1. Chapter 8 Understanding Populations
Bellringer:
You have just been offered a job that will last one month. You have two salary options:
Receive $10 per week with a $5 per week raise every week.
Receive one penny for your 1st day on the job and then double the previous day’s pay for each of the remaining 30 days.

2. I. What is a Population?
__________ members of a species living in the same place at the same time
Population
Populations are also reproductive groups
A group of loblolly pines in central Alabama cannot reproduce with a group of loblolly pines in eastern South Carolina
Population also can refer to the size of a group…the human population

3. II. Properties of a Population
Three factors describe a population:
Size - the number of organisms in the population
Density – Number of individuals per unit area or volume
Dispersion – Distribution or arrangement of the individuals within the population

4. There are three types of dispersion:
Even
Clumped
Random

5. Change in Population Size
III. How Does a Population Grow
___________ change in size of a population over a given period of time
Growth Rate
Change in Population Size
Births
Deaths
Population Increase
Births
Deaths
Population Decrease
Births
Deaths

6. IV. How Fast Can a Population Grow?
_____________ fastest rate at which a population can grow
Biotic potential
Biotic potential is limited by __________________ which is the maximum number of offspring a population can produce
reproductive potential
Reproductive potential varies by species
Increases when organisms have many offspring at once
Decreases when organisms have few offspring at once

7. Exponential Growth – populations that grow extremely FAST
Example:
2 → 4 → 8 → 16 → 32 → 64 → 128, etc…
Only occurs when there is:
plenty of food
plenty of space
no competition
no predators

8. V. What Limits Population Growth?
_______________, the maximum number of organisms that can be supported
Carrying Capacity

9. Carrying capacities are reached when:
Species consume a natural resource at the same rate at which the ecosystem can produce the resource
Competition occurs between members of a population for a specific resource

10. densely populated environments
VI. Two Types of Population Regulation
Density dependent – death within a population occur in…
Crowed conditions
Areas with limited resources
Predation
Disease
densely populated environments
Density independent – death within a population occurs regardless of resources available or population density