DYNAMICS-MIGRATION Population dynamics are affected by emigration or immigration of new individuals in the population area.
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MIGRATION- FOUNDER EFFECT migration lead a loss of genetic variation in the migrating organism from a larger population (founder effect).
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MIGRATION-ALIEN SPECIES an alien specie is a living species migrating and colonizing an habitat different from its origin one, altering is previous balance.
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DYNAMICS-FLUSH AND CASH flush and cash mechanism influence population dynamics, especially with increase and decrease of population size and birth and death rates.
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FLUSH AND CASH-FOUNDER EFFECT a species regenerating after a period of rarity (crash), is subjected to a loss of genetic variation (founder effect).
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DYNAMICS- EVOLUTION population dynamics can lead events as population decline or evolution of species, due to adaptation.
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EVOLUTION-FOUNDERS EFFECT founders effect, decreasing genetic variability, can lead evolution of a species in only one direction.
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EVOLUTION-ADAPTATION genetic adaptation in a changing habitat lead evolution of the biological species.
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ADAPTATION-RED QUEEN red queen hypothesis explain the constant evolution, due to reciprocal adaptation, between competing species.
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EVOLUTION-SPECIATION Speciation is the evolutionary process by which new biological species arise, or a specie evolve.
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BIOTIC FACTORS-CARRYNG CAPACITY carryng capacity of an ecosystem is also defined by biotic interaction between species.
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BIOTIC FACTORS-BIODIVERSITY biotic interaction between populations of species influence species composition and total amount of species (biodiversity)
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BIOTIC FACTORS-INTERACTION biological interactions are considered a biotic factor, affecting the structure of ecological community.
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INTERACTION-BOTTOM UP in Bottom up controlled ecosystems the nutrient supply and productivity control the ecosystem structure and species interactions.
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INTERACTION-TOP DOWN In Top down controlled ecosystems top predator controls the structure or population dynamics of the ecosystem.
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INTERACTION-COMMENSALISM commensalism is a not obligatory symbiotic interaction between two organism in which symbiont don’t damage the host, nor benefit it.
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INTERACTION-MUTUALISM mutualism is a mutual interaction between two organisms of different species with reciprocal benefit.
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INTERACTION-NEUTRALISM neutralism is an interaction between two organism of different species without reciprocal benefit or damages.
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INTERACTION-PARASITISM parasitism is a generally trophic interaction between two organism of different species , in which parasite obtain benefits and the host is damaged.
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INTERACTION-COMPETITION competition is an interaction between organism in the same species, or between different species , for a limiting resource.
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INTERACTION-PREDATION predation is an antagonistic interaction between two organisms, usually of different specie, in which predator feed and the prey is eated.
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INTERACTION-RED QUEEN red queen hypothesis refer to evolutionary adaptation due to organisms and species interaction and cohabitation in the same habitat.
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BIOTIC FACTORS-TROPHIC LEVELS biotic factors includes organisms and species interactions due to their position in the food web; as competition for resources and vertical interaction (prey-predator).
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TROPHIC LEVELS-FOOD WEB trophic levels of an organism represent the position it occupies in the food chain.
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FOOD WEB-PRODUCERS producers are at the first step of the food chain They synthesize organic matter from simple inorganic molecules and transfer energy up in food web.
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PRODUCERS-AUTOTROPH autotrophs are considered producers in the food web, because they are able to produce complex organic compounds from inorganic nutrients utilizing luminous or chemical energy.
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AUTOTROPH-ETEROTROPH autotrophs are feeded by eterotrophs of the first level (primary consumers) for energy and organic matter supply.
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ETEROTROPH-AUTOTROPH eterotrophs of the first level (primary consumers) feed on autotrophs for energy and organic matter supply.
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FOOD WEB-CONSUMERS consumers up to the first step in food chain, they feed on primary producers.
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CONSUMERS-PRODUCERS consumers are opposed to producers. Producer synthesize their own organic matter, consumers are not able to do an feed on living organisms to carry on growth and energetic metabolism.
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CONSUMERS-DECOMPOSER decomposers are consumer because they use organic compounds from other living organisms as source of energy.
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DECOMPOSER-DECOMPOSITION decomposer are saprotrophs or heterotroph organisms which enact decomposition of non-living organic matter as energy source.
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FOOD WEB-DECOMPOSER decomposer play an important role in food web. These organisms are part of the detrital web, in which organic debris are trasformed in simple inorganic molecules.
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CONSUMERS-HETEROTROPH heterotrophs are considered consumers in the food chain, because they can’t synthesize organic matter by their own and they have to take up from other living organisms.
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HETEROTROPH-DECOMPOSITION heterotrophy and decomposition are strictly connected. Decomposer organisms are heterotrophy, because they use organic compounds as source of energy.
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EXTINCTION-FLUSH AND CRASH a species which undergo a period of rarity (crash), is subjected to extinction.
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ANTROPHIC IMPACT-BIODIVERSITY Antrophic impact , whit use or resources, fragmentation or degradation of habitats, reduce biodiversity.
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COMMUNITY-BIOTIC FACTOR community composition and ecology in influenced by biotic factors as species interactions.
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PHOTOSYNTESIS-AUTOTROPH most autotrophic organism , fix carbon trough photosynthesis process, utilizing luminous energy from solar radiation.
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KEYSTONE SPECIES
Keystone Species = a species whose effect is large, and disproportionately large relative to its abundance. Is it not enough for a species to be highly influential; its role must be great in relation to its relative biomass contribution (Power et al., 1996). Such species plays a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and numbers of various other species in the community (Mills et al., 1993). The keystone analogy refers to the architectural element at the apex of an arch that locks the other pieces into position, and is used colloquially to refer to the supporting element of a larger structure. Paine (1969) originally defined a keystone predator as a species that feeds preferentially on the dominant competitor among its prey species, such that the keystone predator’s feeding prevents the dominant prey from excluding other species, and therefore maintains a higher species diversity in the system than in the keystone’s absence.
The sea star Pisaster ochraceus, the original keystone species, feeds preferentially on mussels on northeast Pacific rocky shores. By doing so, the predatory sea star prevents mussels from taking over the entire shore and allows less competitive species to persist, thus enhancing local species diversity.
(Source: Multi-Agency Rocky Intertidal Network)
In the literature of ecological science, keystone predation is now often used to refer to predation on a dominant competitor that, as a consequence, maintains high prey diversity in the system.
The sea otter Enhydra lutris can be considered a keystone predator because its voracious feeding on herbivorous sea urchins allows kelps to flourish along the rocky coast, along with an entire ecosystem associated with these large marine plants. Photo by Matt Knoth. (Source: Wikimedia Commons)
Mills, L.S.; Soule, M.E.; Doak, D.F. (1993). "The Keystone-Species Concept in Ecology and Conservation". BioScience (BioScience, Vol. 43, No. 4) 43 (4): 219–224.
Paine, R.T. 1969. A note on trophic complexity and community stability. American Naturalist 103: 91.
Power, M.E.; Tilman, D.; estes, J.A.; Menge, B.A.; Bond, W.J.; Mills, L.S.; Daily, G.; Castilla, J.C.; Lubchenco, J.; Paine, R.T. 1996 : Challenges in the quest for keystones. Bioscience 46: 609-620
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CHARISMATIC SPECIES
charismatic species= large animal species with widespread popular appeal that environmental activists use to achieve conservation goals well beyond just those species. Prominent examples include the Tiger , California condor , bald eagle , giant panda , harp seal , and humpback whale.
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SUCCESSION
succession= Ecological succession, a fundamental concept in ecology, refers to more-or-less predictable and orderly changes in the composition or structure of an ecological community.
Succession may be initiated either by formation of new, unoccupied habitat (e.g., a lava flow or a severe landslide) or by some form of disturbance (e.g.fire, severe windthrow, logging) of an existing community.
The former case is often referred to as primary succession, the latter as secondary succession. The trajectory of ecological change can be influenced by site conditions, by the interactions of the species present, and by more stochastic factors such as availability of colonists or seeds, or weather conditions at the time of disturbance.
Some of these factors contribute to predictability of successional dynamics; others add more probabilistic elements.
In general, communities in early succession will be dominated by fast-growing, well-dispersed species (opportunist, fugitive, or r-selected life-histories). As succession proceeds, these species will tend to be replaced by more competitive (k-selected) species .
http://www.sciencedaily.com/articles/e/ecological_succession.htm
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SPECIATION
Speciation= is the evolutionary process by which new biological species arise ( Cook, 1906). here are four geographic modes of speciation in nature, based on the extent to which speciating populations are geographically isolated from one another: allopatric, peripatric, parapatric, and sympatric (Boxhorn, 2009).
Allopatric: During allopatric (from the ancient Greek allos, "other" + Greek patrā, "fatherland") speciation, a population splits into two geographically isolated populations (for example, by habitat fragmentation due to geographical change such as mountain building or social change such as emigration). The isolated populations then undergo genotypic and/or phenotypic divergence as: (a) they become subjected to dissimilar selective pressures; (b) they independently undergo genetic drift; (c) different mutations arise in the two populations. When the populations come back into contact, they have evolved such that they are reproductively isolated and are no longer capable of exchanging genes.
Example of allopatric species: Galapogos tortoise
-Peripatric : a subform of allopatric speciation, new species are formed in isolated, smaller peripheral populations that are prevented from exchanging genes with the main population. It is related to the concept of a founder effect, since small populations often undergo bottlenecks. Genetic drift is often proposed to play a significant role in peripatric speciation.
Examples:
The Australian bird Petroica multicolor
Reproductive isolation occurs in populations of Drosophila subject to population bottlenecking
-Parapatric: In this form, new species are formed in isolated peripheral populations; this is similar to allopatric speciation in that populations are isolated and prevented from exchanging genes. However, peripatric speciation, unlike allopatric speciation, proposes that one of the populations is much smaller than the other. Peripatric speciation was originally proposed by Ernst Mayr, and is related to the founder effect, because small living populations may undergo selection bottlenecks (Provine WB , 2004). Genetic drift is often proposed to play a significant role in peripatric speciation . Examples:
- The Larus gulls form a ring species around the North Pole.
- The Ensatina salamanders, which form a ring round the Central Valley in California.
- The Greenish Warbler (Phylloscopus trochiloides), around the Himalayas.
-Sympatric: refers to the formation of two or more descendant species from a single ancestral species all occupying the same geographic location.
In sympatric speciation, species diverge while inhabiting the same place. Often-cited examples of sympatric speciation are found in insects that become dependent on different host plants in the same area (Federj. Et al. 2005) (Berlocher s., 2002). The most widely accepted example of sympatric speciation is that of the cichlids of Lake Nabugabo in East Africa, which is thought to be due to sexual selection.
Cook O. F. (1906). "Factors of species-formation". Science 23 (587): 506–507.
Provine WB (1 July 2004). "Ernst Mayr: Genetics and speciation". Genetics 167 (3): 1041–6.
Feder, J. L., X. Xie, J. Rull, S. Velez, A. Forbes, B. Leung, H. Dambroski, K. E. Filchak, and M. Aluja. 2005. Mayr, Dobzhansky, and Bush and the complexities of sympatric speciation in Rhagoletis. Proceedings of the National Academy of Sciences, USA 1902:6573-6580.
Berlocher, S. H., and J. L. Feder. 2002. Sympatric speciation in phytophagous insects: moving beyond controversy? Annual Review of Entomology 47:773-815
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CLIMAX
Climax = is a biological community of plants and animals which, through the process of ecological succession — the development of vegetation in an area over time — has reached a steady state. This equilibrium occurs because the climax community is composed of species best adapted to average conditions in that area. The term is sometimes also applied in soil development.
The idea of a single climatic climax, which is defined in relation to regional climate, originated with Frederic Clements in the early 1900s. The first analysis of succession as leading to something like a climax was written by Henry Cowles in 1899, but it was Clements who used the term "climax" to describe the idealized endpoint of succession (Cowles, 1899).
Cowles, Henry Chandler. 1899. The Ecological Relations of the Vegetation on the Sand Dunes of Lake Michigan. Botanical Gazette 27(2): 95-117; 27(3): 167-202; 27(4): 281-308; 27(5): 361-391.
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TROPICALIZATION
tropicalization = For tropicalization is the process of settlement in the Mediterranean species from tropical or sub-tropical areas.In some cases, these species (Migration lessepsiana) passed through the Suez Canal, from Red Sea, or of species from the African coast Ocean Atlantic, came through the Straits of Gibraltar. Another channel input is represented by the uncontrolled discharge of ballast water tankers. A contribution to the development of the phenomenon is also given by climate change in progress, with the consequent rise in water temperature. Some of these species are set and played very well at the point of come to displace native species and are commonly caught and marketed. Among them are: the puffer fish (Sphoeroides cutaneus), wrapped the amberjack (Seriola fasciata), the scorpion fish (Pteroides miles), the mullet of the Red Sea (Upeneus moluccensis) and Mediterranean barracuda (Sphyraena viridensis) (Cerrano, 1999).
CERRANO C., PONTI M., SILVESTRI S., 1999 - Guida alla biologia marina del Mediterraneo. R.D.E. Ricerche Design Editrice,(MI): 320 pp
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MERIDIONALIZATION
meridionalization = the northward shift of species distribution area typical of the south coast of this sea (Cerrano, 1999).
CERRANO C., PONTI M., SILVESTRI S., 1999 - Guida alla biologia marina del Mediterraneo. R.D.E. Ricerche Design Editrice,(MI): 320 pp
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BOTTOM UP
bottom up = Bottom up control in ecosystems refers to ecosystems in which the nutrient supply and productivity and type of primary producers (plants and phytoplankton) control the ecosystem structure. An example would be how plankton populations are controlled by the availability of nutrients. Plankton populations tend to be higher and more complex in areas where upwelling brings nutrients to the surface (Chapin et al., 2003).
Chapin F.S. III, Matson, P.A., and Mooney, H.A. (2003). Principles of terrestrial ecosystem ecology. Springer-Verlag, New York, N.Y.
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TOP DOWN
top down = refers to when a top predator controls the structure or population dynamics of the ecosystem. The classic example is of kelp forest ecosystems. In such ecosystems, sea otters are a keystone predator. They prey on urchins which in turn eat kelp. When otters are removed, urchin populations grow and reduce the kelp forest creating urchin barrens. In other words, such ecosystems are not controlled by productivity of the kelp but rather a top predator (Chapin et al., 2003).
Chapin F.S. III, Matson, P.A., and Mooney, H.A. (2003). Principles of terrestrial ecosystem ecology. Springer-Verlag, New York, N.Y.
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CONSERVATION
conservation = is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction (Sahney, S et al., 2008). It is an interdisciplinary subject drawing on sciences, economics, and the practice ofnatural resource management (Soule, Michael E, 1986).
Sahney, S. and Benton, M.J. (2008). "Recovery from the most profound mass extinction of all time" (PDF). Proceedings of the Royal Society: Biological 275 (1636): 759–65.
Soule, Michael E. (1986). Conservation Biology: The Science of Scarcity and Diversity. Sinauer Associates. pp. 584.
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POLLUTION
pollution = is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms (Merriam-webster.com). Pollution can take the form of chemical substances or energy, such as noise, heat, or light. Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels.
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DYNAMICS
Population dynamics is the branch of life sciences that studies short- and long-term changes in the size and age composition of populations, and the biological and environmental processes influencing those changes. Population dynamics deals with the way populations are affected by birth and death rates, and by immigration and emigration, and studies topics such as ageing populations or population decline.
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CARRYING CAPACITY
The carrying capacity of a biological species in an environment is the population size of the species that the environment can sustain indefinitely, given the food, habitat, water and other necessities available in the environment. In population biology, carrying capacity is defined as the environment's maximal load, which is different from the concept of population equilibrium.
For the human population, more complex variables such as sanitation and medical care are sometimes considered as part of the necessary establishment. As population density increases, birth rate often decreases and death rate typically increases. The difference between the birth rate and the death rate is the "natural increase". The carrying capacity could support a positive natural increase, or could require a negative natural increase. Thus, the carrying capacity is the number of individuals an environment can support without significant negative impacts to the given organism and its environment. Below carrying capacity, populations typically increase, while above, they typically decrease. A factor that keeps population size at equilibrium is known as a regulating factor. Population size decreases above carrying capacity due to a range of factors depending on the species concerned, but can include insufficient space, food supply, or sunlight. The carrying capacity of an environment may vary for different species and may change over time due to a variety of factors, including: food availability, water supply, environmental conditions and living space.
Odum Fondamenti di Ecologia Piccin
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HABITAT
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism.
The term microhabitat is often used to describe the small-scale physical requirements of a particular organism or population. A microhabitat is often a smaller habitat within a larger one. For example, a fallen log inside a forest can provide microhabitat for insects that are not found in the wider forest habitat outside such logs. Microenvironment is the immediate surroundings and other physical factors of an individual plant or animal within its pool. A microhabitait can be big or small depending on how much it varies.
From Wikipedia, the free encyclopedia
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HETEROTROPH
A heterotroph is an organism that requires organic substrates to get its carbon for growth and development.
A heterotroph is known as a consumer in the food chain. Consumers are organisms that cannot make their own food supply. They use the food that producers make, or they eat other organisms. Animals are consumers. To stay alive, consumers must get food from other organisms. There are three types of consumers:
Herbivores, Carnivores, and Omnivores.
Odum Fondamenti di Ecologia Piccin
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AUTOTROPH
An autotroph, also called a producer, is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) from simple inorganic molecules using energy from light (by photosynthesis) or inorganic chemical reactions (chemosynthesis). They are the producers in a food chain, such as plants on land or algae in water. They are able to make their own food and can fix carbon. Therefore, they do not utilize organic compounds as an energy source or a carbon source. Autotrophs can reduce carbon dioxide (add hydrogen to it) to make organic compounds. The reduction of carbon dioxide, a low-energy compound, creates a store of chemical energy. Most autotrophs use water as the reducing agent, but some can use other hydrogen compounds such as hydrogen sulfide. An autotroph can produce its own energy through photosynthesis through the inputs of light, carbon dioxide and H2O.
Autotroph can be phototrophs or lithotrophs (chemoautotrophs). Phototrophs use light as an energy source, while lithotrophs oxidize inorganic compounds, such as hydrogen sulfide, elemental sulfur, ammonium and ferrous iron.
Odum Fondamenti di Ecologia Piccin
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ECOLOGICAL NICHE
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other. A shorthand definition of niche is how an organism makes a living. The ecological niche describes how an organism or population responds to the distribution of resources and competitors (e.g., by growing when resources are abundant, and when predators, parasites and pathogens are scarce) and how it in turn alters those same factors (e.g., limiting access to resources by other organisms, acting as a food source for predators and a consumer of prey).
The niche concept was popularized by the zoologist G. Evelyn Hutchinson in 1957. Hutchinson wanted to know why there are so many different types of organisms in any one habitat. The Hutchinsonian Niche views niche as an n-dimensional hypervolume, where the dimensions are environmental conditions that define the range in which a species can persist.
From Wikipedia, the free encyclopedia
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NUTRIENTS
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. Nutrients are the substances that enrich the body. They are used to build and repair tissues, regulate body processes and converted to and used as energy. Methods for nutrient intake vary, with animals and protists consuming foods that are digested by an internal digestive system, but most plants ingest nutrients directly from the soil through their roots or from the atmosphere.
An inadequate amount of a nutrient is a deficiency. Deficiencies can be due to a number of causes including inadequacy in nutrient intake called dietary deficiency, or conditions that interfere with the utilization of a nutrient within an organism. Some of the conditions that can interfere with nutrient utilization include problems with nutrient absorption, substances that cause a greater than normal need for a nutrient, conditions that cause nutrient destruction, and conditions that cause greater nutrient excretion.
Nutrient toxicity occurs when an excess of a nutrient does harm to an organism.
Odum Fondamenti di Ecologia Piccin
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SPECIES
A species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are often used, such as similarity of DNA, morphology or ecological niche. Presence of specific locally adapted traits may further subdivide species into subspecies. The species are not constant over time, as we know from studies in the nineteenth century by Charles Darwin (The Origin of Species "), but in response to changing environmental conditions in which they live organisms. When a population of organisms of the same species is separated into two populations isolated from each other for a long time, they tend to adapt to the environment, changing its characteristics, to be transformed into two new species after hundreds of generations. The birth of a new species from a pre-existing is called "specialization." To give a practical example, the donkey and the horse arising from the same species of origin. This is demonstrated by the fact that horses and donkeys can have children, those mules. However, donkeys and horses are considered two distinct species, respectively, and caballus asinus, because mules are not fertile. Therefore, associations of this kind can not go more than a generation and create offspring. The same is believed to have happened to Homo Neanderthal and Homo Sapiens.
Charles Darwin (1859) The Origin of Species ,London; Encyclopaedia Britannica; appunti delle lezioni
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ALIEN SPECIES
With alien term in biology refers to a living non-native species (animal, vegetable ofungo) which, by human or natural event, is to live and colonize a habitat different from the place of origin. The alien species is included in the new habitat by altering the balance, as it usually happens that is competing with native species. Only in some cases, however, the invasive species that takes over, or those originating in this case the indigenous populations can be reduced to extinction. One of the reasons that can lead invasiveness of introduced species is the absence of specific predators and parasites that may limit the growth of populations. (Mnemiopsis in Black Sea). The spread of alien species is mainly due to human factors, but some cases may be due to natural migration, such as flocks of birds put off course by storms or fish "boundless" in river basins where they were previously absent due to floods exceptional or river catches. Today there are many hundreds if not thousands of alien species introduced in almost all areas of the world, often with considerable impact in recent years also is taking place a real migration of alien species of fish in the Mediterranean from the Red Sea after the opening of the Suez Canal, these species are defined lessepsiane by Ferdinand de Lesseps, who designed and built the canal. In recent years the number of species lessepsiane is also increasing because of the increase in water temperature due to global warming caused by emissions of greenhouse gases by humans.
Mnemiopsis
Ferdinando Boero University of Lecce: Ship-driven biological invasions in the Mediterranean Sea; Ferdinando Boero University of Lecce: State of knowledge of marine and coastal biodiversity in the Mediterranean Sea.
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ECOLOGY
Ecology (from Greek: οἶκος, "house"; -λογία, "study of") is the scientific study of the relation of living organisms to each other and their surroundings. Ecology includes the study of plant and animal populations, plant and animal communities and ecosystems. Ecologists study a range of living phenomena from the role of bacteria in nutrient recycling to the effects of tropical rain forest on the Earth's atmosphere. The word "ecology" ("oekologie") was coined by the German scientist Ernst Haeckel 1834–1919. Haeckel was a zoologist, artist, writer, and later in life a professor of comparative anatomy. When Darwin wrote the Origin of Species the word Ecology did not exist yet, Haeckel coined it later, on the wave of Darwinian thinking, defining it as: “the body of knowledge concerning the economy of nature (…) the study of all those complex interrelationships referred to by Darwin as the condition of the struggle for existence” (in “Morphology of Organisms”, 1866). In a word, ecology is the study of all those complex relationships in which Darwin made reference as to the conditions of the struggle for existence ". In his definition considers the root of the word "oikos" which is the same economic terms (= household management).
Odum, EP (1971) Fundamentals of ecology, third edition, Saunders New
Bullini Luciano, Pignatti Sandro: “Ecologia generale”, UT
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ECOSYSTEM
In ecology, an ecosystem is a community of organisms (plant, animal and other living organisms - also referred as biocenose) together with their environment (or biotope), functioning as a unit.
The term ecosystem first appeared in a 1935 publication by the British ecologist Arthur Tansley. However, the term had been coined already in 1930 by Tansley's colleague Roy Clapham, who was asked if he could think of a suitable word to denote the physical and biological components of an environment considered in relation to each other as a unit.
An ecosystem is a dynamic and complex whole, interacting as an ecological unit. Some consider it is a basic unit in ecology, only a structured functional unit in equilibrium, characterized by energy and matter flows between the different elements that compose it. But others consider this vision or a self-standing unit with coherent and stable flows only to be a bit restrictive.
An ecosystem may be of very different size. It may be a whole forest, as well as a small pond. Different ecosystems are often separated by geographical barriers, like deserts, mountains or oceans, or are isolated otherwise, like lakes or rivers. As these borders are never rigid, ecosystems tend to blend into each other. As a result, the whole earth can be seen as a single ecosystem, or a lake can be divided into several ecosystems, depending on the used scale.
The organisms in an ecosystem are usually well balanced with each other and with their environment. Introduction of new environmental factors or new species can have disastrous results, eventually leading to the collapse of an ecosystem and the death of many of its native species. The abstract notion of ecological health attempts to measure the robustness and capacity for recovery of a natural ecosystem.
Ecosystem and ecoregion terms are often confused (large ecosystems being called ecoregions), but there is a large consensus to define ecoregions as being geographical defined units, relatively large, land or water, with distinctive features. Ecoregions are a way to codify the different regions within which are observed particular patterns or similarities in ecosystems.
Bullini Luciano, Pignatti Sandro: “Ecologia generale”, UT
York; Costanza, R.; d'Arge, R.; de Groot, R.; Farber, S.; Grasso, M.; Hannon, B.; et al., Karin; Naeem, Shahid et al. (1997). The value of the world’s ecosystem services and natural capital example of marine ecosystem
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ENERGY
In physics, energy (from Greek ἐνέργεια - energeia, "activity, operation", fromἐνεργός - energos, "active, working") is a quantity that is often understood as the ability to perform work. This quantity can be assigned to any particle, object, or system of objects as a consequence of its physical state.
Different forms of energy include kinetic, potential, thermal, gravitational, sound,elastic and electromagnetic energy. The forms of energy are often named after a related force. German physicist Hermann von Helmholtz established that all forms of energy are equivalent — energy in one form can disappear but the same amount of energy will appear in another form. A restatement of this idea is that energy is subject to a conservation law over time.
Any form of energy can be transformed into another form. When energy is in a form other than thermal energy, it may be transformed with good or even perfect efficiency, to any other type of energy. With thermal energy, however, there are often limits to the efficiency of the conversion to other forms of energy, due to the second law of thermodynamics. As an example, when oil reacts with oxygen, potential energy is released, since new chemical bonds are formed in the products which are more stable than those in the oil and oxygen. The released energy resulting from this process may be converted directly to electricity (as in a fuel cell) with good efficiency. Alternately it may be converted into thermal energy if the oil is simply burned. In the latter case, however, some of the thermal energy can no longer be used to perform work at that temperature, and is said to be "degraded." As such, it exists in a form unavailable for further transformation. The remainder of the thermal energy may be used to produce any other type of energy, such as electricity.
In all such energy transformation processes, the total energy remains the same. Energy may not be created nor destroyed. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.
Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but non-zero kinetic energy (and higher total energy) relative to the Earth.
Energy is a scalar physical quantity. In the International System of Units (SI), energy is measured in joules, but in some fields other units such as kilowatt-hours and kilocalories are also used.
Harper, Douglas. "Energy". Online Etymology Dictionary. Retrieved May 1, 2007.
"Retrieved on 2010-Dec-05". Faculty.clintoncc.suny.edu. Retrieved 2010-12-12.
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ANTHROPIC IMPACT
The anthropic impact is a process by which humans modify the natural environment. The human colonization of natural areas always involves little or existing environmental changes. The word derives from the greek anthropos meaning man.
Human activities are a factor that can cause effects on the environment and fauna, in particular with regard to many species affected by a variety of direct or indirect interactions with humans.
The fragmentation and degradation of habitats, the number of tourists, the direct use activities (hunting and fishing) and wildlife-related entries (with particular reference to alien species introductions and restocking) are factors that can drastically affect the behavior, demographics the genetic structure and, ultimately, the survival of populations.
Eugene Odum, Gary W. Barrett: “Fundamentals of ecology” , Thomson Brooks/Cole
Bullini Luciano, Pignatti Sandro: “Ecologia generale”, UTET
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EXTINCTION:
Is the end of an organism or of a group of organisms (taxon), normally a species. The moment of extinction is generally considered to be the death of the last individual of the group. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively.
From Wikipedia, the free encyclopedia
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EVOLUTION:
The history of life is characterized by a succession of events that occurred in a random way and it does not follow a predetermined pattern. Evolution is linked to change, so that episodic events leading to changes which overcome some attractors are instrumental in determining world’s makeup. Evolution of organisms affects their environment which, in turn, is the driving force of evolution, because the environment evolves while continuing to function.
Ecology and evolutionary biology deal with patterns and processes occurring over different time scales. Darwin was aware of the importance of the environment in the evolutionary processes. Reductionism pervades both evolutionary biology ( with a tendency to interpret evolution as an genetic phenomenon) and ecology (with a tendency to interpret the environment as an essential thermodynamic system). The distinction between ecology and evolutionary biology is the perception of time.
Ecological time runs faster than evolutionary time, but both “are dials of the same clock”, they measure the history of life. Evolution is both gradual and saltational. Populations can develop according to the logistic curve, but they can also go through sudden flushes and crushes.
Boero, F., 1996. Episodic Events: Their Relevance to Ecology and Evolution. P.S.Z.N. I: Marine Ecology, 17 (1-3): 237-250 (1996)
0 19% Blackwell Wissenschafts-Verlag, Berlin ISSN 0173-9565
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FLUSH AND CRASH
Flush and crash is a speciation model according to which some are species can be pre-adapted to the new situation, taking the place of the declining dominant species. The latter can also regenerate after the decline (undergoing a period of rarity). The rare species is subjected to selective pressures, for example founder effect that is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.
Boero, F., 1994. Fluctuations and Variations in Coastal Marine Environments. P.S.Z.N. I: Marine Ecology, 15 (1): 3-25 Blackwell Wissenschafts-Verlag , Berlin ISSN 0173-9565
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FOUNDER EFFECT
That is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population
Boero, F., 1994. Fluctuations and Variations in Coastal Marine Environments. P.S.Z.N. I: Marine Ecology, 15 (1): 3-25 Blackwell Wissenschafts-Verlag , Berlin ISSN 0173-9565
Boero, F., Marcus, N.H., 1998. Minireview: The importance of benthic-pelagic coupling and the forgotten role of life cycles in coastal aquatic systems. Limnol. Oceanogr., 43(5), 1998, 763-768 0 1998, by the American Society of Limnology and Oceanography, Inc.
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FUNCTIONING
Ecosystems function: it through three basic cycles of matter and energy: extraspecific cycles (biogeochemical cycles), intraspecific cycles(life cycle and histories), and interspecific cycles(food web). The evolution of biodiversity increases the complexity of ecosystems with different organisms performing different functions.
In non linear systems changes in biodiversity can cause changes in ecosystem functioning, changing the shape of environmental attactors. There are links between structure (species composition) and function ( cycles of matter and energy) in ecosystem.
Boero, F.,2004. From biodiversity and ecosystem functioning to the roots of ecological complexity. Ecological Complexity 1, 101–109
Boero, F., & Erik Bonsdorff, E. A conceptual framework for marine biodiversity and ecosystem functioning. Marine Ecology 2007, 28 (Suppl. 1), 134–145 ª 2007 The Authors. Journal compilation ª 2007 Blackwell Publishing Ltd
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MIGRATION
Occurs when individuals of a population moving into another population of the same specie to reproduce. This can happen between the mainland and islands, between islands, or along a environmental gradient and his effect will be to dilute the effect of reproductive isolation between the populations, and thus slow down the process of genetic divergence.
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BIODIVERSITY
Biodiversity can have many interpretations, and it depends on the people you're talking to. So it can be interpreted as:
• genes diversity
• species diversity
• ecosystems diversity
• bioms diversity
Even if we concentrate only on species diversity the perception of the number of species change among people, as a taxonomist would take into consideration all the species in the world, also the undescribed ones, while an ecologist would focus on species that we know, and going further to socio-economists the number of species would decrease, becoming only the species that have a value. A general meaning can be: variation of life at all levels of biological organization. But at the end, whatever is the definition biodiversity is important and so it must be carefully conserved. The United Nations declared the year 2010 as the International Year of Biodiversity. Life on Earth today consists of many millions of distinct biological species and every species has its own importance, as a matter of fact biodiversity supports a huge number of natural ecosystem processes and services. Some ecosystem services that benefit society are air quality, climate (e.g., CO2 sequestration), water purification and prevention of erosion.
-Global Biodiversity Assessment. UNEP, 1995, Annex 6, Glossary.
-Biodiversity Synthesis Report by the Millennium Ecosystem Assessment (MA, 2005)
-Ferdinando Boero, Alberto Gennari, Fabio Tresca, Anna Maria Miglietta: “Marine biodiversity and ecosystem functioning”
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DECOMPOSITION
Decomposition is the process by which dead tissues of an organism break down into simpler forms of matter. The process is essential for new growth and development of living organisms as it recycles the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death. This is caused by two factors: autolysis, the breaking down of tissues by the body's own internal chemicals and enzymes, and putrefaction, the breakdown of tissues by organisms. Most decomposers are bacteria or fungi, though scavengers also play an important role in decomposition if the body is accessible.
-Bullini Luciano, Pignatti Sandro: “Ecologia generale”, UTET
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PHOTOSYNTHESIS
Photosynthesis is a process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria. Photosynthetic organisms are called photoautotrophs, since they can create their own food. In plants, algae, and cyanobacteria, photosynthesis uses carbon dioxide and water, releasing oxygen as a waste product. So the equation is:
2n CO2 + 2n H2O + photons → 2(CH2O)n + 2n O2
Photosynthesis is vital for all aerobic life on Earth. As well as maintaining the normal level of oxygen in the atmosphere, nearly all life either depends on it directly as a source of energy, or indirectly as the ultimate source of the energy in their food (the exceptions are chemoautotrophs that live in rocks or around deep sea hydrothermal vents). As well as energy, photosynthesis is also the source of the carbon in all the organic compounds within organisms' bodies. Although photosynthesis can happen in different ways in different species, some features are always the same. For example, the process always begins when energy from light is absorbed by proteins called photosynthetic reaction centers that contain chlorophylls. Then it occurs in two stages. In the first stage, light-dependent reactions or light reactions capture the energy of light and use it to make the energy-storage molecules ATP and NADPH. During the second stage, the light-independent reactions use these products to capture and reduce carbon dioxide.
The first were Cyanobacteria which appeared around 3,000 million years ago, and they drastically changed the Earth when they began to oxygenate the atmosphere. This new atmosphere allowed the evolution of complex life.
-“Photosynthesis,” McGraw-Hill Encyclopedia of Science and Technology, Vol. 13, p. 469, 2007
-Bullini Luciano, Pignatti Sandro: “Ecologia generale”, UTET
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ADAPTATION
Adaptation is the evolutionary process with which a population becomes better suited to its habitat. This process takes place over many generations, All adaptations help organisms survive in their ecological niches. The adaptive traits may be structural, behavioral or physiological. Structural adaptations are physical features of an organism such as shape, body. Behavioural adaptations are composed of inherited behaviour chains: behaviours may be inherited in detail (instincts), or a tendency for learning may be inherited, for instance searching for food, mating, vocalizations. Physiological adaptations allow the organism to perform special functions (for instance making venom, phototropism); but also more general functions such as growth and development, temperature regulation, ionic balance and other aspects of homeostasis are concerned by adaptation. Adaptation, then, affects all aspects of the life of an organism.
GLOBAL WARMING
Global warming is the increase in the average temperature of Earth's near-surface air and oceans since the mid-20th century. According to the 2007 Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), global surface temperature increased 0.74 ± 0.18 °C during the 20th century. Most of the observed temperature increase since the middle of the 20th century has been caused by increasing concentrations of greenhouse gases. Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from CO2, methane, tropospheric ozone, CFCs and nitrous oxide. Fossil fuel burning has produced about three-quarters of the increase in CO2 from human activity over the past 20 years. Most of the rest is due to land-use change, particularly deforestation. Climate model projections summarized in the latest IPCC report indicate that the global surface temperature is likely to rise a further 1.1 to 6.4 °C during the 21st century. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers, permafrost and sea ice. Other likely effects include changes in the frequency and intensity of extreme weather events, species extinctions, and changes in agricultural yields. Moreover as a result of contemporary increases in atmospheric carbon dioxide, the oceans have become more acidic, a result that is predicted to continue.
-Eugene Odum, Gary W. Barrett: “Fundamentals of ecology” , Thomson Brooks/Cole
-Bullini Luciano, Pignatti Sandro: “Ecologia generale”, UTET
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RED QUEEN'S HYPOTHESIS
This hypothesis was originally proposed by Leigh Van Valen (1973). The term is taken from the Red Queen's race in Lewis Carroll's Through the Looking-Glass. The Red Queen said, "It takes all the running you can do, to keep in the same place. For an evolutionary system, this hypothesis explains the constant evolutionary arms race between competing species. Because every improvement in one species lead to a selective advantage for that species, since in general different species are co-evolving, the other species will improve itself in order to obtain the same advantages. An example of this effect are the "arms races" between predators and prey where the only way predators can compensate for a better defense by the prey is by developing a better offense.
-Van Valen L. (1973). "A new evolutionary law". Evolutionary Theory 1: 1–30.
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GLOBAL WARMING
Global warming is the increase in the average temperature of Earth's near-surface air and oceans since the mid-20th century. According to the 2007 Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), global surface temperature increased 0.74 ± 0.18 °C during the 20th century. Most of the observed temperature increase since the middle of the 20th century has been caused by increasing concentrations of greenhouse gases. Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from CO2, methane, tropospheric ozone, CFCs and nitrous oxide. Fossil fuel burning has produced about three-quarters of the increase in CO2 from human activity over the past 20 years. Most of the rest is due to land-use change, particularly deforestation. Climate model projections summarized in the latest IPCC report indicate that the global surface temperature is likely to rise a further 1.1 to 6.4 °C during the 21st century. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers, permafrost and sea ice. Other likely effects include changes in the frequency and intensity of extreme weather events, species extinctions, and changes in agricultural yields. Moreover as a result of contemporary increases in atmospheric carbon dioxide, the oceans have become more acidic, a result that is predicted to continue.
-IPCC (2007) Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)]. Geneva, Switzerland: IPCC. http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_synthesis_report.htm.
-http://environment.nationalgeographic.com/environment/global-warming/gw-overview.html
-http://www.ipcc.ch/
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ORGANISMS inside ecosystem can be identified with their food strategies: producers (photosynthetic organisms) , herbivores , carnivores, omnivores, decomposers ( they are able to degrade organic matter, they break down dead plant and animal material and wastes and release it again as energy and nutrients into the ecosystem for recycling. Decomposers, such as bacteria and mushrooms, feed on waste and dead matter, converting it into inorganic chemicals that can be recycled as mineral nutrients for plants to use again), detritivores ( they feed on detritus, manure), scavengers ( they feed on the dead organic matter).
or through their trophic level:
Producers are typically plants or algae. Plants and algae do not usually eat other organisms, but pull nutrients from the soil or the ocean and manufacture their own food using photosynthesis. For this reason, food chain. An exception occurs in deep-sea hydrothermal ecosystems, where there is no sunlight. Here primary producers manufacture food through a process called chemosynthesis.
Consumers (primary consumers, secondary consumers…) cannot manufacture their own food, and need to consume other organisms. They are usually animals. Animal that eat primary producers (like plants) are called herbivores. Animals which eat other animals are called carnivores, and animals which eat both plant and other animals are called omnivores.
-Cunningham W., Cunningham M. A., Saigo B. W., “Fundamentals of ecology” , McGraw-Hill., 2007. Cap 6, pag. 149;154
-Lecture notes of ANIMAL SYSTEMATIC AND PHYLOGENESIS with prof. F.Boero (2008
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POPULATION is a group of individuals from the same species living in the same ecosystem. These individuals are represented by the features of the group and not by the individual features.
It' s the basic unit of evolution; it is not a static unit, but a population is influenced by some factors ( natality, mortality, immigration, emigration) affecting the dinamics of population.
Other factors, such as deseases, predation, competition with individuals from different species, resources availability influence the population's enhancement, wich has a logistic curve with a fixed limit, that is the actual carrying capacity of the environment in which population live.
-Lecture notes of ANIMAL SYSTEMATIC AND PHYLOGENESIS with prof. F.Boero (2008)
-Cunningham W., Cunningham M. A., Saigo B. W., “Fundamentals of ecology” , McGraw-Hill., 2007. Cap 6, pag. 148
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COMMUNITY is a group of interacting organisms sharing a populated environment.Traditionally a "community" has been defined as a group of interacting people living in a common location.
In ecology, a community is an assemblage of populations of different species, occupying the same geographical area and interacting with one another.
-Lecture notes from ANIMAL SYSTEMATIC AND PHYLOGENESIS with prof. F.Boero (2008)
-Cunningham W., Cunningham M. A., Saigo B. W., “Fundamentals of ecology” , McGraw-Hill., 2007. Cap 6, pag. 148
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r/K STRATEGYrelates to the selection of combinations of traits in an organism that trade off between quantity or quality of offspring. The focus upon either increased quantity of offspring at the expense of individual parental investment, or reduced quantity of offspring with a corresponding increased parental investment, is varied to promote success in particular environments.
In unstable or unpredictable environments, r-selection predominates and the ability to reproduce quickly is crucial. There is little advantage in adaptations that permit successful competition with other organisms, because the environment is likely to change again. Traits that are thought to be characteristic of r-selection include: high fecundity, small body size, early maturity onset, short generation time, and the ability to disperse offspring widely. Organisms with r-selected traits range from bacteria and diatoms, through insects and weeds, to various semelparous cephalopods and mammals, especially small rodents.
In stable or predictable environments, K-selection predominates as the ability to compete successfully for limited resources is crucial and populations of K-selected organisms typically are very constant and close to the maximum that the environment can bear. Traits that are thought to be characteristic of K-selection include: large body size, long life expectancy, and the production of fewer offspring that require extensive parental care until they mature. Organisms with K-selected traits include large organisms such as elephants, trees, humans and whales, but also smaller, long-lived organisms such as Arctic Terns.
-MacArthur, R. and Wilson, E.O. (1967). The Theory of Island Biogeography, Princeton University Press
-Lecture notes from FUNDAMENTAL ECOLOGY with prof. A. Basset (2007)
-Cunningham W., Cunningham M. A., Saigo B. W., “Fundamentals of ecology” , McGraw-Hill, 2007. Cap 9, pag. 229-234
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TROPHIC LEVEL of an organism is the position it occupies on the food chain. Food chains start at trophic level 1 with primary producers, move to herbivores at level 2, predators at level 3 and typically finish with carnivores or apex predators at level 4 or 5. The path along the chain forms a one-way flow along which energy travels in the form of food.
Trophic levels can be represented by numbers, starting at level 1 with plants. Further trophic levels are numbered subsequently according to how far the organism is along the food chain.
- Level 1: Plants and algae make their own food and are called primary producers.
- Level 2: Herbivores eat plants and are called primary consumers.
- Level 3: Carnivores which eat herbivores are called secondary consumers.
- Level 4: Carnivores which eat other carnivores are called tertiary consumers.
- Level 5: Apex predators which have no predators are at the top of the food chain.
-Cunningham W., Cunningham M. A., Saigo B. W., “Fundamentals of ecology” , McGraw-Hill., 2007. Cap 6, pag. 149
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FOOD WEBS are representations of the predator-prey relationships between species within an ecosystem or habitat. A food web is a series of related food chains displaying the movement of energy and matter through an ecosystem. The food web is divided into two broad categories: the grazing web, beginning with autotrophs, and the detrital web, beginning with organic debris. There are many food chains contained in these food webs.
In a grazing web, energy and nutrients move from plants to the herbivores consuming them to the carnivores or omnivores preying upon the herbivores.
In a detrital web, plant and animal matter is broken down by decomposers, e.g., bacteria and fungi, and moves to detritivores and then carnivores.
There are often relationships between the detrital web and the grazing web. Mushrooms produced by decomposers in the detrital web become a food source for deer, squirrels, and mice in the grazing web. Earthworms eaten by robins are detritivores consuming decaying leaves.
-Egerton FN (2007) Understanding food chains and food webs, 1700-1970. Bulletin of the Ecological Society of America 88:50-69.
-Cunningham W., Cunningham M. A., Saigo B. W., “Fundamentals of ecology” , McGraw-Hill., 2007. Cap 6, pag. 152-153
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COMPETITION
The competition can be defined as an interaction between biological organisms or species for which the attitude (or biological adaptation) is reduced to a Due to the presence of the other. There is a limitation on the amount a resource used by both organisms or species that resource can be food, water, land, possibility of mating. The competition is one of several biotic and abiotic factors that affect the structure of ecological communities. The competition between members of the same species is called intraspecific competition and that which takes place between members of different species is interspecific competition. The competition is a phenomenon not always simple and direct, but it can also happen indirectly. According to the principle of competitive exclusion species less likely to compete must meet or, otherwise, they are forced to become extinct. According to the theory of competition within a species and between species plays a key role in natural selection
(- , -).
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Types of competition:
Intraspecific Competition : It happens when members of the same species are necessitated to make use of that resource in an ecosystem, such as a territory or of places where to build nests.
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Interspecific competition: It happens between individuals of different species that share a common resource in the same area. If the resource is not enough to keep both populations, the result is a reduction in fertility, growth and survival of one or more species. Interspecific competition may affect populations, communities and the evolution of species included. For example, lions and cheetahs or chitas and their prey in Africa. All are fed the same prey and sometimes find themselves in conflict.
Competition for interference: It happens directly between individuals during the act of aggression, etc.. when an individual interferes with others for food, survival, reproduction, or to settle in a portion of the habitat.
Exploitation Competition: It happens indirectly because of the common limited resource that acts as an intermediary. For example, the use of a resource shortage for some cause or other, including competition for space.
Sea anemones competing for territory
Apparent Competition: It happens when two species indirectly, for example, are common prey of a predator. In this case there is competition for space by predators.
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PREDATION
Predation is a type of antagonistic interaction in which a predator body uses food as a source of prey to another body. There is talk of prey in both the animal and vegetable field. Due to predation, predators can play a key role in the food chain, controlling the population of prey and encouraging the evolutionary thrust, leading to the development of predator adaptations (- , +).
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SYMBIOSIS
The term symbiosis (from the greek sun and that is life with the bios) it indicates the relationship that develops between two individuals of different species, aimed at mutual benefit or at least one partner without the other will receive damage.
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Type of symbiosis:
MUTUALISM: is a form of mutual interaction between two individuals of different species, thanks to which both are able to receive benefits.
This concept is also extended to the social sphere, coming to show an association between two or more individuals that is based on rules of reciprocity (+ , +).
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NEUTRALISM: is a biological relationship in which none of the interspecific individuals receive the benefit or injury (0 , 0).
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AMENSALISM: is a type of interaction between species where one impedes and diminishes the success of another, without at the same time draw neither advantage nor disadvantage (- , 0).
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COMMENSALIS: not obligatory symbiotic interaction between two living beings in which one takes advantage of the food waste or the other without causing pain or discomfort (+ , 0).
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PARASSITISM: is a form of biological interaction, generally of trophic between two species of organisms, one of which is called the parasite and the other guest. The parasite obtains a benefit (food, protection) at the expense of the guest biological damage assessed (+ , -).
Begon, M., Townsend, C., Harper, J. (1996). Ecology: Individuals, populations and communities (Third edition). Blackwell Science, London.
Begon, M.; Harper, J. L.; Townsend, C. R. (1996) Ecology: Individuals, populations and communities Blackwell Science.
Henry George Liddell, Robert Scott. A Greek-English Lexicon at Perseus Project
Sahney, S., Benton, M.J. and Ferry, P.A. (2010). "Links between global taxonomic diversity, ecological diversity and the expansion of vertebrates on land" (PDF). Biology Letters 6 (4): 544–547.
Solomon, EP, Berg, LR, e Martin, DWP (2002). Biology, sesta edizione . (N. Rosa, ndr.). Stanford, CT: Thomson Learning.
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ABIOTIC FACTORS
A non-living chemical or physical factor in the environment, such as soil, pH, forest fire, etc.
Abiotic factors may be grouped into the following main categories:
- climatic factors - include sunlight, humidity, temperature, atmosphere, etc.
- edaphic factors - include the nature and type of the soil, geology of the land, etc.
- social factors - include land use, water resources, etc.
Many different abiotic factors an animal or plant species and also interact and change with time themselves.
For example: temperature is dependent upon:solar radiation, wind speed, time of year, time of day, altitude and aspect.
Temperature affects water loss from organisms and respiration, and for plants the rate of photosynthesis. Changes in temperature affect relative humidity and evaporation from water bodies and soils.
-http://sciencebitz.com/?page_id=23
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BIOTIC FACTORS
Biotic Factors: Biotic factors are the organisms that living in a certain ecosystem and also what they make up in this ecosystem.
The biotic components usually have:
1. Producers: they convert the sun's energy into chemical/food i.e. plants
2. Consumers: they depend upon producers for food.
3. Decomposers: they take the chemicals from producers and consumers and break them into simpler form so they can be reused. i.e. fungi & bacteria.
Biotic components are the living things that shape an ecosystem. They are, any living component that affects another organism. As opposed to abiotic components (non-living components of an organism's environment, such as temperature, light, moisture, air currents, etc.), biotic components are the living components of an organism environment, such as predators and prey. E.G. competition between organisms for resources such as food, oxygen, light, etc. Biotic factors are the living factors in an ecosystem instead abiotic factors are non-living such as the temperature/climate or the area surrounding it. Also the interactions among the organisms are included in the biotic factors. Abiotic factors include human influence, in a measure also more damages respect to biotic components. ( Wikipedia)
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BIOGEOCHEMICAL CYCLES
Biogeochemical cycle or nutrient cycle is a pathway by which a chemical element or molecule moves through both biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) compartments of Earth. In effect, the element is recycled, although in some cycles there may be places (called reservoirs) where the element is accumulated or held for a long period of time (such as an ocean or lake for water). Water, for example, is always recycled through the water cycle. The water undergoes evaporation, condensation, and precipitation, falling back to Earth clean and fresh. Elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another through the biogeochemical cycles.
All chemical elements occurring in organisms are part of biogeochemical cycles. In addition to being a part of living organisms, these chemical elements also cycle through abiotic factors of ecosystems such as water (hydrosphere), land (lithosphere), and the air (atmosphere). The living factors of the planet can be referred to collectively as the biosphere. All the nutrients—such as carbon, nitrogen, oxygen, phosphorus, and sulfur—used in ecosystems by living organisms operate on a closed system; therefore, these chemicals are recycled instead of being lost and replenished constantly such as in an open system.
The flow of energy in an ecosystem is an open system; the sun constantly gives the planet energy in the form of light while it is eventually used and lost in the form of heat throughout the trophic levels of a food web. Carbon is used to make carbohydrates, fats, and proteins, the major sources of food energy. These compounds are oxidized to release carbon dioxide, which can be captured by plants to make organic compounds. The chemical reaction is powered by the light energy of the sun.
It is possible for an ecosystem to obtain energy without sunlight. For istance, ecosystems in the deep sea, where no sunlight can penetrate, use sulfur compounds. Hydrogen sulfide near hydrothermal vents can be utilized by organisms such as the giant tube worm. In the sulfur cycle, sulfur can be forever recycled as a source of energy. Energy can be released through the oxidation and reduction of sulfur compounds (e.g., oxidizing elemental sulfur to sulfite and then to sulfate). (Wikipedia)
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CONSUMERS
Consumers are animals that eat or consume food as opposed to producers (plants) that make their own food.
Consumers can be:
- Herbivores-- animals that eat plants.
- Carnivores-- animals that eat other animals.
- Omnivores-- animals that eat everything.
Consumers are the next link in a food chain. There are three levels of consumers. The levels start with the organisms that eat plants. Scientists named this first group of organisms the primary consumers. They are also called herbivores. They are the plant eaters of the chain. It might be a squirrel or it might be an elk. It will be out there eating plants and fruits. It will not eat animals.
Secondary consumers eat the primary consumers. A mouse might be a primary consumer and a cat might be the secondary. Secondary consumers are also called carnivores. Carnivore means "meat eater."
In some ecosystems, there is a third level of consumer called the tertiary consumer (that means third level). These are consumers that eat the secondary and primary consumers. A tertiary consumer could be a wolf that eats the cat and the mouse.
There are also consumers called omnivores. Omnivores can either be secondary or tertiary consumers. Humans and bears are considered omnivores: we eat meat, plants, and just about anything.
McGraw-Hill, Marine Biology 2003
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PRODUCERS
Producers are the beginning of a simple food chain. Producers are organisms that produce complex organic compounds (such as carbohydrates,fats, and proteins) from simple inorganic molecules using energy from light (by photosynthesis) or inorganic chemical reactions (chemosynthesis). They are the producers in a food chain, such as plants on land or algae in water. Plants are at the beginning of every food chain that involves the Sun. All energy comes from the Sun and plants are the ones who make food with that energy. Plants also make loads of other nutrients for other organisms to eat.
There are also photosynthetic protists that start food chains. Producers can be phototrophs or lithotrophs (chemoautotrophs). Phototrophs use light as an energy source, while lithotrophs oxidize inorganic compounds, such as hydrogen sulfide, elemental sulfur, ammonium and ferrous iron. Phototrophs and lithotrophs use a portion of the ATP produced during photosynthesis or the oxidation of inorganic compounds to reduce NADP+to NADPH in order to form organic compounds.
McGraw-Hill, Marine Biology 2003
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DECOMPOSERS
The last links in the chain are the decomposers. Decomposers (or saprotrophs) are organisms that break down dead or decaying organisms, and in doing so carry out the natural process of decomposition. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrients for growth and development. Decomposers use deceased organisms and non-living organic compounds as their food source.
Decomposers break down nutrients in the dead "stuff" and return it to the soil. The producers can then use the nutrients and elements once it's in the soil. The decomposers complete the system, returning essential molecules to the producers.
I.e. fungi and bacteria are decomposers but also some worms are considered decomposers.
McGraw-Hill, Marine Biology 2003
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