Population Ecology

Question 1

what are the three methods for population dispersion within a given density?

Answer 1

1. clumping
2. uniform
3. random

Question 2

what is density dynamics and what are the 2 main ways populations change?

Answer 2

density dynamics = interplay between:
1. emigration = individuals leave a pop
2. immigration = individuals enter a pop

Question 3

what is a life table?

Answer 3

-age specific summaries of the survival patterns for a population ex . how long do most members survive for

Question 4

what are the three types of life cycles?

Answer 4

type 1: low death rates in young/middle age, high death rates in old age
type 2: constant death rate over entire life span
3: high death rates in young, less for survivors

Question 5

how can changes in population be calculated?

Answer 5

change in population = R

R = births - deaths

Question 6

what do the units r, R, N, and T mean?

Answer 6

r = growth per unit time
R = births - deaths / pop change
N = population size
T = time

Question 7

what is the exponential growth model?

Answer 7

-population growth under ideal conditions:
no immigration / emigration, no predation or competition / limit to food

-results in a J shaped curve. r is constant but the population accumulates quicker and quicker

Question 8

what is carrying capacity / K?

Answer 8

the maximum population size that the environment can hold

Question 9

what is a logistic growth curve?

Answer 9

an S shaped curve: pop starts small, gradually increases, and begins to level out as the population gets closer to the carrying capacity (as N = K)

Question 10

what are life history strategies?

Answer 10

traits that affect an organisms birth / death rate
outcomes due to environmental pressures & natural selection

Question 11

what are the 5 types of life history strategies?

Answer 11

1. reproduction
2. clutch size
3. age to maturity
4. level of parental care
5. trade offs

Question 12

what are the two types of reproduction?

Answer 12

1. semelparity: flood environment with offspring one big time and then die
2. iteroparity: produce fewer offspring and spend more time caring for them, but with a higher chance of survival

Question 13

what is clutch size?

Answer 13

the # of offspring produced per reproductive event

Question 14

what is age to maturity and why is it important?

Answer 14

more mature quicker = bigger clutch = more offspring

Question 15

what is the principle of allocation?

Answer 15

-limited # of resources available to an organism = natural selection chooses investment strategy that maximizes reproduction and survival of offspring

Question 16

what are the two types of selection / growth models?

Answer 16

1. selection is sensitive to pop density and favored at high density = K Selection
2. selection is based on max reproductive success at low density = r Selection

Question 17

what are density dependent variables and density independent variables?

Answer 17

density dependent = space, food, nesting sites: K Selected Species [affected by pop size]

density independent = climate change, fire, earthquakes: r Selected

Question 18

what is density dependent population regulation?

Answer 18

a negative feedback mechanism that regulates population growth through many different mechanisms

Question 19

what are the 5 types of density dependent population regulation?

Answer 19

1. competition for resources
2. territoriality
3. disease
4. predation
5. intrinsic factors

Question 20

how does resource competition affect pop regulation?

Answer 20

increasing pop density = increasing competition for resources

Question 21

what is territoriality?

Answer 21

animals marking what their territory is - which can reduce or regulate population size