1. Studying Populations
Chapter 1
Lesson 2

2. Direct Observation Count each population (any living thing)
individually.
1,2,3,4,5,6,7,8,

3. If 1 bear lives in every cave, there are approximately 30 bears.
Indirect Observation
Make an estimation –
For example
There are 30 caves in the
Southern part of the
Shawnee Natl. Forest
If 1 bear lives in every cave, there are approximately 30 bears.

4. Sampling Estimate Again…………………… Say you measure off 100 square meters
of forest and find 8 trees.
You know that the WHOLE forest is 100 times that size……………………………….
So you have 800 trees.

5. Mark and Recapture
Go to a pond…………..Catch 100 turtles and mark them with a dot or a tag.
Release them back into nature…………..Wait
two weeks and capture 100 turtles. If they have a mark, do not recount them.
If they don’t have a mark, tag them too.

6. Birth Rate vs. Death Rate
If birth rate is greater than death rate
the population goes UP.
If death rate is greater than birth rate
the population goes DOWN.

7. Immigration vs. Emigration
Immigration – Coming INTO a population.
Remember I for into
Ways to join a population
Moving into
Being born
Emigration –
Exiting a population
Remember E for exit
Ways to exit
Dying
Moving away

8. Factors that can cause a population to decrease (go down).
Limiting Factors
Food
Water
Space
Weather Conditions
Factors that can cause a population to decrease (go down).