Population Ecology II - Survey Methods & Structure

Question 1

Absolute Population Size

Answer 1

actual abundance

Question 2

relative population size

Answer 2

the number of individuals in one time or place relative tot he number in another; related to absolute population size

Question 3

Quadrat-based Method

Answer 3

• immobile organisms
• commonly used by plant ecologists
• sample a portion of an area and draw inferences about larger habitat as a whole

Question 4

Line-Transect method

Answer 4

• observations of individuals from a transect line
• ex. common in bird surverys

Question 5

Mark- Recapture

Answer 5

• for mobile organisms
• capture and marking animals in some way, releasing them, and catching them back later
• portion caught in the first sample should equal the proportion marked in the second sample

Question 6

Species distribution modeling

Answer 6

• incorporates info about an organisms niche
• predicts a species’ distribution based on conditions at locations the species is known to occupy
• can also use these models to project changes in distributions with climate change
• lots of citizen science can be used here

Question 7

Life Tables

Answer 7

bookkeeping device to track births and deaths in populations, from which to estimate survival

Question 8

Survivorship Curve

Answer 8

graphic summary of pattern of survival in a population, based on life table data

Question 9

Cohort Life Table

Answer 9

• identify individuals (cohort) born at same time and keep records from birth
• provides the most accurate data, but often very difficult to collect as they require tracking individuals

Question 10

Static Life Table

Answer 10

• record age at death of large number of individuals over narrow window of time
• snapshot in time
• requires accurate estimate of age at death

Question 11

age distribution

Answer 11

• calculate difference in proportion of individuals in each age class
• assumes differences in numbers from one age class to next due to mortality

Question 12

Survivorship Curves

Answer 12

• species display different survivorship curves
• as the number of survivors is standardizes at 1000 at birth, we can easily compare curves among species

Question 13

Type 1 Survivorship Curve

Answer 13

• high survival of young
• most individuals survive to old age
• ex. most large vertebrates, annual plants, rotifers, humans

Question 14

Type 2 Survivorship Curve

Answer 14

• consistent rate of survival
• the change of surviving remains constant throughout a lifetime
  ex. most birds

Question 15

Type 3 Survivorship Curve

Answer 15

• low survival of young
• high death rates for young, but those who reach adulthood have high survival rates
• ex. fish, trees, other plants

Question 16

What is an Age Distribution?

Answer 16

shows the proportions of individuals across age classes
- this is reflective of a species history of survival, reproduction, and growth potential

Question 17

What can we predict by studying the history of a population?

Answer 17

• periods of successful reproduction
• periods of high and low juvenile/adult survival
• whether older individuals are being replaced by younger individuals, and at what rate
• if populations are in decline

Question 18

Sex ratios

Answer 18

• the relative frequency of each sex type in population
• population sex ratios can change depending on relative fitness of different sexes

Question 19

why are sex ratios usually equal?

Answer 19

• males and females invest differently in reproduction
• the female is always going to have high fitness, because she is always going to find a mate

Question 20

frequency-dependent selection

Answer 20

• if the ability to produce females us genetic, the relative frequency of female producing individuals is going to increase in the population as time goes on, in subsequent generations