The Biosphere
Chapter 49
Mader: Biology 8th Ed.
Outline
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Climate and the Biosphere
– Global Wind Circulation
Terrestrial Communities
Aquatic Communities
– Life Zones
– Lakes
– Estuaries
– Seashores
– Oceans
Mader: Biology 8th Ed.
Climate and the Biosphere
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Climate refers to prevailing weather
conditions in a region.
– Dictated by temperature and precipitation.
 Influenced by a multitude of factors
including tilt of the earth’s axis and
topography.
Mader: Biology 8th Ed.
Effect of Solar Radiation
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Distribution of solar energy due to a
spherical planet and the rotation and path of
the Earth around the sun affect how the
wind blows and the amount of rainfall
various regions receive.
Mader: Biology 8th Ed.
Global Wind Circulation
Mader: Biology 8th Ed.
Rain Shadow
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As winds cross a coastal mountain range,
they rise and release their moisture on the
windward side of the mountain.
– Leeward side receives relatively little rain
and is said to lie in a rain shadow.
Mader: Biology 8th Ed.
Formation of a Rain Shadow
Mader: Biology 8th Ed.
Terrestrial Communities
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Biome has a particular mix of plants and
animals adapted to living under certain
environmental conditions.
– Often delineated by climate.
 Temperature and precipitation varies
according to latitude and altitude.
Mader: Biology 8th Ed.
Biome Distribution
Mader: Biology 8th Ed.
Climate and Biomes
Mader: Biology 8th Ed.
Tundra
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Arctic tundra encircles Earth just south of
ice-covered polar seas in Northern
Hemisphere.
– Covers 20% of Earth’s land surface.
 Trees are not found in the tundra
because growing season is too short.
 Roots cannot penetrate permafrost.
Mader: Biology 8th Ed.
Tundra
Mader: Biology 8th Ed.
Coniferous Forests
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Taiga typifies coniferous forest with conebearing trees.
– Trees well adapted to cold.
 Leaves and bark have thick covering.
 Needle-like leaves can withstand
weight of heavy snowfall.
Temperate Rainforest (Old-Growth Forests)
of Pacific Northwest.
– Evergreen forest.
Mader: Biology 8th Ed.
Temperate Deciduous Forests
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Found south of taiga in eastern North
America, eastern Asia, and much of Europe.
– Well defined season with long growing
seasons.
– Tallest trees form a canopy.
– Ground-life is plentiful.
Mader: Biology 8th Ed.
Temperate Deciduous Forest
Mader: Biology 8th Ed.
Tropical Forests
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Found in equatorial regions.
– Plentiful rainfall.
– Most animals live in trees.
 Abundant insect life.
– Epiphytes grow in many areas.
– Soils are nutrient-poor.
 Rapid recycling of nutrients.
– Swidden agriculture successful but
destructive.
Mader: Biology 8th Ed.
Shrublands
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Tend to occur along coasts that have dry
summers and receive most of their rainfall in
the winter.
– Shrubs adapted to withstand arid
conditions.
– Dense shrubland in California known as
chaparral.
Mader: Biology 8th Ed.
Grasslands
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Grasslands occur where annual rainfall is
greater than 25 cm, but generally insufficient
to support trees.
– Grasses well adapted to changing
environment.
– Temperate Grasslands
– Savannas
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Temperate Grassland
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Savanna
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Deserts
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Usually found at latitudes of about 30o in
both north and south hemispheres.
– Descending winds lack moisture.
 Annual rainfall less than 25 cm.
– Large temperature differential between
day and night.
Mader: Biology 8th Ed.
Deserts
Mader: Biology 8th Ed.
Aquatic Communities
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Lakes
– Bodies of water classified by their nutrient
status.
 Oligotrophic - Nutrient-poor.
 Eutrophic - Nutrient-rich.
– Lake Stratification
 In temperate zones, deep lakes are
stratified in the summer and winter.
Mader: Biology 8th Ed.
Mader: Biology 8th Ed.
Life Zones
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Plankton are important community
components in fresh water and salt water.
– Phytoplankton - Algae
– Zooplankton - Animals
Life Zones
– Littoral zone - Closest to shore.
– Limnetic zone - Sunlit areas.
– Profundal zone - Below light penetration.
– Benthic zone - Soil-Water interface.
Mader: Biology 8th Ed.
Zones of a Lake
Mader: Biology 8th Ed.
Coastal Communities
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Estuaries
– Partially enclosed bodies of water where
fresh water and seawater meet and mix.
 Organisms must be able to adapt to
changing salinity.
 Estimated over half of all marine
fishes develop in protective
environment of estuaries.
Mader: Biology 8th Ed.
Estuary Structure and Function
Mader: Biology 8th Ed.
Seashores
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Littoral zone lies between high and low
water marks.
– Littoral zone of rocky beach divided into
subzones.
– Organisms cannot attach to shifting,
unstable sands; therefore nearly all
permanent residents dwell underground.
Mader: Biology 8th Ed.
Seacoasts
Mader: Biology 8th Ed.
Oceans
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Major ocean currents move heat from the
equator to cooler parts of the biosphere.
– Gulf Stream warms east coast of North
America and parts of Europe.
– El Nino Southern Oscillation
 Cold upwelling off west coast of South
America subsides.
Mader: Biology 8th Ed.
Ocean Currents
Mader: Biology 8th Ed.
Oceans
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Pelagic Division
– Neritic Province
 High concentration of organisms due to
sunlight penetration and supply of
inorganic nutrients.
 Coral Reefs
 Oceanic Province
 Lacks inorganic nutrients and thus
does not have high concentration of
phytoplankton.
Mader: Biology 8th Ed.
Mader: Biology 8th Ed.
Oceans
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Benthic Division
– Includes organisms that live on or in the:
 Continental Shelf (sublittoral zone)
 Continental Slope (bathyal zone)
 Abyssal Plain (Abyssal zone)
 Interrupted by hydrothermal vents.
– Organisms are dependent on debris
floating down from above.
Mader: Biology 8th Ed.
Review
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Climate and the Biosphere
– Global Wind Circulation
Terrestrial Communities
Aquatic Communities
– Life Zones
– Lakes
– Estuaries
– Seashores
– Oceans
Mader: Biology 8th Ed.
Mader: Biology 8th Ed.