1. Living Things! Factors that affect living things are: Biotic factors – things that are alive or were alive (other organisms) Abiotic factors – things that are non-living (temperature, water etc.) The interaction of all biotic and abiotic factors creates an ecosystem.

7. Roles of Organisms Organisms can be either producers or consumers in terms of energy flow through an ecosystem. All living things need energy to survive and grow. The source of this energy is the sun. Plants through photosynthesis (an endothermic process) create food (sugar), to store energy for later use. To release stored energy from the sugar the plants carry out respiration ( an exothermic process). Not all organisms can produce their own food, so some must depend on other organisms as a source of food (energy).

8. Producers: are self feeding organisms (autotrophs) that make organic molecules (glucose) during the process of photosynthesis. Photosynthesis uses energy from the sun plus the inorganic molecules CO 2 and H 2 O. Examples: Algae, grasses, trees, etc.

9. Consumers: are heterotrophs, organisms that cannot make their own food, they depend on other living organisms for food. Primary Consumers: Herbivores that each vegetation Ex. : Grasshoppers, rabbits, snails, etc. Secondary Consumers: Carnivores that eat the herbivores Ex. : cats, ladybugs, foxes, owls, etc. Tertiary Consumers: Top carnivores. Ex. : Lions, bears, wolves, etc.

10. The Decomposers (Detritivores) : They decompose dead organic material or wastes to return essential nutrients to the soil. These nutrients help plants grow. Ex. : Bacteria and mushrooms

11. Trophic (feeding) level refers to the organisms position in the food chain Autotrophs are at the base (first trophic level). Organisms that eat autotrophs are called herbivores or primary consumers (second trophic level). An organism that eats herbivores is a carnivore and a secondary consumer. (third trophic level) A carnivore that eats a carnivore that eats a herbivore is a tertiary consumer (forth trophic level). Omnivores eat both animals and plants.

12. Example of a food chain and the associated trophic (feeding) levels OrganismsGrassesGrasshopperLadybugRavenMushrooms Bacteria TypeProducter (plants) Primary Consummer (herbivore) Secondary Consumer (carnivores) Teriary Consumer (top carnivore) Decomposer Trophic Levels FirstSecondThirdFourthFeed off all levels

13. Organism Classification Consumer levelTrophic levelFood source Plants ------------------First------------------ Herbivoresprimary Second plants Carnivores secondary or higher (top) Thirdanimals Omnivoresall levels plants & animals Detritivores--------------- ---------------- detritus An overview of Trophic and Consumer levels

14. Energy and Nutrient Flow Through the Ecosystem The movement of energy is shown by the dark arrows. The movement of the inorganic nutrients is shown by the open arrows

15. ENERGY At each level of the food chain, about 90% of the energy consumed is lost in the form of heat. The total energy passed from one level to the next is only about one-tenth of the energy received from the previous level organism. As you move up the food chain, there is less energy available to pass on to the next level. As you move up the food chain animals get larger and need more food to meet their energy needs. NOTE!! Each organism in the food chain is only transferring one-tenth of its energy consumption to the next organism.

16. To summarize 1.The ultimate source of energy (for most ecosystems) is the sun. 2.The ultimate fate of energy in ecosystems is for it to be lost as heat. 3.Energy and nutrients are passed from organism to organism through the food chain as one organism eats another. 4.Decomposers remove the last energy from the remains of organisms and release nutrients back into the soil. 5.Inorganic nutrients are cycled, energy is not.

17. Food Chains and Webs A food chain is the path of food from a given final consumer back to a producer. (The arrow points to the consumer.) grass  grasshopper  mouse  snake  hawk Identify the autotrophs and heterotrophs, and classify each as a herbivore, carnivore, etc.

18. Feeding Levels

19. The real world is more complicated than a simple food chain. A more realistic depiction of who eats whom is called a food web which depicts interlocking food chains.

20. Questions to answer From the previous slide identify: 1. Producers 2. Primary consumers 3. Secondary consumers 4. Tertiary consumers 5. Top carnivores