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population equilibrium

balance between births and deaths

exponential increase

a geometric progression

population explosion

exponential growth in a population

biotic potential

number of possible offspring produced under optimal conditions

environmental resistance

all biotic and abiotic factors that can limit population growth


survival of organisms to enter breeding population

r strategy

many offspring (high biotic potential); many die

k strategy

few offspring (low biotic potential); nurture them all

replacement level

the rate at which organisms are replaced when they die

dynamic balance

birth rate and death rate are approx. equal

carrying capacity (K)

maximum number of organisms that can be supported by an ecosystem


maximum upper limit of the S-curve

population density

number of individuals per unit area; directly porportional to environmental resistance

limiting factors

biotic and abiotic factors which limit population growth

density dependent factors

limiting factors affected by the population size; (S Curve)

density independant factors

not affected by population size; (J Curve)

critical number

minimum number of individuals in a population needed to prevent extinction


the actions of predators upon their prey


an agent carrying the parasite from one host fo another


herbivores' depletion of plants faster than they can grow back

Third Basic Principle

The size of consumer populations in ecosystems is maintained such that overgrazing and other forms of overuse do not occur

competitive exclusion

one species is forced out of the niche

interspecific competition

competition between different species


air plants that live on other tree's limbs; they are not parasitic

balanced herbivory

a balance among competing plant populations, kept in check by herbivores


growth of a single species in an area; prone to attack by host-specific orgaisms


relating to, living, or located on the bank of a natural watercourse


organisms defending an area against members of their OWN species

instraspecific competition

competition between members of the same species


characteristics of an organism


deoxyribonucleic acid


composted of sugar, phosphate, and nitrogen base


segment of DNA coding for a specific protein


cell division


formation of gametes


alternate forms of the same gene


a random mistake in the gene sequence

lethal mutation

results in the death of the individual

neutral mutation

does not benefit or harm the individual

selective pressures

biotic and abiotic limiting factors of environmental resistance

natural selection

natural modification of the gene pool

genetic variation

genetic differences between individuals in a population

gene pool

all the genes in a population

differential reproduction

some members of a species reproduce more than others

biological evolution

changes in the gene pool over time

selective breeding

breeding is done to bring out specific traits; example of artificial selection


adaption to the point of becmong a new species through natural selection and mutations

tectonic plates

slabs of rock moving on top of an elastic moleten rock layer

convergent plate boundary

plates meet "converge" and one goes underneath


oceanic plate slides under a contintal plate

divergent plate boundary

plate moves apart (sea floor spreading)

transform fault

plates move past each other laterally

continental plate collision

two plates converge and push upward

Cambrian explosion

most major groups of animals first appear in fossil record


evolutionary change at or above species level


evolutionary change in alleles

stewardship of life

to prevent extinction and to preserve biodiversity

mass extinction

a cyclical event; 5 major ones in history

Equilibrium theory

ecosystems are stable environments with competition and predation occurring (biotic interactions)

Noneqilbrium theory

ecosystems are in a constant stae of change

primary succession

the first species colonizations in a previously barren area


mutualistsc algae and fungi

climax ecosystem

a stable, balanced ecosystem not undergoing further succession

secondary succession

re-colonization of an area after disturbance

chaos theory

first stages of ecosystem development are extremely important; ecosystems are very sensitive to small changes


maintenance of normal functioning and integrity even through a disturbance

resilience mechanisms

how an ecosystem recovers and deals with a disturbance

Fourth basic principle

Ecosystems show resilience when subject to disturbance

Fifth basic principle

Ecosystems depend on biodiversity

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