Unit 4: Terrestrial ecosystems and resources

Transcription

1 Unit 4: Terrestrial ecosystems and resources Chapter 5: Climate and terrestrial biodiversity > Climate > Terrestrial Ecosystems Chapter 10: Sustaining biodiversity (ecosystem approach) Chapter 11: Sustaining biodiversity (species approach)

2 What patterns do you see? What affects the distribution of various climates? Blue = tropical Red/Orange = dry Green = temperate (moist, mild winters) Purple/blue green = continental (moist, severe winters) Grey = polar

3 Climate and Weather Climate: region's long-term weather patterns. Weather: short term atmospheric conditions (temperature, precipitation, humidity, wind speed and direction, cloud cover, pressure). 2 main factors characterizes different climates: average temperature and average precipitation

4 Climate and Weather What causes different climates? 1. Latitude (distance from equator) 2. Earth's tilt 3. Global air circulation: Coriolis effect (caused by earth's rotation), atmospheric cells, and prevailing winds. 4. Ocean currents 5. Proximity to water 6. Topography (Mountains) 7. Elevation (height above sea level)

5 1. Latitude Latitude: Distance from the equator > Uneven heating of earth's surface by the sun Cold Intermediate temperatures Hot Intermediate temperatures Cold John Fuller: Boise State University

6 2. Tilt of Earth's Axis Seasons (tilt of earth's axis)

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8 3. Global air circulation Uneven heating of earth --> Convection Rotation of earth on axis --> Coriolis effects > Northern Hemisphere: Deflected to right. > Southern Hemisphere: Deflected to left. Convection + Coriolis effects = Global wind patterns that distribute heat and moisture (prevailing winds)

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10 Global air circulation: Convection Convection: distribution of heat by the movement of masses of fluids (liquid or gas)

11 Global air circulation: Convection Uneven heating of earth's surface results in three convection cells. Hadley cell-explains distribution of tropical rain forests and deserts > Air rises at the equator (most sun) Air rising = low pressure > As air rises and cools, water condenses and precipitates (rains a lot over the equator) > Air gets "pushed" north and south from the equator > Cool air falls, is compressed, and warms. Air falling = high pressure > Warm dry air over land = low precipitation, takes moisture from surface --> Deserts!

12 Hadley cell-explains distribution of tropical rain forests and deserts Air rises at the equator (most sun) Air rising = low pressure As air rises and cools, water condenses and precipitates (rains a lot over the equator) Air gets "pushed" north and south from the equator Cool air falls, is compressed, and warms. Air falling = high pressure Warm dry air over land = low precipitation, takes moisture from surface --> Deserts! *Air moves from high to low pressure

13 Global air circulation: Coriolis effect Coriolis effect: deflection of moving air masses as a result of the rotation of earth > Northern Hemisphere: Deflected to right. > Southern Hemisphere: Deflected to left.

14 Global Air Circulation Convection + Coriolis effects = Global wind patterns that distribute heat and moisture (prevailing winds) polar easterlies prevailing westerlies trade winds *Winds are named by their origin

15 4. Ocean Currents Ocean currents distribute heat and nutrients > Redistributes heat from uneven heating of the sun. Factors that determine currents: > Oceans absorb heat from the air (especially in tropic regions) and create density differences > Location of continents > Winds > Earth's rotation (Coriolis effect) Clockwise in northern hemisphere Counterclockwise in southern hemisphere

16 Ocean Currents Surface currents > Wind is main force > Coriolis > Land forms Deep-sea currents > Thermohaline circulation

17 5. Proximity to water Heat is absorbed and released more slowly by water than by land* Bodies of water moderate climate. Sea breeze Land breeze

18 6. Topography (mountains) Mountains interrupt the flow of prevailing surface winds. Windward side: Air is forced up the mountain. Air expands, cools, and loses moisture as rain and snow. Leeward side: Air flows down mountain. Air sinks, contracts, heats up, and the dry air mass draws moisture out of plants and soil below. *Rain shadow effect

19 7. Elevation Parallel changes in vegetation type occur when we travel from the equator to the poles, or from lowlands to mountaintops. You can find extremely cold climates near the equator at high altitudes (Ex: Andes mountains)

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21 Other factors Monsoons: continents near warm oceans experience heavy rains called monsoons. Intense heating of land during summer creates low pressure air masses -> draws moisture from ocean -> leads to heavy rainfall. Microclimates > Concrete/asphalt absorb and hold more heat. Human impact (vehicles, appliance use) release lots of heat and pollutants. > Results in higher temperatures, lower wind speeds (buildings block winds) Greenhouse effect

22 November 07, 2014 Biomes The distribution of organisms is determined largely by climate. Different climates support different communities of organisms.

23 Biomes Biomes are large terrestrial regions characterized by similar climate, soil, plants, and animals. Biomes are not uniform. Just a general characterization of an area. List of biomes: 1. Desert (Tropical, temperate, cold) 2. Grasslands > Tropical grasslands (savannas) > Temperate grasslands > Polar grasslands (tundra) > Chapparral 3. Forests > Tropical rain forest > Temperate deciduous forests > Evergreen coniferous forests > Temperate rain forest 4. Mountain biomes 5. Polar Ice

24 Desert Evaporation > Precipitation 30% land surface Interior of continents, rain shadow Hot day, cold night

25 Desert Tropical desert: Hot, dry. Few plants. Rocks and sand Temperate desert: High temperature in summer, low in winter. More precipitation. Drought resistant shrubs and cacti/succulents. Cold desert: Cold winters, low precipitation, sparse vegetation

26 Desert Organisms: beat the heat, every drop of water counts > Plants (stomata, water storage, leaves, root systems, life cycle) > Animals (small, burrow, thick skin, dry feces/urine) > Fragile ecosystems Slow plant growth (LF=water) Low species diversity Low nutrient cycling (low bacterial activity

27 Grasslands and Chaparral Interiors of continents too moist for deserts, too dry for forests Characteristics: > seasonal drought > grazing > occasional fires > low average precipitation > range in average temperatures Three types: Tropical Temperate Polar

28 Grasslands Tropical Grasslands/Savannas Warm temp year-round alternating dry/wet seasons Drought + grazing + fire inhibit growth of trees/bushes Animals: farsighted, fast, stealthy. > Grazing and browsing hoofed animals > Migration to seasonal watering holes > Specialized eating Plants: survive drought Human impact: rangeland, overgrazing, trees for firewood --> desert

29 Grasslands Temperate grasslands Cold winter, hot dry summer Sparse precipitation Drought + fire + grazing + winds prevent trees and bushes Fertile soil due to decomposition of grasses + root systems Tall v. short grass Human impact: raise crops, raise cattle, build towns/ cities

30 Grasslands Polar grasslands/arctic tundra ("marshy plain") Low precipitation, mostly snow Grasses, mosses, lichen, dwarf shrubs --> spongy mat Growth in "summer" 6-8 weeks (fragile biome) Permafrost: frozen soil > Prevents melted snow/ice from soaking into ground and forms seasonal wetlands, lakes, marshes, bogs, ponds Organisms: insects, migratory birds, *need to survive cold Human impact: oil drilling, mines, military bases

31 Chaparral Borders deserts, coastal Longer, rainy winters, foggy Vegetation: low-growing evergreen shrubs, small trees, leaves that reduce evaporation Dry summers lead to fires! > Seeds sprout > Release nutrients

32 November 07, 2014 Forest Biomes Lots of precipitation to support trees Forest = trees + other vegetation 3 types > Tropical > Temperate > Boreal (polar)

33 Forest Tropical rain forest Extremely diverse ecosystem Plants: broadleaf evergreen, huge trees (buttresses), dense canopy, vines *NPP

34 Forest Tropical rain forest Stratification of specialized plants and animal niches > Plants at bottom have little sunlight--huge leaves Lots of resources = lots of specialized species Adaptation for pollination (no wind) Acidic, low nutrient soil--nutrients stored in biomass (quick recycling), not soil. Human impact: logging, crops, grazing, minerals Tropical dry forest

35 Tropical grassland v. Tropical forest Think Lion King

36 Forest Temperate deciduous forests moderate average temperature, change with seasons long warm summer, cold winters, abundant precipitation vegetation: broadleaf deciduous trees, more plant life at ground level, leaf litter animals: predators, deer, small mammals Human impact: fragmentation or loss of habitats, industrialization and urbanization *most disturbed

37 Forest Evergreen coniferous forests (boreal, taigas) Subarctic: long dry, cold winters, short cool summers, large variation in sunlight Vegetation: coniferous evergreen trees (needle-shaped, waxy leaves, low diversity, grow fast in summer Acidic, low nutrient soil Animals: bears, wolves, moose, lynx, many burrowing rodent species Muskegs (acidic bogs)

38 Forest Temperate rain forest (coastal coniferous forest) Rain and moisture from ocean fog Moderate temperatures Evergreens, ferns, mosses

39 Mountain Biomes Dramatic changes in altitude, climate, soil, and vegetation Erosion (slopes) when vegetation removed by natural disturbance or human Islands of biodiversity > Forests, endemic species, sanctuaries for animals (people tend to not build on mountains) Regulate climate: glacial ice (freshwater), ice/snow reflect solar radiation, gradually release melting ice, snow, and water

40 Human Impact Humans use, waste, or destroy 10-55% of NPP

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