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Ecosystems and Energy Transfer

Ecosystems and Energy Transfer. Ecosystem Ecology Basics. We know Earth is a system , in which energy flows and matter cycles in E cosystems and Ecosystems are composed of biotic and abiotic factors and form the Biosphere . What are ecosystems? What are biotic and abiotic factors?

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Ecosystems and Energy Transfer

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  1. Ecosystems and Energy Transfer

  2. Ecosystem Ecology Basics We know Earth is a system, in which energy flows and matter cycles in Ecosystems and Ecosystems are composed of biotic and abiotic factors and form the Biosphere. • What are ecosystems? • What are biotic and abiotic factors? • How can we model ecosystem interactions and the flow of energy and nutrients?

  3. Energy Flow in Ecosystems can be modeled in Food Chains & Food Webs Food Chains Show 1 feeding relationship from producer consumers Food Webs Interconnected food chains They show all of the feeding relationships in an ecosystem

  4. Ultimate source of energy  Sun

  5. Producers • Organisms that produce their own energy are producers. Most producers utilize photosynthesis, but not all…. • Autotrophs: self-feeding • Producers also use cellular respiration to convert chemical energy of food into a different form of chemical energy, ATP • Any energy unused by the producer or released as heat/waste is available to other organisms C6H12O6 + 6O2 6H2O + 6CO2 + ATP

  6. Consumers • Heterotrophs- “other feeders” • Primary (1st order) consumers eat producers; Herbivores; Trophic Level 2 • Secondary (2nd order) consumers eat primary consumers; Omnivores or carnivores; Trophic Level 3 • Tertiary (3rd order) consumers eat secondary consumers; Typically carnivores; Trophic level 4

  7. Other Heterotrophs… • Decomposers- Breakdown (no mouth parts) organic matter and return the nutrients to the soil Ex. Fungi and Bacteria • Detritivores- Eat (mouth parts) organic matter and help return nutrients to the soil Ex. earthworms • Scavengers- Eat carcasses- they like a “free lunch”; Keep disease at bay in ecosystems Ex. Turkey Vultures, Hyena

  8. Construct a food web using the following organisms: • Black bear • Rabbit • Grass • Hawk • Blueberries • Squirrel • Acorns (Oak Tree)

  9. Example Food Web Black Bear Hawk Rabbit Squirrel Grass Blueberries Acorns (oak)

  10. Can you identify… • Autotrophs & Heterotrophs? • Which organism(s) are producers? • Which organism(s) is an omnivore? • Which organism(s) is a carnivore? • Do any organisms occupy more than one trophic level? • What heterotrophs are missing?

  11. Example Food Web TL 2/3 1° /2 ° Consumers Omnivore TL 3 2° Consumers Omnivores or Carnivores Black Bear Hawk TL 2 1° Consumers Omnivores Rabbit Squirrel TL 1 Producers Grass Blueberries Acorns (oak)

  12. Food Chains- One line of Energy Transfer in an Ecosystem The transfer of energy from producer to primary consumer then to higher order consumers. One linear feeding relationship.

  13. More Food Chain Examples

  14. Food Webs- Interconnected food chains They show all of the feeding relationships in an ecosystem

  15. How Many Chains are in this web?

  16. Identify the Producers, Consumers, & Decomposers: Count the Food Chains!

  17. Energy in an Ecosystem Energy FLOWS through ecosystems • Only 10% of the energy is available to organisms in the next trophic level; 10% rule. • 90% of the energy is unavailable due to maintaining life functions, respiration, and heat energy transferred to the atmosphere. • So, more energy is stored in producers than available to top-level consumers.

  18. 10% rule in action • What trophic level should the bulk of the biomass be in an ecosystem? Producers • Example- The Savanna of Africa • 100 km2 of grasses (10 km x 10 km) • Herd of 450 wildebeests • Pride of 20 lions • The higher up the food chain, the less available energy  less top-level consumers • 4th or 5th level consumers are rare in nature

  19. Energy Pyramids Show • Amount of available energy decreases for higher consumers • Amount of available energy decreases down the food chain • It takes a large number of producers to support a small number of primary consumers • It takes a large number of primary consumers to support a small number of secondary consumers

  20. Trophic Levels indicate feeding position in ecosystems TL 4 0.1% TL 3 1% TL 2 10% TL 1 100%

  21. Identify 1st, 2nd, 3rd and 4th level consumers in this food web.

  22. Vultures TED Talks The significance of scavengers: http://www.ted.com/talks/munir_virani_why_i_love_vultures.html

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