Population Growth Flashcards
Birth Rate
number of births in a given period of time
Death Rate
number of deaths in a given period of time
Immigration Rate
individuals entering a community
Emigration Rate
individuals leaving a community
What do the birth, death, immigration, emigration ratios look like in a stable population?
B + I = D + E
What do the birth, death, immigration, emigration ratios look like in a growing population?
B + I > D + E
What do the birth, death, immigration, emigration ratios look like in a decreasing population?
B + I < D + E
Exponential Growth
growth of a population that appears to continue unchecked
shows a J-curve on a graph
Logistic Growth
growth of a population that does not grow past a certain limit
shows an S-curve
Carrying Capacity
the number of organisms in a population that the environment can maintain or “carry” with no net increase or decrease
Types of limiting factors
density-dependent and density-independent
density-dependent factors
A factor that limits a population more as the population density increases
ex) food availability, water availability, shelter
density-independent factors
Factors that limit populations but are unrelated to population size or density
ex) weather, natural disasters, flood acidity
What do all density-independent factors have in common?
they’re all abiotic
lag phase of growth curves
when the population is beginning to colonize an area
