The Circle of Life: Food Webs

1. The Circle of Life: Food Webs

2. Food Chain: Nature’s Electricity • A food chain shows how each living thing gets its food. • energy is passed from one link to another.

3. Food Chain vs. Food Web • Too many links in a single food chain = animals at the end of the chain would not get enough food/energy to stay alive. • Most animals are part of more than one food chain and eat more than one kind of food in order to meet their food and energy requirements. • food web = multiple food chains • Most food chains have no more than four or five links.

4. Everybody’s Different • Top-level carnivore---carnivore without predators itself. • Carnivore---animal which eats herbivores, omnivores and other carnivores. • Omnivore---animals which eat plants and animals (zooplankton and phytoplankton). • Herbivore---animals which eat plants only. • Producer---plants and microscopic organisms which convert sunlight to energy (marine plants, phytoplankton).

5. Antarctic Food Web

6. Little Things Mean a Lot Microbes The Sun

7. Why are there more herbivores than carnivores ? • Herbivore: only a fraction of the energy (from the plant food) becomes new body mass; • energy is lost as waste or used up (by the herbivore as it moves). • Carnivore: only a portion of the energy from the animal food is stored in its tissues. • organisms along a food chain pass on much less energy (as body mass) than they receive.

8. ***Change in the size of one population in a food chain will affect other populations. • Interdependence within a food chain helps maintain the balance of populations within a community. • http://ecokids.earthday.ca/pub/eco_info/topics/frogs/chain_reaction/assets/flash/chain_reaction.swf

9. For example: • when there are too many giraffes; there will be insufficient trees and shrubs for all of them to eat. Many giraffes will starve and die. • Less giraffes means more time for the trees and shrubs to grow to maturity and multiply. • Less giraffes also means less food is available for the lions to eat and some lions will starve to death. When there are fewer lions, the giraffe population will increase.

10. Law of survival: • Adapt • Migrate • Perish

11. Your Activity: Plants and Animals of the Chaparral

12. Your Job: Classify and Rank

13. Sources: • http://www.gould.edu.au/foodwebs/kids_web.htm • http://www.vtaide.com/png/foodchains.htm • http://www.coralreefnetwork.com/educate/shows/foodwebs/end.htm • http://www.lalc.k12.ca.us/uclasp/urban_science/food_chains/intro_chains.html • http://www.circleoflife.org/ • http://www.nineplanets.org/