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An ecosystem (or ecological system) is a system that environments and their organisms form through their interaction. [2]: 458 The biotic and abiotic components are linked together through nutrient cycles and energy flows. Ecosystems are controlled by external and internal factors.
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 ...
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 ...
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.
A consumer in a food chain is a living creature that eats organisms from a different population. A consumer is a heterotroph and a producer is an autotroph.Like sea angels, they take in organic moles by consuming other organisms, so they are commonly called consumers.
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.
Plants are the primary producers in most terrestrial ecosystems and form the basis of the food web in those ecosystems. [82] Plants form about 80% of the world biomass at about 450 gigatonnes (4.4 × 10 11 long tons; 5.0 × 10 11 short tons) of carbon. [83]
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. However, most marine primary production comes from organisms which use photosynthesis on the carbon dioxide dissolved in the water.