Mader: Biology 8 th Ed. The Biosphere Chapter 49

Mader: Biology 8th Ed.

The Biosphere

Chapter 49


Outline

• Climate and the Biosphere– Global Wind Circulation

• Terrestrial Communities• Aquatic Communities

– Life Zones– Lakes– Estuaries– Seashores– Oceans


Climate and the Biosphere

• 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.


Effect of Solar Radiation

• 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.


Global Wind Circulation


Rain Shadow

• 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.


Formation of a Rain Shadow


Terrestrial Communities

• 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.


Biome Distribution


Climate and Biomes


Tundra

• 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.


Tundra


Coniferous Forests

• Taiga typifies coniferous forest with cone-bearing 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.


Temperate Deciduous Forests

• 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.


Temperate Deciduous Forest


Tropical Forests

• 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.


Shrublands

• 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.


Grasslands

• 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


Temperate Grassland


Savanna


Deserts

• 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.


Deserts


Aquatic Communities

• Lakes– Bodies of water classified by their nutrient

status.Oligotrophic - Nutrient-poor.Eutrophic - Nutrient-rich.

– Lake StratificationIn temperate zones, deep lakes are

stratified in the summer and winter.



Life Zones

• 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.


Zones of a Lake


Coastal Communities

• 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.


Estuary Structure and Function


Seashores

• 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.


Seacoasts


Oceans

• 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.


Ocean Currents


Oceans

• Pelagic Division– Neritic Province

High concentration of organisms due to sunlight penetration and supply of inorganic nutrients.

Coral ReefsOceanic Province

Lacks inorganic nutrients and thus does not have high concentration of phytoplankton.



Oceans

• 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.


Review

• Climate and the Biosphere– Global Wind Circulation

• Terrestrial Communities• Aquatic Communities

– Life Zones– Lakes– Estuaries– Seashores– Oceans


Documents

Mader: Biology 8 th Ed. The Biosphere Chapter 49