Global Ecology and Human Impacts

1. Global Ecology and Human Impacts Chapter 27

2. LEARNING OBJECTIVE 1 • Define biome • Describe the nine major terrestrial biomes, including their climate, soil, and characteristic plants

3. KEY TERMS • BIOME • A large, relatively distinct terrestrial region characterized by a similar climate, soil, plants, and animals

4. Major Biomes

5. Biomes 1 • Tundra • Northernmost biome • Frozen layer of subsoil (permafrost) • Low-growing vegetation adapted to extreme cold • Short growing season

6. Tundra

7. Biomes 2 • Boreal forest • Acidic, mineral-poor soil • Coniferous trees adapted to cold winters • Short growing season • Temperate rain forest • Receives high precipitation • Large conifers dominate

8. Boreal Forest

9. Temperate Rain Forest

10. Biomes 3 • Temperate deciduous forest • Occurs where precipitation is relatively high and soils are rich in organic matter • Broadleaf trees that lose their leaves seasonally

11. Temperate Deciduous Forest

12. Biomes 4 • Temperate grassland • Deep, mineral-rich soil • Moderate but uncertain precipitation • Temperate grassland • Wet, mild winters and dry summers • Thickets of small-leaf evergreen shrubs and trees

13. Temperate Grassland

14. Chaparral

15. Biomes 5 • Desert • Found in both temperate (cold deserts) and subtropical or tropical regions (warm deserts) • Low levels of precipitation • Plants with specialized water-conserving adaptations

16. Desert

17. Biomes 6 • Savanna • Tropical grassland • Low or seasonal rainfall • Widely scattered trees interspersed with grassy areas

18. Savanna

19. Biomes 7 • Tropical rain forest • Mineral-poor soil • High rainfall evenly distributed throughout year • High species richness and productivity

20. Tropical Rain Forest

21. Precipitation and Temperature

22. Elevation and Latitude

23. ELEVATION ZONES LATITUDE ZONES High elevation North Pole Snow/ice Polar region Alpine tundra Arctic tundra Subalpine coniferous forest Boreal forest Deciduous forest Temperate forest Low elevation Midlatitudes Fig. 27-12, p. 551

24. Rain Shadow

25. Windward side Leeward side Dry air Moist air Fig. 27-13, p. 552

26. LEARNING OBJECTIVE 2 • Identify the biomes that make the best agricultural land • Explain why they are superior

27. Biomes and Agriculture • Best agricultural lands have fertile soil and enough precipitation to grow crops • Temperate deciduous forests were among first biomes converted to agricultural use • Moist temperate grasslands are so well suited to agriculture that few remain

28. LEARNING OBJECTIVE 3 • Define environmental sustainability

29. KEY TERMS • ENVIRONMENTAL SUSTAINABILITY • Ability of the natural environment to meet humanity’s needs indefinitely without going into a decline from human-caused stresses

30. LEARNING OBJECTIVE 4 • Identify the various levels of biodiversity: genetic diversity, species richness, and ecosystem diversity

31. Biological Diversity 1 • Genetic diversity • Genetic variety within a species, both among individuals within a given population and among geographically separate populations • Species richness • The number of species of archaea, bacteria, protists, plants, fungi, and animals

32. Biological Diversity 2 • Ecosystem diversity • The variety of ecosystems (forests, prairies, deserts, lakes, coastal estuaries, coral reefs, other ecosystems) • Biological diversity is important because it provides ecosystem services

33. KEY TERMS • ECOSYSTEM SERVICES • Important environmental services that ecosystems provide • Examples: clean air to breathe, clean water to drink, fertile soil in which to grow crops

34. LEARNING OBJECTIVE 5 • Distinguish among extinct species, endangered species, and threatened species

35. KEY TERMS • EXTINCTION • Elimination of a species, either locally (no longer living in an area where it used to be found, but still found in other areas) or globally (no longer living anywhere in the world)

36. KEY TERMS • ENDANGERED SPECIES • A species whose numbers are so severely reduced that it is in imminent danger of extinction throughout all or a part of its range

37. KEY TERMS • THREATENED SPECIES • A species in which the population is small enough for it to be at risk of becoming extinct but not so small that it is in imminent danger of extinction

38. KEY TERMS • ENDEMIC SPECIES • Localized, native species that are not found anywhere else in the world • Many endangered and threatened species are endemic species

39. An Endangered Species

40. LEARNING OBJECTIVE 6 • Discuss important causes of declining biological diversity

41. KEY TERMS • BIOLOGICAL DIVERSITY • Variety of living organisms considered at three levels: genetic diversity, species richness, and ecosystem diversity

42. KEY TERMS • HABITAT FRAGMENTATION • Division of habitats that formerly occupied large, unbroken areas into smaller pieces by roads, fields, cities, and other human land-transforming activities • The most important cause of declining biological diversity

43. Habitat Destruction

44. Minimum Critical Size of Ecosystems Project

45. KEY TERMS • INVASIVE SPECIES • A foreign species that, when introduced into an area where it is not native, upsets the balance among organisms living there and causes economic or environmental harm • An important cause of declining biological diversity

46. LEARNING OBJECTIVE 7 • Define conservation biology • Compare in situ and ex situ conservation measures

47. KEY TERMS • CONSERVATION BIOLOGY • A multidisciplinary science that focuses on the study of how humans impact species and ecosystems and on development of ways to protect biological diversity

48. KEY TERMS • RESTORATION ECOLOGY • Scientific field that uses principles of ecology to help return a degraded environment as closely as possible to its former undisturbed condition • An aspect of in situ conservation

49. Restoring Damaged Lands

50. Conservation Measures • In situ conservation • Efforts to preserve biological diversity in the wild • Urgently needed in world’s biodiversity hotspots • Ex situ conservation • Conserving individual species in human-controlled settings