Ch. 19 Flashcards
uniform dispersion-why+ex.
equal distances between every organisms-try to stay as far as possible ex. birds nesting
major factors to human population growth
better control of disease, better hygiene/ sanitation, stable food supply
problems associated with small populations
inbreeding, vulnerable to extinction
three types of population dispersion
uniform, clumped, random
random-ex.
where food supply is- snakes
survivorship curves
probability that members of a population will survive
survivorship curves type l+ex.
very likely to survive younger but less likely when older ex. humans,large mammals,eagles
survivorship curves type ll+ ex.
chance of dying/living doesn’t change during lifetime ex. birds, squirrels
survivorship curves type lll+ex.
very likely to die when young and less likely to die when older ex.salmon, insects
limiting factors+ ex.
any factor that restrains the growth of a population ex. space, food, clean water
carrying capacity (k)
number of individuals the environment can support over a long period of time
density-independent factors+ ex.
reduce the population by the same proportion regardless of populations size ex. weather, floods, fires
density-dependent factors+ ex.
include resources limitations and are triggered by increasing population density ex.shortages of food or nesting sites
lynx and hare study
Elton thought their cycles were related- more hare= more lynx, less hare= less lynx
lynx and hare/ moose and wolves on island royale
small populations are in much more danger than large populations