is a collection of
results in each species occupying a unique ecological
in the community due to
Similar species can coexist in a community if they occupy different
Competition may result in
, where certain characteristics exhibit more divergence between
populations of two species than between
populations of the same two species.
Predation occurs when the
kills and eats the
is an interspecific relationship where two or more species live in direct and intimate contact with one another.
is a relationship where the
one species while the other is not affected.
of a community can be quantified by two
The feeding relationships in a community make up its
its organisms often form a complex
The diversity of some
may depend on one
Some organisms act as
by causing physical changes in the environment; some can act as
in the community.
Natural communities often experience periodic
and undergo changes in diversity in a process called
Species richness in many communities is affected by climatic factors such as
, which can be measured by
as well as
The diversity of isolated ecosystems can be predicted by the island
An ecosystem consists of all the organisms in a
, and all the abiotic factors with which they interact.
through ecosystems, while
Energy entering an ecosystem is converted to
energy by primary
, and can be quantified by
can be represented in a
In most ecosystems, this low trophic efficiency is also reflected in a
Chemicals released by humans can become
in successive trophic levels in a process called
becoming toxic to higher level consumers.
The chemical nutrients
is driven by solar energy on a global scale.
reflects the reciprocal processes of
involves local cycles between organisms and soil or water.
is relatively localized.
added to the soil can runoff into streams, and together with
discharge, can lead to
, excessive algal
in aquatic ecosystems.
Burning fossil fuels releases excess levels of
into the atmosphere, which is associated with global
due to the
Combustion of fossil fuels also releases excess
into the atmosphere, causing
The release of
) has resulted in