Food Chains & Food Webs
What is a food chain? • A Linear depiction of the transfer of energy from one organism to another as each is eaten. • This is the typical depiction: beginning with photosynthesis at the bottom and ending with a large carnivore at the top of the chain. • Note: linear and incomplete (no people or decomposers)
What is a food web? • A more accurate depiction of the interaction among the members of an ecosystem • Shows that individual organisms might have multiple food sources and multiple predators • Note: Non-linear; Includes conditions necessary for photosynthesis and decomposers, but still no people
Great activity for kids • Construct a food web for the organisms in your schoolyard, neighborhood, city, or state. • Requires direct observation or research into the plant and animals of the community. • Requires understanding of the multiple interactions among the members. • Would almost certainly include the human factor.
Step 2 of great activity for kids • Have them add or remove, increase or decrease one organism in their web. • Construct a plausible explanation about what would be the factors that might cause this change. • Discuss the short-term and long-term effects this change might have upon the other organisms and the entire web. (Possibly redraw the web to reflect these changes) • Discuss how this change might be enhanced (if it seems to improve the web) or be avoided (if it seems a detriment to the web). • Discuss how this relates to the world web as a whole and what our individual, community, and national responsibilities might be towards the ecosystems we affect.
A fun computer simulation • Quick interactive game : Plants, Rabbits, and Foxes http: //puzzling. caret. cam. ac. uk/game. php? game=f oodchain A fun non- computer simulation • A non-technical interactive game : • From the Sept. 23 rd Webinar • Oh Deer Power. Point
For further information and ideas, check these out on the Wiki: IRC: Food Chains and Food Webs IRC: Producers, Consumers, and Decomposers IRC: Interactions within Ecosystems IRC: Environmental Conditions that Affect Survival and Adaptations IRC: Human Contributions to Extinctions of Some Species