1. © 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey Chapter 37 Communities and Ecosystems

2. Introduction  Natural ecosystems are valuable because they –provide natural resources, –support outdoor recreation, and –provide natural services including –buffering against hurricane damage, –recycling nutrients, –preventing erosion, and –pollinating crops. © 2012 Pearson Education, Inc.

3. Figure 37.0_1 Chapter 37: Big Ideas Community Structure and Dynamics Ecosystem Structure and Dynamics Energy flow C h e m i c a l c c y l i n g

4. Figure 37.0_2

5. COMMUNITY STRUCTURE AND DYNAMICS © 2012 Pearson Education, Inc.

6. 37.1 A community includes all the organisms inhabiting a particular area  Community ecology is concerned with factors that –influence species composition and distribution of communities and –affect community stability. © 2012 Pearson Education, Inc.

7. 37.1 A community includes all the organisms inhabiting a particular area  A biological community is –an assemblage of all the populations of organisms living close enough together for potential interaction and –described by its species composition.  The boundaries of a community vary with the research question to be investigated. For example, the boundaries of a community could be defined as –a pond or –the intestinal microbes of a pond organism. © 2012 Pearson Education, Inc.

8.  Interspecific interactions –are relationships with individuals of other species in the community, –greatly affect population structure and dynamics, and –can be categorized according to their effect on the interacting populations. 37.2 Interspecific interactions are fundamental to community structure © 2012 Pearson Education, Inc.

9.  Interspecific competition occurs when populations of two different species compete for the same limited resource. –In mutualism, both populations benefit. –In predation, one species (the predator) kills and eats another (the prey). –In herbivory, an animal consumes plant parts or algae. –In parasitism, the host plants or animals are victimized by parasites or pathogens. 37.2 Interspecific interactions are fundamental to community structure © 2012 Pearson Education, Inc.

10. Table 37.2

11. 37.3 Competition may occur when a shared resource is limited  An ecological niche is the sum of an organism’s use of the biotic and abiotic resources in its environment.  Interspecific competition occurs when the niches of two populations overlap.  Competition lowers the carrying capacity of competing populations because the resources used by one population are not available to the other population. © 2012 Pearson Education, Inc.

12. Figure 37.3A

13. Figure 37.3B

14. 37.4 Mutualism benefits both partners  Reef-building corals and photosynthetic dinoflagellates illustrate the win/win nature of mutualism. Photosynthetic dinoflagellates –gain shelter in the cells of each coral polyp, –produce sugars used by the polyps, and –provide at least half of the energy used by the coral animals. © 2012 Pearson Education, Inc.

15. Figure 37.4

16. 37.5 EVOLUTION CONNECTION: Predation leads to diverse adaptations in prey species  Predation benefits the predator but kills the prey.  Prey adapt using protective strategies that include –camouflage, –mechanical defenses, and –chemical defenses. © 2012 Pearson Education, Inc.

17. Figure 37.5A

18. Figure 37.5B

19.  Herbivores and plants undergo coevolution, –a series of reciprocal evolutionary adaptations in two species, –in which change in one species acts as a new selective force on another. 37.6 EVOLUTION CONNECTION: Herbivory leads to diverse adaptations in plants © 2012 Pearson Education, Inc.

20. 37.6 EVOLUTION CONNECTION: Herbivory leads to diverse adaptations in plants  A plant whose body parts have been eaten by an animal must expend energy to replace the loss. –Thus, numerous defenses against herbivores have evolved in plants. –Plant defenses against herbivores include –spines and thorns and –chemical toxins. © 2012 Pearson Education, Inc.

21. Figure 37.6 Eggs Sugar deposits

22. Figure 37.6_1

23. Figure 37.6_2 Eggs

24. Figure 37.6_3 Sugar deposits

25. 37.7 Parasites and pathogens can affect community composition  A parasite lives on or in a host from which it obtains nourishment. –Internal parasites include nematodes and tapeworms. –External parasites include mosquitoes, ticks, and aphids.  Pathogens are disease-causing microscopic parasites that include –bacteria, –viruses, –fungi, or –protists. © 2012 Pearson Education, Inc.

26. Figure 37.7

27.  Non-native pathogens can have rapid and dramatic impacts. –The American chestnut was devastated by the chestnut blight protist. –A fungus-like pathogen is currently causing sudden oak death on the West Coast.  Non-native pathogens can cause a decline of the ecosystem. 37.7 Parasites and pathogens can affect community composition © 2012 Pearson Education, Inc.

28. 37.8 Trophic structure is a key factor in community dynamics  The trophic structure of a community is a pattern of feeding relationships consisting of several different levels. –The sequence of food transfer up the trophic levels is known as a food chain. –The transfer of food moves chemical nutrients and energy from producers up through the trophic levels in a community. © 2012 Pearson Education, Inc.

29.  Producers –are autotrophs and –support all other trophic levels.  Consumers are heterotrophs. –Herbivores are primary consumers. –Secondary consumers typically eat herbivores. –Tertiary consumers typically eat secondary consumers. –Quaternary consumers typically eat tertiary consumers. 37.8 Trophic structure is a key factor in community dynamics © 2012 Pearson Education, Inc.

30.  Detritivores derive their energy from detritus, the dead material produced at all the trophic levels.  Decomposers –are mainly prokaryotes and fungi and –secrete enzymes that digest molecules in organic materials and convert them into inorganic forms, in the process called decomposition. 37.8 Trophic structure is a key factor in community dynamics © 2012 Pearson Education, Inc.

31. Figure 37.8_s1 Trophic level Plant A terrestrial food chainAn aquatic food chain Producers Phytoplankton

32. Figure 37.8_s2 Trophic level Plant A terrestrial food chainAn aquatic food chain Producers Phytoplankton Grasshopper Primary consumers Zooplankton

33. Figure 37.8_s3 Trophic level Plant A terrestrial food chainAn aquatic food chain Producers Phytoplankton Grasshopper Primary consumers Zooplankton Mouse Secondary consumers Herring

34. Figure 37.8_s4 Trophic level Plant A terrestrial food chainAn aquatic food chain Producers Phytoplankton Grasshopper Primary consumers Zooplankton Mouse Secondary consumers Herring Tuna Snake Tertiary consumers

35. Figure 37.8_s5 Trophic level Plant A terrestrial food chainAn aquatic food chain Producers Phytoplankton Grasshopper Primary consumers Zooplankton Mouse Secondary consumers Herring Tuna Snake Tertiary consumers Killer whaleHawk Quaternary consumers

36. 37.9 Food chains interconnect, forming food webs  A food web is a network of interconnecting food chains.  Notice that –consumers may eat more than one type of producer and –several species of consumers may feed on the same species of producer. © 2012 Pearson Education, Inc.

37. Figure 37.9 Quaternary, tertiary, and secondary consumers secondary consumers Tertiary and Secondary and primary consumers Primary consumers Producers (plants)

38. Figure 37.9_1 Primary consumers Producers (plants)

39. Figure 37.9_2 Quaternary, tertiary, and secondary consumers secondary consumers Tertiary and Secondary and primary consumers Primary consumers

40. 37.10 Species diversity includes relative abundance and species richness  Species diversity is defined by two components: 1.Species richness, the number of species in a community, and 2.Relative abundance, the proportional representation of a species in a community. © 2012 Pearson Education, Inc.

41. 37.10 Species diversity includes relative abundance and species richness  Plant species diversity in a community affects the species diversity of animals.  Species diversity has consequences for pathogens.  Low species diversity is characteristic of most modern agricultural ecosystems. © 2012 Pearson Education, Inc.

42. Figure 37.10A Woodlot A

43. Figure 37.10B Woodlot B

44. Table 37.10

45. 37.11 Keystone species have a disproportionate impact on diversity  A keystone species –is a species whose impact on its community is larger than its biomass or abundance indicates and –occupies a niche that holds the rest of its community in place.  Examples of keystone species in marine ecosystems include –Pisaster sea stars and –long-spined sea urchins. © 2012 Pearson Education, Inc.

46. Figure 37.11A Keystone absent

47. Figure 37.11B

48. Figure 37.11C

49. 37.12 Disturbance is a prominent feature of most communities  Disturbances –are events that damage biological communities and –include storms, fires, floods, droughts, overgrazing, or human activity. –The types, frequency, and severity of disturbances vary from community to community. © 2012 Pearson Education, Inc.

50.  Communities change drastically following a severe disturbance that –strips away vegetation and –removes significant amounts of soil.  Ecological succession results from colonization by a variety of species, which are replaced by a succession of other species. 37.12 Disturbance is a prominent feature of most communities © 2012 Pearson Education, Inc.

51.  Primary succession begins in a virtually lifeless area with no soil.  Secondary succession occurs when a disturbance destroys an existing community but leaves the soil intact. 37.12 Disturbance is a prominent feature of most communities © 2012 Pearson Education, Inc.

52. Figure 37.12A

53. Figure 37.12B Annual plants Perennial plants and grasses Shrubs Softwood trees such as pines Hardwood trees Time

54. 37.13 CONNECTION: Invasive species can devastate communities  Invasive species –are organisms that have been introduced into non-native habitats by human actions and –have established themselves at the expense of native communities. –The absence of natural enemies often allows rapid population growth of invasive species. © 2012 Pearson Education, Inc.

55. 37.13 CONNECTION: Invasive species can devastate communities  Examples of invasive species include the deliberate introduction of –rabbits into Australia and –cane toads into Australia. © 2012 Pearson Education, Inc.

56. Figure 37.13A Key Frontier of rabbit spread 1900 1890 1880 1870 1860 1920 1900 1910 1980 1910 1920 1910 1920 1880 1890 1910 600 km

57. ECOSYSTEM STRUCTURE AND DYNAMICS © 2012 Pearson Education, Inc.

58. 37.14 Ecosystem ecology emphasizes energy flow and chemical cycling  An ecosystem consists of –all the organisms in a community and –the abiotic environment with which the organisms interact.  In an ecosystem, –energy flow moves through the components of an ecosystem and –chemical cycling is the transfer of materials within the ecosystem. © 2012 Pearson Education, Inc.

59.  A terrarium –represents the components of an ecosystem and –illustrates the fundamentals of energy flow. 37.14 Ecosystem ecology emphasizes energy flow and chemical cycling © 2012 Pearson Education, Inc.

60. Figure 37.14 Energy flow Chemical energy Light energy Bacteria, protists, and fungi Chemical elements Heat energy C h e m i c a l c c y l i n g

61. 37.15 Primary production sets the energy budget for ecosystems  Primary production –is carried out by producers, –is the amount of solar energy converted to chemical energy by an ecosystem’s producers for a given area and during a given time period, and –produces biomass, the amount of living organic material in an ecosystem.  Different ecosystems vary in their –primary production and –contribution to the total production of the biosphere. © 2012 Pearson Education, Inc.

62. Figure 37.15 Open ocean Estuary Algal beds and coral reefs Desert and semidesert scrub Tundra Temperate grassland Cultivated land Boreal forest (taiga) Savanna Temperate deciduous forest Tropical rain forest 05001,0001,5002,0002,500 Average net primary productivity (g/m 2 /yr)

63. 37.16 Energy supply limits the length of food chains  A caterpillar represents a primary consumer.  Of the organic compounds a caterpillar ingests, about –50% is eliminated in feces, –35% is used in cellular respiration, and –15% is used for growth. © 2012 Pearson Education, Inc.

64. Figure 37.16A Plant material eaten by caterpillar 100 kilocalories (kcal) 50 kcal 35 kcal 15 kcal Feces Cellular respiration Growth

65. 37.16 Energy supply limits the length of food chains  A pyramid of production shows the flow of energy –from producers to primary consumers and –to higher trophic levels.  Only about 10% of the energy stored at each trophic level is available to the next level. © 2012 Pearson Education, Inc.

66. Figure 37.16B Tertiary consumers Secondary consumers Primary consumers Producers 10 kcal 100 kcal 1,000 kcal 10,000 kcal 1,000,000 kcal of sunlight

67. 37.17 CONNECTION: A pyramid of production explains the ecological cost of meat  When humans eat –grain or fruit, we are primary consumers, –beef or other meat from herbivores, we are secondary consumers, and –fish like trout or salmon, we are tertiary or quaternary consumers. © 2012 Pearson Education, Inc.

68. 37.17 CONNECTION: A pyramid of production explains the ecological cost of meat  Only about 10% of the chemical energy available in a trophic level is passed to the next higher trophic level.  Therefore, the human population has about ten times more energy available to it when people eat plants instead of the meat of herbivores.  Eating meat of any kind is expensive –economically and –environmentally. © 2012 Pearson Education, Inc.

69. Figure 37.17 Trophic level Vegetarians Corn Cattle Meat-eaters Primary consumers Secondary consumers Producers

70. Figure 37.17_1 Trophic level Vegetarians Corn Primary consumers Secondary consumers Producers

71. Figure 37.17_2 Corn Cattle Meat-eaters Trophic level Primary consumers Secondary consumers Producers

72. 37.18 Chemicals are cycled between organic matter and abiotic reservoirs  Ecosystems are supplied with a continual influx of energy from the –sun and –Earth’s interior.  Except for meteorites, there are no extraterrestrial sources of chemical elements.  Thus, life also depends on the recycling of chemicals. © 2012 Pearson Education, Inc.

73.  Biogeochemical cycles include –biotic components, –abiotic components, and –abiotic reservoirs, where a chemical accumulates or is stockpiled outside of living organisms.  Biogeochemical cycles can be –local or –global. 37.18 Chemicals are cycled between organic matter and abiotic reservoirs © 2012 Pearson Education, Inc.

74. Figure 37.18 Consumers Producers Decomposers Nutrients available to producers Abiotic reservoirs Geologic processes 4 1 2 3

75. 37.19 The carbon cycle depends on photosynthesis and respiration  Carbon is –the major ingredient of all organic molecules and –found in –the atmosphere, –fossil fuels, and –dissolved in carbon compounds in the ocean.  The return of CO 2 to the atmosphere by respiration closely balances its removal by photosynthesis.  The carbon cycle is affected by burning wood and fossil fuels. © 2012 Pearson Education, Inc.

76. Figure 37.19 CO 2 in atmosphere Cellular respiration Burning Wood and fossil fuels Higher-level consumers 5 3 2 4 Decomposition Decomposers (soil microbes) Detritus Wastes; death Primary consumers Plant litter; death Plants, algae, cyanobacteria Photosynthesis 1

77. 37.20 The phosphorus cycle depends on the weathering of rock  Organisms require phosphorus for –nucleic acids, –phospholipids, and –ATP. © 2012 Pearson Education, Inc.

78. 37.20 The phosphorus cycle depends on the weathering of rock  The phosphorus cycle does not have an atmospheric component.  Rocks are the only source of phosphorus for terrestrial ecosystems.  Plants absorb phosphate ions in the soil and build them into organic compounds.  Phosphates are returned to the soil by decomposers.  Phosphate levels in aquatic ecosystems are typically low enough to be a limiting factor. © 2012 Pearson Education, Inc.

79. Figure 37.20 Uplifting of rock Weathering of rock Phosphates in rock Phosphates in solution Runoff Assimilation Rock Decomposition Phosphates in soil (inorganic) Precipitated (solid) phosphates Decomposers in soil Detritus Animals Plants 3 1 2 4 5 6

80. 37.21 The nitrogen cycle depends on bacteria  Nitrogen is –an ingredient of proteins and nucleic acids, –essential to the structure and functioning of all organisms, and –a crucial and often limiting plant nutrient.  Nitrogen has two abiotic reservoirs: 1. the atmosphere, of which about 80% is nitrogen gas, and 2. soil. © 2012 Pearson Education, Inc.

81. 37.21 The nitrogen cycle depends on bacteria  Nitrogen fixation –converts N 2 to compounds of nitrogen that can be used by plants and –is carried out by some bacteria. © 2012 Pearson Education, Inc.

82. Figure 37.21 Nitrogen (N 2 ) in atmosphere Plant Animal Nitrogen-fixing bacteria in root modules Free-living nitrogen-fixing bacteria Detritus Decomposers Ammonium (NH 4  ) in soil Nitrifying bacteria Denitrifiers Assimilation by plants Nitrates in soil (NO 3  ) 8 6 5 3 4 7 2 1

83. 37.22 CONNECTION: A rapid inflow of nutrients degrades aquatic ecosystems  In aquatic ecosystems, primary production is limited by low nutrient levels of –phosphorus and –nitrogen.  Over time, standing water ecosystems –gradually accumulate nutrients from the decomposition of organic matter and fresh influx from the land, and –primary production increases in a process known as eutrophication. © 2012 Pearson Education, Inc.

84. 37.22 CONNECTION: A rapid inflow of nutrients degrades aquatic ecosystems  Eutrophication of lakes, rivers, and coastal waters –depletes oxygen levels and –decreases species diversity.  In many areas, phosphate pollution leading to eutrophication comes from –agricultural fertilizers, –pesticides, –sewage treatment facilities, and –runoff of animal waste from feedlots © 2012 Pearson Education, Inc.

85. 37.22 CONNECTION: A rapid inflow of nutrients degrades aquatic ecosystems  Eutrophication of aquatic systems may also result from increased levels of nitrogen from –feedlots and –applications of large amounts of fertilizer. © 2012 Pearson Education, Inc.

86. Figure 37.22B WinterSummer G u l f f o M e x i c o G u l f f o M e x i c o

87. Figure 37.22B_1 Winter G u l f f o M e x i c o

88. Figure 37.22B_2 Summer G u l f f o M e x i c o

89. 37.23 CONNECTION: Ecosystem services are essential to human well-being  Although agricultural and other managed ecosystems are necessary to supply our needs, we also depend on services provided by natural ecosystems.  Healthy ecosystems –supply fresh water and some foods, –recycle nutrients, –decompose wastes, and –regulate climate and air quality. © 2012 Pearson Education, Inc.

90. 37.23 CONNECTION: Ecosystem services are essential to human well-being  Enormous increases in food production have come at the expense of –natural ecosystems and –the services they provide.  Human activities also threaten many forest ecosystems and the services they provide. © 2012 Pearson Education, Inc.

91. You should now be able to 1.Define a biological community. Explain why the study of community ecology is important. 2.Define interspecific competition, mutualism, predation, herbivory, and parasitism, and provide examples of each. 3.Define an ecological niche. Explain how interspecific competition can occur when the niches of two populations overlap. 4.Describe the mutualistic relationship between corals and dinoflagellates. 5.Define predation. Describe the protective strategies potential prey employ to avoid predators. © 2012 Pearson Education, Inc.

92. You should now be able to 6.Explain why many plants have chemical toxins, spines, or thorns. Define coevolution and describe an example. 7.Explain how parasites and pathogens can affect community composition. 8.Identify and compare the trophic levels of terrestrial and aquatic food chains. 9.Explain how food chains interconnect to form food webs. 10.Describe the two components of species diversity. 11.Define a keystone species. © 2012 Pearson Education, Inc.

93. You should now be able to 12.Explain how disturbances can benefit communities. Distinguish between primary and secondary succession. 13.Explain how invasive species can affect communities. 14.Compare the movement of energy and chemicals within and through ecosystems. 15.Compare the primary production of tropical rain forests, coral reefs, and open ocean. Explain why the differences between them exist. 16.Describe the movement of energy through a food chain. © 2012 Pearson Education, Inc.

94. You should now be able to 17.Explain how carbon, nitrogen, and phosphorus cycle within ecosystems. 18.Explain how rapid eutrophication of aquatic ecosystems affects species diversity and oxygen levels. 19.Explain how human activities are threatening natural ecosystems. © 2012 Pearson Education, Inc.

95. Figure 37.UN01 Quaternary consumers Tertiary consumers Secondary consumers Primary consumers Producers

96. Chemical elements Figure 37.UN02 AutotrophsHeterotrophs Producer Light Energy Decomposer Detritus Carnivore (secondary consumer) Herbivore (primary consumer) Inorganic compounds (chemical elements)

97. Figure 37.UN03 Approximately 90% loss of energy at each trophic level Energy

98. Figure 37.UN04

99. Figure 37.UN05