Chapter 5

1. Chapter 5 How Ecosystems Work

2. Energy Flow • Energy from the sun enters an ecosystem when a plant uses sunlight to make sugar molecules

3. Photosynthesis • This process in which sunlight, carbon dioxide, and water are used by plants, algae and bacteria to make carbohydrates, oxygen, and water • 6CO2 + 12H2O  C6H12O6 + 6O2 + 6H2O

4. Energy Flow • Organisms use carbohydrates to carry out daily activities such as movement, growth, and reproduction

5. Producer • Organisms that makes its own food • Also known as: • Autotrophs- are at the base of the food chain • Ex. Plants, algae, and some bacteria

6. Consumers Organisms that get their energy from eating other organisms Also known as: Heterotrophs

7. Primary Consumers • Also known as herbivores; these organisms eat autotrophs • Ex. Insects, fish, rabbits, cows

8. Secondary Consumers • Known as carnivores; these organisms eat herbivores • Ex. Chameleon, fish, rats

9. Tertiary Consumer • a carnivore which eats a carnivore which eats a herbivore • Ex. Snake, fish, seal

10. Quaternary Consumer • eat tertiary consumers; have no natural enemies • Hawks and a shark

11. Omnivore • eat both plant and animal (primary consumers and secondary consumers) • Ex. Bears, pigs, and humans

12. Decomposers Decomposers eat dead plants and animals to help break down complex compounds into simpler ones. fungi, bacteria,

13. *So how do organisms use the energy they get? • By a process called cellular respiration • C6H12O6 + 6O2 = 6CO2 + 6H2O + energy (ATP) • -during cellular respiration cells absorb oxygen and use it to release energy from food occurs within the mitochondria of the cell

14. Energy Transfer A way to visualize this loss of energy from one trophic level is through an: energy pyramid- with the lowest trophic level on the bottom (pg. 131)

15. Energy Transfer Also visualize the transfer of energy through food chains and food webs also helps us determine which organisms in an ecosystem depend on other organisms to survive

16. Food Chain a sequence in which energy is transferred from one organism to the next as each organism eats another

17. Food Web shows many feeding relationships that are possible in an ecosystem

18. Energy loss Decreased amount of energy at each trophic level results in fewer organisms at the higher trophic levels and also limits the number of trophic levels Only 10% of the energy is available at each level

19. Cycling of Materials 3 Main Cycles Carbon Cycle Nitrogen Cycle Phosphorus Cycle

20. Carbon Cycle Essential for proteins fats and carbohydrates Carbon enters ecosystem by way of plants; convert carbon dioxide into carbohydrates Consumers eat the producers and get carbon from the carbohydrates Some of the carbon is then released back into the air as carbon dioxide Cycle (pg. 132)

21. Nitrogen Cycle Needed to build proteins 78% of gases in atmosphere Must be altered or fixed from the atmosphere Nitrogen-fixing bacteria accomplish this task Excess nitrogen is released into the soil Animals get nitrogen by eating plants Cycle (pg. 134)

22. Phosphorus Cycle Needed for bones and teeth Plants get it from soil and water; absorb through roots Animals get it by eating plants or from herbivores Added to soil and water by decomposition Some washes off the land into the ocean Some comes from the erosion of rocks Some from fertilizers Cycle (pg. 135)

23. Ecological Succession A gradual process of change and replacement of the types of species in a community can take hundreds or thousands of years each new community that arises often makes it harder for the previous community to survive or the new community will not survive at all

24. Primary Succession Succession that occurs on a surface where no ecosystem has existed before; such as on rocks, cliffs, newly formed islands, sand dunes, occurs in areas where there is no soil

25. Secondary Succession Occurs on a surface where an ecosystem has previously existed occurs in ecosystems that have been disturbed by humans, animals, or by natural processes (fires, volcano’s, etc.) occurs faster than primary succession

26. Pioneer Species Plants that will colonize the area and begin the process of ecological succession make the new area habitable for other species

27. Succession Over time, pioneer species and other species will continue to grow and inhabit the disturbed ecosystem Eventually it will forma final and stable community: Climax community

28. Old Field Succession Occurs when farmland is abandoned First pioneer species take over (grasses and weeds) taller grasses and perennial plants grow in the area (eventually killing the pioneer plants) over time the taller plants are taken over by taller growing trees Finally, the land returns to the community that existed before the farmers cleared it for farmland