1. Population Ecology Chapter 19 1. Overview of Population Ecology
2. Population Growth Models 3. Human Population Growth

2. What is population ecology?
Population: a group of individuals of a single species that occupy the same area at the same time
Ecology: Branch of biology that studies the interactions among organisms and their environment

3. What is population ecology?
Population Ecology studies the changes in populations and the factors that regulate populations over time
What factors could contribute to population change?

4. Local populations being studied

5. Population characteristics
Population density
Age structure
Population size
Population distribution

6. Age structure
Shows the age structure of males in a population of cactus finches on the Galápagos Islands in 1987

7. Population Distribution
Species may have a random, clumped, or uniform distribution. Plants such as (a) dandelions with wind-dispersed seeds tend to be randomly distributed. Animals such as (b) elephants that travel in groups exhibit a clumped distribution. Territorial birds such as (c) penguins tend to have a uniform distribution.

8. Exponential growth model

9. Logistic growth model

11. Human population growth
For most of human history birth rate = death rate

12. Human population growth
Advances in sanitation, medical care, nutrition led to decrease in death rates. Birth rate remained same.

13. Human population growth
1962 – birth rate peaks.
Effective contraceptive methods lower birth rate
Difference between birth rate and death rate decrease after this peak

14. Human population growth

15. Our ecological footprint
An ecological footprint is an estimate of the area of land and water required to provide the resources an individual or a nation consumes, including
food, fuel, and housing and
the ability to absorb the waste a nation generates, of which carbon emissions are a major component
Comparing our demand for resources with Earth’s capacity to renew these resources, or biocapacity, gives us a broad view of the sustainability of human activities.

16. Our ecological footprint
According to the World Wildlife Fund, in 2008 (the most recent year for which data are available), the average ecological footprint for the world’s population was roughly 1.5 times the planet’s biocapacity per person.
By overshooting Earth’s biocapacity, we are depleting our resources.
Measure your ecological footprint
What was your percentage?
In what area can you most improve?