Ecology

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)