1. Biotic/Abiotic factors Carrying capacity Techniques of Field Ecology
Unit 2 Ecology
Biotic/Abiotic factors
Carrying capacity
Techniques of Field Ecology

2. Environments & Ecosystems
What is the relationship between the environment and an ecosystem?
The environmental factors that affect ecosystems:
Biotic
Abiotic

3. Can you identify the biotic and abiotic factors in this ecosystem?

4. Populations Can you write your own definition for the term population?
Populations will grow if the ___________ rate exceeds the ________ rate.
Populations ____________ grow indefinitely forever.
Why?

5. Population Growth rates
Factors that limit population growth are called limiting factors; they can be either biotic or abiotic factors
Examples of limiting factors
- predators
- food
- reproductive mates
- weather

6. Graph of population growth
2. What is part A of the graph?
1. What is going on in this part of the graph?

7. Counting the size of Populations
Is not easy! Often the populations are inaccessible to humans
Ecologists try to determine population sizes in order to assess species diversity and to predict changes over time
Ecologists use several different methods to count population sizes in the field
Capture & release
Random sampling
Quadrant studies

8. Capture & release

9. Quadrant sampling
It would be practically impossible to count every organism in the entire area

10. Random sampling
Scientists take samples from various accessible places to get an estimate of population size

11. Analysis of populations over time