Chapter 2: Principles of Ecology

1. Chapter 2: Principles of Ecology

2. Ecology • The study of the interactions between organisms and their environment • Includes both Biotic (living) and abiotic (nonliving) factors • Abiotic factors might include: • Temperature • Water availability/quality • Terrain (mountains, flat land, etc.) • Soil chemistry • Etc.

3. The biosphere • The portion of Earth that contains life • Stretches from the high atmosphere to the deepest ocean • “Skin of an apple”

4. Levels of Ecological organization • Organism=1 • Population=group of same species in same area who interbreed • Community=interacting populations • Ecosystem=communities and abiotic factors • Biosphere=portion of planet that supports life

5. So very important! • Within populations and communities, there is competition for limited resources (i.e. food, water, shelter, etc.)

6. 2 types of ecosystems • Terrestrial= on, under, or near land • Aquatic=in water • These ecosystems do occasionally overlap (pelicans, frogs, etc) but are in their own category and are influenced by different things.

7. Habitat vs. Niche • An organism’s habitat is simply where it lives • An organism’s niche is the role or position of the organism in the habitat

8. Symbiosis • Sym=together (think “symmetry”) • Bio=life • Means “living together” • 3 types, defined by how they impact one another

9. Mutualism (+/+) • Both organisms are benefitted

10. Commensalism (+/0) • One organisms gets a benefit, the other is unaffected

11. Parasitism (+/-) • One organism is benefitted, the other is harmed • Usually does not kill host, because it relies on it for survival

12. Nutrition and Energy Flow • Terms: • Autotroph: “Auto”=Self “troph”=nourishment • A.k.a. Producer • Organism that makes its own energy (ex. Plants and some bacteria) • Heterotroph: “Hetero”=other • A.k.a. consumers • Get energy from consuming other living matter (ex. Animals, fungi) • Decomposers • Break down dead/dying matter into nutritional materials (ex. Fungi)

13. Types of Heterotrophs • Herbivore-only eats plants • Carnivore=“only” eats other animals • Omnivore=eats plants and animals • Scavengers=only eat dead organisms

14. How energy moves through an ecosystem • Diagrams • Food chain-simple diagram showing where energy goes • Producer (Autotroph)→Primary Consumer (Herbivore)→Secondary consumer (carnivore)→Decomposer • NOTE: Arrows show where the ENERGY is going, not what is eating what

15. Food web • More complex than food chain • Shows all possible feeding relationships • More realistic, but seldom perfect

16. Trophic Levels • Feeding step in energy chain • Begin with autotrophs • 1st order heterotroph (herbivore) • 2nd order heterotroph (carnivore) • 3rd order heterotroph (carnivore or scavenger • Decomposer (everything ends with decomposers!)

17. Energy Pyramids • Model to show how much energy is available at each level • As energy moves on, only a small portion (10%) is available at the next stage • The rest is lost to the environment as heat (metabolism) while with the organism • Biomass-mass of living matter at each level

18. Cycles in Nature • Water cycle • Carbon cycle • Nitrogen cycle • Phosphorus cycle With a partner, draw each of the cycles using your own design (do not copy the book, but use it as a reference) One person will dictate what to draw. The second person will draw. Switch roles for each one. Both should be able to answer questions about the pictures. We’ll vote to see which ones should be posted in the room.