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

2. 13.1 Ecologists Study Relationships Ecologists study environments at different levels of organization. EcologyEcology is the study of the interactions among living things, and between living things and their surroundings.

3. 13.1 Ecologists Study Relationships Organism organismAn organism is an individual living thing, such as an alligator.

4. 13.1 Ecologists Study Relationships Organism Population A population is a group of the same species that lives in one area.

5. 13.1 Ecologists Study Relationships Organism Population Community A community is a group of different species that live together in one area.

6. 13.1 Ecologists Study Relationships Organism Population Community Ecosystem An ecosystem includes all of the organisms as well as the climate, soil, water, rocks and other nonliving things in a given area.

7. 13.1 Ecologists Study Relationships Organism Population Community Ecosystem Biome A biome is a major regional or global community of organisms characterized by the climate conditions and plant communities that thrive there.

8. 13.1 Ecologists Study Relationships Ecological research methods include observation, experimentation, and modeling. Observation is the act of carefully watching something over time. Observations of populations can be done by visual surveys. –Direct surveys for easy to spot species employ binoculars or scopes. –Indirect surveys are used for species that are difficult to track and include looking for other signs of their presence.

9. 13.2 Biotic and Abiotic Factors KEY CONCEPT Every ecosystem includes both living and nonliving factors.

10. 13.2 Biotic and Abiotic Factors An ecosystem includes both biotic and abiotic factors. Biotic factors are living things. –plants –animals –fungi –bacteria plants

11. 13.2 Biotic and Abiotic Factors Abiotic factors are nonliving things. –moisture –temperature –wind –sunlight –soil moisture sunlight

12. 13.2 Biotic and Abiotic Factors Changing one factor in an ecosystem can affect many other factors. Biodiversity is the assortment, or variety, of living things in an ecosystem. Example: Rain forests have more biodiversity than other locations in the world, but are threatened by human activities.

13. 13.2 Biotic and Abiotic Factors A keystone species is a species that has an unusually large effect on its ecosystem. keystone

14. 13.2 Biotic and Abiotic Factors Keystone species form and maintain a complex web of life. –Example: Beaver creation of wetland ecosystem increased waterfowl Population increased fish population nesting sites for birds keystone species

15. 13.3 Energy in Ecosystems KEY CONCEPT Life in an ecosystem requires a source of energy.

16. 13.3 Energy in Ecosystems Producers provide energy for other organisms in an ecosystem. Producers get their energy from non-living resources. autotrophsProducers are also called autotrophs because they make their own food.

17. 13.3 Energy in Ecosystems Producers provide energy for other organisms in an ecosystem. Consumers are organisms that get their energy by eating other living or once-living resources. heterotrophsConsumers are also called heterotrophs because they feed off of different things.

18. 13.3 Energy in Ecosystems Almost all producers obtain energy from sunlight 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. carbon dioxide + water + hydrogen sulfide + oxygen sugar + sulfuric acid

19. 13.4 Food Chains And Food Webs KEY CONCEPT Food chains and food webs model the flow of energy in an ecosystem.

20. 13.4 Food Chains And Food Webs food chain A food chain is a model that shows a linear 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. DESERT COTTONTAILGRAMA GRASSHARRIS’S HAWK

21. 13.4 Food Chains And Food Webs Consumers are not all alike. –Herbivores –Herbivores eat only plants. –Carnivores –Carnivores eat only animals. –Omnivores –Omnivores eat both plants and animals. –Detritivores –Detritivores eat dead organic matter. –Decomposers –Decomposers are detritivores that break down organic matter into simpler compounds. carnivore decomposer

22. 13.4 Food Chains And Food Webs

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

24. 13.4 Food Chains And Food Webs Trophic levelsTrophic levels are the nourishment levels in a food chain. –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 depending on the situation

25. 13.4 Food Chains And Food Webs food web 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. 13.4 Food Chains And Food Webs

27. 13.5 Cycling of Matter KEY CONCEPT Matter cycles in and out of an ecosystem.

28. 13.5 Cycling of Matter Water cycles through the environment. The hydrologic, or water, cycle is the circular pathway of water on Earth. Organisms all have bodies made mostly of water. precipitation condensation transpiration evaporation water storage in ocean surface runoff lake groundwater seepage

29. 13.5 Cycling of Matter Elements essential for life also cycle through ecosystems. biogeochemical cycleA biogeochemical cycle is the movement of a particular chemical through the biological and geological parts of an ecosystem. The main processes involved in the oxygen cycle are photosynthesis and respiration.

30. 13.5 Cycling of Matter Oxygen cycles indirectly through an ecosystem by the cycling of other nutrients. oxygen respiration carbon dioxide photosynthesis

31. 13.5 Cycling of Matter fossil fuels photosynthesis carbon dioxide dissolved in water decomposition of organisms respiration carbon dioxide in air photosynthesis combustion respiration Carbon is the building block of life. –The carbon cycle moves carbon from the atmosphere, through the food web, and returns to the atmosphere. –Carbon is emitted by the burning of fossil fuels. –Some carbon is stored for long periods of time in areas called carbon sinks.

32. 13.5 Cycling of Matter nitrogen in atmosphere animals denitrifying bacteria nitrifying bacteria nitrifying bacteria ammonium ammonification decomposers plant nitrogen-fixing bacteria in soil nitrogen-fixing bacteria in roots nitrates nitrites The nitrogen cycle mostly takes place underground. –Some bacteria convert gaseous nitrogen into ammonia through a process called nitrogen fixation. –Some nitrogen-fixing bacteria live in nodules on the roots of plants; others live freely in the soil.

33. 13.5 Cycling of Matter –Ammonia released into the soil is transformed into ammonium. nitrogen in atmosphere animals denitrifying bacteria nitrifying bacteria nitrifying bacteria ammonium ammonification decomposers plant nitrogen-fixing bacteria in soil nitrogen-fixing bacteria in roots nitrates nitrites –Nitrifying bacteria change the ammonium into nitrate. –Nitrogen moves through the food web and returns to the soil during decomposition.

34. 13.5 Cycling of Matter geologic uplifting rain weathering of phosphate from rocks runoff sedimentation forms new rocks leaching phosphate in solution animals plants decomposers phosphate in soil The phosphorus cycle takes place at and below ground level. –Phosphate is released by the weathering of rocks. –Phosphorus moves through the food web and returns to the soil during decomposition. – Phosphorus leaches into groundwater from the soil and is locked in sediments. – Both mining and agriculture add phosphorus into the environment.

35. 13.6 Pyramid Models KEY CONCEPT Pyramids model the distribution of energy and matter in an ecosystem.

36. 13.6 Pyramid Models energy transferred energy lost energy pyramid 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. Called the “10% Rule”

37. 13.6 Pyramid Models Other pyramid models illustrate an ecosystem’s biomass and distribution of organisms. BiomassBiomass is a measure of the total dry mass of organisms in a given area. tertiary consumers secondary consumers primary consumers producers 75 g/m2 150g/m2 675g/m2 2000g/m2 producers 2000g/m2

38. 13.6 Pyramid Models pyramid of numbersA pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem. tertiary consumers secondary consumers primary consumers producers 5 5000 500,000 5,000,000 producers A vast number of producers are required to support even a few top level consumers.