Introduction to Ecology

1. Introduction to Ecology Chapter 18

2. Ecology: the study of the interactions between organisms and the living and nonliving components of their environment. eco – environment ology – study of

3. Interdependence: the dependence of every organism on its connection with other living and nonliving parts of its environment.

4. Levels of Organization Biosphere Ecosystem Population Community Organism

5. The thin volume of Earth and its atmosphere that supports life. It is about 20km (13mi) thick and extends from about 8 to 10km (5 to 6mi) above the Earth’s surface to the deepest parts of the ocean. The Biosphere

6. Ecosystems What are the components of a pond ecosystem? The term ecosystem includes all of the organisms and the nonliving environment found in a particular place.

7. Community: all the interacting organisms living in an area.

8. Population: a group of living things of the same species that live in the same place or ecosystem at the same time.  A change in the size of one population often causes a change in the size of another population.

9. Biotic The living components of the environment.

10. Abiotic • The physical and chemical characteristics of the environment. • includes:

11. Types of Habitats Beaver Dam Spider Web African Plains

12. HABITAT A place where an organism lives. It provides the organism with: water place to reproduce food shelter

13. NICHE The role of an organism within its environment.

14. Generalists: species with broad niches; they can tolerate a range of conditions and use a variety of resources. • Found much across the U.S. • Feeds on from eggs and dead animals to fruits and plants Virginia Opossum

15. Feeds only on the leaves of a few species of eucalyptus trees. Specialists: species that have narrow niches.

16. 3 Types of Organisms

17. Photosynthesizes Organisms that use light energy to make their own food.

18. Chemosynthesizers Organisms that use energy stored in organic molecules to produce carbohydrates. Beggiatoa

19. Distribution of Energy Gross Primary Productivity: the total amt. of chemical energy stored by photosynthesis. Much of that energy is used by: Biomass: organic material that has been produced in an ecosystem. Producers add biomass to an ecosystem by making organic molecules. Net Primary Productivity: the remaining energy, that which is available for the consumer as food.

20. One way to measure NPP of a community is to find the mass of all producers. Mass: the amt. of matter an object has. Producers must first be dried for a truer estimate of their mass. The greater the NPP of a community, the greater the amt. of food that is available to consumers, the more consumers can live in the community. Same amt. of energy, different mass

21. Herbivores Primary Consumers Organisms that cannot make their own food; they must eat plants, animals, or both.

22. Carnivores Secondary Consumers Omnivores

23. Detritivores Consumers that feed on the “garbage” of an ecosystem.

24. Consumers that break down the bodies of dead plants and animals in the process of decay.

25. Energy Flow

26. Trophic level: indicates the organism’s position in a sequence of energy transfers.

27. Food Chain A pathway of energy and materials through a community. The arrows in a diagram show the direction in which the energy moves.

28. Food Web Food chains connected in a community. It shows how energy moves through a community.

30. Energy is eventually lost as heat on the top of the pyramid The last level contains secondary, tertiary consumers – heterotrophs, carnivores, omnivores The second level has primary consumers – heterotrophs, herbivores. 10% of the energy from the 1st trophic level is available to the 2nd trophic level The first level always has autotrophs 90% of the energy at any given trophic level is used for growth and reproduction, and is eventually lost as heat.

31. Ecosystem Recycling

32. Water Cycle: • Movement of water between various reservoirs • Include: living things, bodies of water, the atmosphere, and the ground (groundwater) • Three important processes: evaporation, transpiration, and precipitation. Evaporation adds water as vapor to the atmosphere. Transpiration is the process by which water evaporated from the leaves of plants. Precipitation is the way water leaves the atmosphere.

34. Carbon Cycle: • Based on the processes of photosynthesis and cellular respiration • Plants use carbon dioxide along with water and solar energy to make carbohydrates • Both autotrophs and heterotrophs use oxygen to break down carbohydrates during cellular respiration • Byproducts of cellular respiration are carbon dioxide and water • Decomposers release carbon dioxide into the atmosphere when they break down organic compunds

35. Nitrogen Cycle: • The complex pathway that nitrogen follows in an ecosystem • Nitrogen gas, N2, makes up about 78% of the atmosphere • Most plants can use nitrogen only in the form of nitrate, NO3 • Nitrogen fixation: the process of converting N2 gas to nitrate • Nitrogen-fixing bacteria transform nitrogen gas into a usable form; live in the soil and in certain plant roots (beans, peas, and alfalfa) • Plants supply carbohydrates for bacteria and bacteria supply usable nitrogen for plants • Additional nitrogen is released into the soil

36. Recycling Nitrogen • Bodies of dead organisms as well as urine and dung contain nitrogen in proteins and nucleic acids • Decomposers break down these materials and release nitrogen as ammonia NH3, which in soil becomes ammonium NH4; process is called ammonification • Soil bacteria take up ammonium and oxidize it into nitrites (NO2) and nitrates (NO3) ; process is called nitrification • Nitrogen is returned to the atmosphere through denitrification. Anaerobic bacteria break down nitrates and release nitrogen gas into the atmosphere • Plants absorb nitrates from the soil, but animals cannot