1. 36.1 Feeding relationships determine the path of energy and chemicals in the ecosystem

3. I. Energy Flow and Chemical Cycling A. Energy enters an ecosystem as light. B. Photosynthetic producers, like plants, change light energy to chemical energy (organic compounds). C. Consumers obtain chemical energy by feeding on producers or on other consumers. D. Decomposers break down wastes and dead organisms.

4. E. As living things use chemical energy, they release heat/thermal energy. F. Energy is not recycled within an ecosystem, but flows through it and out. (light energy into chemical energy into heat energy) G. Chemicals, such as C, O, & N, can be recycled between living & nonliving parts of ecosystems & the biosphere

5. II. Food Chains A. A food chain is a pathway of food transfer from one trophic level (feeding level) to another (see Figure 36-2). B. Producers make up the trophic level that supports all others. C. Consumers are the organisms in trophic levels above producers.

6. D. Consumers can be categorized by what they eat: 1. Herbivores eat only producers. (i.e. cow eats grass) 2. Carnivores eat only other consumers. (i.e. lion eats zebra) 3. Omnivores eat both consumers and producers. (i.e. bear eats salmon & berries)

7. E. Consumers can be categorized by position in a food chain. 1. Primary consumers feed directly on producers (i.e.grasshoppers eating plants) 2. Secondary consumers eat primary consumers. (i.e. mice eating grasshoppers); Tertiary eat secondary… F. Decomposers feed on & break down detritus (wastes & remains of dead organisms). 1. The main decomposers are bacteria and fungi; they’re abundant in soil. 2. All ecosystems include decomposers even though most food chains don’t show decomposers.

9. III. Food Webs A. Feeding relationships are usually more complicated than shown in simple food chains. B. Ecosystems contain many different species that have a variety of food sources. C. Food webs show the feeding relationships between interconnected & branching food chains

10. A Desert Food Web

12. 1.Identify the organisms in this ecosystem that eat producers. Gila woodpecker, grasshopper mouse, antelope squirrel, wood rat, pallid-winged grasshopper, and red harvester ants A Desert Food Web

13. 2.Explain why the grasshopper mouse is both a primary and secondary consumer. The grasshopper mouse eats both producers (brittlebrush) and primary consumers (grasshoppers). A Desert Food Web

14. 36.2 Energy flows through ecosystems

15. I. Productivity of Ecosystems A. Available energy or energy budget is limited in an ecosystem. B. For most ecosystems, the amount of sunlight that enters the ecosystem determines the budget. C. Earth’s producers make billions of kilograms of organic material, or biomass, each year. D. The rate at which producers build biomass is called primary productivity.

18. Productivity E. Primary productivity determines the maximum amount of energy available to all the higher trophic levels in an ecosystem. F. Productivity is different for different ecosystems: 1. Tropical rainforests have the highest productivity. Why? Their warm moist climate supports year- round growing.

19. Productivity 2. Productivity is low in typically dry & cold Tundra. 3. Conditions are more moderate for producers in grasslands G. Exception – organisms living in deep dark ocean do not get their energy from the sun; prokaryotic producers can extract energy from sulfur compounds released by hydrothermal vents to make organic compounds.

20. II. Ecological Pyramids A. Energy is “spent” at each step of the food web. B. As each consumer feeds, some energy is transferred from the lower trophic level to the higher trophic level. C. An average of 10% of the available energy at a trophic level is converted to biomass in the next higher trophic level. D. The rest of the energy (about 90%) is lost as heat.

21. E. The amount of energy available to top-level consumers is tiny compared to that available to primary consumers. F. It takes a lot of vegetation to support higher trophic levels. G. Most food chains are limited to three or four levels because there is not enough energy at the top of the energy pyramid to support another trophic level. H. Ecological pyramids are diagrams used to depict information about energy, biomass, and numbers of organisms at different trophic levels.

23. An Energy Pyramid

28. 1. Summarize how the energy available for conversion to biomass changes with each step up the pyramid. Only 10 percent of the available energy at one trophic level is converted to biomass in the next higher trophic level. An Energy Pyramid

29. 2. Based on this energy pyramid, calculate the energy that might be available for new biomass among quaternary consumers. 1 kcal An Energy Pyramid

30. 36.3 Chemicals cycle in ecosystems

31. I. The Basic Pattern of Chemical Cycling A. Chemical cycles usually involve three general steps: 1. Producers incorporate chemicals from the nonliving environment into organic molecules. 2. Consumers feed on the producers, incorporating some of the chemicals into their own bodies and releasing some back into the environment as waste.

32. 3. Organisms die & decomposers break them down, supplying soil, water, & air with chemicals in inorganic form. The producers gain a renewed supply of raw materials for building organic matter, & the cycles continue. B. Part of each chemical’s cycle involves nonliving processes like rain and fires.

33. II. The Carbon and Oxygen Cycle A. Carbon is found in inorganic form in the atmosphere as CO 2 gas and dissolved in water as HCO 3 -. B. Producers use the carbon and oxygen atoms to form organic compounds during photosynthesis. C. Some organic compounds cycle to consumers as food.

34. Carbon-Oxygen Cycle D. During cellular respiration producers & consumers break down organic compounds and release CO 2 gas as a waste product. E. Decomposers break down detritus and release CO 2 gas. F. Burning fossil fuels (coal, oil, natural gas) & wood releases CO 2 gas into the atmosphere. G. Volcanic eruptions add CO 2 gas to atmosphere.

35. Carbon-Oxygen Cycle

37. 1.What process moves carbon from the atmosphere into living organisms? photosynthesis by plants and phytoplankton

38. Carbon-Oxygen Cycle 2.What processes return carbon from organisms to the nonliving environment? cellular respiration, decomposition of organisms and waste, and burning

39. III. The Nitrogen Cycle A. Nitrogen is found in all living organisms in amino acids & other essential molecules. B. Almost 80% of Earth’s atmosphere is nitrogen gas (N 2 ). C. Most producers can only use nitrogen in the form of compounds like ammonium (NH 4 + ) and nitrate (NO 3 - ). D. Nitrogen-fixing bacteria convert N 2 gas to ammonia (NH 3 ) in a process called nitrogen fixation.

40. Nitrogen Cycle E. Nitrogen-fixing bacteria live in soil and in nodules on roots of plants (peas, beans, alfalfa). F. Other bacteria in soil convert NH 4 + to nitrates in a process called nitrification. G. Producers absorb ammonium and nitrates and use them to build amino acids, proteins, and nucleic acids.

41. Nitrogen Cycle H. Consumers that eat producers obtain nitrogen. I. Decomposers release nitrogen (ammonium) from wastes and decaying organisms. J. Denitrifying bacteria in soil convert some nitrates to N 2 gas back into atmosphere.

42. Nitrogen Cycle

44. 1.What role do decomposers have in the nitrogen cycle? Decomposers return NH 4 + to the soil.

45. Nitrogen Cycle 2.What process converts N 2 into NH 3 ? nitrogen fixation

46. IV. Water Cycle A. Sun’s energy evaporates water putting water vapor into atmosphere. B. Water vapor cools and condenses and falls as precipitation. C. Plants absorb fresh water from soil. D. Consumers obtain water from eating and drinking. E. Water evaporates from the leaves of plants = transpiration. F. Some water runs off land into rivers and streams and some restores groundwater.

47. Water Cycle

49. 1.How are evaporation and transpiration related? Transpiration is a form of evaporation that occurs from the surfaces of leaves. Both processes return water from Earth’s surface to the atmosphere.

50. Water Cycle 2.By which processes does water move from the atmosphere to Earth’s surface? condensation and precipitation

51. 36.4 Human activities can alter ecosystems

52. I. Human Activities Impact Carbon Cycle A. Deforestation – clearing forests for agriculture, lumber, etc., affects carbon cycle by eliminating the plants that remove CO 2 from atmosphere. - burning the trees would increase CO 2 and accounts for about 20% of CO 2 added to atmosphere by human activity. B. Burning fossil fuels increases CO 2 levels & accounts for about 80% of CO 2 added to atmosphere by human activity.

53. Impact the Carbon cycle C. Adding CO 2 increases greenhouse effect (a natural process) 1.CO 2 & water vapor are some heat absorbing gases. 2. These greenhouse gases let sunlight through but then trap heat radiated from Earth’s surface. 3. increasing them could possibly lead to global warming (see Fig. 36-14

54. Impact the Carbon cycle D. Global warming is an increased average temperature worldwide E. Possible effects of global warming (even by just a few degrees): 1. melting of glaciers & polar ice caps. 2. rise in sea level & flooding low-lying coastal areas. 3. changes in weather patterns (precipitation). 4. boundaries between biomes might shift and affect species.

55. Carbon dioxide

56. II. Human Activities Impact Nitrogen Cycle A. Some sewage treatment plants release dissolved nitrogen compounds into streams & rivers. B. Fertilizers can run off into streams & ponds. C. High levels of nitrogen (and phosphates) in the water can cause eutrophication – rapid growth of algae (algal bloom), which later die. Bacteria decompose algae and use up so much of the oxygen that the body of water can no longer support other organisms.

57. Eutrophication

58. Impact Nitrogen Cycle D. Burning fossil fuels releases nitrogen and sulfur compounds into air. These compounds combine with water in the air and form nitric and sulfuric acid. Precipitation with these acids is called acid rain. 1. Compounds in the atmosphere can travel great distances. Compounds produces in the Midwest of the U.S. create acid rain problems in Eastern Canada 2. Clean Air Act has lessened problem in U.S. by reducing levels of sulfur emissions.

59. Hubbard Brook Project

60. III. Human Activities Impact Water Cycle A. Deforestation of tropical rainforests greatly reduces amount of water vapor added to atmosphere by transpiration. - this can affect precipitation patterns which affects ecosystems. B. Drawing water from rivers and underground aquifers faster than it’s replaced could cause the aquifers to run dry.

61. IV. Other Effects of Pollution A. Biological Magnification – the process by which pollutants become more concentrated in successive trophic levels of a food web - example: PCBs from industrial wastes were detected in tissues of organisms from the Great Lakes. PCB levels increased from 0.025 parts per million (ppm) in phytoplankton to 124 ppm in herring gull eggs. - example: DDT caused shells of eagle eggs to break easily. DDT use has been banned in the U.S. and population of eagles has recovered.

62. Biomagnification

63. Effects of Pollution B. The Ozone Shield, which absorbs harmful ultraviolet radiation, has been thinning since the 1970’s. Chlorofluorocarbons (CFCs) released from aerosol cans, refrigeration units, etc., destroy ozone (O 3 ) molecules (see Fig. 36-18) 1. Increased exposure to UV radiation can cause: - increased rates of skin cancer & cataracts. - crop yields lessened & other producers harmed. 2. CFCs have been banned in many countries.

64. Ozone

65. 36.5 Conservation biology can slow the loss of biodiversity

66. I. Why Diversity Matters A. Many of the species in an ecosystem are interconnected. -Ex. if one species disappears, other species & the health of the whole ecosystem may be affected. B. People value biodiversity (variety of life on Earth) because: 1. organisms & ecosystems are sources of beauty & inspiration. 2. organisms are sources of oxygen, food, clothing, & shelter. 3. 25% of all medicines contain substances that come from plants. C. It’s important to conserve biodiversity for future uses & needs.

67. II. Threats to Biodiversity A. Throughout Earth’s history species have become extinct – the last member of the population died and the species no longer exists on Earth. B. Periods of mass extinction occurred as a result of dramatic climate changes from volcanic eruptions & asteroid impacts. (ex. Dinosaur extinction at end of Cretaceous period).

68. Biodiversity - Hot Spots

69. Threats to diversity C. Currently a mass extinction is taking place on Earth. It’s scale is uncertain because the 1.5 million known species are only a fraction of the total on Earth. There are signs that species are disappearing at a dramatic rate (page 806). D. What threatens biodiversity?

70. Threats to diversity 1. Pollution 2. Habitat Destruction – as human population grows, more land is cleared for agriculture, roads, and communities. 3. Introduced (non-native) Species often prey on native species & compete with them for resources. 4. Overexploitation – the practice of harvesting or hunting to such a degree that the small number of remaining individuals may not be able to sustain a population.

71. III. Conservation Biology A.Focusing on Biodiversity Hot Spots, small geographic areas with high concentrations of species (see Fig. 36-23) 1.Many tend to be hot spots for extinction. 2.Global efforts are being taken to preserve some hot spot areas. B. Understanding an Organism’s Habitat – to manage existing habitat or to create a new one for a species

72. Conservation biology C. Balancing Demands for Resources – efforts to save species often conflict with the economic & social needs of people. D. Planning for a Sustainable Future 1. Nations establish zoned reserves – areas of land that are relatively undisturbed by humans, surrounded by buffer zones which are minimally impacted by humans. 2. Sustainable development – developing natural resources so that they can renew themselves & be available for the future. (ex. Selectively harvesting timber)

73. Costa Rica

74. Fer de lance

75. Bullet Ant

76. Howler Monkey

77. Leatherback turtle

78. Wild Orchid

79. Bonus A Lake Placid pH of 7.8 Lake Anna pH of 5.0 What is an example of a natural buffer. Which lake would benefit from a natural buffer? Why?

80. Bonus B John tries to find a paramecium using a microscope. He places the slide on the stage and sets the microscope to medium power. When he looks in he sees a ½ moon shape with light on one side and black on the other. What can he do to correct this problem (3 possibilities- 1 pt each).