Population Dynamics

Population Dynamics

describes how pop. Inc Inc or DecDec.

immigration

birthemmigration

death

Remember a population…

group of organisms of the same species that live together in one place at one

time and interbreed.

Remember …

Population-Limiting Factors

• Density-independent factors

• Density-dependent factors

competition

Populations!Populations!Density, distribution, and growth rate

Population Density

Number of individuals per unit area

Dispersion

the pattern of spacing of a population

Uniform

Clustered

Random

Remember … growth growth raterate

Remember … carrying carrying capacitycapacity

small organism

Short life span

Produces many offspring

Rate Strategy

r-strategy

larger organism

Long life span

Produces few offspring

Carrying Capacity Strategy

k-strategy

Age Structure

Zero Population Growth

occurs when:birthrate = death rate.

Human Population Growth

The study of human population size, density, distribution, movement, and birth and death rates is demography.

Today, the world

population is more than 6

billion people and is

increasing.

Why so many Humans???? .

• Better sanitation and hygiene,

• disease control, • agricultural technology• Medicine/vaccines

As more humans live on the planet, more resources will be needed to support them. As demand for resources increases, more pressure will be put on Earth’s ecosystems.

You tricky tricky humans

• For thousands of years, environmental conditions kept the size of the human population in check.

• Humans have learned to alter the environment in ways that appear to have changed its carrying capacity.

Our own Carrying capacity?

• Sci are concerned about human popexceeding carrying capacity.

• resources from biosphere that are usedby each person.

Human Growth Rate

•Although the human population is still growing,the rate of its growth has slowed.