The Biosphere: Earth

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The Biosphere Earths Diverse Environment

• Chapter 34

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• Ecology the study of the interactions of
  organisms with their environments.
• Biosphere extends from the atmosphere to the
  depths of the ocean.
• Biomes major types of ecological associations
  that occupy broad geographic regions of land or
  water.

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8 major terrestrial biomes

• Distinguished by
• vegetation
• temperature
• rainfall
• biological community

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Tropical forests

• Temperature warm to high
• Rainfall varied - heavy
• Plants thorny shrubs, deciduous trees,
  succulents. (very diverse)
• Sunlight little reaches the forest floor.
• Habitats floor gt canopy.
• Poor soil, due to high temp heavy rains
  (leaching).
• Animals monkeys, birds, snakes, bats, frogs
  tree dwelling.

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Savannas

• Temperature warm year round
• Rainfall moderate rainfall (with long periods of
  drought) BIOME DEFINED MAINLY BY THIS
• Plants grasses scattered trees.
• growing point below ground resistance to
  periods of drought.
• Habitats migratory
• Poor soil, lack of moisture, grazing animals,
  fires inhibit most trees.
• Animals large grazing mammals, insects,
  burrowing animals, predators (lions cheetahs).

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Deserts

• Temperature very hot,
• and cold (Antarctica)
• Rainfall dry
• Plants none, deep rooted shrubs, succulents.
• waxy coating to prevent water loss
• many seeds that remain dormant until it rains
• Sunlight extreme
• Habitats burrows, active at night
• Animals ants, birds, rodents, lizards, snakes,
  hawks.

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Chaparral

• Temperature mild winter, hot summer
• Rainfall rain in winter, dry in summer
• Plants dense shrubs with tough evergreen leaves.
  Seasonal plants.
• Food reserves in roots allow for rapid growth
  after frequent fires.
• Seeds only germinate
• after hot fire.
• Animals deer, birds, rodents,
• lizards snakes

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Temperate grasslands (prairies)

• Temperature relatively cold
• Rainfall rain, but periodic severe droughts
• Plants grass, mostly treeless
• fire grazing prevents tree growth
• Habitats bird nests on ground, burrows.
• Animals large grazing mammals (bison, wild
  horses).
• Soil supports diverse microorganisms small
  animals.
• One of the most productive agricultural regions
  in the world

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Temperate (Deciduous) forests

• Temperature cold winter, hot summer
• Rainfall high precipitation
• Plants deciduous trees (oak, hickory, maple)
• Habitats rich soil, leaf litter, burrow
• Animals invertebrates, mice, shrew, squirrels,
  birds, bobcats, foxes, bears, mountain lions.
• Most destroyed by loggers urban development.

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Taiga (Coniferous forests)

• Temperature long cold winters, short wet summers
• Rainfall considerable precipitation (snow)
• Plants cone bearing evergreens
• (spruce, pine, fur)
• Habitats soil thin acidic
• Animals moose, elk, bears,
• wolves, hares, migratory birds.
• Heavily logged.
• Largest terrestrial biome!

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Tundra

• Temperature extremely cold
• Rainfall little
• Plants no trees, shrubs, grasses, mosses, and
  lichens.
• Permafrost prevents deep root penetration
• Sunlight little light for much of the winter,
  constant daylight in summer
• Habitats migratory (summer is a breeding
  ground), high altitude, permafrost, soil
  continually saturated due to poor drainage and
  slow evaporation.
• Animals well insulated (oxen caribou),
  lemmings, fox, snowy owl.
• During the summer, clouds of
• mosquitoes fill the air due to the
• marshy ground.

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Aquatic Biomes

• Oceans cover about 75 of the Earths surface
• Light and the availability of nutrients are the
  major factors that shape aquatic communities.

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• photic zone is the portion of the ocean into
  which light penetrates.
• continental shelf where coral reefs are found in
  warm tropical waters.
• The pelagic zone is the open ocean
• aphotic zone is a vast, dark region of the ocean.
• benthic zone is the
• ocean bottom

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• The pelagic zone is the open ocean

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• Estuaries are productive areas where rivers meet
  the ocean.
• They are often bordered by wetlands
• The intertidal zone is the wetland at the edge of
  an estuary or ocean, where water meets land

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• Freshwater biomes include lakes, ponds, rivers,
  streams, and wetlands

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Review Questions

• Describe the chemical and physical factors that
  affect the biosphere
• Discuss the role of abiotic and biotic factors in
  the survival of an organism
• Describe the characteristics of aquatic biomes
• Explain the factors contributing to the
  characteristics of terrestrial biomes
• Describe the eight major terrestrial biomes