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Food chain in a Swedish lake. Osprey feed on northern pike, which in turn feed on perch which eat bleak which eat crustaceans.. A food chain is a linear network of links in a food web, often starting with an autotroph (such as grass or algae), also called a producer, and typically ending at an apex predator (such as grizzly bears or killer whales), detritivore (such as earthworms and woodlice ...
Ecosystem classifications are specific kinds of ecological classifications that consider all four elements of the definition of ecosystems: a biotic component, an abiotic complex, the interactions between and within them, and the physical space they occupy. Biotic factors of the ecosystem are living things; such as plants, animals, and bacteria ...
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").
A freshwater aquatic food web. The blue arrows show a complete food chain (algae → daphnia → gizzard shad → largemouth bass → great blue heron). A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community.
Ecosystem services are ecologically mediated functional processes essential to sustaining healthy human societies. [6] Water provision and filtration, production of biomass in forestry, agriculture, and fisheries, and removal of greenhouse gases such as carbon dioxide (CO 2) from the atmosphere are examples of ecosystem services essential to public health and economic opportunity.
Also Gause's law. A biological rule which states that two species cannot coexist in the same environment if they are competing for exactly the same resource, often memorably summarized as "complete competitors cannot coexist". coniferous forest One of the primary terrestrial biomes, culminating in the taiga. conservation biology The study of Earth's biodiversity with the aim of protecting and ...
For example, among aquatic ecosystems, higher rates of production are usually found in large rivers and shallow lakes than in deep lakes and clear headwater streams. [25] Among terrestrial ecosystems, marshes, swamps, and tropical rainforests have the highest primary production rates, whereas tundra and alpine ecosystems have the lowest. [25]
In small, forested streams, for example, the volume of higher levels is greater than could be supported by the local primary production. Energy usually enters ecosystems from the Sun. The primary producers at the base of the pyramid use solar radiation to power photosynthesis which produces food.