Download Slide 1 - willisworldbio

POPULATIONS
1
HOW POPULATIONS GROW
OBJECTIVES: 5.1
List the characteristics used to describe a
population.
Identify factors that affect population size?
What are exponential growth and logistic growth.
2
Three important characteristics of a population
are its geographic distribution, _____, and
growth rate.
Geographic distribution, or ______, is a term
that describes the area inhabited by a population.
Population ______ is the number of individuals
per unit area.
3
Three factors can affect population size: the
number of _____, the number of ______, and the
number of individuals that either enter or leave
the population.
births
deaths
Entering (leaving)
4
Populations grow if the birthrate is greater than
the death rate, or if individuals move into an area
(__________).
Populations remains the same when the birthrate
equals the death rate.
Populations decreases when the death rate is
greater than the birthrate, or if individuals move
out of an area (________).
5
________ growth occurs when the individuals in a
population reproduce at a constant rate (only
occurs under ____ conditions).
2-4-8-16-32-64-128-256-512-1024-____?
Always a J-shaped curve.
6
______ growth occurs when a population’s
growth slows or stops following a period of
exponential growth.
_______ (K) capacity is the largest number of
individuals of a population that a given
environment can support.
Always an S-shaped curve.
7
LIMITS TO GROWTH
OBJECTIVES: 5.2
Identify factors that limit population growth.
Differentiate (identify the difference) between
density-dependent and density-independent
limiting factors.
8
A ______ factor (2 types)is a factor that causes
population growth to decrease.
______-dependent limiting factor depends on
population size (numbers).
1.
2.
3.
4.
Competition for resources
Predation (predator-prey relationship)
Parasitism
Disease
9
Density-______factors affect all populations
in similar way, regardless of the population.
1.
2.
3.
4.
Weather
Natural disasters
Seasonal cycles
Human activities
a. damming rivers
b. clear cutting forests
10
HUMAN POPULATION GROWTH
OBJECTIVES: 5.3
Describe how the size of the human population
has changed over time.
Explain why population growth rates differ from
country to country.
11
Like the populations of many other living
organisms, the size of the human population
tends to ______ with time.
500 years ago the human population began to
grow rapidly.
1. Agriculture and industry made life easier
2. Food supply more reliable.
12
3. Essential goods could be shipped around the
world.
4. Improved sanitation
5. Improved medicine and health care
_________ is the scientific study of human
populations.
Demographic _______ is the change in population
from a high birth and death rates to low birth and
death rates.
13
Age-structure diagrams show the population of
country broken down by gender and age group.
The table on p.132 predicts that the human
population will reach ~9 billion by the year
2050.
14