Ecology biology test Flashcards
Organisms, e.g. fungi and certain bacteria, that break down and absorb nutrients
from dead organisms.
decomposer
A model that expresses all the possible feeding relationships at each trophic level in a
community.
food web
Organism in a food chain that represents a feeding step in the passage of energy
and materials through an ecosystem.
trophic level
An increase in the size of a population over time.
Population Growth
As a population gets larger, it grows at a faster rate.
Exponential Population Growth
The number of organisms of one species that an environment can support.
carrying capacity
Any biotic or abiotic factor that restricts the existence, numbers, reproduction, or
distribution of organisms.
limiting factor
Include disease, competition, parasites, and food
Density-dependent factors
Most are abiotic factors, such as temperature, storms, floods, drought, habitat
destruction, and pollution
Density-independent factors
The variety of life in an area; usually measured as the # of species that live there.
biodiversity
The disappearance of a species when the last of its members dies.
extinction
A species is considered endangered if its numbers become so low that
extinction is possible.
Endangered Species
When the population of a species is likely to become endangered.
Threatened Species
deforestation for agriculture, cattle, or lumber
habitat loss
The separation of wilderness areas from other wilderness
areas
habitat fragmentation
