1. Ecology
Ecology is the scientific study of the interaction between organisms and between organisms and their environment.

2. Levels of Organization
1. Biosphere
2. Ecosystem
3. Community
4. Population
5. Organism

3. Ecological Methods
Scientists conduct research using 3 basic approaches.
1. Observing – could be behavior observations about an animal.
2. Experimenting – test a hypothesis
3. Modeling – gain insight into complex phenomena like global warming.

4. Notes: 3-2 Energy Flow
Sunlight is the main energy source for life on Earth.
Autotrophs – capture energy from sunlight and use that energy to produce food. Also called producers.

5. Heterotrophs – rely on other organisms for their energy and food supply. Also called consumers.
Herbivores – eat plants
Carnivores – eat animals
Omnivores – eat both
Detritivores – eat dead matter

6. Food Chains
Food Chains – a series of steps in which organisms transfer energy by eating and being eaten.
Example: plankton –dragonfly-salamander-snake

7. Food Web
Food Web – links all the food chains in an ecosystem together.

8. Trophic Level Each step in a food chain/web is called a trophic level.
(herbivore)

9. Pyramids – 3 types
1. Energy Pyramid – transfer of energy from one trophic level to the next. Measured in kcals.
**10% rule** - only 10% of the energy is transferred from one trophic level to the next.
Why?
It is lost in respiration, movement and reproduction.

10. Energy Pyramids Cont’d
100 K/cals
1,000 K/cals
10,000 K/cals

11. Types of Pyramids
2. Biomass Pyramid – transfer of biomass from one trophic level to the next.

12. Types of Pyramids
3. Pyramid of Numbers – the total number of individuals at each trophic level. (may not look like a pyramid)