1. Notes: Ecology Chapters 3&4

2. I) Introduction:  A) How would you describe our community at BHS?

3. B) Natural History:  The study of animals and plants in their habitat

4. II) Ecology:  A) 1869 the term ecology was derived by Haeckel from the Greek word “oikos” meaning house or place one inhabits.

5. B) In 1960….  Ecology became a household word in response to the emerging “green movements.”  DDT pesticide killed insects but also made the eggs of bald eagles weak and they became endangered

6. C) Utilizes several disciplines of science including…  Geology  Chemistry  Physics  Biology

7. D) Ecology is the study of  Interactions between organisms and their environment

8. E) The environment  (or habitat) includes both biotic and abiotic factors.  i) a biotic factor is anything that meets the characteristics of life within an environment.  ii) an abiotic factor is anything that is non living within an environment that surrounds the biotic factors  1. air currents  2. temperature  3. moisture  4. soil/ rocks

9. III) The biosphere  A) The area of the earth where life exists.  B) size: 8 km (5 miles) above the Earth’s surface & 11 km (7 miles) below the ocean surface.

10. c) The biosphere is  Always changing/ very dynamic due to the interdependence and interactions of organisms within the environment

11. VI) Energy Flow  A) importance of the sun  i) Energy!  ii) scientists estimate that an average square inch of the Earth’s surface receives over 1 calorie per minute  In everyday terms, daily solar input into the biosphere equals the energy contained in more than 100,000,000 atomic bombs

12. B) How organisms obtain energy:  i) autotrophs: organisms that use sun or chemicals to make their own food.  autotrophs = producers (plants & algae)  Examples:  A) photosynthesis: uses light to produce energy  B) chemosynthesis: uses chemical compounds to produce energy

13. B) How organisms obtain energy:  ii) Heterotrophs: Organisms that depend on consuming autotrophs or other heterotrophs for energy. They cannot produce their own food.  Heterotrophs = consumers

14. 1) Heterotroph Examples  A) carnivore: organisms that kills and eat other heterotrophs  B) scavengers: organisms that eat heterotrophs that have already died.  C) omnivore: organisms that eat both heterotrophs and autotrophs  D) decomposer: organisms that break down and absorb nutrients from dead organisms (bacteria, fungi)  E) detritivore: organisms that eat detritus (dead matter) examples: worms, snails  F) (ADD TO NOTES) herbivore: organism that eats only autotrophs

15. VII) Feeding relationships  A) food chains are a simple model to show how matter and energy move through an ecosystem.  They are unidirectional and rarely have more than 5 links!  * Arrows point to where energy is going!!!

17. B) Food webs  Are models that consist of all the possible food chains in an ecosystem. A complex interactive system  Food webs are multidirectional and have numerous links!

18. C) Ecological Pyramids  i) shows the amount of energy or matter at each trophic level.  1) trophic levels: what each organism eats (energy)  A) base = producers  B) 2 nd level = herbivore  C) 3 rd level = carnivore  D) 4 th level = carnivore

20. 2) The shape of the energy pyramid reveals the flow of the food web  Types of pyramids:  1) energy pyramids (10% rule)  2) biomass pyramids  3) pyramid of numbers

21. Energy Pyramid

22. Biomass Pyramid

23. Pyramid of numbers

24. iii) Biological magnification  When concentrations of a harmful substance increase in organisms at top trophic levels in a food web.  1) top carnivores are at the peak.

25. 2) Example of Biological magnification:  a) 1939- pesticide DDT (dichloro-diphenyl- trichloroethane) was used as a pesticide to control the mosquito population.  b) DDT is not biodegradable and is not eliminated from animal’s bodies.  c) it is stored in aquatic plants and algae

26. 2) Example of Biological magnification:  d) The concentration was magnified as one moved up the ecological pyramid upsetting the overall balance.  e) Rachel Carson published Silent Spring in 1962 when DDT threatened the bald eagle with extinction.

27. D) Energy is crucial to an ecosystem  E) Nutrients/ water are vital components (95% of the body is S,P,O,N,C,H!)  * Energy flows and matter cycles through ecosystems!

28. VIII) Biogeochemical Cycles- homeostasis in ecosystems  A) water  B) carbon  C) nitrogen (driven by bacteria in soil and legume plants)  D) phosphorous

29. Carbon Cycle

30. Nitrogen Cycle

31. IX) The laws of thermodynamics (how energy flows)  A) first law of thermodynamics:  i) energy is neither created or destroyed  ii) it changes form – light, chemical, heat, motion….  iii) Application: energy flows through the food chains and is lost as heat (biological loss)

32. IX) The laws of thermodynamics (how energy flows)  B) Second law of thermodynamics:  i) entropy- things tend to become more disordered over time  ii) energy (molecules) spread out  iii) Therefore as energy is passed from one trophic level to another, some energy will become unusable.

33. X) Nutrient limitations  A) Limiting nutrient: when an ecosystem is limited by a single nutrient that is scarce.  i) example: farmers use fertilizer containing nitrogen (N), phosphorous (P), and potassium (K) to boost productivity by avoiding a limiting nutrient.

34. ii) Example: Algal bloom  Occurs when aquatic systems receive a large input of limiting nutrients from runoff; not enough consumers to eat the excess algae.

35.  B) when humans, feeding relationships, nutrient amounts, and populations change, the community will naturally change in response.

36. Ecological Succession:  As an ecosystem changes, older inhabitants gradually die out and new organisms move in causing more changes to the community.

37. Primary Succession:  Occurs after events like volcanic eruptions (bare rock; no soil)  First organisms to settle are called the pioneer species (usually lichen or moss).  Ex: new rock formed after volcanic eruption (no existing soil or plants)

38. Primary Succession:  Once primary succession slows, the community of the pioneer species becomes stable and therefore is called a climax community.  Pioneer species then begin to die and decay into soil providing a new environment for a new community to develop.

39. Primary Succession:

40. Secondary Succession:  Disturbance occurs on land in which land returns to its original condition.  Ex: existing community disturbed by forest fires, floods, farmer stops farming land….

41. Secondary Succession:  Pioneer species are different than those of primary succession.  The process takes several years to reach the climax community.

42. XII) Community Interactions  A) Competition:  i) Organisms use the resources such as sun, water, nutrients, and space  Competitive exclusion principle: no two species can occupy the same niche in the same habitat at the same time.

43. B) Predation:  One organism captures and feeds (predator) on the other (prey).

44. C) Symbiosis  Any relationship where two organisms live closely together.  Three types of symbiosis:  Mutualism  Commensalism  Parasitism

45. Mutualism:  Both species benefit from the relationship.  Flower and pollinator  Acacia tree and ants

46. Commensalism:  One species benefits, the other is neither helped or harmed.  Barnacles on whales  Trees and birds  Orchid and tree

47. Parasitism:  One organism lives on or in another and harms it.  Tapeworms  Mosquitoes  Ticks  Fleas  Lice

48. XIII) The Overall Shaping of an ecosystem  A) biotic  B) abiotic  C) community interactions (competition/ symbiosis)  D) nutrient limitations  E) Available niches  All of these factors shape ecosystems!!