exam 3 pt 6 (population ecology -> trade off)

population ecology

study of populations in relation to environment, including environmental influences on..

A) density

B) distribution

C) age structure

D) population size

population

a group of individuals of a single species living in the same area

density

the number of individuals per unit area or volume

dispersion

the pattern of spacing among individuals within boundaries of the population

what factors change population density/population size?

A) immigration

B) emigration

C) birth rate

D) death rate

immigration

influx of new individuals from other areas

emigration

the movement of individuals out of a population

what are the patterns of dispersion?

A) clumped

→ individuals aggregate in patches influenced by resource availability + behavior

B) uniform

→ individuals are evenly distributed; may be influenced by social interactions such as territoriality

C) random

→ individual’s position is dependent on others’; occurs in the absence of strong attractions or repulsions

what distribution is this?

clumped

what distribution is this?

uniform

what distribution is this?

random

survivorship curve

graphic way of representing the data in a life table

what are the types of survivorship curves?

A) type 1

→ high survivability of young-middle aged; increased death in old age

B) type 2

→ at any age, the organism has an equal probability of surviving

C) type 3

→ high probability of death in youth; increased probability of old age

semelparity (big-bang reproduction)

reproduce once and die

iteroparity

repeated reproduction

unpredictable environments favor what kind of reproduction?

semelparity

dependable environments favor what kind of reproduction?

iteroparity

survival vs. reproduction trade off

organisms cannot devote the same amount of energy to survival and reproduction

→ they have to make a trade… either reproduce a lot, and have little energy to survive; or survive and have a little energy to reproduce