Food Chains & Food Webs Science 10 Ms. Lowrie

Food Chains Show the flow of energy through an ecosystem Linear pictures of how energy moves (is transferred) from one organism to the next

Food Chains Notes:  All food chains start with a producer (a plant)  Arrows point in the direction of energy flow Not who eats who Ex: algae fish bear

Examples of food chains: 1. Lichen  Snail  Toad  Bird 2. Wild Berries  Field Mouse  Fox 3. Phytoplankton  Zooplankton  Salmon  Eagle

Activity – You & Food Chains Think about what you last ate. Whatever it was, its main ingredients were once part of living organisms  Plant matter in was made by plants, using sunlight, carbon dioxide, water, nutrients in soil  Animal matter was made from items the animal ate (plants, animals, or both) By eating, you become another link in this chain of life!

You In a Food Web 6

Activity – You & Food Chains 1. List all food eaten in your last 2 meals For processed foods, list all ingredients that come from living things 2. Organize the items from #1 into a t-chart Plant MatterAnimal Matter (includes eggs, milk, butter & cheese)

Activity – You & Food Chains 3. Identify all items under the ‘Animal Matter’ column as either a(n): Herbivore Omnivore Carnivore

Activity – You & Food Chains 4. Create three food chains to which you are linked. Use ideas from the data in your chart. Food Chain 1: Food Chain 2: Food Chain 3:

Activity – You & Food Chains Answer the following questions:  Brainstorm answers with your table 1. What kinds of organisms are at the start of every food chain? 2. Do any of your food chains have more than three links? Suggest a reason why or why not. 3. For what species might you become a source of food? When or why might this happen?

You In a Food Web 11

Food Web Show interactions among food chains Most animals:  eat more than one type of food  are eaten by more than one predator  are part of more than one food chain

Activity – Creating Food Chains Task: Create 3 different food chains from the food web

Trophic Levels Positions in a food chain  Depends on number of organisms 1 st trophic level = producer 2 nd trophic level = primary (1º) consumer 3 rd trophic level = secondary (2º) consumer  Etc … Last tropic level = largest omnivore / top carnivore

Trophic Levels: Example

Trophic Levels: Examples

Example (please copy)

Energy Flow Less energy available to pass to next trophic level  More ‘links’ = less energy  Usually 10% available

The 10% Rule About 10% of energy:  Stored in tissues  Available to be transferred when eaten Other 90% is used for growth, reproduction or released to environment

Energy Loss (please copy)

Any questions?