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Minds On – Step 1. Brainstorm the following by yourself on a blank page: Think of an ecosystem that you know, have seen or can imagine. Write down all the organisms (e.g. plants and animals) that you can think of. (2 minutes). Minds On – Step 2. Work together in your table groups:
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Minds On – Step 1 Brainstorm the following by yourself on a blank page: • Think of an ecosystem that you know, have seen or can imagine. • Write down all the organisms (e.g. plants and animals) that you can think of. (2 minutes)
Minds On – Step 2 Work together in your table groups: • Organize your group page into the following categories: • Producers: Organisms that produce .their own food • Herbivores: Organisms that only eat plants, seeds, etc. • Carnivores: Organisms that eat other animals or insects • Sort your organisms from step #1 into these categories. (4 minutes)
Minds On – Step 3 Brainstorm in your table groups: • Select a list of organisms that provide food for each other as follows: • One Producer • One Herbivore • One Carnivore or More (if they eat another carnivoire) • Brainstorm how you would show this “eating” relationship in a simple diagram.
Minds On – An Example • Producer = Berries • Herbivore = Chipmunk • Carnivore 1 = Raccoon • Carnivore 2 = Wolf Berries Chipmunk Raccoon Wolf
Food Chains & Food Webs Energy Flow in Ecosystems
Food Chain • A step-by-step sequence of who eats who in an ecosystem • Linear relationship (all in a line) • Arrows point in direction of energy flow Berries Chipmunk Raccoon Wolf Producer 1st Tropic Level Primary Consumer 2nd Tropic Level Secondary Consumer 3rd Tropic Level Top Consumer 4th Tropic Level
Definitions • Trophic Level • Refers to how an organism gains energy • Identifies the organism’s position in the food chain • Producers • Make their own food (example: plants) • First Trophic level • Primary consumers (Herbivores) • Feed on producers • Second Trophic level • Secondary consumers (Carnivores) • Feed on primary consumers • Third (fourth, fift, etc.) Trophic Level Omnivores?
Limits of Food Chains • Food chains are very good at showing simple relationships. • But how do we show: • Multiple producers & Herbivores • Herbivores that eat multiple producers • Omnivores (organisms eating both plants and animals) Berries Chipmunk Raccoon Wolf
Food Webs • An interconnected feeding relationship for an ecosystem • Bottom-up links with many possible paths • Arrows point in direction of energy flow Wolf Secondary & Higher Consumers 3rd & Greater Tropic Levels Raccoon Primary Consumer 2nd Tropic Level Chipmunk Producer 1st Tropic Level Shrub / Berries
Food Web of the Redside Dace Great Blue Heron Third Trophic Level Yellow Perch Water Snake Dragonfly grasshoppers Mayflies Second Trophic Level Dragonfly Nymph Mayfly Nymph Water Boatman Tadpole Small crustaceans Zooplankton Bacteria and fungi First Trophic Level Phytoplankton Dead Plants and Animals Mineral Nutrients
Completing The Cycle • What happens when things die? • What organisms help to return nutrients to the ecosystem? • How do we show this in a food chain or food web?
Decomposers & Detritivores • Examples of Decomposers • Mushrooms (Fungi), • Bacteria • Examples of Detritivores • Maggots & worms • Vultures & Hyenas • Role (Niche) • use and modify the decomposing abiotic (non-living) material • Return nutrients back to the environment (that were previously locked in organisms)