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Community and Population Ecology > Midterm 1 > Flashcards

Midterm 1 Flashcards

1
Q

What is ecology?

A

The study of living organisms’ interactions with EACH OTHER and their ENVIRONMENT

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2
Q

What is population ecology?

A

The study of the factors controlling

  1. population size,
  2. age structure,
  3. density
  4. and distribution.
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3
Q

What is the law of parsimony?

A

The simpler solutions are more likely to be correct than the complex ones (problem-solving principle)

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4
Q

What is a population?

A

A group of organisms of the SAME SPECIES LIVING and REPRODUCING together.

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5
Q

What are the assumptions of exponential growth model?

A
  1. No I or E
  2. No age structure
  3. No genetic structure
  4. Continuous growth (no time lags)
  5. b and d are constant (unlimited resources)
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6
Q

What is a discret exponential population growth?

A

It’s a population that grows not continuously over time with non-overlapping generations.

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7
Q

What are the differences between r and lambda?

A

r : units

lambda : no unit, specific from t to t+1

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8
Q

What implies a model of stochastic variation?

A

When r varies.

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9
Q

In a model of environmental stochasticity, when do you know there will be an extinction?

A 
When variance (pie2r) is > 2r.
𝝈𝟐𝒓 >𝟐r
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10
Q

Name some factors that explain why exponential growth decreased in density-dependant models.

A
  1. Space limitations
  2. Food limitations
  3. Accumulations of waste products
  4. Competitors
  5. Predators
  6. Disease, parasites
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11
Q

What is K?

A

K is the carrying capacity: the maximum population size that can be supported under limited resources

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12
Q

When to use the logistic model?

A

When there is limited resources

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13
Q

What are the assumptions of the logistic growth model?

A
  1. No I or E
  2. No age structure
  3. No genetic structure
  4. Continuous growth (no time lags) (like in exponential growth)
  5. CARRYING CAPACITY IS CONSTANT
  6. LINEAR DENSITY-DEPENDENCE (per capita population growth rate) IS LINEAR

*biggest difference with exponential model: b d are not unlimited

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14
Q

What is a time lag in pop ecology?

A

Delay in population response to factors affecting population growth.

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15
Q

When is the population growth rate is maximal in a logistic growth model?

A

Under limited resources (logistic growth model), population growth rate is maximal when N = K/2

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16
Q

What is a time lag?

A

A time lag is a delayed density-dependence (as density-dependent growth is effectively a negative feedback of N on dN\dt)

17
Q

In a logistic population with a time lag, explain the population trajectoire.

A
  1. rtau small : logistic growth
  2. rtau moyen: not constant oscillations
  3. rtau grand: stable cycles
18
Q

For time lag, what is amplitude and what is period?

A

Amplitude: increases with increasing rtau
Period: 4tau

19
Q

When does rd exhibits chaos?

A

When rd > 2.570

20
Q

Explain why the period is always about 4τ.

A

The distance from K to the amplitude is about one quarter of the cycle. The distance is equal to tau, because it’s the amount of time need so the system response to the carrying capacity. If tau is about ¼ of a cycle, then a full cycle is about 4*tau.

21
Q

What are the assumptions of the age-structured exponential growth model?

A
  1. Closed population (no E or I)
  2. No genetic structure
  3. No time lags
  4. B and D constant FOR EACH AGE CLASS
  5. Stable age distribution
22
Q

What is r and k selection?

A

r selection: lof of offspring, low survivor (small bodied)

k selection: not a lof of offspring, high survivorship

23
Q

What is b(x)?

A

b(x) = fecundity schedule: the average number of females offspring by females of a particular age

24
Q

What is S(x)?

A

S(x) = cohort survival: the number of individuals of a cohort that survive from birth to age x

25
Q

What is l(x)?

A

l(x) = survivorship schedule: the probability that an individual survives from birth up to age x

26
Q

What is g(x)?

A

g(x) = survival probability: the survival probability that an individual from age x survives to the next

27
Q

What are the types of survivorship?

A

Type I: high as babies, low as elders (humans)
Type II: constant (birds)
Type 3: low as babies, high as elders (trees)

28
Q

What is R0?

A

R0= net reproductive rate: mean number of female offspring produced per female over her entire lifetime

29
Q

What is G?

A

Generation time: the average interval between the birth of an individual and the birth of its offspring

30
Q

What is the birth pulse-model?

A

Assumes that females give birth to all of their offspring on the day they enter a new age class.

31
Q

What is the post-breeding census?

A

Individual are counted right after they give birth.

32
Q

What is local vs regional extinction?

A

Local extinction: disappearance of a single population in a metapopulation
Regional extinction: all the population in the landscape die out.

33
Q

Whats the difference between Pn =(1-pe)n and = 1-(pe)x?

A

(1-pe): Local persistence

1-(pe)x: Regional persistence

34
Q

What is a metapopulation?

A

A group of local population (subpopulatons) linked by immigration and emigration.

35
Q

What are the assumptions of the metapopulation model?

A
  1. Homogenous patches
  2. No spatial structure
  3. No time lag
  4. Constant pe and pi
  5. Except in the island-mainland model, regional occurence f affects pi and pe
  6. Large number of patches
36
Q

What a propagule rain?

A

An external source of migrants ( such as Island Mainland)

37
Q

What is i?

A

i is a constant measuring how much probability of colonization of empty sites (pi) increases with the fractions of site occupied f

38
Q

What is e?

A

e is a constant measuring how much probability of extinction pe decreases with the fraction of sites occupied f

39
Q

Whats a stationary age distribution?

A

When pop exhibits an intrinsic rate of growth equals to zero.

Community and Population Ecology (2 decks)

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