environmetal science vocabulary

ecology
the study of how organisms interact with one another and their environments.
species
a group of individuals that interbreed and produce fertile offspring.
population
the members of a species that live in the same area.
community
all of the population in a particular area.
ecosystem
all living things and their physical environments within a particular area.
biosphere
the Earth and all of its organisms and environments.
biotic factor
any part of an ecosystem that is living
habitat
the specific environment in which an organism lives.
resource
anything an organism needs; includes nutrition, shelter, mates, and breeding sites.
population size
the number of individual organisms present in a population at a given time.
population density
the number of individuals in a population per unit of area.
population distribution
how organisms are arranged within an area; sometimes called population dispersion.
age structure
the relative number of organisms of each age within a population; also called age distribution.
age structure diagram
a chat that shows the age distribution of a population; also called age pyramid.
sex ratio
the proportion of males to females in a population.
survivorship curve
a graph showing the likelihood of survival within a group or population by age.
immigration
the arrival of individuals from outside a given area.
emigration
the movement of individuals away from a given area.
migration
the seasonal movement of organisms into and out of an area.
exponential growth
the pattern of population growth in which a population increases by a fixed percentage each year.
limiting factor
a characteristic of the environment that restricts population growth.
carrying capacity
the largest population a given environment can support.
logistic growth
the pattern of population growth in which exponential growth is slowed and finally stopped by limiting factors.
density-dependent factor
a limiting factor whose influence changes with population density; includes competition, predation, and disease.
density-independent factor
a limiting factor whose influence is not affected by population density; includes catastrophic events.
biotic potential
the growth rate of a population under ideal conditions.
abiotic factor
any part of an ecosystem that has never been living.