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