Population Ecology

Question 1

variables determining the growth rate of a population

Answer 1

age classes, sex ratio, generation time,

Question 2

life table

Answer 2

fecundity (# of offspring/female -> birth rate)
survivorship (fraction of individuals living to each age –> death rate)

Question 3

variables on a life table

Answer 3

overall survivorship- age/# survivors
age specific fecundity- average # offspring prof of that age
total offspring prod- average fecundity x survivorship x # survived
offspring/original females- add

Question 4

survivorship curve types

Answer 4

type 1- healthy throughout all life -> death
type 2- linear line, rate of death is the same as you get older
type 3- rate of death is low from young

Question 5

life history strategy trade offs (relationship between fecundity and survivorship)

Answer 5

high fecundity -> low survivorship
low fecundity -> high survivorship

Question 6

difference between r-selected and k-selected species

Answer 6

r-selected: prod large # of offspring the fastest (fruit flies, weedy plants, mold) - near carrying capacity
k-selected: waits to reproduce with quality and wins competition (bears, kiwis, whales)

Question 7

exponential density independent growth

Answer 7

birth rate, death rate (immigration and emigration)
its exponential growth if r=1 and N0=2
if r=1, for every individual add 1 next gen
N1=N0+rN0

r: rate of birth- death
N0: pop @ gen 0
N1: pop @ gen 1

Question 8

logistic density dependent growth

Answer 8

limitations added (sunlight, H20, food, shelter)
growth slows as population size increases
max pop reached when growth ceases (k)
per capita rate increases depending on N distance to K

N1=N0+rmax(k-N0/K) N0

Question 9

fluctuations in population size

Answer 9

density dependent factors- time delayed
- when pop increases, pop crashes due to food resources, predator increase

density independent factors- vary over time
- seasonal temp changes, natural disasters can affect

Question 10

metapopulation

Answer 10

when population is divided into individual populations capable of exchanging individuals
- birth and death rates
- immigration and emigration rates
- local extinction rates

extinction rates: pop size, patch size/quality, environment variability
recolonization rates: patch size/quality, distance/size of other patch, intervening environments, species mobility