1. Unit 2 Ecology Populations, Communities, & Ecosystems

2. Living Things and the Environment Organism- a living thing. Habitat- the environment that contains the things a living organism needs to live, grow, and reproduce. An organism interacts with both living and non-living parts of its habitat.

3. Living Things and the Environment Biotic factors- living parts of the habitat Examples: grass, other organisms, worms, fungi, bacteria Abiotic Factors- non-living parts of the habitat Examples: water, sunlight, oxygen, temperature, soil

5. Living Things and the Environment Photosynthesis- the process through which plants make food using sunlight, carbon dioxide, and water

6. Living Things and the Environment There are 5 levels or organization in an ecosystem: 1. Organism- Example: prairie dog 2. Species- group of organisms that are physically similar and can reproduce to make viable offspring Example: prairie dogs 3. Population- all of the members of a species that live in a certain area Example: all of the prairie dogs in Augusta Broad Specific

8. 4. Community- the different populations that live together in an area Example: the prairie dogs, grass, hawks, and other organisms in Augusta 5. Ecosystem- the community of organisms together with the nonliving things in an area Example: the prairie dogs, grass, hawks, other organisms, soil, water, and sunlight in Augusta Living Things and the Environment Broad Specific

9. Studying Populations Direct Observation- Counting all of the members of a population

10. Studying Populations Indirect Observation- Observing signs of organisms (counting nests, counting entrance holes)

11. Studying Populations Estimation- an approximation of a number, based on reasonable assumptions.

12. Studying Populations Mark-Recapture Method - Type of estimation Pop. size= number marked x total number captured number recaptured (marked) See page 689 for more info.

13. Example: 40 turtles in a bay are caught, ecologists count the turtles and mark their shells. Two weeks later, ecologists recapture 30 turtles. Of the 30 recaptured, 15 have been marked. What is the estimated population size of turtles in the bay? Number marked= 40 Number recaptured= 30 Number recaptured and marked= 15 40 x 30 = 80 estimated turtles 15

14. Studying Populations Birth rate- the number of births in a certain amount of time Death Rate- number of deaths in a certain amount of time When does a population increase in size? Birth rate > death rate When does a population decrease in size? Birth rate < death rate Immigration- moving into a population

15. Studying Populations Emigration- leaving a population Population Density- the number of individuals in a certain area Population Density= Number of individuals Unit area Example: If 100 birds live in a field that is 20 square miles in size, what is the population density of birds living in the field? 100 birds = 5 birds/sq mile 20 sq. mi.

16. Limiting Factor- an environmental factor that causes a population to decrease Examples: food, water, space, weather conditions 1. Carrying Capacity- the largest population that an area can support for a long period of time 2. Space 3. Weather Studying Populations

17. Interactions Among Living Things Natural Selection- Individuals have a trait that allows them to survive better in their environment, their offspring inherit the trait and pass it on to their offspring. Adaptations- the result of natural selection, the behaviors and physical traits that allow organisms to live successfully in their environments. Every organism has a variety of adaptations that are suited to its specific living conditions.

18. Interactions Among Living Things Niche- The role an organism plays in its environment

19. Interactions Among Living Things There are 3 types of interactions among organisms. 1. Competition- the struggle between organisms to survive Example: Warblers avoid competition by living in different parts of spruce trees

20. Interactions Among Living Things 2. Predation- one organism kills another for food a. Predator- the one that hunts (cheetah) Adaptations: run fast, poisons, sticky, big eyes, sonar b. Prey- the one that’s hunted (antelope) Adaptations: camouflage, alertness, mimicry, protective covering, false coloring, warning coloring, toxins that taste bad

24. Interactions Among Living Things 3. Symbiosis- a close relationship between 2 species that benefits at least one of the species a. Mutualism- both benefit (+ / +) Example: acacia trees and ants, you and bacteria b. Commensalism- one benefits, one is unharmed (+ / 0 ) Example: red-tailed hawks and cactus c. Parasitism- one benefits, one harmed (+ / - ) Example: dog and flea Parasite: benefits- flea Host: harmed- dog

26. Energy flow in an ecosystem

27. Energy Flow in Ecosystems 1. Producers- capture energy from sunlight and store it as food energy. - Autotrophs- make their own food. The source of all of the food in an ecosystem.

29. Energy Flow in Ecosystems 2. Consumers- get energy by eating other organisms - Herbivores- Eat only plants (deer, caterpillars) - Carnivores- Eat only meat (tigers, spiders) - Omnivores- Eat both plants and meat (crows, humans)

30. Energy Flow in Ecosystems 3. Decomposers- break down wastes and dead organisms, return the raw materials to the ecosystem (mushrooms, bacteria). Nature’s recyclers.

31. Energy Flow in Ecosystems Food Chain- series of events where one organism eats another and obtains energy. – Energy only flows in ONE direction. – Arrows indicate direction of energy flow. Producer Primary Secondary Consumer Consumer

32. Energy Flow in Ecosystems Food Web- Consists of many overlapping food chains. - Energy flows in MANY directions.

34. Energy Flow in Ecosystems Energy Pyramid- Shows the amount of energy that moves from one feeding level to another in a food web. – Energy is lost as you go up the levels (used to move, grow, etc). 2 nd level consumers (10 kcal) 3 rd level consumers (1 kcal) 1 st level consumers (100 kcal) Producers (1000 kcal)