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Chapter 17

Chapter 17. Ecosystems. I. What is an Ecosystem?. Organisms interact with each other and their environment. 1. All of earth’s inhabitants are interwoven in a complex web of relationships. In 1866, Ernst Haeckel gave the name to the study of how organisms fit into their environment-ecology.

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Chapter 17

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  1. Chapter 17 Ecosystems

  2. I. What is an Ecosystem? • Organisms interact with each other and their environment. 1. All of earth’s inhabitants are interwoven in a complex web of relationships.

  3. In 1866, Ernst Haeckel gave the name to the study of how organisms fit into their environment-ecology. 3. Ecology-the study of the interactions of living organisms with one another and with their physical environment.

  4. Habitat- The place where a particular population of a species lives. • Community- The place where a particular population of a species lives. 6. Ecosystem-Community and all the physical aspects of its habitat.

  5. Abiotic factors- The physical aspects of a habitat. 8. Biotic factors-Living organisms in a habitat.

  6. B. Ecosystems support Diverse Communities • The number of species living within an ecosystem is a measure of its biodiversity. 2. The number of animals, trees, plants, shrubs, insects, fungi, ect is an example of biodiversity.

  7. C. Ecosystems change over time. • When a volcano forms a new island, a glacier recedes and exposes bare soil, or a fire burns an area, new habitat is created. 2. The first organisms to live in new habitat are small fast growing plants called pioneer species.

  8. Pioneer species

  9. Succession 3. A somewhat regular progression of species replacement is called succession.

  10. Primary succession 4. Succession that occurs where plants have not grown before is called primary succession.

  11. Secondary succession 5. Succession that occurs in areas where there has been previous growth, such as in abandoned fields or forest clearings is called secondary succession.

  12. D. Glacier Bay 1. A good example of primary succession is a receding glacier.

  13. II. Energy Flow in Ecosystems • How energy moves through ecosystems. 1. Everything that organisms do in ecosystems-running, breathing and growing, requires energy.

  14. The primary energy source. 1. The rate at which organic material is produced by photosynthetic organisms in an ecosystem is called primary productivity.

  15. Organisms that first capture energy, the producers, including plants some kinds of bacteria and algae. 3. Consumers are those organisms that consume plants or other organisms to obtain energy.

  16. C. Trophic levels • Trophic level- a graphic organizer based on the organism’s source of energy.

  17. 2. The path of energy through the trophic level is called a food chain.

  18. 3. Herbivores-animals that eat plants or other primary producers. • Carnivores- Animals that eat herbivores. 5. Omnivores- animals that eat both plants and animals.

  19. Detritivores- Organisms that obtain their energy from eating dead bodies. 7. Decomposers- bacteria and fungi are decomposers because they cause decay.

  20. Food web

  21. D. Energy is lost in a food chain • During energy transfer of energy within an ecosystem, energy is lost as heat. 2. An energy pyramid is a diagram in which each trophic level is represented by a block and the blocs are stacked on top of one another, with the lowest trophic level on the bottom.

  22. Trophic levels are limited • Most terrestrial ecosystems involve only three, or rare instances, four levels. • See figure 17.10 in book! • It takes 10 times more grain to feed a cow to feed us than if we were to eat only grain.

  23. 4. Biomass is the dry weight of tissue and other organic matter found in a specific ecosystem.

  24. 17.3 Ecosystems Cycle Materials • Materials cycle between living and non living things. 1. Humans throw away tons of garbage every year as unwanted or unusable. 2. Nature does not throw anything away.

  25. 3. In each biogeochemical cycle, a pathway forms when a substance enters living organisms such as trees from the atmosphere, water or soil; stays for a time in the living organism; then returns to the nonliving environment.

  26. B. The water cycle is driven by the sun. • Ground water, which is water retained beneath the surface of the Earth. 2. After passing through a plant, the water moves into the atmosphere by evaporating from the leaves, a process called transpiration.

  27. The water cycle

  28. C. The carbon cycle • Carbon also cycles between the nonliving environment and living organisms. 2. Carbon atoms may return to the pool of carbon dioxide in the air in three ways.

  29. Respiration-organisms breathing. • Combustion- Burning 5. Erosion- Sediments being moved and transported.

  30. D. Plants and bacteria take part in the phosphorus and Nitrogen cycle. • Assimilation- The absorption and incorporating of nitrogen into plant and animal compounds. 2. Ammonification- The production of ammonia by bacteria during the decay of nitrogen containing urine.

  31. Nitrification- the production of nitrate from ammonia. 4. Denitrification- is the conversion of nitrate to nitrogen gas.

  32. 5. The growth of plants in ecosystems is often limited by the availability of nitrate and ammonia in the soil.

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