Ecology

1. Ecology

2. Ecology • Ecology = the study of the interactions among organisms and their environment

3. Abiotic Factors The nonliving or physical things in an environment are called ABIOTICfactors. Examples: - Sunlight - Temperature - Rainfall - Air • Soil • Earthquakes

4. Biotic Factors The living or biological things in an environment are called the biotic factors. Examples: • parasitism • disease • predators • prey • competition

5. Levels of Organization • Ecologists study organisms ranging from the various levels of organization: • Species • Population • Community • Ecosystem • Biome • Biosphere

6. Species =a group of similar organisms that can breed and produce fertile offspring Levels of Organization

7. Levels of Organization Population =group of organisms, all of the same species, which interbreed and live in the same area. EX: all the turtles in Town Lake

8. Levels of Organization Community = a collection of different populations that live together

9. Levels of Organization Ecosystem = a collection of interacting populations and their physical surroundings (abiotic factors)

10. Temperate grassland Tropical rain forest Temperate forest Tundra Northwestern coniferous forest Mountains and ice caps Tropical dry forest Desert Temperate woodland and shrubland Tropical savanna Boreal forest (Taiga) Levels of Organization Biome = a group of ecosystems with the same climate and dominant communities

11. Levels of Organization Biosphere= the part of the earth where life exists including land, water, air, and atmosphere • It extends from high in the atmosphere to the bottom of the oceans. • If the earth could be shrunk to the size of an apple, the biosphere would be no thicker than the apple's skin.

12. HABITAT - home Place where an organism lives Lots of organisms have the same habitat NICHE - job Role and position a species has in its environment Organisms want a unique niche Habitat vs. Niche

13. HABITAT Ex: red fox’s habitat is the forests’ edge, meadows, and river bank NICHE Ex: red fox’s niche is a predator which feeds on the small mammals etc. that is active at night Habitat vs. Niche

14. Symbiotic Relationships Symbiosis = permanent (living together) relationship between two different organisms 3 types: • Mutualism • Commensalism • Parasitism

15. Symbiotic Relationships • Mutualism = when both organisms benefit from each other EX: clownfish and sea anemone EX: lichen EX: flower and bee

16. Symbiotic Relationships 2. Commensalism = one organism benefits, the other is not helped or harmed EX: pilot fish and shark (fish eats scraps from the shark’s food)

17. Symbiotic Relationships 3. Parasitism = one organism benefits, the other is harmed EX: tapeworms EX: ticks

18. Predation Relationships • Predator = an animal that feeds on another animal • Prey = that animal that is killed and eaten EX: lion (predator) hunts and eats the zebra (prey)

19. Population Size • Size of a population changes over time. • Most populations stabilize rather than grow endlessly. • Why? Because of demands on the ecosystem (ex. Enough food?)

20. Limiting Factors • Limiting Factors = any environmental factors that limit the size of a population EX: • Availability of food • Availability of water • Availability of oxygen • Availability of sunlight

21. Density- Dependent Limiting Factors • Limit the growth of a population when the pop gets to a certain size • Population density = the # of organisms in a given area

22. Density- Dependent Limiting Factors Two Main Factors • Competition- when a pop gets big, organisms compete for available resources EX: group of trees fighting for sunlight, soil, or water

23. Density- Dependent Limiting Factors 2. Predation – if the predator population becomes too large, there will not be enough prey to support it

24. Density-Independent Factors • Limit the growth of a population regardless of its size EX: • Climatic events like extreme cold/heat, tidal waves, volcanoes, flooding, drought

25. Carrying Capacity • Carrying capacity = the largest population that a given environment can support over a long period of time • Important for conservationists in managing wildlife pops

26. http://io.uwinnipeg.ca/~simmons/1116/images/niche.jpg Competition • Fundamental niche • Realized niche (remember: niche = occupation habitat = home) http://www.copernicusproject.ucr.edu/ssi/HSBiologyResources.htm

27. Key features cont. • Dispersion • Random, even, clumped distributions http://www.fao.org/docrep/009/a0337e/A0337E125.jpg GREAT WEBSITE: http://www.geo.arizona.edu/Antevs/nats104/00lect21.html

29. QUESTIONS • Which of the following is a symbiotic relationship where both organisms benefit? a. mutualism b. commensalism c. altruism d. competition

30. Questions 2. Which of the following pairs of animals are most likely to have a predator-prey relationship? a. dog and tapeworm b. buffalo and tickbird c. spider and fly d. whale and barnacle

31. Questions 3. Some species of shark allow small fish to enter their mouths without eating them. Inside the mouth, the small fish feed on debris around the teeth. The sharks get their teeth cleaned, which reduces the risk of decay and infection. Which term best categorizes this relationship? a. predation b. mutualism c. commensalism d. parasitism

32. Questions 4. Which of the following is a density-dependent limitation on population growth? a. wildfire b. competition c. unlimited nutrients d. severe drought