the identity of species present in the community.Two communities could have identical species diversity values, but have completely different species.The identity of species is critical to understanding community structure.
Trophic facilitation occurs when
a consumer is indirectly facilitated by a positive interaction between its prey and another species.
Dominant species (foundation species) can have a large effect on other species and species diversity by virtue of
high abundance or biomass.Dominant species may also be dominant by virtue of being good competitors for space, nutrients, or light
Critical species in environment
Some dominant species are ecosystem engineers—they ...
create, modify, or maintain physical habitat for themselves and other species ie trees
Context-dependent species interactions can
change under different environmental conditions.
Some keystone species play important roles in their communities in one context, but not in another.
Each feeding category, or trophic level, is based on
the number of feeding steps by which it is separated from autotrophs.
Concept 20.1: Trophic levels describe the
feeding positions of groups of organisms in ecosystems.
Concept 20.2: The amount of energy transferred from one trophic level to the next depends on
food quality and consumer abundance and physiology.
Concept 20.3: Changes in the abundances of organisms at one trophic level can influence
energy flow at multiple trophic levels.
Concept 20.4: Food webs are conceptual models of the
trophic interactions of organisms in an ecosystem.
Much of the input of detritus into streams, lakes, and estuarine ecosystems is derived from terrestrial organic matter.These external energy inputs are called ---------------.Energy produced by autotrophs within the system is ----------------
The second law of thermodynamics states that
during any transfer of energy, some is lost due to the tendency toward an increase in disorder (entropy).Energy will decrease with each trophic level.