ecosystem dynamic Flashcards
carry capacity
maximum population size of a species that can be supported indefinitely
environmental resistance
sum of total environmental limiting factors that will impact the carrying capacity of an ecosystem
limiting factors
a biotic or abiotic factor that controls (limits) the growth of population
limiting factors may be…
density-dependent or density-independent
density-dependent
factors that depend on population size and affect can becomes greater with an increase in population
density-independent
limiting factors that will affect a population regardless of its size
example of density-independent factor
human disturbance eg. hunting
natural disasters - weather related
example of density-dependent factor
competition, predation, disease
patterns of population growth
exponential, j-curve and logistic, s-curve
exponential growth, j-curve
the growth of a population in an ideal, unlimited environment
characteristics of exponential growth, j-curve
- cannot continue in the real world as resources become too depleted.
- tend to have a boom before the carrying capacity or another factor dramatically reduces the bust.
characteristics of logistic growth, s-curve
- occurs when a few members of a species colonise a new favourable habitat
- population increases at a fast rate until resources are used and population growth approaches 0
- the carrying capacity may be determined by shelter, nest sites, and food
logistic growth, s-curve
population growth that levels off as population sizes approaches the carrying capacity
when can a carrying capacity change?
if the environmental conditions change
population change
change in number of individuals in a given time period
population change formula
population change = (births + immigrants) - (deaths + emigrants)
lincoln index
a formula we substitute values into based on a sampling technique (capture, mark, recapture)
capture-recapture method
method of estimating population density involves animals being captures, marked, and released
lincoln index formula
Size of population (N) = (M × n) / m
M, m, n meanings in lincoln index
M = number of originally marked individuals
n = total number captured in the second sample
m = number of recaptured (marked) in the second sample
