Changing population Flashcards

1
Q

What Limits A Population?

A

Density-Dependent and Density-Independent Factors

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2
Q

What is Density-Dependent?

A

factors that affect population size In Relation to population density

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3
Q

what is Density-Independent

A

factor that affect population size Regardless of population density

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4
Q

What are the Density Independent Factors?

A
  • natural disasters
  • pollutants
  • extreme temperatures
  • events in which the population size doesn’t matter
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5
Q

What are the Negative Density dependence Factors?

A

mostly happens in Big population
- Disease
- Competition (food, shelter, space)
- more individuals = not enough resources

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6
Q

What is Law of Constant Final Yield?

A

No matter how many seeds were sown, the final amount of biomass was the same because
- resources are limited
- increasing amount of seeds doesn’t increase the biomass of plants because they are overcrowded causing their biomass to level off instead

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7
Q

What are the Positive Density Dependence

A

happens in tiny population
Causes Allele effect

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8
Q

What is Allele effect?

A

increase ease of finding a mate, sex rations, reduced inbreeding
- lacks genetic diversity
- when the allele effect ease, rapid growth is seen

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9
Q

In graph, Positive Density Dependence would

A

Increase Breeding pairs = Increase in Population Growth

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10
Q

In graph, Negative Density Dependence would

A

Increase resource competition = Decrease population growth

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11
Q

What do methods depend on to quantify population size?

A
  • type of organism
  • density of organism
  • their environment
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12
Q

What is Sub-sampling?

A

To estimate abundance over large areas
- uses Quadrats and transects
- typically used for sessile (doesn’t move) organism

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13
Q

What is Mark-Recapture?

A

Organism is captured -> mark -> releases in habitat -> repeat and look how many are marked
M/N = R/C

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14
Q

What is carrying capacity (K)

A
  • result of Negative density-dependent factors
  • no set of numbers which means it depends on the quality of the environment which would eventually level off
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15
Q

This equation (1 - (N/K)) in Logistic Growth Model mean

A
  • decline in growth rate as population approaches K
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16
Q

This equation (1 - (N/K)): when population is Small

A
  • N/K ~ 0, term in bracket ~ 1
  • would grow rapidly as its exponential, not near the carrying capacity
17
Q

This equation (1 - (N/K)): when population is Large

A
  • N/K ~ 1, term in brackets ~ 0
  • growth rate approaches 0 so population is slowing down
18
Q

What is Inflection point in Carrying Capacity?

A

The point of fastest growth after which growth begins to slow

19
Q

What is Overshoot?

A

population grows beyond carrying capacity
- may occur if habitat carrying capacity decreases

20
Q

What happens when a population overshoot?

A

when population is still growing but carrying capacity is depleting then it would overshoot
followed by Die-Off (when a massive crash in pop’n)

21
Q

What is Population Cycle?

A

population would go up and down, repeat overshoot and die-off (due to availability to resources and carrying capacity)

22
Q

What is Delayed Density Dependence?

A

Delayed b/w environmental change and the time population reproduces
- population is not as responsive so population growth delays
- uses population in THE PAST instead of using the population in the present

23
Q

Size of Oscillations depends on what factors?

A
  • magnitude of time delay [ increase time, decrease in responsiveness which means more likely to overshoot]
  • growth rate [ grow rapidly, capacity drops (leads to overshoot as they can’t control pop’n growth) ]
24
Q

What is No Oscillations?

A

population size is easily reached

25
What is Dampened Oscillation?
population size is mid range, delay, grows quickly and eventually find carrying capacity (level off)
26
What is Stable Limit Cycle?
population size is continuous cycle
27
Energy reserves can cause oscillations because?
they can cushion themselves against carrying capacity
28
High-Energy stores means?
- energy stores keep growing - overshot and no more reserves
29
Low-Energy stores means?
population grows quickly, overshot (a little bit) and stay near carrying capacity
30
Small population also have high risk of extinction because?
of Demographic stochasticity: random variation in birth and death rates and of Environmental stochasticity; such as changing in weather
31
Positive Density Dependent factors cause small population to grow quickly only when?
all individuals have equal birth rate and likelihood of dying based on Deterministic model - so small population have higher extinction probability in Short Term