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Biomes Chapter 4
Biomes • Large terrestrial regions with similar climate: • Autotrophs? • Heterotrophs?
Human Use of Biomes • Warm Temp.; Abundant rain • Allows for: • Warm Temp.; Less rain • Allows for: • Colder Temp • Allows for:
Latitude and Elevation Elevation Mountain ice and snow Tundra (herbs, lichens, mosses) Coniferous Forest Deciduous Forest Latitude Tropical Forest Tundra Tropical Forest Deciduous Forest Polar ice and snow Coniferous Forest Latitude is distance from equator. Elevation is altitude. Fig. 7-9, p. 147
Three Types of Deserts • Deserts in general: • Tropical deserts • Hot and dry most of the year. • Mostly sand • Lots of dust storms • Temperate deserts • Hot daytime temperature; Low temps at night. • More precipitation than tropical deserts. • Cold deserts • Bitter cold winters and warmer summers • Little precipitation – in form of snow
30C=86F 20C=68F 10C=50F 0C=32F -10C=14F -20C=-4F -30C=-22F -40C=-40F Stepped Art Fig. 7-11, p. 149
What Are The Plant Adaptations For The Desert? The stem stores all of its water keeping the plant alive until the next rain. The stem is green - Photosynthesis occurs here. Many cacti have thorns to keep them safe from many animal predators. Cactus The white hairy surface reflects some of the sun’s heat. Old Man Cactus Transpiration occurs in stomata of the leaves. Desert plant leaves have few stomata and they open only at night. The waxy surface of the aloe plant acts like a plastic wrapper, keeping precious water inside.
Animal Adaptations in Desert • Humps contain fat which releases water when burned for energy. • Temperature changes from 96˚F to 106˚F. • Noses trap water vapor. • Thick coat reflects light. • Long legs keep body away from hot sand. • Kidneys and intestines retain water – urine like syrup and feces so dry they fuel fires.
Grasslands • Mostly in interior continents. • More moist than desert and drier than forest. • Seasonal drought - Leads to fires. • Tropical Grasslands – Savannas • Autotrophs: • Herbivores: • Resource Partitioning
Temperate Grasslands - Prairies • Bitter cold winters, hot summers. • Autotrophs: • Hetertrophs:
Cold Grasslands - Tundra • Frigid winds, ice, snow – permafrost • Little precipitation • Autotrophs • Heterotrophs
30C=86F 20C=68F 10C=50F 0C=32F -10C=14F -20C=-4F -30C=-22F -40C=-40F Fig. 7-12, p. 151
Anthropogenic Effects • Tundra • Global warming causing the permafrost to melt in some areas. • Prairies • Cultivation for crops removes the tangled network of roots and the topsoil is subject to severe wind erosion. • Savannas • Habitat loss due to increase in population.
Temperate Shrubland • Chaparral • Costal areas bordering on the deserts. • More rainfall due to closeness to the sea. • Near the sea: nice climate: fires and mud slides • Plants • Low growing evergreen shrubs, small trees. • Soil thin and not very fertile. • Prone to fires in the dry season • Chaparral is maintained by fires. • Vegetation has fire resistant roots and seeds that sprout only after a hot fire.
Chaparral Fig. 7-14, p. 152
Three Major Types of Forests • Dominated by trees • Tropical • Temperate • Cold.
Tropical Rain Forest • Broadleaf evergreen plants. • Keep leaves year round. • Incredible biodiversity 50% of plant and animal species. • Much species richness not species evenness. • Many plants used for medicines.
Epiphytes • Epiphytes are plants that live on the surface of other plants, especially the trunk and branches. • They grow on trees to take advantage of the sunlight in the canopy. • Most are orchids, bromeliads, and ferns.
Temperate Forest • Long warm summers; cold but not severe winters. • Broadleaf deciduous trees drop their leaves in winter and become dormant. • Leaves form layer of decaying leaf litter which stores nutrients in soil. • Much of these areas have been cleared for crops and urban areas. • Most large mammals have lost their habitats. • Deer, small mammals, birds.
Evergreen Forest • Called the Tiaga, Boreal Forest • Long very cold winters; short summers cool to warm • Coniferous trees – cone bearing • Needles instead of leaves. • Needles are wax covered and hang down. • Decomposition slow due to cold temperatures and waxy covering of needles.
Anthropogenic Effects • Deforestation – for the purpose of crops BUT: • Decomposition very fast due: decomposers. • Soil is nutrient poor. • Even though the trees are tall they do not have extensive roots but rather buttresses for support.
Mountains • Steep high lands covering ¼ of earth’s surface. • 18% of population live on mountain ranges or edges. • 59% people depend on mountains for water. • Soil is easily eroded by natural or man-made disasters including mining.
Ecological Role of Mountains • Contain the majority of the world’s forests. • Habitats for endemic species. • Help regulate the earth’s climate. • Ice and snow high albedo. • Melting of glaciers exposes dark rocks that absorb heat. • Can affect sea levels – melting glaciers. • Major storehouses of water • Role in hydrologic cycle