Chapter 53 - Population Ecology

Question 1

population

Answer 1

A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring.

Question 2

Describe density and its three main sampling techniques

Answer 2

The number of individuals per unit area or volume.

Three sampling techniques:

• Randomly selected plots
  
  • Works best in homogeneous areas
• Indirectly
  
  • Counting nests, burrows, tracks, fecal droppings
• Mark-Recapture methods
  
  • Best for highly mobile species

Question 3

dispersion

Answer 3

Pattern of spatial arrangement or distribution of individuals w/i environ.

• Largely det by patchiness of habitat
• Uniform, clumped, or random

Question 4

mark-recapture method

Answer 4

A sampling technique used to estimate the size of animal populations.

• Capture random sample
• Tag/mark (m)
• Release
• Wait
• Recapture random sample
  
  • n = total # of 2nd sample
  • x = # marked recaptured

N = m*n / x

Question 5

Assumptions of mark-recapture method

Answer 5

Assumptions of mark-recapture method:

• un/marked individuals have same probability of being captured
• marked orgs completely mix back into population
• no births/deaths or im/emigration during re-sampling interval

Question 6

immigration

Answer 6

The influx of new individuals into a population from other areas.

Question 7

emigration

Answer 7

The movement of individuals out of a population.

Question 8

territoriality

Answer 8

A behavior in which an animal defends a bounded physical space against encroachment by other individuals, usually of its own species.

Question 9

demography

Answer 9

The study of changes over time in the vital statistics of populations, esp birth and death rates; survival and reprod rates

Question 10

life table

Answer 10

An age-specific summary of the survival pattern of a population.

Question 11

cohort

Answer 11

A group of individuals of the same age in a population.

Question 12

Describe how to build a life table

Answer 12

Life table:

• Calc # individuals that die in ea age-group (cohort)
• Calc proportion of cohort surviving fr one age class to next
• Typ, divide by total to calc proportion

Question 13

survivorship curve

Answer 13

Plot of proportion/# in cohort still alive at ea age.

• One way to represent age-specific mortality.

Question 14

Summarize the three main types of survivorship curves

Answer 14

Question 15

reproductive table

Answer 15

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

• Simple view of demographics: females giving rise to females.
• Shows # of female offspring produced by ea age group.

Question 16

zero population growth (ZPG)

Answer 16

A period of stability in population size, when additions to the population through births and immigration are balanced by subtractions through deaths and emigration.

Question 17

exponential (geometric) population growth

Answer 17

Growth of a population in an ideal, unlimited environ, represented by a J-shaped curve when population size is plotted over time.

• E.g. bac in lab conditions

Question 18

Formula for per capita rate of increase

Answer 18

r = b - d

rate = births - deaths

r > 0 → pop growing

Question 19

carrying capacity

Answer 19

The maximum population size that can be supported by the available resources, symbolized as [italicized] “K.”

Question 20

logistic population growth

Answer 20

Population growth that levels off as population size approaches carrying capacity.

• Not enough resources for reprod/survival → ↓ births/↑ deaths → ↓ rate
• # of additional individuals environ can support: K - N
• Fraction of environ avail for pop growth: (K - N) / K

Question 21

Assumptions of logistic model of pop growth

Answer 21

Assumptions of logistic model of pop growth

• Populations adjust instantaneously to growth
• The approach toward carrying capacity is smooth
  
  • Realistically, ‘lag’ time exists → over/undershooting K

Question 22

life history

Answer 22

The traits that affect an organism’s schedule of survival/reprod.

• Trade-off b/w survival and reprod.
• When reprod beings
• How often org’s reprod
• How many offspring produced
• NOT a conscious choice

Question 23

semelparity

Answer 23

Reproduction in which an organism produces all of its offspring in a single event; also known as big-bang reproduction.

Question 24

iteroparity

Answer 24

Reproduction in which adults produce offspring over many years; also known as repeated reproduction.

Question 25

K-selection [italicized “K”]

Answer 25

Selection for life history traits that are sensitive to population density; also called density-dependent selection.

Question 26

r-selection [italicized “r”]

Answer 26

Selection for life history traits that maximize reproductive success in uncrowded environments; also called density-independent selection.

Question 27

density independent

Answer 27

Referring to any characteristic that is not affected by population density.

Question 28

density dependent

Answer 28

Referring to any characteristic that varies with population density.

Question 29

population dynamics

Answer 29

The study of how complex interactions between biotic and abiotic factors influence variations in population size.

Question 30

metapopulation

Answer 30

A group of spatially separated populations of one species that interact through immigration and emigration.

Question 31

demographic transition

Answer 31

In a stable population, a shift from high birth and death rates to low birth and death rates.

Question 32

age structure

Answer 32

The relative number of individuals of each age in a population.

Question 33

ecological footprint

Answer 33

The aggregate land and water area required by a person, city, or nation to produce all of the resources it [he/she] consumes and to absorb all of the wastes it [he/she] generates.

Question 34

What are the three D’s of population ecology?

Answer 34

Density

Dispersion

Demographics