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Ecosystems

Explore the fascinating world of ecosystems and learn about the interactions between organisms, the flow of energy, and the cycling of materials. Discover the importance of biodiversity and sustainable agriculture.

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Ecosystems

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  1. Ecosystems Chapter 17

  2. Section 17-1 What is an ecosystem?

  3. Organisms Interact with Each Other • Ecology is the study of the interactions of living organisms with one another and their environment • A habitat is the place where a population lives • A community is the many different species that live together in a habitat

  4. Organisms Interact with Each Other • An ecosystem consists of a community and all the physical aspects of its habitat like soil, water and weather • The physical aspects of the habitat are abiotic factors (non-living) • The living organisms in a habitat are biotic factors

  5. Ecosystems support diverse communities The number of species living within an ecosystem is a measure of its biodiversity

  6. Ecosystem inhabitants • Includes all of the large animals, small animals, trees, soil, water, insects and so on

  7. Ecosystems Change over time • The first organisms to live in a new habitat are small fast growing plants called pioneer species

  8. Succession • A somewhat regular progression of species replacement is succession • Primary succession occurs where plants have not grown before • Secondary succession occurs in areas where there has been previous growth

  9. Section 17-2 Energy flow in ecosystems

  10. Primary Energy Source • Most life on earth depends on photosynthetic organisms • Why? • They capture sunlight and store it as chemical energy!

  11. Primary Energy Source cont… • Primary productivity is the rate at which organic material is produced by photosynthetic organisms • Primary productivity determines the amount of energy available in an ecosystem

  12. Primary Energy Source cont… • Producers, like plants, are organisms that first capture energy (sunlight) • Consumers are organisms that consume organisms to obtain energy

  13. Trophic Levels • Ecologists study how energy moves through an ecosystem by assigning organisms to a specific level or trophic level • The level is determined by the organisms source of energy

  14. Trophic Levels cont… • The path of energy through the trophic levels of an ecosystem is called a food chain

  15. Trophic Levels cont… • Producers are the lowest level • Herbivores are on the second level and called primary consumers • Secondary consumers are carnivores and omnivores • Tertiary consumers are carnivores that eat other carnivores

  16. Trophic Levels • Detrivores are organisms that get energy from organic waste • Bacteria and fungi are called decomposers because they cause decay

  17. Food Web • In ecosystems, energy does not follow a straight path because man animals feed at different trophic levels • This causes an interconnected group of food chains called a food web

  18. Energy Transfer • Energy is lost within the ecosystem as heat • It is not a useful source of energy in ecosystems • As we move up the trophic levels, the energy store by the organism is 1/10th of the energy stored by the previous level

  19. Pyramid of Energy • An energy pyramid is a diagram in which each trophic level is represented by a block, stacked one on top of the other

  20. Section 17-3 Ecosystems cycle materials

  21. Materials Cycle between Living and Non-Living Things • Water, carbon, nitrogen and phosphorus pass from the nonliving environment to living organisms and back to nonliving environment • That cycle is called a biogeochemical cycle

  22. Water Cycle is Driven by the Sun • Water has the greatest influence on an ecosystem • Water vapor condenses, rains, seeps into the Earth and becomes ground water • Water is heated by the sun, evaporates and reenters the atmosphere

  23. The Carbon Cycle is Linked to Energy • Respiration: Organisms use oxygen and produce CO2 • Combustion: Carbon returns to the air through combustion or burning • Erosion: Marine organisms use CO2 to make shells. Shells become sediment and as the sediments erode, carbon is made available

  24. Plants and Bacteria use Nitrogen and Phosphorus • Nitrogen and phosphorus build proteins and nucleic acids • Phosphorus is part of ATP • The atmosphere is 79% Nitrogen • Nitrogen fixing bacteria (combine H and N to form ammonia) live in the soil

  25. Nitrogen Cycle • Assimilation or absorption of nitrogen into plant and animal compounds • Ammonification is the production of ammonia by bacteria during decay • Nitrification is the production of nitrate from ammonia • Denitrification is the conversion of nitrate to Nitrogen gas

  26. Sustainable Agriculture • The growth of plants is limited by the availability of nitrogen in the soil • Decomposers return mineral nutrients to the soil, however crops are harvested and nutrients were lost • Sustainable Ag is farming that remains productive, profitable and replenishes the soils nutrients, reduces erosion and controls weeds and pests

  27. Sustainable Agriculture • Farmers will plant cover crops after harvest to keep the soil from eroding away, store water and provide nutrients to bacteria and insects after being plowed under • Farmers will rotate their cattle and sheep in several pastures to prevent overgrazing

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