**Population Growth**

END OF SECTION

As resources

become less available

, the growth of a population slows or stops.

Logistic growth

occurs when a population's growth slows or stops following a period of exponential growth.

Carrying Capacity (K)

– the largest number of individuals an environment can support.

Logistic Growth

Exponential growth in a population slows down or stops as

resources become limited.

rate of immigration increases.

rate of emigration decreases.

birth rate increases.

5-1

An S-shaped curve on a graph of population growth is characteristic of

exponential growth.

logistic growth.

carrying capacity.

delayed growth.

5-1

Limiting Factors

Immigration

- the movement of individuals into an area.

Emigration

- the movement of individuals out of an area.

Population Growth

per km2

What factors affect population size?

Population Growth

Three important characteristics of a population are its:

geographic distribution

population density

growth rate

Characteristics of Populations

Exponential growth rate means that each new generation of a population

adds the same number of new individuals as the previous generation did.

increases at the same rate as the previous generation.

is the same size as the generation before.

increases by a varying amount.

5-1

When the birthrate of a population exceeds its death rate, the population

decreases.

increases.

stays the same.

increases then decreases.

5-1

Population density is the number of individuals

that are born each year.

per unit area.

that immigrate.

that emigrate.

5-1

Logistic growth is characterized by an S-shaped curve.

Logistic Growth

Exponential Growth

Exponential Growth

Under

ideal conditions

with unlimited resources, a population will grow exponentially.

Exponential growth

occurs when the individuals in a population reproduce at a constant rate.

Exponential Growth

Three factors can affect population size:

number of births

number of deaths

number of individuals that enter or leave the population

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

Population Growth

**5-1 How Populations Grow**

Copyright Pearson Prentice Hall

Could exponential growth

occur indefinitely?

How would this look on a graph?

Human Effects on Climate

and the Biosphere

How are humans contributing to global

climate change?

If limited resources control populations,

which important resources are in danger

of becoming limited for us?

Human Population Growth

Global Temperature Increased

History of Atmospheric Carbon Dioxide

400,000 years ago to 1950

Carbon Dioxide Levels Today

What are the consequences

of a warming world?

Our Only Home

Image of Saturn by Cassini

July, 2013

Earth

Earth and the Moon as seen

from Cassini orbiting Saturn

July, 2013

Earth from Saturn

July, 2013