Studied by 28 people
Abiotic Factor
Physical, or nonliving, factor that shapes an ecosystem.
Age structure
The distribution of individuals among different ages in a population.
Biodiversity
The diversity of plant and animal life in a particular habitat (or in the world as a whole).
Biosphere
The part of the earth, including air, land, surface rocks, and water, within which life occurs.
Biome
A major biotic community characterized by the dominant forms of plant life and the prevailing climate.
Biotic factor
Biological influence on organisms within an ecosystem.
Carrying capacity
Largest number of individuals of a population that a environment can support.
Community
All the different populations that live together in an area.
Density dependent factor
Limiting factor that depends on population size.
Gross primary productivity
The rate at which producers in an ecosystem capture energy.
Net primary productivity
The rate at which biomass accumulates in an ecosystem.
Habitat
The place where an organism lives.
Nutrient cycle
Continuous flow of nutrients into and out of stores in the ecosystem; balanced, unless disturbed by human activity.
Competition
Organisms compete for the limited number of biotic and abiotic factors.
Interspecific competition
In a community competition for resources between members of different species.
Intraspecific competition
In a community competition for resources among members of the same species.
Distribution
The arrangement of something across Earth's surface.
K-selection (density-dependent selection)
Selection for life history traits that are sensitive to population density.
R-selection (density-independent selection)
Selection for life history traits that maximize reproductive success in uncrowded environments.
Logistic growth
Growth pattern in which a population's growth rate slows or stops following a period of exponential growth.
Exponential growth
Growth pattern in which the individuals in a population reproduce at a constant rate.
Species
A group of similar organisms whose members can mate with one another and produce fertile offspring.
Keystone species
A species that is critical to the functioning of the ecosystem in which it lives because it affects the survival and abundance of many other species in its community.
Parasite
An organism that lives on or in a host and causes harm to the host.
Photoautotroph
Organism that uses energy from sunlight to convert carbon dioxide and water to carbon compounds.
Population
A group of organisms of the same species populating a given area.
Population growth
The increasing and decreasing of a population.
Pollution
Undesirable state of the natural environment being contaminated with harmful substances as a consequence of human activities.
Primary consumer
An organism that eats producers.
Secondary consumer
An organism that eats primary consumers.
Quadrat
Any of a group of small, usually rectangular plots of land arranged for close study of the distribution of plants or animals in an area.
Rate of increase
Birth rate minus the death rate, suggesting the annual rate of population growth without considering net migration.
Niche
An organism's particular role in an ecosystem, or how it makes its living.
Ecological pyramid
Diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or food web.
Trophic level
Step in the movement of energy through an ecosystem; an organism's feeding status in an ecosystem.
Ten percent rule
The general observation that only ten percent of energy available at one trophic level is actually passed up to the next.
Trophic efficiency
The percentage of production transferred from one trophic level to the next.
Ecological succession
The gradual and orderly process of change in an ecosystem brought about by the progressive replacement of one community by another until a stable climax is established.
Ecosystem
Collection of all the organisms that live in a particular place, together with their nonliving environment.
Limiting factor
Any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms.
Migration
The periodic passage of groups of animals (especially birds or fishes) from one region to another for feeding or breeding.
Mortality
Death rate in a population; the probability of dying.
Mutualism
Symbiotic relationship in which both species benefit from the relationship.
Survivorship curve
A plot of the number of members of a cohort (group) that are still alive at each age (one way to represent age-specific mortality).
Host
An organism that provides a source of energy or a suitable environment for a virus or for another organism to live.
Symbiosis
The living in a mutually helpful association of two dissimilar organisms.
Commensalism
A symbiotic relationship in which one organism benefits and the other is unaffected.
Transpiration
The process by which water is lost through a plant's leaves.
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