Population and Community Ecology

Question 1

What are the 5 different scopes of ecological research?

Answer 1

1. global ecology
2. landscape ecology
3. ecosystem ecology
4. community ecology
5. population ecology

Question 2

How do community and population ecology differ?

Answer 2

Community - Interspecific

Pop - intraspecific

Question 3

What factors influence the distribution of a species?

Answer 3

• dispersion/reproduction
• abiotic factors (climate-light, fire, moisture, temp; salinity, o2)
• biotic (predation, herbivory, competition, pathogens, disease)

Question 4

Define population

inter or intra specific?

Answer 4

group of organisms of the same species occupying a particular space at the same time.
genetic and ecological units in which a species’ members interact with one another.
Intra

Question 5

Define metapopulation

Answer 5

spatially separated, disjunct population which is distributed in patches across a heterogeneous landscape and interconnected by immigration (dispersal).

Question 6

By which mechanism are meta metapopulations connected?

Answer 6

dispersal

Question 7

What are advantages are dispersal?

Answer 7

1. range expansion
2. increased gene flow
3. inbreeding avoidance
4. reduced resource competition

Question 8

What are 3 patterns of dispersal?

Answer 8

1. natal dispersal
2. presaturation dispersal
3. saturation dispersal

Question 9

What conditions affect the decision/ability to disperse?

Answer 9

age
condition
carrying capacity reached?
despite dependent/independent

Question 10

Describe natal dispersion

- who is this most common with in mammals?

Answer 10

The dispersion from birth place before the first breeding/before sexual maturity.
in mammals - usually males disperse

Question 11

Describe presaturation dispersal

Answer 11

animals in good condition
dispersal before the carrying capacity is reached
density independent

Question 12

Describe saturation dispersal

Answer 12

animals in poor condition
young/small
carrying capacity has been reached or exceeded
density dependent

Question 13

Dispersal is from ____ to _____ - _____ filled by _______

Answer 13

Dispersal is from source to a sink- empty habitat filled by immigration

Question 14

Have you done the required reading on UMLearn?

- determinants of habitat selection

Answer 14

Yes

Question 15

What are the determinants of habitat selection?

Answer 15

Genees and environment

Tradition

Question 16

What are properties of populations that help in measuring them?

Answer 16

density 
dispersion
sex ratios
age structure
mortality
natality

Question 17

How is density used to measure a population?

Answer 17

1 - count all individuals in a population
2 - estimate using sampling
3 - mark-recapture method depends on likelihood of recapturing the same individual

Question 18

Define density

Answer 18

number of organisms occupying a defined unit of space

Question 19

Define crude density

Answer 19

of individuals per unit area

Question 20

Define ecological density

Answer 20

measured in terms of useable habitat

rarely estimated - very difficult to measure what portion of habitat represent living space

Question 21

List 3 patterns of spatial dispersion.

What are they strongly influenced by?

Answer 21

1. uniform
2. random
3. clumped
   - strongly influenced by landscape and interactions among members of the population

Question 22

What type of dispersion are the most even? why?

Answer 22

uniform - infraspecific comp.

(ex. territoriality)

Question 23

Define random dispersion

Answer 23

position of each individual is independent of others or the occupation of each is equally likely

Question 24

is random dispersion common or rare? when does it occur?

Answer 24

rare!
envr uniform
resources equally available all year
interactions among members of pop produce no patterns of attraction or avoidance

Question 25

what is the most common type of distribution pattern?

Answer 25

clumped - habitat differences - daily and seasonal changes - reproductive patterns and social behaviour

Question 26

What are some reasons that clumped distribution patterns can occur?

Answer 26

poor dispersal capability of young patchy distribution of resources social organization

Question 27

Define sex ratios

Answer 27

proportion of males to females - 1:1 in most sexually reproducing organisms

Question 28

1degree sex ratio

Answer 28

ratio at conception

Question 29

2degree sex ratio

Answer 29

ratio at birth | - usually weighted towards males in mammals

Question 30

Demographics

Answer 30

population dynamics

Question 31

what is a life table? what can it be used for?

Answer 31

an age-specific summary of the survival pattern of a population. producing survivorship curves

Question 32

Describe exponential growth model

Answer 32

uncontrolled growth applicable to only initial growth after colonization of an unexploited habitat not biologically realistic or sustainable

Question 33

Two examples of exponential growth

Answer 33

St Paul reindeer herd | Rabbits

Question 34

Describe the logistic growth model

Answer 34

idealized model of growth, slowed by limiting environmental factors reach K - carrying capacity

Question 35

give two examples and boom and bust cycles

Answer 35

hares and lynx | snowy owls and lemmings

Question 36

give two examples and boom and bust cycles

Answer 36

hares and lynx | snowy owls and lemmings

Question 37

What is Life History and what do these traits include?

Answer 37

``` series of events from birth to reproduction, to death - age @ first repro. - freq. of repro. - # offspring amount of parental care given energy cost of repro. ```

Question 38

What are the 2 major life history strategies?

Answer 38

r-selection | k-selection

Question 39

Describe r-selection

Answer 39

"live fast, die young" - reach sexual maturity early - large # offspring - litte/no parental care - generally short lived

Question 40

Describe k - selection

Answer 40

"live long and prosper" - reach sexual maturity late - small # offspring - parental care - generally long-lived

Question 41

What are r-selected species usually limited by? What about k-selected species?

Answer 41

r = density-independent factors --> can easily colonize new habitats k= density-dependent factors

Question 42

When is population ecology more important?

Answer 42

applied research - endangered species - manage wildlife populations - human pop. growth * SARA

Question 43

What are the 2 steps to in the SARA process?

Answer 43

1. scientific evaluation | 2. listing by government

Question 44

define mutualism

Answer 44

both organisms benefit

Question 45

define commensalism

Answer 45

one benefits, other with no loss/no gain

Question 46

define amensalism

Answer 46

one no effect, one negative

Question 47

how could a community be controlled bottom-up?

Answer 47

nutrients

Question 48

how could a community be controlled top-down?

Answer 48

predators

Question 49

how does production efficiency range between birds/mammals, fish, and insects?

Answer 49

``` birds/mammals = 1-3% (endothermy) fish = 10% insects = 40%+ ```

Question 50

required reading on bison??

Answer 50

Yes

Question 51

how are bisons suggestion to shift ecosystem functions?

Answer 51

graze so intensely they they freeze plants in early spring for weeks at a time, preventing them from maturing. This forces them to continuously produce young shoots - increases nutrients in plants by 50-90% by end of summer - extra food - prolongs growing season - accelerates growth

Question 52

What are properties of a population

Answer 52

``` density dispersion sex ratio age structure mortality natality ```

Question 53

What are some reasons for a clumped distribution?

Answer 53

poor dispersion of young patchy distribution of resources social organization

Question 54

Example of a mammal discussed in class that displayed exponential growth?

Answer 54

St. Paul Reindeer