Population (Distribution/Abundance, Growth/Regulation, Dynamics)

Question 1

Distribution

Answer 1

large scale geographic range over which a species may occur

Question 2

Dispersion

Answer 2

spatial arrangement of individuals within a population – depends on location of essential resources, competition, dispersal, and behavioral interactions

Question 3

what factors alter Nt+1?

Answer 3

The number of individuals in the population at time t, the growth rate of the population and the value for t – i.e. how MUCH time?

Question 4

Random dispersion

Answer 4

Neutral interactions between individuals (no competition) and neutral interactions between individual and enviro

Question 5

Regular dispersion

Answer 5

Antagonistic interactions between individuals or local depletion of resources.

Question 6

Clumped dispersion

Answer 6

Attraction between individuals or attraction of individuals to a common resource

Question 7

Why and for what types of organisms do you use a mark recapture study?

Answer 7

to determine population abundance, used for mobile organisms

Question 8

When do you use N = (m*c)/r ?

what does each variable stand for?

Answer 8

for mark recapture studies
N = estimated pop abundance, m = initial count captured and marked,
c = total recaptured, r = marked recaptured

Question 9

When do you use the exponential growth equation and when do you use the geometric growth equation?

Answer 9

Use exponential when the population growth is continuous (i.e. reproduce year round)
Use geometric when the population grows over discrete time intervals (i.e. growth is not continuous)

Question 10

How is the per capita rate of increase related to body size?

Answer 10

In general, the bigger the species, the smaller the rate of increase. Exception - Large ectotherms can have a larger growth rate because they can put more energy into reproduction

Question 11

What is the purpose of a Life table?

Answer 11

Summarize the likelihood that organisms in a population will live/die and/or reproduce at different life stages

Question 12

Static Life Tables

what are they, and which kinds of organisms is it useful for?

Answer 12

“snapshot” of age specific survival and fecundity in a population over a short period of time. Used for mobile organisms

Question 13

Cohort Life Tables

what are they, and which kinds of organisms are they useful for?

Answer 13

selects individuals born at the same time and keeps records from birth until at least one dies. Used for plants, invertebrates, etc.

Question 14

For predicting the future population size of a population growing exponentially or geometrically, what key assumptions must be made?

Answer 14

Environmental conditions must remain constant
No immigration or emigration
No genetic structure in birth/death – i.e. no predisposition to not be capable of reproduction or to dying sooner
No age or size structure
Continuous growth with no time lags

Question 15

Explain a type I survivorship curve

Answer 15

probability of survival is great at a young age then decreases with age (ex- humans, large mammals)

Question 16

Explain a type II survivorship curve

Answer 16

The probability of dying is constant throughout entire life span (ex- animals with high predation rates: birds, mice, etc.)

Question 17

Explain a type III survivorship curve

Answer 17

survivorship of offspring is low- these organisms produce lots of offspring (ex- fish, coral, plants)

Question 18

How are age distributions useful?

Answer 18

they indicate if a population is stable, growing, or shrinking

Question 19

What is carrying capacity (K)

Answer 19

the max number of individuals that can be supported due to limiting resources (birth rate = death rate)

Question 20

What is the inflection point?

Answer 20

K/2

Question 21

Demographic stochasticity

Answer 21

randomness associated with birth and death

Question 22

Environmental stochasticity

Answer 22

random environmental fluctuations

Question 23

Allee effects

Answer 23

when r or λ decreases because of low population density

Question 24

effective pop size

Answer 24

number of individuals in a pop who contribute offspring to the next generation

Question 25

What genetic problems plague small populations?

Answer 25

Inbreeding depression, genetic drift, loss of heterozygosity

Question 26

Interspecific competition

Answer 26

competition among individuals of 2 or more species

Question 27

Intraspecific competition

Answer 27

competition among members of the same species

Question 28

Exploitative competition

Answer 28

use of resources by one or more individuals, thereby reducing the available resources for other individuals (ex: plants competing for resources in soil, etc.)

Question 29

Interference competition

Answer 29

direct, aggressive interaction between individuals

Question 30

What is the competitive exclusion principle?

Answer 30

If Niche overlap is high and competition is uneven, the stronger competitor will potentially drive the weak competitor to extinction

Question 31

fundamental niche

Answer 31

niche space defined only by physical factors and resource requirements (absence of other organisms)

Question 32

realized niche

Answer 32

niche space determined by combining physical and biological factors (competition, predation, etc.)

Question 33

What is character displacement

Answer 33

evolution stemming from selection to reduce resource competition between species
(ex- differing finch beak size when competition is present)

Question 34

Predation

Answer 34

individuals of one species (predator) benefit by feeding on and directly harming another species (prey)

Question 35

Parasitism

Answer 35

predator (parasite) lives symbiotically on or in the prey (host) and consumes certain tissues; may not necessarily kill the host

Question 36

Pathogens

Answer 36

parasites that cause disease

Question 37

Hyperparasitoids

Answer 37

parasites of parasites. they specialize in parasitizing insects that themselves are parasitic on other insects

Question 38

what is lx on a life table? How do you calculate it?

Answer 38

survivorship - how many individuals make it from birth to age class of interest
Nx(interest)/Nx(0)

Question 39

what is Sx on a life table? How do you calculate it?

Answer 39

survival rate - proportion of individuals of one age class that survive to the next
Nx+1/Nx

Question 40

what is Fx on a life table?

Answer 40

fecundity - average number of offspring produced per female