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Chapter 18, 19, 20

TermDefinition
Abiotic factor An environmental factor that is not associated with the activities of living organisms
acclimation An organism's change in response to a change in the organism's environment
Ammonification The formation of ammonia compounds in the soil by the action of bacteria on decaying matter
biogeochemical cycle The circulation of substances through living organisms from or to the environment.
biomass Plant material, manure, or any other organic matter that is used as an energy Delete repeated word
biosphere The part of Earth where life exists.
biotic factor an environmental factor that is associated with or results from the activities of living organisms
carbon cycle The movement of carbon from the nonliving environment into living things and back
carnivore an organism that eats animals
chemosynthesis the production of carbohydrates through the use of energy from inorganic molecules instead of light
community a group of various species that live in the same habitat and interact with each other
consumer an organism that eats other organisms or organic matter instead of producing its own nutrients or obtaining nutrients from inorganic sources.
decomposer an organism that feeds by breaking down organic matter from dead organisms
Denitrification the liberation of nitrogen from nitrogen- containing compounds by bacteria in the soil
detritivore a consumer that feeds on dead plants and animals
dormancy a state in which seeds, spores, bulbs, and other reproductive organs stop growth and development and reduce their metabolism
ecological model A model that represents or describes the relationships between the components of an ecological system
ecology the study of interactions of living organisms with one another and with their environment
food chain the pathway of energy transfer through various stages as a result of the feeding patterns of a series of organisms.
food web a diagram that shows the feeding relationships between organisms in an ecosystem.
gross primary productivity The rate at which organic matter is assimilated by plants and other producers during a period of time over a certain area.
groundwater the water that is beneath Earth's surface
habitat the place where an organism usually lives
herbivore an organism that eats only plants
interdependence the dependence of every organism on its connections with other living and nonliving parts of its environment
migration any movement of individuals or populations from one location to another
Net primary productivity the rate at which biomass accumulates in an ecosystem
niche the unique position occupied by a species
nitrification the process by which nitrites and nitrates are produced by bacteria in the soil
nitrogen cycle the cycling of nitrogen between organisms, soil, water, and the atmosphere
nitrogen fixation the process by which gaseous nitrogen is converted into ammonia, a compound that organisms can use to make amino acids and other nitrogen- containing organic molecules.
nitrogen- fixing bacteria Bacteria that convert atmospheric nitrogen into ammonia
omnivore Eats both plants and animals
phosphorus cycle the cyclic movement of phosphorus in different chemical forms from the environment to organisms and then back to the environment
population a group of organisms of the same species that live in a specific geographical area
producer an organism that can make organic molecules from inorganic molecules; a photosynthetic autotroph that serves as the basic food source in an ecosystem
tolerance curve a graph from the performance of an organism versus the value of an environmental variable
transpiration the process by which plants release water vapor into the air through stomata
trophic level one of the steps in a food chain or food pyramid
water cycle the continuous movement of water between the atmosphere, land, and oceans.
age structure the classification of members of a population into groups according to age
agricultural revolution the change from a hunting and gathering society to an agricultural society that began about 10,000 years ago
birth rate the number of births that occur in a period of time in a given area
carrying capacity the largest population that an environment can support at any given time
death rate the number of deaths occurring in a period of time
demographic transition the general pattern of demographic change form high birth and death rates to low birth and death rates.
density- dependent factor a variable affected by the number of organisms present in a given area
developed country a modern, industrialized country in which people are generally better educated and healthier and live longer than people in developing countries do
developing country a country in which the society is less modern and less industrialized and in which inhabitants are generally poorer than they are in developed countries
dispersion the pattern of distribution of organisms in a Ignore
emigration the movement of an individual or group out of its native area
exponential model a model of population growth in which a constant and unlimited growth rate results in geometric increases in population size
growth rate an expression of the increase in the size of an organism or population over a given period of time
hunter- gatherer lifestyle a way of life in which people obtain their food by hunting and gathering wild animals and plants
immigration the movement of an individual or a group to a new community or region
inbreeding the crossing or mating of plants or animals with close relatives
life expectancy the average length of time that an individual is expected to live
limiting factor an environmental factor that prevents an organism or population from reaching its full potential of distribution or activity
logistic model a model of population growth that assumes that finite resource levels limit population growth
population a group of organisms of the same species that live in a specific geographical area
population density the number of individuals of the same species that live in a given unit of area
survivorship curve Graph showing the number or proportion of individuals surviving to each age for a given species or group
climax community a final, stable community in equilibrium with the environment
commensalism a relationship between two organisms which one organism benefits and the other is unaffected
disturbance an event that changes a community by removing or destroying organisms or altering resource availability
ecological succession a gradual process of change and replacement in a community
interspecific competition a relationship between two species in which both species compete for limited resources such that both species are negatively affected by the Delete repeated word
mutualism a relationship between two species in which both species benefit
parasitism a relationship between two species in which one species, benefits from the other species which is harmed
pioneer species a species that colonizes an uninhabited area and that starts an ecological cycle in which many other species become established
predation an interaction between two organisms in which one organism kills and feeds on the other organism
primary succession succession that begins in an area that previously did not support life
secondary succession the process by which one community replaces another community that has been partially or totally destroyed
species evenness a measure of the relative abundance of each species in an ecological community
species richness the number of different species in an area or community
species- area effect a pattern in which the number of species in an area increases as the area increases
stability the tendency of a community to maintain a relatively constant structure
symbiosis a relationship in which two different organisms live in close association with each other
Created by: SnowRider1021