1. DO NOT TAKE HOME, THANKS!
Lesson 1.5: Populations

2. Population Density:
Population density refers to the number of individuals per unit area.
(Example: A population of ducks in a pond may have a low density, while fish and other animals in the same pond community may have higher densities.)

3. Population Dispersion:
Dispersion refers to how individuals in a population are spaced out across the range of the population—randomly, uniformly, or in clumps.
(Ex. Dolphins travel in pods or clumps)

4. Population Growth Rate:
A population’s growth rate determines whether the population size increases, decreases, or stays the same.
How do we determine growth rate?
Birth rate = +
Death rate = -
Immigration (enter) = +
Emigration (exit) = -

5. Population Capacity:
Carrying capacity is the maximum number of individuals of a particular species that a particular environment can support.
When (Birth rate + Immigration = Death rate + Emigration) population growth stops and you get your carrying capacity.

6. How Scientists Get Population Info?
How do scientists determine the density, dispersion, growth rate, & carrying capacity of a population?
By safely sampling or capturing organisms and recording information (2 common examples):
Random Sampling Technique
Mark & Recapture Technique

7. How Scientists Get Population Info?
1. Random Sampling Technique
Best when you have a large population of organisms
Scientists use different sized grids to count organisms
Multiply a grid of organisms per unit area to estimate population density

8. How Scientists Get Population Info?
2. Mark & Recapture Technique
Best when you have a small population of organisms
Scientists catch an organism and mark it with a tag and/or tracking device
They can record the number recaptured organisms as well as gather data from tracking devices