1. Chapter 13 Final Review

2. 13.1: Ecologists Study Relationships Ecology is the study of relationships among organisms and their environment. Ecologists study environments at different levels of organization. The levels of organization in ecology from the smallest to the largest is as follows: organism, population, community, ecosystem, and biome.

3. 13.1: Ecologists Study Relationships A community is a group of different species that live together in one area, such as groups of alligators, turtles, birds, fish, and plants that live in the Florida Everglades. An ecosystem includes all of the organisms as well as the climate, soil, water, rocks, and other nonliving things in an area. A biome is a major regional or global community of organisms. Examples: savannah, tropical rainforest, etc.

4. 13.2: Biotic and Abiotic Factors Every ecosystem includes both living (biotic) and nonliving (abiotic) factors. Changing one of these factors can affect the many other factors within the same ecosystem. Biodiversity is the variety of living things in an ecosystem. Some areas have more biodiversity than others, for example rain forests have a large amount of biodiversity.

5. 13.3: Energy in Ecosystems Life in an ecosystem requires a source of energy. Producers are organisms that get their energy from nonliving resources, meaning they make their own food. Producers provide energy for other organisms in an ecosystem. Almost all producers get energy from sunlight.

6. 13.3: Energy in Ecosystems Consumers get their energy by eating other living things, such as plants and animals. Consumers often eat producers.

7. 13.4: Food chains and Food Webs Food chains and food webs model the flow of energy in an ecosystem. A food chain is a model that shows a sequence of feeding relationships. Example: grass gets eaten by a rabbit, the rabbit gets eaten by a hawk. A food web shows a complex network of feeding relationships. Example: plankton is eaten by shrimp, shrimp are eaten by fish, fish are eaten by sharks.

8. 13.4: Food chains and Food Webs There are different types of consumers: Herbivores eat only plants. (e.g. cows) Carnivores eat only animals. (e.g. sharks) Omnivores eat both plants and animals. (e.g. bears, humans) Decomposers break down organic matter. Example: mushrooms

9. 13.4: Food chains and Food Webs Trophic levels are the levels of nourishment in a food chain. Carnivores are at the highest trophic level. Herbivores are at the second highest trophic level. Producers are the first (or bottom) trophic level. Energy flows up the food chain from the lowest trophic level to the highest.

10. 13.5: Cycling of Matter Matter cycles in and out of an ecosystem. Water cycles through the environment. Elements that are essential for life also cycle through ecosystems. The hydrologic (water) cycle is the circular pathway of water on Earth, from the atmosphere to the surface, below ground, and back.

11. 13.5: Cycling of Matter A biogeochemical cycle is the movement of a particular chemical through the biological and geological (living and nonliving) parts of an ecosystem. Biogeochemical cycles include the oxygen cycle, the carbon cycle, the nitrogen cycle, and the phosphorus cycle. Nitrogen fixation is the part of the nitrogen cycle when certain types of bacteria convert nitrogen gas into ammonia.

12. 13.6: Pyramid Models Pyramids model the distribution of energy and matter in an ecosystem. An energy pyramid shows the distribution of energy among the trophic levels. Other pyramid models illustrate and ecosystem’s biomass and distribution of organisms. An energy pyramid compares the energy used by producers, consumers, and other trophic levels in an ecosystem.