Ecologists study environments at different levels of organization.

1. KEY CONCEPT 13.1 Ecology is the study of the relationships among organisms and their environment.

2. Ecologists study environments at different levels of organization. • Ecology is the study of the interactions among living things, and between living things and their surroundings.

3. Organism Organism • An organism is an individual living thing, such as an alligator.

4. Population Population Organism Organism • A population is a interbreeding group of the same species that lives in one area.

5. Community Community Population Population Organism Organism • A community is a group of populations that live together in one area.

6. Ecosystem Ecosystem Community Community Population Population Organism Organism • An ecosystem includes all of the organisms as well as the climate, soil, water, rocks and other nonliving things in a given area.

7. Biome Ecosystem Ecosystem Community Community Population Population Organism Organism • A biome is a major regional or global community of organisms characterized by the climate conditions and plant communities that thrive there.

8. Ecological research methods include observation, experimentation, and modeling.

9. Experiments are performed in the lab or in the field.

10. KEY CONCEPT 13.2 Every ecosystem includes both living and nonliving factors.

11. plants An ecosystem includes both biotic and abiotic factors. • Biotic factors are living things. • plants • animals • fungi • bacteria

12. sunlight moisture • moisture • temperature • wind • sunlight • soil • Abiotic factors are nonliving things.

13. Changing one factor in an ecosystem can affect many other factors. • Biodiversity is the assortment, or variety, of living things in an ecosystem. • Rain forests have more biodiversity than other locations in the world, but are threatened by human activities.

14. keystone • A keystone species is a species that has an unusually large effect on its ecosystem.

15. creation of wetland ecosystem increased waterfowl Population keystone species increased fish population nesting sites for birds • Keystone species form and maintain a complex web of life.

16. KEY CONCEPT 13.3 Life in an ecosystem requires a source of energy.

17. Producers provide energy for other organisms in an ecosystem. • Producers get their energy from non-living resources. • Producers are also called autotrophs because they make their own food.

18. Producers provide energy for other organisms in an ecosystem. • Consumers are organisms that get their energy by eating other living or once-living resources. • Consumers are also called heterotrophs because they feed off of different things.

19. carbon dioxide + water + hydrogen sulfide + oxygen sugar + sulfuric acid Almost all producers obtain energy from sunlight. • Photosynthesis in most producers uses sunlight as an energy source. • Chemosynthesis in prokaryote producers uses chemicals as an energy source.

20. KEY CONCEPT 13.4 Food chains and food webs model the flow of energy in an ecosystem.

21. GRAMA GRASS DESERT COTTONTAIL HARRIS’S HAWK A food chain is a model that shows a sequence of feeding relationships. • A food chain links species by their feeding relationships. • A food chain follows the connection between one producer and a single chain of consumers within an ecosystem.

22. carnivore decomposer • Herbivores eat only plants. • Carnivores eat only animals. • Omnivores eat both plants and animals. • Detritivores eat dead organic matter. • Decomposers are detritivores that break down organic matter into simpler compounds. • Consumers are not all alike.

23. Specialists are consumers that primarily eat one specific organism or a very small number of organisms. • Generalists are consumers that have a varying diet.

24. Primary consumers are herbivores that eat producers. • Secondary consumers are carnivores that eat herbivores. • Tertiary consumers are carnivores that eat secondary consumers. • Omnivores, such as humans that eat both plants and animals, may be listed at different trophic levels in different food chains. • Trophic levels are the nourishment levels in a food chain.

25. A food web shows a complex network of feeding relationships. • An organism may have multiple feeding relationships in an ecosystem. • A food web emphasizes complicated feeding relationships and energy flow in an ecosystem.

26. KEY CONCEPT 13.5 I can describe how matter cycles in and out of an ecosystem.

27. Matter cycles through ecosystems through • Biogeochemical cycles • Bio- • Geo- • Chemical-

28. The 4 most common biogeochemical cycles are: • Hydrologic cycle-(water cycle) • Carbon cycle • Nitrogen cycle • Phosphorus cycle

29. precipitation condensation transpiration evaporation surface runoff lake water storage in ocean groundwater seepage • Hydrologic cycle-

30. carbon dioxide in air respiration combustion photosynthesis respiration photosynthesis decomposition of organisms carbon dioxide dissolved in water fossil fuels • Carbon Cycle

31. nitrogen in atmosphere animals plant nitrates nitrogen-fixing bacteria in roots decomposers nitrifying bacteria ammonification nitrites nitrogen-fixing bacteria in soil ammonium nitrifying bacteria denitrifying bacteria • Nitrogen Cycle

32. rain geologic uplifting weathering of phosphate from rocks runoff plants animals phosphate in soil phosphate in solution leaching sedimentation forms new rocks decomposers • Phosphorus Cycle-

33. KEY CONCEPT 13.6 Pyramids model the distribution of energy and matter in an ecosystem.

34. energy lost energy transferred An energy pyramid shows the distribution of energy among trophic levels. • Energy pyramids compare energy used by producers and other organisms on trophic levels. • Between each tier of an energy pyramid, up to 90 percent of the energy is lost into the atmosphere as heat. • Only 10 percent of the energy at each tier is transferred from one trophic level to the next.

35. tertiary consumers 75 g/m2 150g/m2 secondary consumers primary consumers 675g/m2 2000g/m2 2000g/m2 producers producers Other pyramid models illustrate an ecosystem’s biomass and distribution of organisms. • Biomass is a measure of the total dry mass of organisms in a given area.

36. 5 tertiary consumers secondary consumers 5000 primary consumers 500,000 producers 5,000,000 producers 5,000,000 • A pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem. • A vast number of producers are required to support even a few top level consumers.