CH 7 Population ecology

Question 1

What is a population?

Answer 1

A population comprises all the individuals of a species that live in the same geographic area and interbreed

Question 2

What is a minimum viable population?

Answer 2

The smallest number of individuals that would still allow a population to persist or grow

Question 3

Population density?

importance?

Answer 3

the number of individuals per unit area

• too low= hard to find mates
• too high= increased competition, spread of disease, fighting

Question 4

how is annual population growth rate calculated?

Answer 4

It is calculated by subtracting birth rate (births/1000 individuals) from death rate (deaths/1000 individuals)

Question 5

What is biotic potential?

Answer 5

Biotic potential refers to the (usually) exponential growth of a population when there are no limits to growth

Question 6

When do we typically see exponential growth in nature?

Answer 6

• it is typically seen when a species enters a new environment or there is an influx of new resources
• or a loss of predators

Question 7

Two factors necessary for exponential growth to occur?

Answer 7

1. population must have a high birth rate

2. and a low death rate

Question 8

Difference between exponential growth and logistic growth?

Answer 8

Exponential growth continues to grow exponentially without any limit.
Logistic growth may begin to grow exponentially but eventually hits a limit (carrying capacity) and levels out

Question 9

What are some density dependent factors?

Answer 9

• Competition
• Disease
• Predators

Question 10

What are some density independent factors? (stochastic events)

Answer 10

• Fires/Floods
• Storms
• Avalanche & other natural disasters

Question 11

What are r-adapted (selected) species?

Answer 11

• R adapted species such as deer mice, adapt well to unpredictable environments, and have a high rate of increase.
• Short life, rapid growth, early maturation, abundant offspring, little parental care, adapted to unstable environment, prey, niche environment

Question 12

What are k-adapted (selected) species

Answer 12

• K adapted species such as wolves reproduce slowly and have a lower rate of increase
• long life, slower growth, late maturation, few offspring, high parental care, adapted to stable environment, predators, niche specialists

Question 13

Boom bust cycle

Answer 13

occur when predator and prey populations increase and decrease in response to their interactions over time

Question 14

Top down tropic cascade?

Answer 14

a trophic cascade where the top consumer/predator controls the primary consumer population.

Question 15

Main reason species are endangered?

Answer 15

Habitat destruction

Question 16

How many animals are threatened with extinction?

Answer 16

26,000