Lecture 8: Distributions Dispersal and Populations

Question 1

Dispersal…

Answer 1

How do they get where they are?

Question 2

Dispersion…

Answer 2

Spatial patterns

Question 3

Dispersal is…

Answer 3

The movement of individuals or gametes from their place of origin

Question 4

Zoochory is…

Answer 4

The dispersal of plant seeds, gametes, or clones by animals

Question 5

Some ways of seed dispersal…

Answer 5

-Wind/water
-Gravity
-Ballistic
-Zoochory
-Endozoochory

Question 6

Some ways of pollen dispersal…

Answer 6

-Wind
-Animal-mediated (i.e, animal pollination)

Question 7

T/F) Animal dispersal can also occur at several life stages

Answer 7

True

Question 8

Some ways of animal dispersal…

Answer 8

-Gametes
-Zygotes/eggs
-Juveniles and adults

Question 9

Why disperse?

Answer 9

-Escape diseases/predators
-Reduces competition
-Facilitate gene-flow/avoid in-breeding

Question 10

Janzen-Connell hypothesis…

Answer 10

Positive density-dependent predation + dispersal facilitates co-existence of rainforest tree species

Question 11

Optimal outcrossing distance…

Answer 11

The distance between mating partners that best balances the risk of inbreeding depression with the risk of losing locally adapted genotypes

Question 12

T/F) Different dispersal modes can lead to different dispersion patterns

Answer 12

True

Question 13

Dispersion…

Answer 13

Describes the distribution pattern of objects in space relative to one another

Question 14

Dispersion (ecological) is…

Answer 14

The spacing of individuals with respect to one another within the geographic range of a population

Question 15

Spatial structure of populations reveals processes _________ the recruitment and persistence of individuals

Answer 15

Affecting

Question 16

Can ecological context modify dispersion patterns?

Answer 16

Yes

Question 17

What is an example of ecological context modifying dispersion patterns

Answer 17

Ant dispersed plants and ant-ant competition

Question 18

Myrmecochory is…

Answer 18

-Ant-mediated seed dispersal
-Often results in a random dispersion pattern
-In the absence of ant dispersers, highly local dispersal results in clumped dispersion patterns

Question 19

Population ecology is…

Answer 19

The study of population abundance and dynamics and the factors contributing to those dynamics

Question 20

Why do we study populations?

Answer 20

-Endangered species (e.g, conservation)
-Noxious species (e.g, pest control)
-Resources (e.g, fish & game management)
-Diseases (e.g, epidemiology)
-Humans (e.g, planning, insurance, resource management)

Question 21

Sampling is…

Answer 21

The selection of a subset of individuals from within a statistical population to estimate characteristics of the whole population

Question 22

Trade-offs of sampling…

Answer 22

-Time
-Cost
-Effects on sampled organisms

Question 23

Line transect…

Answer 23

Allows estimation of relative abundance, but not density (thus, not population size)

Question 24

Belt transect…

Answer 24

Allows estimation of relative abundance, density (and thus pop size), and % cover

Question 25

Estimation relies on making _______

Answer 25

Assumptions

Question 26

What happens in assumptions are not met…

Answer 26

The estimate will be biased

Question 27

M=

Answer 27

Total # counted on the first day (and marked afterward)

Question 28

C=

Answer 28

Total number counted on the second day

Question 29

R=

Answer 29

Total number of marked individuals counted on second day

Question 30

N*=

Answer 30

True population size

Question 31

N=

Answer 31

Estimate of total population size

Question 32

FIVE MAIN POINTS

Answer 32

1) Dispersal mediates competition, predation, diseases, and gene flow
2) Dispersion patterns result from interacting processes (dispersal, resource dynamics, species interactions)
3) Populations change through birth, death, immigration, and emigration
4) Populations are (usually) measured by sampling (as opposed to counting all individuals)
5) Sampling methods rely on meeting certain assumptions