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Biology > Chp. 53 Population Ecology > Flashcards

Chp. 53 Population Ecology Flashcards

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1
Q

What does population ecology explore?

A

Explores how biotic and abiotic factors influence density, distribution, size, and age structure of populations.

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2
Q

What is a population?

A

Group of individuals of a single species living in the same general area

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3
Q

What 2 things describe a population?

A
  • Boundaries
  • Size
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4
Q

What is density?

A

The number of individuals per unit area or volume

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5
Q

What is dispersion?

A

Pattern of spacing among individuals within the boundaries of the population

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6
Q

What are the 3 sampling techniques that can be used to determine population size?

A
  1. Extrapolation from small samples
  2. Index of population size (ex. number of nests)
  3. Mark-recapture method
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7
Q

What are the steps of using the Mark-recapture method?

A
  1. Scientists capture, tag, and release a random sample of individuals (s) in a population
  2. Marked individuals are given time to mix back into the population
  3. Scientists capture a second sample of individuals (n), and note how many of them are marked (x)
  4. Population size (N) is estimated by N = sn/x
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8
Q

What is immigration?

A

Influx of new individuals from other areas

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9
Q

What is emigration?

A

Movement of individuals out of a population

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10
Q

What two things add individuals to a population?

A
  1. births
    2, immigration
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11
Q

What two things will remove individuals from a population?

A
  1. Death
  2. Emigration
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12
Q

What two things does clumped dispersion depend on?

A
  1. resource availability
  2. behavior
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13
Q

What happens in a clumped dispersion?

A

Individuals aggregate in patches

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14
Q

What are the 3 patterns of dispersion?

A
  1. Clumped
  2. Uniform
  3. Random
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15
Q

What is territoriality?

A

Defense of a bounded space against other individuals

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16
Q

What happens in a random dispersion?

A

The position of each individual is independent of other individuals

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17
Q

What happens in uniform dispersion?

A

Individuals are evenly distributed

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18
Q

What is demography?

A

Study of the vital statistics of a population and how they change over time

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19
Q

What is a life-table?

A

A graphic way of representing the data in a life table.

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20
Q

What is a cohort?

A

A group of individuals of the same age

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21
Q

What is a survivorship curve?

A

Age-specific summary of the survival pattern of a population

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22
Q

What is type 1 survivorship curve?

A

Low death rates during early and middle life and an increase in death rates among older age groups

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23
Q

What is type 2 survivorship curve?

A

A constant death rate over the organism’s life span

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24
Q

What is type 3 survivorship curve?

A

High death rates for the young and a lower death rate for survivors

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25
Q

What is a reproductive table/fertility schedule?

A

An age-specific summary of the reproductive rates in a population

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26
Q

What does the exponential model describe?

A

Describes population growth in an idealized, unlimited environment

27
Q

What is the formula of the change in population size?

A

Change in population size = births + immigrants - Death + emigrants

28
Q

What is the population growth rate formula?

A

delta N /delta t = B - D

  • delta N = change in population size
  • delta t = time interval

*B = number of births, D = number of deaths

29
Q

How to calculate birth?

A

B = bN

b = annual per capita birth rate, N = population size

30
Q

How to calculate death rate?

A

D = mN

m = per capita death rate, N = population size

31
Q

What is the zero population growth (ZPG)?

A

Occurs when the birth rate equals death rate

32
Q

What is the exponential population growth?

A

Population increase under idealized conditions?

33
Q

What type of curve does the exponential population growth result in?

A

J-shaped curve

34
Q

What is the carrying capacity (K)?

A

The maximum population size the environment can support

35
Q

What does the logistic population growth model show?

A

Shows that the per capita rate of increase declines as carrying capacity is reached

36
Q

What does capital N refers to?

A

Population size

37
Q

What does the lower case r refer to?

A

per capita rate of increase

38
Q

What happens when N is small compared to K?

A

term (K–N)/K is close to 1 and the per capita rate of increase approaches the maximum

39
Q

What happens when N is large compared to K?

A

term (K–N)/K is close to 0 and the per capita rate of increase is small

40
Q

What happens when N equals to K?

A

Population stops growing

41
Q

What happens when the N approaches K in a logistic growth model?

A

Population growth rate decreases

42
Q

What shape does the logistic growth model show?

A

Sigmoid (s-shaped) curve

43
Q

What is the Allee effect of a population?

A

Individuals have a more difficult time surviving or reproducing if the population size is too small

44
Q

What does an organism’s life history comprise of?

A

Comprises of traits that affect its schedule of reproduction and survival

45
Q

What are the 3 main variables of life history?

A
  1. The age at which reproduction begins
  2. How often the organism reproduces
  3. How many offspring are produced per reproductive episode
46
Q

What is semelparity?

A

Big-bang reproduction, species reproduce once and die

47
Q

What is iteroparity?

A

Repeated reproduction, species reproduce offspring repeatedly

48
Q

Which environments prefer semelparity and iteroparity?

A

Semelparity: highly variable or unpredictable environments

Iteroparity: Dependable environments

49
Q

What is K-selection?

A

Density-dependent selection, selects for life history traits that are sensitive to population density

50
Q

What is r-selection?

A

Density-independent selection, selects for life history traits that maximize reproduction

51
Q

What are the 2 general questions about regulation of population growth?

A
  1. What environmental factors stop a population from growing indefinitely?
  2. Why do some populations show radical fluctuations in size over time, while others remain stable?
52
Q

What happens in density-independent populations?

A

Birth and death rate don’t change with population density

53
Q

What happens in density-dependent populations?

A

Birth rates fall and death rates rise with population density

54
Q

What kind of feedback are density-dependent birth and death rates

A

negative feedback

55
Q

What happens in crowded populations?

A

Increasing population density intensifies competition for resources and results in a lower birth rate

56
Q

What are the 6 mechanisms of density-dependent regulation?

A
  • competition for resources
  • disease
  • predation
  • territoriality
  • intrinsic factors
  • toxic wastes
57
Q

What is the study of population dynamics?

A

Focuses on the complex interactions between biotic and abiotic factors that cause variation in population size

58
Q

What is metapopulations?

A

Groups of populations linked by immigration and emigration

59
Q

How to maintain population stability for humans?

A

Via zero population growth =

high birth rate - high death rate

or

low birth rate - low death rate

60
Q

What is the demographic transition?

A

Move from the first state to the second state

61
Q

What is age structure?

A

The relative number of individuals at each age

62
Q

What is the ecological footprint concept?

A

Concept that summarize the aggregate land and water area needed to sustain the people of a nation

63
Q

What does r(inst) refer to?

A

Refers to the instantaneous per capita rate of increase

Biology (34 decks)

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