CHAPTER 34 The Biosphere: An Introduction to Earth's Diverse Environments

1. CHAPTER 34The Biosphere: An Introduction to Earth's Diverse Environments Modules 34.1 – 34.6

2. A Mysterious Giant of the Deep • Ecology is the scientific study of the interactions of organisms with their environment • The ocean is Earth’s largest and least explored ecosystem • Recent explorations of the deep sea have brought previously unknown species to light, such as this “mystery squid”

3. It can accommodate a pilot and two other people • It is equipped with instruments to view and sample the ocean at depths of up to 2,500m • Deep-sea submersibles like Alvin allow the exploration of the deep sea

4. Scientists have found seafloor life whose ultimate energy source is not sunlight, but energy that comes from the interior of the planet • This energy is emitted from hydrothermal vents near the edges of Earth’s crustal plates

5. Many animals thrive in the extreme environment around hydrothermal vents • Tube worms were unknown to science until hydrothermal vents were explored • They live on energy extracted from chemicals by bacteria

6. 34.1 Ecologists study how organisms interact with their environment at several levels • Ecologists study environmental interactions at the organism, population, community, and ecosystem levels • These clams that live near an ocean vent constitute a population Figure 34.1

7. Ecosystem interactions involve living (biotic) communities and nonliving (abiotic) components • Abiotic components include energy, nutrients, gases, and water • Organisms are affected by their environment • But their presence and activities often change the environment they inhabit

8. THE BIOSPHERE 34.2 The biosphere is the total of all of Earth's ecosystems • The global ecosystem is called the biosphere • It is the sum of all the Earth's ecosystems • The biosphere is the most complex level in ecology Figure 34.2A

9. except for energy obtained from the sun and heat lost to space • Patchiness characterizes the biosphere • Patchiness occurs in the distribution of deserts, grasslands, forests, and lakes • Each habitat has a unique community of species • The biosphere is self-contained Figure 34.2B

10. 34.3 Connection: Environmental problems reveal the limits of the biosphere • Human activities affect all parts of the biosphere • One example is the widespread use of chemicals

11. Carson documented her concerns in the 1962 book Silent Spring • This book played a key role in the awakening of environmental awareness • Rachel Carson was one of the first to perceive the global dangers of pesticide abuse Figure 34.3

12. DDT concentration:increase of10 million times DDT infish-eating birds25 ppm • Chemical pesticides are concentrated in food chains by biological magnification DDT inlarge fish2 ppm DDT insmall fish0.5 ppm DDT inzooplankton0.04 ppm DDT in water0.000003 ppm Figure 38.3B

13. 34.4 Physical and chemical factors influence life in the biosphere • The most important abiotic factors that determine the biosphere's structure and dynamics include • solar energy • water • temperature

14. Disturbances such as fires, hurricanes, and volcanic eruptions are also abiotic factors Figure 34.4

15. 34.5 Organisms are adapted to abiotic and biotic factors by natural selection • The presence and success of a species in a particular place depends upon its ability to adapt • Natural selection adapts organisms to abiotic and biotic factors • Biotic factors include predation and competition Figure 34.5

16. 34.6 Regional climate influences the distribution of biological communities • Climate often determines the distribution of communities • Earth's global climate patterns are largely determined by the input of solar energy and the planet's movement in space

17. This is a result of the variation in solar radiation at different latitudes • Most climatic variations are due to the uneven heating of Earth's surface North Pole 60º N Low angle ofincoming sunlight 30º N Tropic ofCancer Sunlight directlyoverhead 0º (equator) Tropic ofCapricorn 30º S Low angle ofincoming sunlight 60º S Figure 34.6A Atmosphere South Pole

18. The seasons of the year result from the permanent tilt of the plant on its axis as it orbits the sun MARCH EQUINOX(equator facessun directly) JUNE SOLSTICE(NorthernHemisphere tiltstoward sun) DECEMBERSOLSTICE(NorthernHemisphere tiltsaway from sun) SEPTEMBEREQUINOX Figure 34.6B

19. The tropics experience the greatest annual input and least seasonal variation in solar radiation • The direct intense solar radiation near the equator has an impact on the global patterns of rainfall and winds

20. Ascending moist airreleasesmoisture Descendingdry airabsorbsmoisture Descendingdry airabsorbsmoisture Trade winds Trade winds Doldrums 0º 23.5º 23.5º 30º 30º TROPICS TEMPERATEZONE TEMPERATEZONE Figure 34.6C

21. As the air rises, it cools and releases much of its water content • This results in the abundant precipitation typical of most tropical regions • After losing their moisture over equatorial zones, high altitude air masses spread away from the equator • Warm, moist air at the equator rises

22. This explains the locations of the world's great deserts • As the dry air descends, some of it spreads back toward the equator • This creates the cooling trade winds that dominate the tropics • They cool and descend again at latitudes of about 30° north and south

23. Temperate zones are located between the tropics and the Arctic Circle in the north and the Antarctic Circle in the south • They have seasonal variations in climate • The temperatures are more moderate than in the tropic or polar regions

24. In the tropics, Earth's rapidly moving surface deflects vertically circulating air, making the winds blow from east to west • In temperate zones, the slower-moving surface produces the westerlies, winds that blow from west to east • Prevailing winds result from the combined effects of the rising and falling of air masses and Earth's rotation Figure 34.6D

25. Ocean currents have a profound effect on regional climates by warming or cooling coastal areas • They are created by winds, planet rotation, unequal heating of surface waters, and the locations and shapes of continents

26. Fresno100º 40 miles • Local high temperatures for August 6, 2000, in Southern California DeathValley119º Bakersfield100º Pacific Ocean Burbank90º Santa Barbara 73º San Bernardino 100º Key Riverside 96º Los Angeles(Airport) 75º 70s (ºF) Santa Ana84º Palm Springs 106º 80s 90s 100s 110s San Diego 72º Figure 34.6E

27. Landforms, such as mountains, can affect local climate East Winddirection PacificOcean CascadeRange CoastRange Figure 34.6F

28. CHAPTER 34The Biosphere: An Introduction to Earth's Diverse Environments Modules 34.7 – 34.11

29. AQUATIC BIOMES 34.7 Oceans occupy most of Earth's surface • Oceans cover about 75% of the Earth's surface • Light and the availability of nutrients are the major factors that shape aquatic communities

30. The saltiness of estuaries ranges from less than 1% to 3% • They provide nursery areas for oysters, crabs, and many fishes • They are often bordered by extensive coastal wetlands • Estuaries are productive areas where rivers meet the ocean Figure 34.7A

31. Salt marshes, sand and rocky beaches, and tide pools are part of the intertidal zone • It is often flooded by high tides and then left dry during low tides • The intertidal zone is the wetland at the edge of an estuary or ocean, where water meets land Figure 34.7B

32. Intertidal zone • Abiotic conditions dictate the kinds of communities that ocean zones can support Continental zone Photiczone Pelagiczone Benthiczone(seafloor) Aphoticzone Figure 34.7C

33. It supports highly motile animals such as fishes, squids, and marine mammals • Phytoplankton and zooplankton drift in the pelagic zone • The benthic zone is the ocean bottom • It supports a variety of organisms based upon water depth and light penetration • The pelagic zone is the open ocean

34. Photosynthesis occurs here • The aphotic zone is a vast, dark region of the ocean • It is the most extensive part of the biosphere • Although there is no light, a diverse and dense population inhabits this zone • The photic zone is the portion of the ocean into which light penetrates

35. They support a huge diversity of invertebrates and fishes • Coral reefs are easily degraded by • pollution • native and introduced predators • human souvenir hunters • Coral reefs are found in warm tropical waters above the continental shelf Figure 34.7D

36. 34.8 Freshwater biomes include lakes, ponds, rivers, streams, and wetlands • Lake and pond communities are shaped by • light • temperature • the availability of nutrients and dissolved oxygen

37. A river environment changes greatly between its source and its mouth • Temperature, nutrients, currents, and water clarity vary at different points Figure 34.8A

38. Wetlands are among the richest biomes in terms of species diversity Figure 34.8B

39. TERRESTRIAL BIOMES 34.9 Terrestrial biomes reflect regional variations in climate • Climatic differences, mainly temperature and rainfall, shape the major biomes that cover Earth's land surface • Biomes tend to grade into each other • Within each biome there is local variation • This gives vegetation a patchy, rather than uniform, appearance

40. Major terrestrial biomes 30º N Equator 30º S Tropical forest Polar and high-mountain ice Temperate deciduous forest Savanna Chaparral Coniferous forest Desert Temperate grassland Tundra (arctic and alpine) Figure 34.9

41. 34.10 Tropical forests cluster near the equator • Several types of tropical forests occur in the warm, moist belt along the equator Figure 34.10

42. Large-scale human destruction of tropical rain forests continues to endanger many species • It may also alter world climate • The tropical rain forest is the most diverse ecosystem on Earth

43. 34.11 Talking About Science: Ecologist Arial Lugo studies tropical forests in Puerto Rico • The Luquillo Experimental Forest in Puerto Rico allows ecologists to study the effects of disruption on tropical forests • It contains deforested as well as still-forested areas Figure 34.11B

44. He and other scientists have offered valuable insight into the peril these forests face as well as the promise they hold • Studies indicate that tropical forests recover from natural disasters much more readily than they do from human destruction • The forest ecologist Dr. Ariel Lugo has been one of the key scientists at the Luquillo Experimental Forest Figure 34.11A

45. CHAPTER 34The Biosphere: An Introduction to Earth's Diverse Environments Modules 34.12 – 34.18

46. 34.12 Savannas are grasslands with scattered trees • Drier, tropical areas and some nontropical areas are characterized by the savanna Figure 34.12

47. 34.13 Deserts are defined by their dryness • Deserts are the driest of all terrestrial biomes • They are characterized by low and unpredictable rainfall • Desertification is a significant environmental problem Figure 34.13

48. 34.14 Spiny shrubs dominate the chaparral • The chaparral biome is a shrubland with cool, rainy winters and dry, hot summers • Chaparral vegetation is adapted to periodic fires Figure 34.14

49. 34.15 Temperate grasslands include the North American prairie • Temperate grasslands are found in the interiors of the continents, where winters are cold • Drought, fires, and grazing animals prevent trees from growing • Farms have replaced most of North America's temperate grasslands Figure 34.15

50. 34.16 Deciduous trees dominate temperate forests • Temperate deciduous forests grow where there is sufficient moisture to support the growth of large trees • Nearly all of the original deciduous forests in North America have been drastically altered by agriculture and urban development Figure 34.16