Ch. 53: Population Ecology

Question 1

Predict the distribution pattern for male bearded dragons who actively defend territory.

Answer 1

uniform

because they are territorial

Question 2

Would you expect an r or k species to exhibit a Type III survivorship curve? Why or Why not?

Answer 2

Type III: density dependent: most die at an early age (L)
r- species: density - independent
k- species: density - dependent

expect k species to exhibit Type III survivorship

Question 3

Why are natural populations’ growth trajectories better modeled using logistic rather than exponential growth?

Answer 3

Logistical model is more realistic

• shows there is a limited number of resources
• carrying capacity

Question 4

What determines the carrying capacity for a population?

Answer 4

number of people or animals in a population
number of resources

carrying capacity: limit to how many organisms can survive in a certain population

Question 5

Has the Earth reached the carrying capacity for humans? Defend your answer.

Answer 5

• have seen a slower population growth
• means either quickly approaching the carrying capacity or have overshot
• with this economy, it is most likely that we have overshot and have reached carrying capacity

Question 6

Provide 6 examples of density-dependent regulation.

Answer 6

1) Competition for resources
2) Predation
3) Disease/Pathogens
4) Territoriality: more space required, few places for others to live
5) Intrinsic factors: hormones; mechanics within organism you are looking at
6) Toxic wastes

Question 7

Biological processes influence

Answer 7

population density, dispersion, and demographics

Question 8

The exponential model describes

Answer 8

population growth in an idealized, unlimited environment

Question 9

The logistic moder describes

Answer 9

how a population grows more slowly as it nears its carrying capacity

Question 10

Life history traits are

Answer 10

products of natural selection

Question 11

Many factors that regulate population growth are

Answer 11

density dependent

Question 12

The human population is…

Answer 12

no longer growing exponentially but is still increasing rapidly

Question 13

3 patterns of dispersion

Answer 13

1) Clumped
2) Uniform
3) Random

Question 14

Clumped

Answer 14

Starfish

water source, food, sunlight

Question 15

Uniform

Answer 15

equal distance (rare in nature)
- territoriality, aggression

• Penguins

Question 16

Random

Answer 16

doesn’t seem like any pattern

trees, wind dispersion

Question 17

carrying capacity

Answer 17

limit to how many organisms can survive in a certain population

Question 18

Overshoot

Answer 18

temporary defiance of carrying capacity

- generally associated with temporary increase in resources

Question 19

r-selection

Answer 19

density independent

• make as many offspring as possible
• low parental investment
• high mortality @ early age

i.e. dandelions, shrimp, nematodes, spiders

Question 20

k-selection

Answer 20

density dependent

• make fewer offspring
• parental investment high
• low mortality @ early age

i.e. humans, whales

Question 21

Ecology

Answer 21

the study of organisms in relation to their environment

Question 22

Abiotic Factor

Answer 22

physical, nonbiological

i.e. light, temperature, moisture (water, humidity, rain/snow), chemicals (nutrients, toxic, etc)

Question 23

Biotic Factors

Answer 23

other living things

i.e. predators, prey, parasite, competitors, benefactors, mates

Question 24

Population

Answer 24

group of individuals of the same species with potential for interaction
- same place @ same time

Question 25

Cohort

Answer 25

group of individuals that are studied together

Question 26

Life Table

Answer 26

an age-specific summary of the survival pattern of a population

3 types

Question 27

Type I

Answer 27

relatively low death rates in earlier years, but higher at older age

-parental care, more competition, 
density dependent ( 7 )

i.e. humans

Question 28

Type II

Answer 28

same death rate throughout life ( \ )

Question 29

Type III

Answer 29

Density independent ( L )

most die at early age

i.e. insects, shrimp

Question 30

Demography

Answer 30

the study of changes over time in the vital statistics of populations, especially birth rates and death rates