Ecology Part 2 Ecosystems

1. Communities + Abiotic Factors Ecology Part 2Ecosystems Organisms interact with each other and their environment.

2. Unit 11: Key learnings • Living things are connected in a web of life through which matter and energy are passed. • Biodiversity strengthens an ecosystem; its decline is an indicator of instabilities that may result in severe species loss.

3. Unit 11: Essential question How does matter and energy flow through natural cycles in the worlds ecosystems?

4. Unit 11: Concepts • Ecosystem structure (E) • Matter and energy cycling (I) • Ecosystem change (C) • Models of extinction (I)

5. Essential question 1.1: How are ecosystems, communities and populations related?

6. I. Ecologyis the study of interactions of living organisms with one another (biotic factors),and with elements of their physical environment such as soil, water, air, etc. (abiotic). You Are Here • A habitat is just the place where an organism lives. • Populations are groups of individuals from the same species who live together in the same place at the same time. • Acommunity is the collection of many different species that live together in one habitat (biotic factors). • An ecosystem is a community and all the physical aspects of its habitat (abiotic + biotic).

7. II. Diverse communities exist within many ecosystems. • You can expect to find great biodiversity(diversity of life)within any healthy ecosystem. • The more biodiversity an ecosystem has, the more stable it is. • Loss of biodiversity often signals environmental distress. • Due to the abiotic factors, some areas naturally have more biodiversity than others. (EQ’s 4.1 & 4.2)

8. III. Ecosystem boundaries are defined as a matter of convenience. • Depending on the focus of your study, an ecosystem might be a large area or a small one. • Examples: Forest, lake, rotting log, etc.

9. Biotic Factors Name 3 items that would qualify as biotic. Trees Fish Coral

10. Abiotic Factors Name 4 items that would qualify as abiotic. Air Sand Water Salinity

11. Question: What are the abiotic factors that influence human population growth in Mechanicsburg? • Space • Fresh water • Building materials • Temperate climate • Etc.

12. Unit 11: Concepts • Ecosystem structure (E) • Matter and energy cycling (I) • Ecosystem change (C) • Models of extinction (I)

13. Essential question 2.1: How does the productivity of a community determine the number of trophic levels it can support?

14. Activation strategy:Why do you think an energy pyramid has the shape it does?

15. I. The Sun is the Earth’s primary energy source. • Primary productivity is the rate at which autotrophs produce organic material by photosynthesis. • This is done by organisms called producers. • Productivity determines the amount of energy that is available for use by consumers.

16. I./2. The angle that light strikes the Earth, determines how much solar energy is delivered.

17. II. Energy moves from one trophic level to the next as it moves through a food chain.

18. Page 71

19. Trophic levels in an aquatic ecosystem

20. III. Many food chains are connected to make one food web. • Many animals feed at multiple trophic levels. • Removing one species can have drastic consequences. • Higher biodiversity makes a food web more stable.

21. Grassland food web

22. IV. Energy is lost from a food chain as it is passed through the trophic levels. • Most organisms uses 90% of the energy it acquires for homeostasis and stores the rest. • Since only 10% is stored that means that only 10% of the original energy is available to a future consumer. • We show the energy available at each trophic level with an Energy pyramid. • Since only 1/1000 of the energy stored by photosynthesis is available to tertiary consumers.

23. Question: What rule can explain the energy available and the number of individuals found at each trophic level at the same time? The 10% rule

24. A rare example of a 4 to 5 consumer food web

25. IV./5. Since the number of individuals does not give a true indication of the amount of energy stored, we measure the biomass(dry weight) at each level.

26. Summarizer: Why must the number of secondary consumers always be smaller than the number of primary consumers? Since much of the energy of production that was taken in by primary consumers is lost as heat, the number of secondary consumers that can be supported is much smaller.

27. Create your own food web • Teacher will distribute assignment • Read and follow all directions • Extra credit may be available for a poster that is of classroom display quality.

28. Essential question 2.2: How are water, carbon and nitrogen passed through their biogeochemical cycles?

29. V. Materials cycle between living and nonliving things. • Energy flows in one direction, but nonliving materials flow in a circular cycle. • Carbon, nitrogen, phosphorus, sulfur and water(H2O) are the most important elements (SPONCH). • Magnesium, sodium, calcium and iron in smaller amounts. • Cobalt, manganese and others are required in trace amounts (very small). • The pathway materials take from the nonliving, to the living and back again are called biogeochemical cycles. • At any given time, the majority of these materials are locked within living reservoirs. • In areas like rainforests, which have very high biodiversity, up to 90% of the key elements are locked within the biotic component.

30. Question: Why might clear cutting and slash/burn practices in rainforests permanently damage the environment? Since the organisms contain the majority of the resources, taking them away, or burning them off results in the loss of those geochemical resources to future life. Additionally the soil erosion that follows can cause irreparable damage.

31. V./3. Three well documented cycles are responsible for circulating matter and energy. • The water cycle is driven by the heat of the sun. • The carbon cycle is linked to the flow of energy. • The nitrogen cycle is driven by bacteria and provides the soil with rich nutrients necessary for continued production.

32. Biogeochemical cycle essays • Teacher will distribute assignment. • The pictures on the following pages will help you on your way to complete this assignment. • Outside of class research will be required.

33. The water cycle

34. The carbon cycle

35. The nitrogen cycle

36. Question:What would happen if one of these cycles stopped? Living things would quickly lose the ability to build new material, as the effects are seen rising through the energy pyramid.

37. Unit 11: Concepts • Ecosystem structure (E) • Matter and energy cycling (I) • Ecosystem change (C) • Models of extinction(I)

38. Essential question 3.1: How do interruptions in natural cycles disrupt ecosystems?

39. II. Many human activities are disruptive to biogeochemical cycles. • Farming is very disruptive within a particular watershed. • Nutrients are extracted from the soil and often never returned. • Fertilizers (high in nitrates) mixed with rain water and irrigation will end up in lakes, rivers and oceans. Fertilizer runoff causes algal blooms that reduce available oxygen and decrease biodiversity. • Clear cutting removes resources from a rainforest area and turns it into desert within a few years.

40. III. Erosion and sedimentation change the nutrients available in the soil. • Topsoil is eroded when plant cover is removed for extended periods. • When topsoil is lost, the remaining soil is not rich enough to support a diverse community. • The area where deposition occurs will be incredibly rich, so one areas loss can be another’s gain.

41. IV.New techniques allow farmers to grow crops with less damage to the environment. • Organic farming uses crop rotation, “green” manure, compost and integrated pest management to prevent the use of fertilizers and pesticides. • No till farming prevents the release of green house gases that escape when soil is turned over.

42. Essential question 3.2: How does the process of succession produce a climax community?

43. I. Ecosystems change gradually over time. • Newly formed habitats are colonized first by pioneer species. • Succession is a somewhat regular progression of species replacement. • Primary succession occurs in areas that plants have yet to colonized due to a lack of soil. (other immigrants later outcompete the pioneers) • Secondary succession occurs in areas that have previously had plant growth and consequently already have soil. (abandoned fields, forest clearings) • Pioneers (generally r-strategists)are eventually replaced by K-strategists that tend to be stronger competitors. • No two successions will be exactly the same since environmental factors influence competition.

44. Succession

45. Unit 11: Concepts • Ecosystem structure (E) • Matter and energy cycling (I) • Ecosystem change (C) • Models of extinction (I)

46. Essential Questions 4.1 & 4.2 • How do we define Biodiversity? • What locations on Earth demonstrate high biodiversity?

47. Biodiversity • Most people think of biodiversity as the variety of living things (species) on the Earth. This however fails to understand true diversity in living systems. • Biodiversity should be thought about on 3 different levels. • Genes and alleles • Species • Ecosystems

48. Biodiversity is unequally distributed globally. The Biodiversity of an area can typically be traced to 3 influential factors. • Solar Energy • Evolutionary History • Rate of Disturbance

49. 3 factors that influence biodiversity

50. Biodiversity Hotspot :Significant reservoir of diversity under imminent threat of destruction.