Ch 36: Population Ecology

Front 1

What is the age structure of a population?

Back 1

the proportion of individuals in different age groups

Front 2

If an ecosystem has a carrying capacity of 1,000 individuals for a given species, and 2,000 individuals of that species are present, we can predict that the population

Back 2

size will decrease.

Front 3

Assume that there are five alligators per acre in a swamp in northern Florida. This is a measure of the alligator population's

Back 3

density.

Front 4

A tidal wave wipes out the entire population of mice living on an island. This is an example of

Back 4

the effects of abiotic factors on a population (density independent limiting factor).

Front 5

In a population of rabbits, which is the best example of a density dependent facto

Back 5

competition with other rabbits for shelter

Front 6

You drive through Iowa in the spring and notice that along a stretch of several kilometers, every third fence post has a male redwing blackbird perched on it defending its nesting territory. This is an example of

Back 6

uniform dispersion.

Front 7

Which of the following statements best describes features of a logistic growth curve

Back 7

The population grows exponentially at first (when resources are plentiful) but population growth levels off at the carrying capacity due density dependent factors, such intraspecific competition

Front 8

You have been studying a population of 200 shrews for one month. You record 50 shrew births and 10 shrew deaths in this time interval. What is the per capita rate of increase (r)?

Back 8

.2

Front 9

Which of the following refers to individuals of a single species that live in the same general area and can potentially interbreed

Back 9

Population

Front 10

A population that has a high level of parental care and high survivorship through the reproductive years likely has what type of survivorship curve?

Back 10

Type I

Front 11

Population Ecology is concerned with what?

Back 11

changes in population size and the factors that regulate populations over time.

Front 12

Population

Back 12

a group of individuals of a single species that occupy the same general area.

Front 13

Population Density

Back 13

The number of individuals of a species per unit area or volume

Front 14

Dispersion Pattern

Back 14

Dispersion Pattern of a population refers to the way individuals are spaced in their areas.

Front 15

Clumped Dispersion Pattern

Back 15

Grouped, most common in nature, results from unequal distribution of resources in environment, mating, or social behavior. Reduces predation and increases feeding efficiency.

Front 16

Uniform Dispersion Pattern

Back 16

evenly disbursed, often results from interactions between individuals of a population. Animals may exhibit uniform dispersion as a result of territorial behavior.

Front 17

Random Dispersion Pattern

Back 17

unpredictably spaced, without pattern. Varying habitat and social interactions make random dispersion rare.

Front 18

survivorship curves

Back 18

plot survivorships as the proportion of individuals from an initial population that are alive at each age.

Front 19

life tables

Back 19

track survivorship

Front 20

Describe the general type of work performed by population
ecologists.

Back 20

1. develop sustainable foods
2. assess the impact of human activities.
3. balance human needs with the conservation of bio-diversity and resources.

Front 21

The larger the number of sample plots...

Back 21

the more accurate the estimates.

Front 22

Three characteristics of Individuals in a population are?

Back 22

– Rely on the same resources
– Are influenced by the same environmental factors
– Are likely to interact and breed with one another

Front 23

A population increases through...

Back 23

birth and immigration

Front 24

a population is decreased by...

Back 24

death and
emigration out of an area

Front 25

Type I curve

Back 25

humans and other large mammals.
usually produce few offspring, give them good care, increasing the likelihood they will survive to adulthood. (Starts high and curves down)

Front 26

Type II curve

Back 26

Intermediate, survivorship constant over the life span--no more vulnerable than any other point in life. Seen in invertebrates, lizards, rodents.(a straight line decreasing from left to right)

Front 27

Type III curve

Back 27

low survivorship for young, followed by a period when survivorship is high for individuals who live to a certain age. produce large number of offspring.
little to no care.
Seen in invertebrates, oysters, perch. (a sloped L looking curve)

Front 28

exponential population growth model

Back 28

{ G=rN } The rate of population increase under ideal conditions.
J-curve

Front 29

logistic population growth model.

Back 29

{ G = rN * (K- N)/K }

a description of idealized population growth that is slowed by limiting factors as the population size increases.

Front 30

r

Back 30

per-capita rate of increase (the average contribution of of each individual to population growth)

Front 31

G

Back 31

growth rate of the population ( # of individuals added per time interval)

Front 32

N

Back 32

the population size (number on individuals in population at a particular time)

Front 33

J-Curve

Back 33

exponential population growth model

Front 34

S-Curve

Back 34

logistic population growth model.

Front 35

limiting factors

Back 35

environmental factors that restrict population growth.

Front 36

Carrying capacity

Back 36

the maximum population size that a particular environment can sustain or carry.

Front 37

What are three factors that determine population size changes?

Back 37

1. competition among members of a population/density
2. physiological factors
3. abiotic factors/weather

Front 38

Dynamics of many populations result from what?

Back 38

1. complex interaction of both density-dependent birth and death rates.
2. abiotic factors such as climate and disturbances.

Front 39

If a population size is greater than the carrying capacity, what is predicted to happen?

Back 39

resources are finite and if the population size is greater than the carrying capacity the species die off until the population is at carrying capacity.

Front 40

Describe the factors that regulate growth in natural populations.

Back 40

Food and nutrient limitations, insufficient territories, increased disease, predation, accumulation of toxins.

Front 41

What are limiting factors?

Back 41

environmental factors that restrict population growth.

Front 42

What are density independent factors?

Back 42

seasonal changes: fires, floods, storms, habitat disruption by human activity, can affect a population size regardless of its density.

Front 43

What are density dependent factors?

Back 43

competition among members of a population. physiological factors. abiotic factors such as weather.

Front 44

Boom and bust cycles?

Back 44

booms are rapid exponentional growth and are followed by busts (when population levels fall back down to a minimal level)

Front 45

What is maximum sustained yield?

Back 45

harvesting should be done at a level that produces a consistent yield without forcing a population into decline. A population growing according to the logistic model increases the fastest when its density is at an intermediate level relative to its carrying capacity.

Front 46

Explain how the structure of the world’s human population has changed and continues to change.

Back 46

began as exponential growth, but is beginning to level out and is forecasted to drop back down over time.

Front 47

Describe the key factors that affect human population growth.

Back 47

?

Front 48

What is meant by the term demographic transition?

Back 48

a shift from zero population growth in which birth rates and death rates are high but roughly equal, to zero population growth characterized by low birth and death rates.

Front 49

What is meant by the term population momentum?

Back 49

In a population in which r=0, the continuation of a population growth as girls in the pre-reproductive age group reach their reproductive years.