Ecology - Chapter 5

Question 1

What are the four important characteristics of a population?

Answer 1

population size, population density, population growth, and geographic distribution

Question 2

Geographic distribution

Answer 2

describes the area inhabited by a population.

Question 3

Population density

Answer 3

is the number of individuals per unit area.

Question 4

What are three factors that affect the population size?

Answer 4

number of births, number of deaths, number of individuals that enter or leave the population

Question 5

A population can ________ when its birthrate is greater than its death rate.

Answer 5

grow

Question 6

If the birthrate __________ the death rate, the population stays more or less the same size.

Answer 6

equals

Question 7

If the death rate is greater than the birthrate, the population __________.

Answer 7

shrinks

Question 8

Immigration

Answer 8

The movement of individuals into an area is a factor that can cause a population to grow.

Question 9

Emigration

Answer 9

the movement of individuals out of an area, can cause a population to decrease in size.

Question 10

The J-shaped curve indicates that the population is undergoing ____________.

Answer 10

Exponential growth

Question 11

Under ideal conditions with unlimited resources, a population will grow ___________.

Answer 11

exponentially

Question 12

As ___________ become less available, the growth of a population slows or stops.

Answer 12

resources

Question 13

The S-shaped curve indicates that the population is undergoing ___________.

Answer 13

logistic growth

Question 14

___________ of the environment for a particular species is the largest number of individuals that a given environment can support.

Answer 14

Carrying capactiy

Question 15

The primary productivity of an ecosystem can be reduced when there is an insufficient supply of a particular nutrient. Ecologists call such substances _____________.

Answer 15

limiting nutrients

Question 16

A ____________ is a factor that causes population growth to decrease.

Answer 16

limiting factor

Question 17

A limiting factor that depends on population size is called a _____________.

Answer 17

density-dependent limiting factor

Question 18

Density-dependent limiting factors

Answer 18

include competition, predation, parasitism, and disease.

Question 19

Competition among members of the same species is a _______________.

Answer 19

density-dependent limiting factor

Question 20

The regulation of a population by predation takes place within a ______________, one of the best-known mechanisms of population control.

Answer 20

predator-prey relationship

Question 21

Parasitism and disease are ______________________.

Answer 21

density-dependent limiting factors

Question 22

Like predators, ________ take nourishment at the expense of their hosts, often weakening them and causing disease or death.

Answer 22

parasites

Question 23

___________ affect all populations in similar ways, regardless of the population size. Unusual weather, natural disasters, seasonal cycles, and certain human activities - such as damming rivers and clear-cutting forests - are all examples of this.

Answer 23

Density-independent limiting factors

Question 24

Like the populations of many other living organisms, the size of the human population tends to __________ with time.

Answer 24

increase

Question 25

What are some ways why the human population began growing more rapidly over the past 500 years?

Answer 25

agriculture, industry, shipping, food supply, sanitation, medicine, healthcare, high birthrates

Question 26

The human population cannot keep ____________ forever, because Earth and its resources are limited.

Answer 26

growing

Question 27

The scientific study of human population is called _________.

Answer 27

demography

Question 28

What three things help predict why some countries have high growth rates while other countries grow more slowly?

Answer 28

birthrates, death rates, and age structure

Question 29

The _____________ is complete when the birthrate falls to meet the death rate and population growth stops.

Answer 29

demographic transition

Question 30

____________ show the population of a country broken down by gender and age group.

Answer 30

Age-structure diagrams

Question 31

How do you find population density?

Answer 31

number of individuals/unit area