Community Ecology Flashcards
Ecological niche
The distinctive lifestyle and role of an organism in a community. It takes into account all abiotic and biotic aspects of the organism’s existence.
Fundamental niche
The potential ecological niche for an organism.
Realized niche
The niche it actually occupies is its realized niche.
Competitive exlusion principle
Two species cannot occupy the same niche in the same community for an indefinite period; one species is excluded by another as a result of competition for a limiting resource.
Resource partitioning
The evolution of differences in resource use. It reduces competition between similar species.
Character displacement
A way to reduce competition in which their structural, ecological, and behavioral characteristics diverge where their ranges overlap.
Symbiosis
It is any intimate or long-term association between two or more species. There are three types of symbiosis.
Mutualism
Both species benefit from each other.
Commensalism
One organism benefits and the other is unaffected.
Keystone species
They are present in relatively small numbers but are crucial in determining the species composition and ecosystem functioning of the entire community.
Dominant species
In contrast to keystone species, dominant species greatly affect the community of which they are a part because they are very common.
Botton-up processes
If they dominate an ecosystem, the availability of resources such as minerals controls the number of producers, which controls the number of herbivores, which control the number of carnivores.
Top-down processes
They regulate ecosystems from the highest trophic level by consumers eating producers. If top-down processes dominate an ecosystem, an increase in the number of top predators cascades down the food web through the herbivores and producers.
Species richness
The number of species within a community.
Species diversity
A measure of the relative importance of each species within a community based on abundance, productivity or size.
Succession
It is the orderly replacement of one community by another.
Primary succession
It occurs in an area that has not previously been inhabited.
Secondary succession
It begins in an area where there was a pre-existing community and well-formed soil.
Intermediate disturbance hypothesis
According to it, species richness is greatest at moderate levels of disturbance, which create a mosaic of habitat patches at different stages of succession.
The organismic model
It views a community as a “super-organism” that goes through certain stages of development (succession) toward adulthood (climax). Biological interactions are primarily responsible for species composition and organisms are highly interdependent.
Individualistic model
The most supported.
Abiotic environmental factors are the primary determinants of species composition in a community, and organisms are somewhat independent of one another.
