Ecology biology test Flashcards
(25 cards)
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
The total weight of living matter at each trophic level.
- A pyramid of biomass represents the total dry weight of living material available at each trophic level.
biomass
The different conditions along the boundaries of an ecosystem. The edge
of a habitat or ecosystem is where one habitat or ecosystem meets another.
edge effect
The damage to a habitat by pollution.
Habitat Degradation
excess fertilizers and animal wastes, detergents, (industrial)
chemicals, heavy metals, plastics and nets, spills and dumping, etc.
water pollution
garbage, pesticides (DDT)
land pollution
burning fossil fuels, aerosols (CFCs), chemicals, particulate matter
released by industries, etc.
air pollution
The introduction of new species into an ecosystem, either intentionally or not.
exotic species
The study and implementation of methods to protect biodiversity.
Conservation Biology
Those parts of the environment that are useful or necessary for living
organisms.
natural recources
