Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Ecology > Chapter 11: Intraspecific Population Regulation > Flashcards

Chapter 11: Intraspecific Population Regulation Flashcards

1
Q

Exponential population growth is based on assumptions that ?

A
  • essential resources are not limiting and that the environment is constant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Is exponential growth likely to occur in the real world?

A
  • no

- potential exception: human population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Human Population Growth:

- In 2012 population reached?

A
  • 7 billion
  • growing faster than exponential
  • not evenly spread out, might be causing some of the issues (resources )
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Human Population Growth:

- changes to technology and resources used did what for the population?

A
  • dev of agriculture increased quantity and predictability of resources. Change to permanent villages. (not farming yourself)
  • Industrial revolution: animal and human labour replaced by machines fuelled by coal. Change to urban society.
  • Demographic transition: reduced mortality due to better nutrition, personal hygiene, waste disposal and control of disease
  • **all allowed for our pop to take off
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Human Population Growth:

- why have growth rates declined?

A
  • mostly bc having children is costly

- but momentum from large number of young people in developing countries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Human Population Growth:

- why is it difficult to predict human population growth?

A
  • diseases, resources (not evenly spread out), conflicts (war) etc
  • hard to predict where (the change) is going to happen, bc resources are going to change quickly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  1. 1 Population growth is usually limited by the environment:
    - In nature, environment is?
A
  • not constant and resources are limited
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  1. 1 Population growth is usually limited by the environment:
    - mortality, fecundity, competition etc will change as what changes?
A

density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  1. 1 Population growth is usually limited by the environment:
    - usually____ rate declines and ___ increases as density increases.
A
  • birth
  • mortality
  • *enivornment controls how many individuals will be in it
  • changes as pop gets more crowded
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Reindeer herd on Pribilof Islands, Alaska?

A
  • increasing then boom it crashes (fighting, disease etc) (1940ish)
  • we don’t want this to happen to our moose so we regulate it
  • not a typical graph..most species do not drop dead like this
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Carrying capacity?

A
  • max sustainable pop size for particular environmental conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Carrying capacity depend on what?

A
  • supply of resources: food, water, space
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Carrying capacity is a theoretical idea that is easy/hard to determine for a natural population.

A
  • hard
  • but useful concept to include n models of population growth
  • *CC can change due to conditions changing with it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Logistic model of growth incorporates?

A
  • incorporates carrying capacity, K

dN/dt = rN (1-N/K)

  • Two components: rN which is the original exponential term and
  • 1-N/k, also can be written as (K-N)/k, which reduces population growth as the population size approaches k
  • d= change
  • rate size ( slow down component/density component )
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Logistic model of growth:

- As N approaches K, rate of growth?

A
  • decreases
    ex: K= 100
    If N= 10
    (1-N/k)= 0.90
    but if N=99, (1-N/K)=0.01 and there will be virtually no growth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Logistic model of growth

- logistic growth curve showing carrying capacity?

A
  • almost like an S

- K is where it levels off…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Logistic vs Exponential Growth when looking at graphs?

A
  • logistic increases but levels off eventually

- exponential doesn’t stop in terms go growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
  1. 2 Population regulation:

- population can/can’t grow forever?

A

can’t
*limits to its resources
L> food, water, land, space,mate, habitats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q
  1. 2 Population regulation:

- Interactions occur among members of the population that tend to?

A

-regulate population size (push it towards an equilibrium)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q
  1. 2 Population regulation:

- density dependence?

A
  • response of the population depends on its density. Slows the rate of increase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q
  1. 2 Population regulation:

- why is k included in the logistic growth model?

A
  • to add density-dependence
  • *rates change depending on how dense it is
  • more individuals= more interactions (some good other bad), regulate the population size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q
  1. 2 Population regulation:

- In nature, density-dependent mechanisms influence?

A
  • birth and death rates
  • direct effects of resource availability or other factors (disease and parasites)
    *realistic graph shows birth rate declines as the population size increases and death rates increase as population increases
    at carrying capacity they are=? / intersect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Density vs Independent:

  • Not all factors affecting birth and death rates are density-dependent.
  • Density-independent ?
A
  • if the proportion of population affected by an environmental factor is not influenced by density
  • *weather, temperature, precipitation are all density independent (not a dependent factor like birth and death rate - not affected)
24
Q
  1. 3 Competition:

- A carrying capacity means competition occurs when resource(s) are?

A

in short supply

25
Q
  1. 3 Competition:

- Intraspecific competition?

A

-competition among individuals of the same species

26
Q
  1. 3 Competition:
    - Intraspecific competition:
  2. Scramble competition?
A
  • can result in reduction of growth and reproduction of all individuals (equally spread)
27
Q
  1. 3 Competition:
    - Intraspecific competition:
  2. Contest competition?
A
  • some individuals get enough resources while others denied a share (winners and losers)
28
Q
  1. 3 Competition:
    - Intraspecific competition:
  2. exploitation competition?
A
  • if competing individuals don’t interact directly but change level of resource for others
    ex: tree roots(might spread out and absorb all the water - exploiting this resources ahead of someone else)
29
Q
  1. 3 Competition:
    - Intraspecific competition:
  2. Interference competition?
A
  • individuals directly interact and prevent others from occupying a habitat or accessing resources
30
Q
  1. 4 Effects on Growth and Development :

- when density increases, individuals in scrabble competition get ___ food. This ___ growth and ___ reproduction.

A
  • less
  • reduces
  • inhibits
31
Q

11.4 Effects on Growth and Development:
-Intraspecific competition:
ex: tadpoles?
L> high vs low density

A
  • high density=slower growth, longer tadpole phase, lower change of transformation to frog, smaller size frog.
    • at low density they grow much faster
32
Q
  1. 5 Competition can reduce survival:

- ex: horseweed?

A
  • horseweed planted at high density
  • competition resulted in mortality of many seedlings
  • average size of surviving seedlings increased
  • self thinning
  • ** at high density they are small, as density is reduced they grow faster/ more weight. Competition can change growth rate, reproduction rates and survival,
33
Q
  1. 6 Competition can affect reproduction:

- Harp seals?

A
  • in harp seals, onset of sexual maturity is related to body weight
  • occurs earlier when the population size is lower
  • *if they don’t grow fast enough it delays the mount of babies they can have.
  • *results in density-dependent fertility of harp seals : number they can produce will drop (population problem - producing fewer as they get more dense) –> population regulation
34
Q
  1. 7 High density is stressful:
    - ___ contacts increase
    - Stress may trigger?
    - Pheromones?
A
  • aggressive
  • stress may trigger hormonal changes that suppress growth and reproduction as well as the immune system
  • pheromones( chemical signals): can encourage or discourage reproduction in rodents.
  • *so dense that they re giving off hormonal singles , increasing aggression
35
Q
  1. 8 Dispersal can be density-dependent:

- some animals instead of coping with stress will?

A

leave

36
Q
  1. 8 Dispersal can be density-dependent:

- usually ___ driven out by ___ aggression.

A
  • sub-adults
  • adult
  • most die but some find a new suitable area
  • usually doesn’t regulate population size
  • does contribute to population expansion and persistence of local populations
37
Q
  1. 8 Dispersal can be density-dependent:

- dispersal?

A
  • how far you spread offspring (or individuals relocating)
38
Q
  1. 9 Effects of Social Behaviour:

- Intraspecific competition can be expressed in?

A
  • social behaviour
39
Q
  1. 9 Effects of Social Behaviour:

- Mechanism to limit number of animals ???

A
  • living in a particular habitat, having access to a common food supply, reproducing
40
Q
  1. 9 Effects of Social Behaviour:

- what can play a role in population regulation if it affects reproduction and survival in a density dependent way?

A
  • social dominance
41
Q
  1. 9 Effects of Social Behaviour:

- example: Wolf packs and social dominance

A
  • strict social hierarchy with only one breeding pair in the pack ( the alpha male and female)
  • if food is limited, individuals may be expelled (priority of food goes to the alpha pair)
  • when density of wolves is low, wolves leave pack and establish their own packs in unoccupied habitats
42
Q
  1. 10 Territoriality:

- some species defend areas within?

A

their home range (territories

43
Q
  1. 10 Territoriality:

- Benefits of what must outweigh costs of what?

A
  • benefits of sole access to resources in territory must outweigh costs (energy, time) of having a territory.
44
Q
  1. 10 Territoriality:

- can this regulate populations?

A
  • yes

- limits reproduction if excess of individuals of reproductive age.

45
Q
  1. 10 Territoriality:

- explain areas

A
  • size of home ranges and territories indicator of carrying capacity
  • *little factors that come into play for regulating populations apart form birth and death rates
46
Q
  1. 10 Territoriality:

- example?

A
  • when individuals are removed, new pairs take up territories right away
47
Q
  1. 11 Plants can capture Space:

- Plants are not ?

A
  • territorial but do capture space and exclude others from it
48
Q
  1. 11 Plants can capture Space:

- zones of resource depletion associated with?

A
  • canopy and root systems
49
Q
  1. 11 Plants can capture Space:

- This competition can even occur through?

A

the release of organic toxins

50
Q
  1. 12 Density-Independent Influences:

- Many factors can influence the abundance of individuals in a population. Some not density dependent and so can’t?

A
  • regulate a population (which involves feedback)
    exL temperature, precipitation , natural disasters
    **may still limit pop growth
51
Q
  1. 12 Density-Independent Influences:

- ex: heavy snow fall and deer prediction?

A
  • heavy snow you can predict fewer deer born next year….population is going to decline
52
Q

Development of ideas about density dependence vs independence:

  • Historically, two opposing view points in ecology about population regulation (centred on insects)
  • Two schools are?
A
  1. Biotic school of regulation

2. Climate school of regulation

53
Q

Development of ideas about density dependence vs independence:

  • Historically, two opposing view points in ecology about population regulation (centred on insects)
    1. Biotic school of regulation??
A
  • felt that population size was relatively stable and insect populations were controlled by parasites, predators or competition …biology drives it
54
Q

Development of ideas about density dependence vs independence:

  • Historically, two opposing view points in ecology about population regulation (centred on insects)
    2. Climate school ?
A
  • viewed populations as unstable and felt that weather determined abundance e.g. environmental/ physical environment drives it/more important
  • if variable climate then you may argue physical environment has a bigger effect
  • competition , high number of species = biology
55
Q

Development of ideas about density dependence vs independence:

  • controversy for many years
  • Two perspective eventually integrated
  • Now believed that ___ are in usually favourable to species, changes in abidance primarily result of density dependent process.
A
  • favourable
56
Q

Development of ideas about density dependence vs independence:
- controversy for many years
- Two perspective eventually integrated
L> In unfavourable environments?

A
  • changes in abundance are primarily the result of density independent processes.

Ecology (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions