The Diverse Ecosystems APBio

Slideshow Transcript

1. Slide 1: Chapter 29 The Earth’s Diverse Ecosystems
2. Slide 2: Chapter 29 2 Factors That Influence Climate The distribution of life on Earth is dramatically affected by weather and climate • Weather: short-term fluctuations in temperature, humidity, cloud cover, wind, and precipitation; affects individual organisms • Climate: long-term patterns of weather; limits distribution of species
3. Slide 3: Chapter 29 3 The Sun Solar energy drives both weather and climate • It drives the wind, ocean currents, and global water cycle Solar energy reaching outer atmosphere includes • Ultraviolet (UV): short wavelengths; high energy • Visible light: intermediate wavelengths; used for photosynthesis, vision • Infrared (IR): long wavelengths; low energy; radiant heat
4. Slide 4: Chapter 29 4 The Sun Before solar energy reaches Earth's surface it is modified by the atmosphere • Ozone layer: stratosphere (middle layer) rich in ozone (O3) absorbs much of sun's UV, converting it to heat • Dust, water vapor, and clouds scatter light, reflecting some back into space • Greenhouse gases selectively absorb IR energy and trap heat in atmosphere
5. Slide 5: Satellite Image of Chapter 29 5 Antarctic Ozone Hole South America Antarctica The “hole”
6. Slide 6: Chapter 29 6 Physical Factors that Affect Climate Include • Earth’s curvature and tilt • Air currents • Ocean currents • Continent and mountain position
7. Slide 7: Chapter 29 7 Curvature and Tilt The amount of sunlight that strikes a given area of Earth’s surface has a major effect on average yearly temperatures
8. Slide 8: Earth’s Curvature, Tilt Chapter 29 8 Make Seasons & Climate Short days; Long nights; Winter Long days; Short nights; Summer Reversed when on other side of Sun
9. Slide 9: Air Currents Chapter 29 9 and Climatic Regions Air rises & cools near equator • Causes much rain • Tropical rain forests Rising air travels N & S from equator • Descends @ 30° N & S • Very dry air causes deserts there Repeated again at 60° & 90° (poles)
10. Slide 10: Air Currents Chapter 29 10 and Climatic Regions Saharan & Arabian deserts are @ 30° N South African Desert is @ 30° S Congo rain forest is @ 0°
11. Slide 11: Chapter 29 11 Ocean Currents Water heats and cools more slowly than land or air • Reduces temperature extremes in coastal areas Ocean currents are driven by winds and by direct heating of water by the sun
12. Slide 12: Chapter 29 12 Ocean Currents Continents and Earth's rotation produce circular gyres • Gyres rotate clockwise in Northern Hemisphere; opposite in South • Gulf Stream moves warm water from Caribbean up eastern shore of North America and over to Western Europe; warmer, moister climate as result
13. Slide 13: Ocean Circulation Chapter 29 13 Patterns: Gyres N. Pacific N. Atlantic Gyre Gyre S. Pacific S. Atlantic Gyre Gyre
14. Slide 14: Chapter 29 14 Continents and Mountains Regular bands of uniform climate would form if not for presence of continents • Continents heat and cool more quickly than surrounding oceans • Continents have irregular shapes • These factors alter flow of wind and water, resulting in irregular ecosystem distribution
15. Slide 15: Chapter 29 15 Continents and Mountains Variations in elevation within continents further complicate climate zones • At higher altitudes air is thinner and retains less heat • Temperature drops about 3.5 ºF for every 1000 feet rise in elevation
16. Slide 16: Effects of Elevation Chapter 29 16 on Temperature High (Altitude) Low Equatorial (Latitude) Polar
17. Slide 17: Chapter 29 17 Continents and Mountains Mountains also modify rainfall patterns • When moist air is forced over a mountain, it expands and cools • Cooler air holds less moisture, thus rain or snow falls on windward side • As air moves down far side of mountain, it warms but stays dry, forming a local dry area called a rain shadow
18. Slide 18: Chapter 29 18
19. Slide 19: The Sierra Nevada Chapter 29 19 Rain Shadow Average Annual Altitude (m) Precipitation (cm) 150 5000 4000 100 3000 2000 50 1000 0 0 West East
20. Slide 20: Chapter 29 20 Conditions Required for Life Four fundamental resources are required for life • Nutrients from which to construct living tissue • Energy to power that construction • Liquid water to serve as medium for metabolic reactions • Appropriate temperatures in which to carry out these processes
21. Slide 21: Chapter 29 21 How Is Life on Land Distributed? Distribution of terrestrial organisms is limited primarily by water availability and temperature • Water and temperature are unevenly distributed in space and time
22. Slide 22: Chapter 29 22 Terrestrial Biomes Terrestrial communities are dominated and defined by their plant life • Plants are precisely adapted to climate of region (they can't escape their conditions) • Large land areas with similar environmental conditions and characteristic plant communities are called biomes
23. Slide 23: Chapter 29 23 The Distribution of 11 Biomes
24. Slide 24: Rainfall & Temp. Chapter 29 24 Affect Biome Distribution Low (Temperature) High Dry (Rainfall) Wet
25. Slide 25: Chapter 29 25 Tropical Rain Forest
26. Slide 26: Tropical Chapter 29 26 Rain Forest Biome Temp 77-86 °F (25-30 °C) Rainfall 100-160 in (25-40 cm)/y Biodiversity: 50-67% of all Earth’s species 6% of land area • 40% now gone • losing 70 acres/min • > 25000 species go extinct annually Dominated by large, broadleaf, evergreen trees Vertically structured
27. Slide 27: Chapter 29 27 Tropical Deciduous Forest Further from equator Pronounced wet & dry seasons; deciduous trees
28. Slide 28: Chapter 29 28 Savanna
29. Slide 29: Chapter 29 29 The African Savanna Grasses dominate; scattered trees and thorn forests Short rainy season • <12 in. (30 cm) annually • Long, severe droughts African savanna with many large animals Many species in danger of extinction
30. Slide 30: Chapter 29 30 Deserts
31. Slide 31: Chapter 29 31 The Desert Biome Usually found between 20- 30° N & S latitude Less than 10 in. (25 cm) rain annually Plants often spaced very evenly Boom & bust population growth after rain Very fragile ecology
32. Slide 32: Chapter 29 32 Chaparral
33. Slide 33: Chapter 29 33 The Chaparral Biome Often in coastal regions bordering deserts Up to 30 in. rain annually, but all during cool months Summers hot & dry Small trees & large bushes
34. Slide 34: Chapter 29 34 Grasslands
35. Slide 35: Chapter 29 35 Grasslands 10-30 in. (25-75 cm) rain Shortgrass Prairie annually Usually in centers of continents No trees except along rivers • Periodic severe Sagebrush Desert or droughts Shortgrass Prairie • Frequent fires Most fertile soil in world Destroyed by overgrazing
36. Slide 36: Chapter 29 36 Temperate Deciduous Forests
37. Slide 37: The Temperate Deciduous Chapter 29 37 Forest Biome 30-60 in. (75-150 cm) rain annually, most during summer Mostly deciduous trees, bare in winter Leaf litter on soil High diversity of animals
38. Slide 38: Chapter 29 38 Temperate Rain Forest
39. Slide 39: The Temperate Rain Chapter 29 39 Forest Biome Abundant rain Soil seldom frozen Usually coastal
40. Slide 40: Chapter 29 40 Taiga
41. Slide 41: The Taiga (or Northern Chapter 29 41 Coniferous Forest) Biome Northern coniferous forests Northern Canada and Eurasia Winters long and cold Evergreen coniferous trees with needle-like leaves Plant & animal diversity low
42. Slide 42: Chapter 29 42 Tundra
43. Slide 43: Chapter 29 43 The Tundra Biome Treeless region bordering Pacific Ocean < 10 in. rain annually Permanently frozen soil (permafrost) Very fragile, scars last for centuries
44. Slide 44: Chapter 29 44 Survey of Aquatic Ecosystems 71% of Earth's surface Water moderates temperature Energy (top) and nutrients (bottom) affect life
45. Slide 45: Chapter 29 45 Freshwater Ecosystems Less than 1% of Earth's surface • Rivers, streams, ponds, lakes, marshes • Life zones: – based on access to lights/nutrients – vary by depth/clarity of water Human impact • Eutrophication – Accelerated via addition of nutrient wastes – Results in oxygen depletion • Acid rain – Creates appearance of oligotrophy – Almost sterile
46. Slide 46: Chapter 29 46 Lake Life Zones Littoral • Shallow • Well lit • Communities most Littoral Zone diverse Limnetic • Too deep for roots • Well lit, so supports Limnetic Zone phytoplankton Profundal • Too deep for Profundal Zone photosynthesis • Decomposers
47. Slide 47: Chapter 29 47 Marine ecosystems 70% of Earth's surface Bays, wetlands (salt marshes, estuaries), open ocean Coastal marine ecosystems • Support the most abundant life and • Commercially important (crabs, shrimp, fish, recreation, petroleum) Human impact • Wetland destruction equals rain forest destruction • Half of U.S. wetlands have been destroyed
48. Slide 48: Chapter 29 48 Ocean Life Zones Photic zone (photosynthesis) • Intertidal; Alternately covered • Near tidal; below low tide but shallow • Pelagic; open ocean to 200 ft Aphotic zone (no photosynthesis) • Below 200 ft • Supported by drift from photic zone Hydrothermal vents
49. Slide 49: Near-Shore Chapter 29 49 Ecosystems Estuaries: where rivers meet the ocean Kelp beds: in photic zone
50. Slide 50: Chapter 29 50 Coral Reefs & Open Ocean Coral Reefs: Bodies of corals & algae Many fish & invertebrates Delicate Open Ocean: Most life in photic zone Swim or float
51. Slide 51: Chapter 29 51 Hydrothermal Vent Communities Found where sea floor is spreading (>250 m deep) First discovered in 1977 Vents spew superheated, nutrient-rich water Chemosynthetic sulfur bacteria primary producers • One survives @ 248°F • Sulfur is oxidized for energy • Others eat the bacteria, etc. 248 new species and 22 new families
52. Slide 52: Chapter 29 The End