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Food Chains Lecture 7 Honors and General Marine Biology Ecosystems Ecosystems – The biotic community and its abiotic environment functioning as a system. What are the parts of the ecosystem pictured at left? What are the biotic and abiotic factors here? How do they affect the food chain? What about your “ecosystem”? What did you have to eat today? Where did the energy come from to make this food? Autotrophs Autotrophs – Those organisms that can harness the suns energy and make their own food. Auto (Automatic) = Self Troph = Feeding Examples of Marine Autotrophs: Because they can make their own food, and food for others, they are called Producers. All autotrophs are Photosynthetic (or Chemosynthetic). Heterotrophs Heterotrophs – Those organisms that can not make their own food. Must eat other things, and so are also called Consumers. Examples of Consumers Types of Heterotrophs Can be classified into three types: 1. 2. 3. Herbivores – Eat Plant matter. Carnivores – Eat Animal Matter Omnivore – Eat Both. Decomposers Decomposers – Are the organisms that eat all dead material, including wastes of others. The “Garbage men” of the environment. i.e. Bacteria. How do they all interact? Look at the hand-out. This is a simple Food Chain. Food Chains Food Chains – Diagrams that map the linear flow of energy (and Biomass) though an ecosystem. Based on the nutritional requirements of the organisms. Is this how nature works? NO! Food Webs Food Webs – Show the complex interrelationships among organisms. However, What is missing? Energy Marine Webs can extend onto the land. Food Pyramids Trophic Levels – refers to Feeding Levels. Each Level gets smaller in Energy and Biomass. Why? 10% Rule – Only 10% of the energy/biomass at one level is available for energy/biomass at the next level. Lets look at the hand-out again. What are the trophoc levels we see? 1st trophic level = Producers •Microscopic (in marine are mostly) •Photosynthetic, produce own food. •Ex. Phytoplankton, algae 2nd trophic level = Primary consumers •Very Small (microscopic?) herbivores. •Feed on producers such as phyto and alage. •Ex. Copepods (like little shrimp) and krill. 3rd trophic level = secondary consumers •Small Carnivores plus…… •Feed on primary consumers. •Examples are mussels, small fish (anchovies), clams and baleen whales. Hand-Out Analysis Con’t 4th trophic level = tertiary consumers •Even larger carnivores. •Examples larger fish (Tuna), seals and birds. 5th trophic level = quaternary consumers •Largest fish such as sharks and toothed whales. The last “level” Decomposers •Bacteria and fungi •Eat dead remains or wastes on seafloor. NOTE: Nutrients are recycled….ENERGY IS NOT!! Food Chains/Webs Activity You have three tasks. 1)Make a food web of local marine life. You must include ten species that are interspaced between the different trophic levels. You may use phytoplankton and zooplankton as generic first two levels. 2)Using your food web, trace a pathway to make a food chain. Draw the food chain of your food web. 3)Using the food chain, start with 1,000,000 grams of phytoplankton biomass. Show the resulting biomass of each trophic level of your food chain. Whales and food Chains? Using the food pyramid, why can whales get so big?