Principles of Ecology

1. Principles of Ecology This unit is application of vocabulary. YOU MUST STUDY YOUR VOCAB!!!

2. What is ecology? • the scientific study of interactions among organisms and their environments • sometimes the “data” collected is not numeric! • qualitativeresearch - descriptions and observations • quantitativeresearch - measurements, actual data

3. Aspects of Ecological Study:Abiotic versus Biotic • abiotic factors - nonliving parts of an organism's environment • biotic factors - all the living organisms that inhabit an environment

4. Aspects of Ecological Study:Habitat versus Niche • habitat - the place where an organism lives out its life • niche - the role and position a species has on its environment • how it meets its needs for food and shelter • how it survives • how it reproduces Unique strategies and structures important for reducing competition with other species

5. Levels of Ecological Organization • Biosphere – portion of Earth that supports all life; all ecosystems • Ecosystem - communities and abiotic factors • Communities - live in the same place at the same time and interbreed Population - interacting populations • Organism/Species - a living thing *Don’t forget all the other levels!

6. There is a neat picture of this in the visual concepts for ch 15.

7. Living Relationships • predators - animals that kill and eat other animals • prey - animals that predators eat • symbiosis - living together in close and permanent associations

8. Kinds of Symbiosis • Commensalism - one species benefits and the other is neither harmed nor helped • Mutualism - both species benefit from the relationship • Parasitism - one organism benefits at the cost of the other

9. How Organisms Obtain Energy • The sun supplies the energy that supports life on Earth. • Producers = autotrophs • Use the sun’s energy and produce food; photosynthesis. • Consumers = heterotrophs • Must “eat” (consume food) to get their energy

10. Feeding Relationships • Herbivore – plant eater • Carnivore – meat eater • Omnivore – eat plants and animals • Scavengers – eat animals that are already dead • Decomposers – break down and absorb nutrients from dead organisms

11. Matter and Energy Flow in Ecosystems • Food chain – shows one way matter and energy moves through an ecosystem • arrow show direction of energy • points to the higher trophic level – feeding step • Usually three to four levels. No more than five because too much energy is lost. • Here is a short movie on food chains. • http://magma.nationalgeographic.com/ngexplorer/0309/quickflicks/index.html

12. Food web • Food web – expresses all the feeding relationships at each trophic level in a community • Let’s make a food web! • http://www.vtaide.com/png/foodchains.htm Why must an ecosystem survive by food webs and not just food chains?

13. Grass, trees, phytoplankton Fish, crustaceans Heron, turtle Alligator Bacteria and Fungi first trophic level, autotroph, producers second trophic level, heterotroph, primary consumer third trophic level, heterotroph, secondary consumer fourth trophic level, heterotroph, tertiary consumer Decomposer Roles Organisms Play

14. Ecological pyramid • shows energy at each trophic level • gets smaller as you go up because… • energy lost to the environment as heat “The atoms of carbon, nitrogen, and other elements that make up the bodies of organisms alive today are the same atoms that have been on Earth since life began. Matter is constantly recycled.”

15. Population Dynamics • Immigration – movement of individuals into a population • Adds to the total population and demands on the environment • Emigration – movement of individuals from a population • Lessens the total population and demands on the environment

16. Population Graphs • Linear (constant) growth – population gets larger at a constant rate; straight line with a positive slope • Exponential growth – as a population gets larger, it increases in size faster; j-shaped graph • Carrying capacity – the number of one species that an environment can support; s-shape on a graph

17. Look at this: • Go to the book online and view the visual concepts for section one! http://go.hrw.com • (Mrs. Davis will have to show you the graphs saved to her desktop.)

18. Limiting factors • Affect the carrying capacity • ex. Food, space • Density-dependent factors – as population density increases, their affect increases • Ex. Disease, predators, food, parasites • Density-independent factors – affect all populations regardless of their density; • usually abiotic factors • ex. Temp, storms, floods, drought, habitat disruption, pollution

19. Biodiversity • Variety of life in an area or number of species in a given area • Sometimes written in fraction form • Increasing area/size increases diversity if they are the same in every other way. • The more diverse, the more stable an environment • One species' loss from an ecosystem may have consequences for other species. How?

20. Threats to Biodiversity • Habitat loss • Habitat fragmentation • Biotic issues - predators, reproduction, food shortages • Abiotic issues - climate change, edge factor • Habitat degradation - pollution • Exotic species (feral) • no predators, exponential growth, take over the habitat