1. © 2010 Pearson Education, Inc. Lectures by Chris C. Romero, updated by Edward J. Zalisko PowerPoint ® Lectures for Campbell Essential Biology, Fourth Edition – Eric Simon, Jane Reece, and Jean Dickey Campbell Essential Biology with Physiology, Third Edition – Eric Simon, Jane Reece, and Jean Dickey Chapter 18 An Introduction to Ecology and the Biosphere

2. Biology and Society: Penguins and Polar Bears in Peril The scientific debate is over. The great majority of scientists now agree that the global climate is changing. Average global temperatures have risen 0.8°C (about 1.4°F) over the past century, mostly over the last 30 years. © 2010 Pearson Education, Inc.

3. AN OVERVIEW OF ECOLOGY Ecology is the scientific study of the interactions between organisms and their environments.

4. © 2010 Pearson Education, Inc. Humans have always had an interest in other organisms and their environments. Extraordinary insight can be gained from a discovery-based approach of –Watching nature –Recording its structure and processes

5. © 2010 Pearson Education, Inc. A Hierarchy of Interactions Many different factors can potentially affect an organism’s interaction with the environment. –Biotic factors are –All of the organisms in the area –The living component of the environment –Abiotic factors –Are the environment’s nonliving component –Include chemical and physical factors, such as temperature, light, water, minerals, and air

6. © 2010 Pearson Education, Inc. The biosphere is the global ecosystem, the sum of all the planet’s ecosystems or all of life and where it lives.

7. © 2010 Pearson Education, Inc. Energy Source All organisms require a usable source of energy to live. Solar energy from sunlight –Is captured by chlorophyll during the process of photosynthesis –Powers most ecosystems

8. Figure 18.5 GREEN = HIGH LEVELS DARKER COLORS = LOW LEVELS Chlorophyll levels around the world.

9. © 2010 Pearson Education, Inc. Temperature affects metabolism. –Few organisms can maintain a sufficiently active metabolism at temperatures close to 0ºC. –Temperatures above 45ºC destroy the enzymes of most organisms. Temperature

10. © 2010 Pearson Education, Inc. Water Water is essential to all life. For terrestrial organisms, the main water problem is drying out. Aquatic organisms –Are surrounded by water –Face problems of water balance if their own solute concentration does not match that of their surroundings

11. Animal cell Plant cell Normal Flaccid (wilts) Lysing Turgid Shriveled Plasma membrane H2OH2O H2OH2O H2OH2OH2OH2O H2OH2O H2OH2O H2OH2O H2OH2O (a) Isotonic solution (b) Hypotonic solution (c) Hypertonic solution Figure 5.14

12. © 2010 Pearson Education, Inc. Nutrients The distribution and abundance of plants is often determined by the –Availability of nitrogen and phosphorus –The structure, pH, and nutrient content of the soil

13. © 2010 Pearson Education, Inc. Other Aquatic Factors Aquatic but not terrestrial ecosystems are more limited by –The levels of dissolved oxygen and salinity –Currents –Tides

14. © 2010 Pearson Education, Inc. Other Terrestrial Factors Terrestrial but not aquatic ecosystems are more limited by –Wind –Storms –Fire

15. Number of lizard species Key = 20+ = 16–20 = 11–15 = 6–10 = 1–5 = 0 Figure 18.10

16. © 2010 Pearson Education, Inc. Anatomical Responses Many organisms respond to environmental challenges with some type of change in –Body shape –Structure Reversible change, such as a heavier fur coat in response to cold, is an example of acclimation.

17. Figure 18.11

18. © 2010 Pearson Education, Inc. Behavioral Responses In contrast to plants, most animals can respond to an unfavorable change in the environment by moving to a new location. –Ectotherms may shuttle between sun and shade. –Migratory birds travel great distances in response to changing seasons. –Humans have an especially rich range of behavioral responses.

19. © 2010 Pearson Education, Inc. BIOMES A biome is –A major terrestrial or aquatic life zone –Characterized by –Vegetation type in terrestrial biomes –The physical environment in aquatic biomes

20. © 2010 Pearson Education, Inc. Aquatic biomes –Occupy roughly 75% of Earth’s surface –Are determined by their –Salinity (what is the salinity of the worlds oceans?) –Other physical factors

21. © 2010 Pearson Education, Inc. Freshwater biomes –Typically have a salt concentration of less than 1% –Include lakes, streams, rivers, and wetlands Marine biomes –Typically have a salt concentration around 3% –Include oceans, intertidal zones, coral reefs, and estuaries

22. © 2010 Pearson Education, Inc. Freshwater biomes –Cover less than 1% of Earth –Contain a mere 0.01% of its water –Harbor about 6% of all described species –Are used for drinking water, crop irrigation, sanitation, and industry Freshwater Biomes

23. Aphotic zone Photic zone Benthic realm Figure 18.15

24. © 2010 Pearson Education, Inc. Wetlands A wetland is a transitional biome between an aquatic ecosystem and a terrestrial one. Wetlands –Support the growth of aquatic plants –Are among the richest of biomes in terms of species diversity

25. Figure 18.18

26. © 2010 Pearson Education, Inc. Marine Biomes Marine biomes are diverse, ranging from vivid coral reefs to perpetually dark realms in the deepest regions.

27. High tide Benthic realm (seafloor from continental shelf to deep-sea bottom) Pelagic realm (open water) Low tide Oarweed (to 2 m) Sea star (to 33 cm) Intertidal zone Continental shelf Sea pen (to 45 cm) Sea spider (1–90 cm) Brittle star (to 60 cm) Glass sponge (to 1.8 m) Sponges (1 cm–1 m) Brain coral (to 1.8 m) Phyto- plankton Zoo- plankton Man-of-war (to 50 m long) Blue shark (to 2 m) Sperm whale (10–20 cm) Hatchet fish (2–60 cm) Rat-tail fish (to 80 cm) Octopus (to 10 m) Gulper eel (to 180 cm) Turtle (60–180 cm) Sea cucumber (to 40 cm) Tripod fish (to 30 cm) Anglerfish (45 cm–2 m) Photic zone Aphotic zone 6,000– 10,000 m 1,000– 4,000 m 200 m No light “Twilight” Figure 18.19

28. © 2010 Pearson Education, Inc. Estuaries –Are a transition area between a river and the ocean –Have a saltiness ranging from nearly that of fresh water to that of the ocean –Are among the most productive areas on Earth

29. Figure 18.22

30. © 2010 Pearson Education, Inc. Estuaries are threatened by –Landfills –Nutrient pollution –Contamination by pathogens or toxic chemicals –Alteration of freshwater inflow –The introduction of non-native species

31. © 2010 Pearson Education, Inc. How Climate Affects Terrestrial Biome Distribution Terrestrial biomes are primarily determined by –Temperature –Rainfall Earth’s global climate patterns are largely the result of –The input of radiant energy from the sun –The planet’s movement in space

32. Low angle of incoming sunlight Sunlight strikes most directly Low angle of incoming sunlight North Pole 60º N 60º S South Pole Tropic of Capricorn 30º S 30º N Tropic of Cancer 0º (equator) Atmosphere Figure 18.23

33. © 2010 Pearson Education, Inc. Heated by the direct rays of the sun, air at the equator rises, then cools forming clouds, and drops rain. This largely explains why rain forests are concentrated in the tropics, the region from the Tropic of Cancer to the Tropic of Capricorn.

34. Descending dry air absorbs moisture Descending dry air absorbs moisture Ascending moist air releases moisture Temperate zone Temperate zone Tropics Doldrums 0º 30º 23.5º Trade winds Figure 18.24

35. © 2010 Pearson Education, Inc. Climate is also affected by –Proximity to large bodies of water –The presence of landforms such as mountain ranges

36. © 2010 Pearson Education, Inc. Terrestrial Biomes Terrestrial ecosystems are grouped into biomes primarily on the basis of their vegetation type.

37. Temperate broadleaf forest Coniferous forest Arctic tundra High mountains (coniferous forest and alpine tundra) Polar ice Tropical forest Temperate grassland Chaparral Desert Savanna Key Tropic of Capricorn 30º N Equator 30º S Tropic of Cancer Figure 18.27

38. © 2010 Pearson Education, Inc. Deserts –Are the driest of all biomes –May be very hot or very cold Desert

39. Precipitation Temperature Figure 18.31

40. © 2010 Pearson Education, Inc. Descending dry air absorbs moisture Descending dry air absorbs moisture Ascending moist air releases moisture Temperate zone Temperate zone Tropics Doldrums 0º 30º 23.5º Trade winds Figure 18.24

41. © 2010 Pearson Education, Inc. Temperate broadleaf forest –Occurs throughout midlatitudes where there is sufficient moisture to support the growth of large trees –Includes dense stands of deciduous trees in the Northern Hemisphere Temperate Broadleaf Forest

42. Temperature Precipitation Figure 18.34

43. © 2010 Pearson Education, Inc. Coniferous forests –Are dominated by cone-bearing evergreen trees –Include the northern coniferous forest, or taiga, the largest terrestrial biome on Earth Coniferous Forest

44. Temperature Precipitation Figure 18.35

45. © 2010 Pearson Education, Inc. Polar ice covers the land at high latitudes north of the arctic tundra in the northern hemisphere and Antarctica in the southern hemisphere. Only a small portion of these land masses is free of ice or snow, even during the summer. Polar Ice

46. Temperature Precipitation Figure 18.37

47. © 2010 Pearson Education, Inc. All parts of the biosphere are linked by the global water cycle. Human activities that affect the global water cycle include –Destruction of forests –Pumping large amounts of groundwater to the surface for irrigation The Water Cycle

48. Oceans Precipitation over the sea Evaporation from the sea Water vapor over the sea Precipitation over the land Water vapor over the land Solar heat Flow of water from land to sea Surface water and groundwater Evaporation and transpiration Net movement of water vapor by wind Figure 18.38

49. © 2010 Pearson Education, Inc. Sustainability is the goal of developing, managing, and conserving Earth’s resources in ways that meet the needs of people today without compromising the ability of future generations to meet their needs. Human Impact on Biomes

50. 2001 1975 Figure 18.39 Satellite photos of a small area in Brazil show how thoroughly a landscape can be altered in a short amount of time.

51. Figure 18.40 Every year, more and more forested land is cleared for agriculture.

52. © 2010 Pearson Education, Inc. The impact of human activities on freshwater ecosystems may pose an even greater threat to life on Earth—including ourselves—than the damage to terrestrial ecosystems. Fresh Water

53. © 2010 Pearson Education, Inc. Global climate patterns are changing because of rising concentration in the atmosphere of –Carbon dioxide (CO 2 ) –Some other gases GLOBAL CLIMATE CHANGE

54. © 2010 Pearson Education, Inc. Greenhouse gases –Include CO 2, water vapor, and methane –Are transparent to solar radiation –Absorb or reflect heat –Contribute to increases in global temperatures The Greenhouse Effect and Global Warming

55. Atmosphere Sunlight Some heat energy escapes into space Radiant heat trapped by greenhouse gases Figure 18.43

56. © 2010 Pearson Education, Inc. The vast majority of scientists are confident that human activities have caused the rising concentrations of greenhouse gases. The Accumulation of Greenhouse Gases

57. Year 2000 15001000500 400 300 350 250 0 Carbon dioxide (CO 2 ) (ppm) Figure 18.45

58. © 2010 Pearson Education, Inc. Overall, the uptake of CO 2 by photosynthesis roughly equals the release of CO 2 by cellular respiration.

59. Ocean Atmosphere Respiration Combustion of fossil fuel Photo- synthesis Figure 18.46

60. © 2010 Pearson Education, Inc. Effects of Climate Change on Ecosystems In many plants and animals, life cycle events are triggered by –Warming temperatures –Day length

61. © 2010 Pearson Education, Inc. As global temperatures warm, and day length remains steady, natural interactions may become out of sync. –Plants may bloom before pollinators have emerged. –Eggs may hatch before dependable food sources are available.

62. © 2010 Pearson Education, Inc. Looking to Our Future Emissions of greenhouse gases are accelerating. From 2000–2005 global CO 2 emissions increased four times faster than in the preceding 10-year span.

63. © 2010 Pearson Education, Inc. The amount of greenhouse gas emitted as the result of the actions of a single individual is that person’s carbon footprint. We can reduce our carbon footprints by –Reducing our use of energy –Driving less –Recycling

64. © 2010 Pearson Education, Inc. In addition, eating locally grown fresh foods may lower the greenhouse gas emissions that result from food processing and transportation.