Chapter 53

Question 1

What is population ecology?

Answer 1

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

Question 2

How does population ecology vary?

Answer 2

in factos of 20x

Question 3

What are three characteristics of a population?

Answer 3

Rely on the same resources,

are affected by the same environmental factors,

and are likely to breed and interact with each other

Question 4

How are populations described?

Answer 4

by boundaries and size

Question 5

what is density?

Answer 5

number of individuals per unit area or volume

Question 6

what is dispersion?

Answer 6

the pattern of spacing among individuals within the boundaries of the population

Question 7

three methods to estimate a population size

Answer 7

Extrapolating small samples

Index of population size (ex-number of nests)

Mark-recapture method

Question 8

3 steps of mark and reacapture method

Answer 8

samples are captured, tagged, and released

time is given for individuals to mix back into the population

The second sample is captured to note how many are marked

Question 9

Mark-recapture equation

Answer 9

N= sn/x

N= population size

n= second sample size

s= first sample size

x= marked amount in the second sample

Question 10

What is density the result of?

Answer 10

interplay between processes that add individuals to a population and those that remove individuals

Question 11

what is immigration?

Answer 11

the influx of new individuals from other areas

Question 12

what is emigration?

Answer 12

movement of individuals out of a population

Question 13

what adds new individuals to a population?

Answer 13

birth and immigration

Question 14

what removed individuals from a population?

Answer 14

death and emigration

Question 15

what influences spacing of individuals of a population?

Answer 15

environmental and social factors

Question 16

what is clumped dispersion?

Answer 16

individuals aggregating in patches

Question 17

what is clumped dispersion influenced by?

Answer 17

resource availability and behavior

Question 18

what is uniform dispersion?

Answer 18

individuals are evenly distributed

Question 19

what is uniform dispersion influenced by?

Answer 19

social interactions like territoriality

Question 20

what is territoriality?

Answer 20

defense of a bounded space against other individuals

Question 21

what is random dispersion?

Answer 21

the position of each individual is independent of other individuals

Question 22

when does random dispersion occur?

Answer 22

in the absence of strong interactions or repulsions

Question 23

what is demography, and examples?

Answer 23

study of vital statistics of a population and how they change over time

Ex- death and birth rates

Question 24

what is a life table?

Answer 24

age-specific summary of the survival pattern of a population, following the fate of a cohort

Question 25

what is a cohort?

Answer 25

a group of individuals of the same age

Question 26

what does a life table provide?

Answer 26

Provides data about population, proportions of sex, and reproduction rate

Question 27

what is survivorship curve?

Answer 27

graphic way of representing the data in a life table

Question 28

What is type 1 survivorship curve?

Answer 28

low death rates during early and middle life, and an increase in death rates among older age

Question 29

what is type 2 survivorship curve?

Answer 29

a constant death rate over the organism’s life span

Question 30

what is type 3 survivorship curve?

Answer 30

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

Question 31

what type of survivorship curve are most species?

Answer 31

an intermediate

Question 32

what do demographers focus on?

Answer 32

females in a population for species with sexual reproduction

Question 33

what is a reproductive table?

Answer 33

age-specific summary of reproductive rates in a population

Question 34

what does a reproductive table focus on?

Answer 34

a cohort from birth to deathw

Question 35

what is reproductive output?

Answer 35

product of the fraction of female at a given age who are breeding and the number of female offspring they make

Question 36

How is population growth studied?

Answer 36

in an idealized situation

Question 37

what does population growth provide?

Answer 37

Helps us understand the capacity of species to increase and the conditions that may facilitate this growth

Question 38

why doesn't ideal population growth occur?

Answer 38

resource is limited

Question 39

what is zero population growth?

Answer 39

when birth rate equals death rate

Question 40

what is exponential population growth (2)?

Answer 40

population increase under idealized conditions Results in a J-shaped curve

Question 41

What is the rate of exponential population growth?

Answer 41

The rate of increase is constant but accumulates more new individuals when unit of time is large than when it is small

Question 42

what is the issue of exponential population growth?

Answer 42

cannot be sustained indefinitely

Question 43

what is carrying capacity?

Answer 43

maximum population size the environment can support

Question 44

how does carrying capcity vary?

Answer 44

abundance of resources

Question 45

what is the most realistic population model?

Answer 45

carrying capacity

Question 46

what is logistic population growth?

Answer 46

per capita rate of increase declines as carrying capacity is reached

Question 47

what makes it difficult to define carrying capacity>

Answer 47

when populations fluctuate

Question 48

what is the Alle effect?

Answer 48

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

Question 49

when is the logistical model used?

Answer 49

Can be used to estimate the size below which populations may become extinct

Question 50

what is life history?

Answer 50

traits affecting its schedule of reproduction and survival

Question 51

What is life history reflected in?

Answer 51

development, physiology, and behavior of an organism

Question 52

what three variables entail life history?

Answer 52

When reproduction begins How often the organism reproduces How many offspring are produced per reproductive episode

Question 53

what is semelparity?

Answer 53

reproduces once and die

Question 54

when is semelparity favored?

Answer 54

Favored in variable or unpredictable environment

Question 55

what is iteroparity?

Answer 55

produce offspring repeatedly

Question 56

when is iteroparity favored?

Answer 56

Favored in a dependable environment

Question 57

why do trade-offs occur?

Answer 57

due to finite resources, trade-offs between survival and reproduction cocur