population ecology

capture mark recapture technique

technique to estimate large population size

-capture small group of individuals (sample 1) mark and release, recapture small group of individuals (sample 2) and record number of marked individuals

estimated population size equation

#of individuals in 1st sample x total # of 2nd sample/ # of marked individuals in 2nd sample

biotic potential ( r )

unrestricted growth resulting in max growth of population (when the species has its highest birth rate and lowest mortality rate)

r =

birth rate -death rate under ideal conditions. for population to survive r must be greater than 0. (r>0)

carrying capacity (k)

maximum populaiton size that can be sustained in specific environment

exponential growth

-growth happens during a short period of time

-j shaped

logistical growth

-s shaped

-long term growth levels off at carrying capacity

t=

time

N=

population size

r

rate of growth (biotic potential)

K=

carrying capacity

no growth if

N=K (population size is equal to carrying capacity)

limits to population growth

1. Negative density-dependent limit

2. positive density dependent limit

negative density dependent limit

wont limit population size, may spur it

positive density dependent limit

has greater % negative effect as population size increases

short term stress (adaptive responses)

more alert, higher blood pressure and heart rate, higher blood sugar, less interest in food and sex, lower tempuerature and immune functoin

long term stress (chronic health problems)

anxiety, cardiovascular problems. diabetes, depression, infection

age structure

number of individuals of each age group in a population

rapid growth

lots of individuals in reproductive age, population grows even if each women has 2 kids

slow growth

fewer individuals in reproductive age, more in retirement age (SS system issues as baby boomers retire)

negative growth

very few individuals in reproductive age (difficulty funding retirement accounts)

r selected species

produce many offspring, little to no parental care, mature early, shor tlifespan, high reproductive rate (high r), thrive in unstable environments, high juvenile mortality

k selected species

produce few offspring, extensive parental care, mature later, long lifespan, population stays near carrying capacity (k), low juvenile mortality, thrive in stable environments