Chap5

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Chap 5 : Climate and Terrestrial biodiversity Objectives: 1. What factors determine the earth’s weather and climate. 2. How climate determines the earth’s biomes. 3. Earth’s major biomes and how humans affect them: a) Deserts b) Grasslands c) Forests d) Mountain and artic Assignment: Read Case Study: Blowing in the wind. Weather: The short-term properties of the troposphere at a particular place and time.

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Climate: The long-term pattern of weather conditions. Two main factors determine a climate: a) Average temperature. b) Average precipitation. See Figure 5-10 to understand this. See figure 5-2 for major climatic zones

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Temperature and precipitation patterns are primarily caused by the way air circulates over the earth’s surface. Global air circulation patterns are determined by: a) Uneven heating of the earth’s surface. - Equator receives more solar energy per unit of area. - Moving away from equator, angle of sun rays increases and this causes a reduction on the amount of solar energy per unit of area. b) Axis of the earth is tilted together with revolution around the sun caused differences in heating. (see Figure 5-3) c) Rotation of the earth on its axis. This causes air masses: - Move to the right on the northern hemisphere. - Move to the left on the southern hemisphere. These two movements create 6 huge convection cells (see figures 5-5, 5-5, and 5-6). Cold area = High pressure =======? Hot area = low pressure air moves

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Ocean currents are created by: a) air circulation, b) differences in water temperature, and c) earth’s rotation. Ocean currents influence climate. - Give an example of the effect of an ocean current on climate. Greenhouse gases play a key role in determining earth’s average temperatures. They are: a) water vapor, b) carbon dioxide (CO2), c) methane, d) nitrous oxide, and e) synthetic chlorofluorocarbons (CFC’s). What is the role of the ozone layer on determining climates. What is the role of topography in creating microclimates. Explain figure 5-8. Mention the effect of the raise of the Himalayas. Mention recent studies on how climate has influence history. Pilgrims first disastrous landing in the USA due to drought. Climate change and the move of the Avers from Mongolia to Europe. At the same time disappearance of large civilizations in America Teotihuacan.

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BIOMES Different associations of plants, micro and macro organisms (Biomes) Different climates Different average temperature and precipitation Global air circulation Latitude, altitude, ocean currents

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See figure 5-9 for major earth’s biomes. Why are plants and animals in each biome different? - Because of evolutionary responses to different climates. We will talk about the following major biomes: 1. Deserts a) Tropical deserts b) Temperate deserts c) Cold deserts 2. Grasslands a) Tropical grasslands and savannas. b) Temperate grasslands. c) Polar grasslands or artic tundra, and alpine tundra 3. Chaparral or temperate shrub-land

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4. Forest a) Tropical rain forests. b) Tropical deciduous forests c) Temperate deciduous forests d) Evergreen coniferous forests or boreal forests e) Temperate rain forests 5. Mountain and alpine. For each of these biomes remember: 1. Key characteristics. 2. How humans impact them. 3. You should be able to tell what kind of biome it is just by looking at a map of its distribution. For example, deserts, boreal forests, etc…

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DESERTS - Is an area where evaporation exceeds precipitation. Cover about 30% of the earth’s surface. Found about 30° north and 30 ° south of the equator Distribution of deserts see figure 6-16. Tropical desert Temperatures are high year round Little precipitation concentrated on 1-2 months. Sahara desert

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Temperate deserts a) Daytime temperatures high in summer and low in winter. b) More rain than in tropical deserts. Mojave desert, CA Grand canyon Nevada and Utah deserts.

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3. Cold desert a) Summers are hot, winters are cold b) Precipitation is low Gobi desert, China What are some major human impacts on deserts?

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GRASSLANDS Regions with enough precipitation to allow grasses to prosper, but precipitation is erratic and periods of drought and fires prevent large stands of trees to grow. Tropical grasslands and savanna High average temperatures. Low to moderate precipitation Prolonged dry season. Large migrations due to dry season Large herds of herbivores Extensive killing of rare species What are some major human impacts on grasslands?

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2. Temperate grasslands a) Winters are extremely cold. b) Summers are hot and dry. c) Annual precipitation is sparse and falls unevenly through out the year. - Found in: a) plain and rolling hills of interior North and South America (pampas), b) Steppes of central Europe and Asia.

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3. Polar grasslands or artic tundra a) Treeless plains. b) Extremely cold. c) Swept by frigid winds. d) Covered with ice and snow.

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FORESTS Areas with moderate to high precipitation with no disturbances. What are some major human impacts on world’s forests? Tropical rain forest a) Warm annual mean annual temperature. b) High humidity. c) Heavy rainfall almost daily.

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2. Tropical deciduous forests a) Warm year round b) Clear dry and rainy seasons. c) Trees loose their leaves during the dry season. d) Trees are shorter than the Tropical rain forest.

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3. Temperate deciduous forests. a) Long warm summers. b) Cold winters. c) Abundant precipitation spread evenly throughout the year. Broadleaf deciduous trees such as oak, hickory, maple, poplar and sycamore.

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4. Evergreen coniferous forests or boreal forests or taigas a) Found just south of the artic tundra in America, Europe and Asia.

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5. Temperate rain forest (coastal coniferous forests). a) Found in scattered coastal temperate areas with ample rainfall and dense ocean fogs. Mostly coast of USA and Canada b) Typical species include: Douglas fir, redwoods.

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MOUNTAIN BIOMES They cover 20% of the land surface. Many mountains or group of mountains are islands of biodiversity. Example, mountain tops “islands in the sky” along the SW deserts in the USA. The majority of forest in the world are in mountains. Antarctica is the most mountainous of all continents. What are some major human impacts on the world’s mountains?