variation in population size Flashcards
why does population size vary
due to abiotic and biotic factors as well as intra and inter species compertion
what are the three factors in population dynamics
size
density
dispersion
what is a contributing factor in size
growth rate
what is groeth rate
birth rate - death rate
what are factors effecting density
immigration and emmigration
define immigaration
individuals movement into a population
define emmigration
individuals movement out of a population
what is dispersion
the moving out of an area
what other factors effect density
dependent factors
independent factors
what are density dependent factors
biotic factors in environment that have an increasing effect as pop size increased
what are density independent factors
abiotic factors in the environment that effect population regardless of their density
how is variation in population size measured
on a population growth culture
what is the first stage in population growth culture
lag pahse
what is the lag phase
a slow rate of growth due to low number of organisms meaning their is a lower reproduction rate
what comes after the lag phase
log phase
what is the log phase
rapid growth
why is their rapid growth in the log phase
greater reproductive rate as their is an unlimited resource
br higher than dr
what comes after log phase
stable phase
why does the stable phse occour
as it reaches carrying capacity
define carrying capacity
maximum number of sustainable organisms in the habitat
how does this stable phase occour
br=dr
what can occour during the stable phase
small fluctuations
what are these small fluctuations due to
changes in resources
what comes after the stable phase
death
