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Biodiversity plays a major role in the productivity and functioning of ecosystems, affects their ability to provide ecosystem services. [2] For example, biodiversity is a source of food, medication, and materials used in industry. Recreation and tourism are also examples of human economic activities that rely on these benefits.
A species that is a dominant primary producer in its ecosystem, both in terms of abundance and influence on other organisms and the environment. founder effect The accumulation of random genetic changes in an isolated population. freshwater biology functional ecology
Gross primary production (GPP) is the amount of chemical energy, typically expressed as carbon biomass, that primary producers create in a given length of time.Some fraction of this fixed energy is used by primary producers for cellular respiration and maintenance of existing tissues (i.e., "growth respiration" and "maintenance respiration").
This means primary producers become the starting point in the food chain for heterotroph organisms that do eat other organisms. Some marine primary producers are specialised bacteria and archaea which are chemotrophs, making their own food by gathering around hydrothermal vents and cold seeps and using chemosynthesis.
Other researchers believe that the relationship between species diversity and productivity is unimodal within an ecosystem. [27] A 1999 study on grassland ecosystems in Europe, for example, found that increasing species diversity initially increased productivity but gradually leveled off at intermediate levels of diversity. [28]
As with the others, this graph shows producers at the bottom and higher trophic levels on top. When an ecosystem is healthy, this graph produces a standard ecological pyramid. This is because, in order for the ecosystem to sustain itself, there must be more energy at lower trophic levels than there is at higher trophic levels.
Primary succession is the beginning step of ecological succession where species known as pioneer species colonize an uninhabited site, which usually occurs in an environment devoid of vegetation and other organisms. In contrast, secondary succession occurs on substrates that previously supported vegetation before an ecological disturbance. This ...
Out of a total of 28,400 terawatt-hours (96.8 × 10 ^ 15 BTU) of energy used in the US in 1999, 10.5% was used in food production, [3] with the percentage accounting for food from both producer and primary consumer trophic levels. In comparing the cultivation of animals versus plants, there is a clear difference in magnitude of energy efficiency.