1. C HAPTER 48 The Biosphere

2. I MPACTS, I SSUES : S URFERS, S EALS, AND THE S EA El Niño and the winter of 1997-1998 was an excellent season for surfers and disastrous for seals and sea lions Displaced currents along the Pacific coast failed to churn up nutrients important to primary producers and marine food webs Effects moved through the food web to fishes and squid, the main food of seals and sea lions

3. B IOGEOGRAPHY The study of the distribution of organisms and the processes that underlie distribution patterns

4. F ACTORS THAT A FFECT D ISTRIBUTION Geologic history Topography Climate Species interactions

5. B IOSPHERE Sum total of the places in which organisms live Includes portions of the hydrosphere, lithosphere, and atmosphere

6. C LIMATE Average weather condition in a region Affected by: amount of incoming solar radiation prevailing winds elevation

7. T HE A TMOSPHERE Three layers Outer mesosphere Middle stratosphere (includes ozone layer) Inner troposphere (where air is warmed by the greenhouse effect)

8. O ZONE L AYER Region 17 to 27 kilometers above sea level in the stratosphere Molecules of ozone absorb most layers of ultraviolet light Protects living organisms from excess exposure to UV light

9. T HERMAL I NVERSION Weather pattern in which a layer of cool, dense air is trapped beneath a layer of warm air cool air warm inversion air cool air Figure 48-7 Page 870

10. A CID D EPOSITION Affects much of eastern North America Caused by the release of sulfur and nitrogen oxides Coal-burning power plants and motor vehicles are major sources

11. B IOMES Regions of land characterized by habitat conditions and community structure Distinctive biomes prevail at certain latitudes and elevations

12. H OT S POTS Portions of biomes that show the greatest biodiversity Conservationists are working to inventory and protect these regions 24 hot spots hold more than half of all terrestrial species

13. S OIL C HARACTERISTICS Amount of humus pH Degree of aeration Ability to hold or drain water Mineral content

14. D ESERTS Less than 10 centimeters annual rainfall, high level of evaporation Tend to occur at 30 degrees north and south and in rain shadows One-third of land surface is arid or semiarid

15. Fig. 48-14a, p.877

16. D RY S HRUBLANDS AND W OODLANDS Semiarid regions with cooler, wet winters and hot, dry summers Tend to occur in western or southern coastal regions between latitudes of 30 and 40 degrees

17. Fig. 48-16, p.878

18. E FFECTS OF D EFORESTATION Increased leaching and soil erosion Increased flooding and sedimentation of downstream rivers Regional precipitation declines Possible amplification of the greenhouse effect

19. T ROPICAL R AIN F ORESTS Have the greatest variety of insects, most bird species Some tropical forest species may prove valuable to humans Forests are in areas with fast-growing human populations

20. A RCTIC T UNDRA Occurs at high latitudes Permafrost lies beneath surface Nutrient cycling is very slow Arctic tundra in Russia in summer

21. Fig. 48-21b, p.883

22. L AKES Bodies of standing freshwater Eutrophic: shallow, nutrient-rich, has high primary productivity Oligotrophic: deep, nutrient-poor, has low primary productivity LITTORAL LIMNETIC LITTORAL PROFUNDAL Figure 48.28 Page 886 Lake Zonation

23. T HERMAL L AYERING In temperate-zone lakes, water can form distinct layers during summer THERMOCLINE Figure 48-28 Page 886

24. S EASONAL O VERTURN In spring and fall, temperatures in the lake become more uniform Oxygen-rich surface waters mix with deeper oxygen-poor layers Nutrients that accumulated at bottom are brought to the surface

25. E UTROPHICATION Enrichment of a body of water with nutrients Can occur naturally over long time span Can be triggered by pollutants

26. Fig. 48-29, p.887

27. E STUARY Partially enclosed area where saltwater and freshwater mix Dominated by salt-tolerant plants Examples are Chesapeake Bay, San Francisco Bay, salt marshes of New England

28. E STUARINE F OOD W EBS Primary producers are phytoplankton and salt- tolerant plants Much primary production enters detrital food webs Detritus feeds bacteria, nematodes, snails, crabs, fish

29. P HYTOPLANKTON Floating or weakly swimming photoautotrophs; form the base for most oceanic food webs Ultraplankton are photosynthetic bacteria

30. P RIMARY P RODUCTIVITY Primary producers are usually the phytoplankton Productivity can vary seasonally north temperate north polar tropical

31. H YDROTHERMAL V ENTS Openings in ocean floor that spew mineral-rich, superheated water Primary producers are chemoautotrophic bacteria; use sulfides as energy source Tube worms at hydrothermal vent Figure 48-38 Page 893

32. U PWELLING Upward movement of water along a coast; replaces surface waters that move away from shore Figure 48-37 Page 892