Autotrophs (producers) Photosynthetic Organisms: Photosynthesis. Chemosynthe*c bacteria

Transcription

1 ALL living things need energy for growth, reproduction, metabolic reactions. Energy can t be created or destroyed only changed into different forms. SUN is source of all energy. Autotrophs (producers): convert solar/chemical energy into stored carbohydrates, which is food energy for themselves and all other living things. Photosynthetic Organisms: convert solar energy * ex: plants, green algae, some bacteria * Photosynthesis. Solar energy used to convert CO 2 and H 2 O into glucose and O 2. * These organisms add oxygen to our atmosphere and removes carbon dioxide. Chemosynthe*c bacteria convert CO 2, H 2 S and O 2 into carbohydrates and sulfur compounds for the ecosystem. 1

2 Carnivore: must ingest organic material (Ex. animals, fungi, most bacteria) Consumer Types: a) carnivores: kill and eat other animals (ex: snake, lion) b) herbivores: eating plant material only (ex: cow, caterpillar) c) omnivores: diet of both plant and animal material (ex: humans, pigs) d) decomposers: chemically breakdown dead organic material into detritus (small pieces of dead and decaying plant and animal remains) (ex: bacteria and fungi) e) detritivores: digest decomposers on or in detritus particles (ex: earthworm) f) scavengers: animals consuming dead carcasses of other animals (ex: vulture) 2

3 KEY IDEA: Energy moves in ONE direction! Energy flows through an ecosystem from producers to various types of consumer. Food Chain: series of steps in which living things transfer energy by eating and being eaten in terrestrial ecosystems, plants are the primary producers in aquatic ecosystems, algae (phytoplankton) are the primary producers Food Web: interconnected food chains role of decomposers: convert dead material in food web into detritus AND recycle nutrients back into soil to be used by producers to keep system going 3

4 1. Pyramid of Energy: shows rela>ve amounts of available energy at each level of a food chain/web * only about 10% of the energy available in one trophic level makes it to the next. * most of the energy is used by the organism (growth and reproduc>on energy to consumers) or lost as heat (cellular respira>on heat to the environment) or waste (eges>on, excre>on, death energy to detritus feeders) * the more levels between a producer and a consumer, the smaller the % of the original producer s energy is available to that consumer * meat is energy expensive! THOUGHT QUESTIONS: 1. What type of organism is missing from all the trophic levels in this pyramid? 1. Explain why a vegetarian diet is considered a more energy- efficient diet for humans than one based on beef, chicken or pork. 4

5 1. Compare and contrast the two pyramids in Model 2. List at least two similari>es and two differences. Both have the same organisms in the same trophic levels. Both have the same number of trophic levels. Pyramid A has 2 oak trees in the first trophic level while Pyramid B has 100,000 oak leaves in the first trophic level. The shape of the pyramids is different. 2. How does the number of organisms change as you move up the levels in Pyramid A compared to Pyramid B? In Pyramid B, the number of organisms decreases from one level to the next. In Pyramid A, the first level has a small number of organisms and the remaining levels follow the same paeern as in Pyramid A. 3. Are the producers levels in the two pyramids in Model 2 referring to the same organisms or different organisms? Explain. The oak tree is the same, but the caterpillars eat only the oak tree leaves. 4. Which of the two pyramids in Model 2 gives a more accurate account of what occurs in this ecosystem? 5

6 1. Biomass is measured as grams of dry mass within an area. What is the mass of the oak trees in Pyramid X of Model 3? 11, What is the mass of the phytoplankton in Pyramid Y of Model 3? Iden>fy the trend in biomass as you move up the trophic levels in Pyramid X. The biomass decreases steadily. 4. Is the trend in biomass in Pyramid X the same as seen in Pyramid Y? Explain. No. The mass of the producers is smaller than the mass of primary consumers. AHer that level, the biomass of each trophic level decreases steadily. Phytoplankton are microscopic aqua*c organisms that are quickly consumed by microscopic animals (zooplankton). Because they are eaten so quickly there is a need for the phytoplankton to reproduce rapidly for survival. 1. Explain why the Pyramid Y ecosystem can exist with a smaller biomass at the producer level. Phytoplankton reproduce rapidly, so they can sustain a large number of primary 6