1. Chapter 13 Principals of Ecology

2. Ecology Study of interactions between organisms and their environments Reveals relationships between living and nonliving parts “ecology” termed by Ernst Haeckel to encourage scientists to study these relationships

3. Levels of organization Organisms Populations Communities Ecosystem Biosphere

4. Organisms An individual Depend on others for food, shelter, reproduction, protection Can interact with others of same species or different species Can interact with abiotic factors

5. Populations Organisms of the same species that interbreed and live in the same area Compete for food, water, mates, etc. Sharing resources determines distances between populations

6. Communities Interacting populations Includes different species that live in the same area Change in one population affects the entire community

7. Ecosystem Interactions of populations and abiotic factors in a community 3 types –Terrestrial –Aquatic –saltwater

8. Biome Major regional or global community of organisms Characterized by climate conditions and plants

9. The living environment Biosphere – portion of earth that supports life –Includes land, air, fresh and salt water –Extends from highest part of atmosphere to bottom of ocean Biotic factors – all living factors in the environment

10. The nonliving environment Abiotic factors – nonliving parts of the environment –Includes air currents, temperature, moisture, light, and soil –Can determine which species survive in a particular area

11. Biodiversity Variety of living things in an ecosystem Amount of biodiversity depends on many things such as temperature and moisture Tropical rain forests account for >50% of the world’s plants and animals Rain forests and barrier reefs are “hot spots” and are richly diverse

12. Keystone species Have a large effect on its ecosystem May hold the dynamic ecosystem together They form a complex web of life Loss of the keystone species affects all species in that ecosystem

13. Feeding relationships 4 types –Autotrophs –Heterotrophs –Scavengers –decomposers

14. Obtaining energy Producers (autotrophs) get their energy from nonliving sources to make their own food –Sunlight or chemicals (chemosynthesis) Consumers (heterotrophs) get their energy by eating other organisms Sun is the ultimate source of energy for all organisms

15. Food chains Links species by their feeding relationships Shows a sample of links that begin with a single producer Model used to show passage of matter and energy through the ecosystem Arrows indicate energy flow No more than 5 links

16. Heterotrophs Depend on autotrophs for food Herbivores eat only plants Carnivores eat other animals Omnivores eat plants and animals Detritivores eat dead organic matter Decomposers break down organic matter into simpler substances

17. Selective eaters Specialists – eat primarily one specific organism or a very small variety of organisms Generalists – have a varying diet

18. Trophic levels Feeding steps in the passage of energy and materials Do not show all relationships

19. Food webs Show complex relationships in an ecosystem Expresses all possible relationships at each trophic level

20. Water (hydrologic) cycle Water on earth is liquid or solid; in atmosphere it’s gas Steps –Precipitation falls to the ground –Water flows into lakes, rivers; can be absorbed into soil; most will feed the oceans –Some water evaporates and enters the atmosphere; released from plants by transpiration –Condensation produces precipitation

21. Water cycle

22. Oxygen cycle Organisms need oxygen for cellular respiration Plants release oxygen during photosynthesis Oxygen is also released by cycling of other nutrients like carbon, nitrogen, and phosphorous

23. Oxygen cycle

24. Carbon forms Carbon dioxide in the atmosphere Bicarbonate dissolved in water Fossil fuels Carbonate rocks (limestone) Dead organic matter

25. Carbon cycle Steps –Plants use CO 2 to make their food –Animals eat plants, release CO 2 when they breathe or die –Decay with NO oxygen makes oil –Burning oil releases carbon dioxide

26. Carbon cycle

27. Nitrogen cycle Gaseous nitrogen makes up 78% of air Lightning / bacteria convert nitrogen gas to useable nitrogen for organisms (nitrogen fixation) Steps –Plants absorb nitrates –Animals eat plants and make proteins –Death / decay return nitrogen to soil –Breakdown of nitrates by bacteria return nitrogen to the atmosphere

28. Nitrogen cycle

29. Phosphorous cycle Steps –Phosphorous released by weathering of rocks –Plants absorb phosphorous –Animals eat plants –Death / decay returns phosphorous to soil and water –Phosphates can also be made into rocks; released by erosion

30. Phosphorous cycle

31. Ecological pyramids Depict energy conversions in an ecosystem 1 st level represents producers Higher levels are stacked on lower levels Sun is energy

32. Energy pyramid