Unit 2, Part 3 Notes

1. Unit 2, Part 3 Notes Food Chains, Food Webs, and the Transfer of Energy

2. Autotrophs • A groups of organisms that can use the energy in sunlight to convert water and carbon dioxide into Glucose (food) • Autotrophs are also called Producers because they produce all of the food that heterotrophs use • Without autotrophs, there would be no life on this planet • Ex. Plants and Algae

3. Autotrophs

4. Autotrophs • Chemotrophs • Autotrophs that get their energy from inorganic substances, such as salt • Live deep down in the ocean where there is no sunlight • Ex. Bacteria and Deep Sea Worms

5. Heterotrophs • Organisms that do not make their own food • Another term for Heterotroph is consumer because they consume other organisms in order to live • Ex. Rabbits, Deer, Mushrooms

6. Heterotrophs

7. Heterotrophs • Consumers • 1. Scavengers/Detritivores – feed on the tissue of dead organisms (both plans and animals) • Ex. – Vultures, Crows, and Shrimp

8. Heterotrophs • Consumers • 2. Herbivores – eat ONLY plants • Ex. – Cows, Elephants, Giraffes Flat teeth for clipping and grinding

9. Heterotrophs • Consumers • 3. Carnivores – eat ONLY meat • Ex. – Lions, Tigers, Sharks

10. Heterotrophs • Consumers • 4. Omnivores – eat BOTH plants and animals • Ex. – Bears and chimps, Humans What type of teeth?

11. Heterotrophs • Consumer type • Decomposers – absorb any dead material and break it down into simple nutrients or fertilizers • Ex. – Bacteria and Mushrooms

12. Transfer of Energy • When a zebra eats the grass, it does not obtain all of the energy the grass has (much of it is not eaten) • When a lion eats a zebra, it does not get all of the energy from the zebra (much of it is lost as heat)

13. Transfer of Energy • The two (2) previous examples of energy transfer show that no organism EVER receives all of the energy from the organism they just ate • Only 10% of the energy from one trophic level is transferred to the next – this is called the 10% law

14. Trophic Levels • Energy moves from one organisms to another when it is eaten • Each step in this transfer of energy is know as a trophic level • The main trophic levels are producers, consumers, and decomposers

15. Food Chains • The energy flow from one trophic level to the other is know as a food chain • A food chain is simple and direct • It involves one organism at each trophic level • Primary Consumers – eat autotrophs (producers) • Secondary Consumers – eat the primary consumers • Tertiary Consumers – eat the secondary consumers, top consumer in ecosystem… Eagles, sharks, man • Decomposers – bacteria and fungi that break down dead organisms and recycle the material back into the environment

16. Food Chain

17. Food Web • Most organisms eat more the JUST one organism • When more organism are involved it is know as a FOOD WEB • Food webs are more complex and involve lots of organisms

18. Food Web These arrows are pointing in the direction of the energy transfer

19. Food Web • Notice that the direction the arrow points → the arrow points in the direction of the energy transfer, NOT “what ate what”

20. Food Web

21. Biomass • The total mass of the organic matter at each trophic level is called biomass • Biomass is just another term for potential energy – energy that is to be eaten and used. • The transfer of energy from one level to another is very inefficient (10% Law)

22. Biomass

23. Ecological Pyramid • An ecological pyramid shows the relationship between consumers and producers at different trophic levels in an ecosystem • Shows the relative amounts of energy or matter contained at each trophic level • The Pyramid shows which level has the most energy and the highest number of organisms

24. Ecological Pyramid

25. Ecological Pyramid

26. Ecological Pyramid • Which level has the most energy? • Which level has the most organisms? • Which level has the least organisms? • Which level has the least energy? • Which level has only producers? • Which level have herbivores? • What are the top consumers called?

27. Symbiosis • A close and permanent association between organisms of different species • Mutualism – a relationship in which both organisms benefit from each other • Example: Birds eating pest off a rhino’s back • Parasitism – A relationship in which one organism benefits and the other is harmed • Example: Ticks on a dog • Commensalism (* Mr. cohen debates whether this actually exists*)– a relationship in which one organism benefits and the other is not apparently affected • Example: Barnacles on a whale

28. Ecological Succession • A change in the community in which new populations of organisms gradually replace existing ones • Primary Succession – occurs in an area where there is no existing communities and for some reason (s) a new community of organisms move into the area. For example, a new island springs from the ocean. It begins with pioneers • ( autotrophs) and the food web develops and niches are filled over time.

29. Ecological Succession . Secondary Succession – occurs in an area where an existing community is partially or totally damaged. • For example; fire, flood, volcanic eruption. • The biome should develop in the same way as the first time as long as the initial conditions still exist. • But what if the conditions now are different?!

30. Climax Community This is the finished (?) product of succession. All of the niches have been competed for and the losers excluded from the population • a community that is stable and has a great diversity of organisms