The Biosphere

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CHAPTER 55

• The Biosphere

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THE BIOSPHERE

• Biosphere the part of the earth in which life
  exists.
• Only a thin layer, 8-10 kilometers above sea
  level and a few meters down into the soil, that
  is as far as roots penetrate and microorganisms
  are found.

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LIFE IN WATERS

• Rivers and Streams
• Continuously moving fresh water.
• Life is determined by the swiftness of the stream
  as it moves downward from its source. Getting fed
  by tributaries increases the volume and decreases
  the speed.
• In swift streams, organisms live in the riffles
  (shallows), where small photosynthetic algae and
  mosses cling to rock surfaces. Also all forms of
  insects live on the underside of rocks and gravel
  in the riffles. Abundance of oxygen and nutrients
  swept thru the flowing waters.
• Riffles are interrupted by quieter pools where
  organic matter can collect and decompose. Few
  plants can live in stream pools but some
  invertabrates such as dragonflies and water
  striders are found here. Trout are known to move
  back and forth between riffles and the pools.

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ture/river.jpg
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LIFE IN WATERS

• Lakes and Ponds
• Body of standing water in various sizes
• Consists of 3 zones littoral, limnetic, and
  profundal
• Littoral zone edege of lake, most richly
  inhabited.
• Angiosperms rooted to the bottom (cattails and
  rushes). Water lilies grow farther out, then a
  free-floating layer of angiosperms
• Angiosperm layer home to various types of
  organisms such as clam, worms, water snakes,
  various insect larvae, water turtles, ducks,
  geese, muskrats and many other animals.
• Limnetic zone open water. Dominant
  photosynthetic organisms phytoplankton. Extends
  down to the limits of light pentration. Habitat
  to fish such as bass, bluegill and trout
• Profundal zone below the limnetic zone. No plant
  life. Detritivores consume organic debris from
  the limnetic zone. Detritivores waste
  recirculates to the upper levels during the over
  turn of water.

http//www.scit.wlv.ac.uk/jphb/canada/pictures/la
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LIFE IN WATERS

• The Oceans
• Cover ¾ of earths surface. Life found in even
  the deepest zones.
• 2 main divisions of open-ocean life pelagic(free
  floating) and benthic(bottom dwelling).
• Major component of pelagic is plankton.Plankton
  algae, heterotrophic protists, small shrimp,
  gelatinous invertebrates and larval form of fish.
• Benthic division contains sessile
  animals(sponges, sea anemones, clams) and motile
  animals(worms, sea stars, snails, crustaceans,
  and fish). Some bacteria and fungi also inhabit
  this zone. Most organisms eat the debris drifting
  down.
• Ocean not as productive as land in terms of
  carbon turned to usable compounds. Per square
  meter is only slightly more productive than
  desert. B/c of low conc. of mineral nutrients in
  areas where light penetrates and photosynthetic
  organisms can survive.
• Ocean currents affected by winds and earths
  rotation, currents affect climates of the coasts.
  N. hemisphere circulation is clockwise. S.
  hemisphere circulation is counterclockwise.
  Example of current is Gulf Stream.
• Upwelling brings cold, nutrient rich water up to
  the surface. These areas contain high densities
  of pelagic life and traditionally support highly
  profitable fishing industries.

http//hjs.geol.uib.no/marinemicro/maps/0-0-1-map-
currents.jpg
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LIFE IN THE WATERS

• The Seashore
• Edges of continents extend 10-20km out, known as
  continental shelves. Dense life b/c of nutrients
  washed from land.
• High primary productivity.Temperate coasts
  primary producers of brown algae. Coral reefs
  also productive in tropical zones.
• Sessile sponges and anemones as well as molusks,
  crustaceans, echinoderms, snails and worms
  habitat the ocean bottoms.
• Seashores sea and and land join

http//www.stanford.edu/ghoe/pics/SpringBreak_web
/Seashore.JPG
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LIFE IN THE WATERS

• The Seashore cont.
• Temperate zones are either rocky, sandy or muddy.
• Rocky coast animals live in the riffles and
  develop ways to hold to rocks. Also have to deal
  with rising and falling tide.
• Supertidal zone, wetted by spray from waves. Dark
  algae and lichen
• Intertidal zone submerged and exposed dependant
  on tides. Brown and red algaes as well as many
  bivalves inhabit this zone.
• Subtidal zone always submerged, kelp forests.
• Zonation due to gradients of light, temp., and
  wave action.
• Sandy beaches fewer organisms b/c of shifting
  sands. Mainly crustaceans live in surface sand
  and beach grasses stabilize sand dunes with
  underground stems.
• Mud flats, salt marshes and estuaries (fresh and
  salt waters mix) spawning ground for marine life.
  Extremely rich in animal life. Protection of
  theses lands is vital b/c of their role in
  nurturing life in the oceans.

http//home.earthlink.net/huskertomkat/zones1.jpg
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LIFE ON THE LAND

• Temp. and precipitation affected by angle of
  earths axis in relation to its orbit around the
  sun. Structure of continents also affects.
• Continents made mostly of light igneous rock
  molten material. Surfaces altered by movements of
  continental plates. Mountain ranges determine
  rainfall patterns.
• Avg. atmospheric temp. decreases about 0.5C for
  each increase in latitude, also each 100m inc. in
  elevation results in a decrease of 0.5C.
• High-latitude and High-altitude environments vary
  greatly.
• Most water vapor in atmosphere which prevents
  heat from leaving earth at night occrus below
  2,000m.

http//www.geo.cornell.edu/ses/earth.jpg
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The Concept of the Biome

• Biomes Divisions of earth surface are
  distinguished by types of dominant plants.Ex.
  Deserts, grasslands, and deciduous forests.
• The same type of biomes on opposite sides of the
  planet appear simliar.
• Not an actual place but a geographic region.
• Where climate is the same the organisms are very
  similar. Simliar biomes provide source of
  convergent evolution.

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rk-grassland.jpg
http//hcs.osu.edu/hcs200d/syllabus/graphics/biome
.jpg
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Temperate Forests

• Temperate deciduous forests warm, mild growing
  season with moderate precipitation. Decidious
  leaf-shedding.
• Soils poor in nutrients cannot support decidious
  forests
• 4 layers of plant growth in deciduous woodlands
• Tree layer, canopy(top) 10-35 meters high usually
  only has 1 or 2 dominant species of trees. The
  prescence of other trees is due to a disturbance,
  fire, wind storm, or cutting.
• Shrub layer, 5 meters. Shrubs resemble trees
  woody and deciduous but branch close to the
  ground
• Field layer, grasses and herbaceous plants,
  including annual flowering plants that bloom in
  spring. Also brachen and ferns with large leaves
  found in field layer
• Ground layer, mosses and liverworts often covered
  with dead leaves.
• Support many small animals such as chipmunks,
  voles, squirrels, raccoons. The larger predators
  that havent been driven out include wolves,
  bobcats, foxes, and moutain lions. Deer live on
  forest borders and feed on shrubs and seedlings.
• Topsoil is rich in organic matter. Myriad
  passageways left by dead roots, fungi and
  earthworms and other animals of the forest make
  the soil a sponge that holds water and nutrients.
  

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Coniferous Forests

• Conifers are evergreens, with needle-shaped
  leaves which are to prevent against water loss.
• Unable to compete w/ deciduous in temperate
  zones.
• Types of coniferous forests are northern
  coniferous forests(taiga), alpine forests, and
  mixed west coast forests.

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es/ecosystems/coniferous.jpg
http//www.pfc.forestry.ca/canforest/images/cwf21.
jpg
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The Taiga
http//www.cs.rice.edu/ssiyer/cam/Banff/.small/Co
nifers20in20the20Taiga..jpg

• Deciduous unable to grow well b/c of shortened
  growing season
• Northern coniferous forests long severe winters
  constant cover of winter snow.
• Ground layer needles, dead twigs and fungal
  mycelia. Few annual plants. Not as many
  invertebrates and litter decomposes slower.
• Elk, moose, deer, black bears, grizzlies are
  leading large animals
• Small animals use dense growths for breeding and
  shelter

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The Pacific Northwest

• Massive evergreen conifers adapted to a wet
  winter/ dry summer environment.
• Deciduous trees along streams.
• Conifers photosynthesize year round
• Able to store water nutrients to use during dry
  season.
• Thick bark and high crowns protect from fires of
  region.
• The forests that evaded the Pleistocene
  glaciation are most ancient individual and
  population of trees in N. America

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The Tundra
http//www.nhptv.org/natureworks/graphics/ox.jpg
http//www.nhptv.org/natureworks/graphics/tundra2.
jpg

• Tundra winter too cold and long for conifers
• Arctic Tundra form of grassland covers 1/10 of
  earths surface
• Similar vegetation found above tree line
  mountainous regions.
• Permafrost layer of permanently frozen subsoil
• Summer ground thaws a few cm deep wet and soggy
• Freezethaw process destroys roots. Keeps plants
  small
• Strong winds also help keep herbaceous plants and
  the flower perennials small.
• Ground layer of mosses and lichens. Ex. Reindeer
  Moss.
• Musk Oxen CaribouNew world. Reindeer Old
  world
• Lemmings, Ptarmigans, white fox, and snowy owl.
• During brief summer insects emerge, migratory
  birds come to eat insects and feed young.
• Growing season often less than 2 months.

http//cgdi.gc.ca/ccatlas/ghaven/physgeog/vegpage/
tundra.jpg
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Temperate Grasslands

• Grasslands transitional areas between temperate
  forests and deserts. Found interior of continents
• Rolling, flat land, hot-cold seasons, droughts
  and fires.
• Bunch grasses, legumes and annuals.
• Short-grassesgreat plains b/c of rainshadow of
  rockies.
• Tall grasses corn belt next to the eastern
  deciduous forests
• Small seed eating animals and large herbivores
• Large herbivores support carnivores lions,
  tigers, wolves and humans(omnivores)

http//www.manishin.com/photos/best_photos/Images/
great_plains.jpg
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Tropical Grasslands Savannas

• Savannas tropical grasslands w/ scattered clumps
  of trees
• Transition open forest to savanna is gradual.
  Determined by severity of dry season, fire, and
  grazing of animals
• Competition for plants is for water and grasses
  are best suited for sandy soil and seasonal rain
  of the savannas.
• Delicate balance between grasses and trees.
• If rainfall increases trees increase.
• If rainfall decreases trees die.
• If grasses are overgraised (usually b/c of
  farming livestock) woody plants take over and
  grasslands are destroyed.
• African savannas are inhabited by many large
  herbivores
• Impala, gazelles, eland, buffalo, giraffe, zebra
  and the wildebeest.

http//www.anselm.edu/homepage/jpitocch/genbios/50
-25bx-Savanna.jpg
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Mediterranean Scrub

• Mild winters and long, dry summers. Southern
  spain and california.
• Small trees, spiny shrubs, and cacti.
• In US called chaparral. Mediterranean called
  maquis. In Chile called matorral.
• Also found in southern Africa, and the coast of
  Austrailia.
• Mule deer live in chaparral during spring.
• Lizards, wren-tits, brush rabbits, and many
  rodents that are small dull colored to match the
  dull colored vegetation.

http//www.cag.lcs.mit.edu/mstephen/Pictures/Scen
ic/calis_amazing.JPG
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The Desert

• The great deserts are located around 30 latitude.
  
• Less than 25cm of rain a year.
• Only 5 of North America.
• Largest Sahara (almost size of United States)
  still growing due to grazing of domestic animals
  along the borders.
• Lack of water vapor in air causes temp. to be
  very hot and very cold at night. Change of up to
  30deg. C from night-day
• Many annuals that form flowers quickly when water
  is available.
• Perennials are succulents (water storage).
• C4 and CAM plants that conserve water are common.
  As well as cacti.
• Animals have adapted as well. Reptiles have
  waterproof coverings and dry excretions.
• Mamals are usually small and nocturnal and
  obtain their water from plants they eat.

http//www.izix.com/personal/travel/southwest/imag
es/SaguaroCactus.jpg
http//home.online.no/gmorgan/sahara/images/2003-
03-21-0206-Sahara-Camel.jpg
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Tropical Forests

• Found in Equatorial Zone. Average daily temp. is
  same all year.
• Rainfall often seasonal. Total rainfall varies
  from one place to another due to mountain ranges
  and their rainshadows.
• Areas where rain is limited they develop small
  water conserving leaves.
• Areas with wet and dry seasons tropical mixed
  forests and monsoon forests
• occur.
• Tropical rain forests
• most complex of all
• ecosystems. Found
• where rainfall is
• abundant year round.

http//www.cagesbydesign.com/graphics/backgrounds/
Tropical20Waterfall.JPG
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Tropical Rain Forests

• Total rainfall 200-400cm/year. More species of
  plants animals than in all the rest of biomes.
• Up to 100 species of tree found in 1 hectacre,
  but each species could be only 1 tree.
• Competition among plants is for light. Top is
  50-60m tall trees. Below those other trees form a
  canopy. Trees of the canopy appear the same.
  Slender trunk branches only _at_ canopy. Crowns
  small b/c of crowding. Soil always wet so roots
  dont go deep, but form a broad anchor. Large
  leaves. Thin bark.
• Woody vines lianas up to 240m long. Epiphytes
  plants that grow on other plants obtain water
  from air. Have to conserve water look like desert
  succulents. Ferns, orchids, mosses and
  bromeliads.
• Many animals live in canopy and make it the most
  populated part of rain forest.
• 0.1-1 of light reaches the forest floor. Few
  plants grow on rainforest floor these plants
  house plants.
• Decomposition of leaf litter is rapid. Low
  nutrient soils, red clay laterites.
• Nutrients that are in the soil are absorbed or
  leeched by rainfall. Nutrients found in the
  plants themselves.

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jpg
http//www.bio.ilstu.edu/armstrong/crtrip/crimages
/rainforest.jpg
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Tropical Forests, Mass Extinction, and Human
Responsibility

• ½ of forested area on earth is Tropical
  rainforests. Rapid destruction
• Thousands of plants and animals not found
  anywhere else.
• Destroyed due to rapid growth of human pop. soils
  have few nutrients and can only support
  short-term farming on the lands.
• Represents mass extinctions of the past except
  direct result of 1 species- humans.
• Destruction of forest leads indirectly to
  extinctions in other biomes.
• Along w/ increase in CO2 and decrease in use of
  CO2 by trees increases greenhouse gases and in
  turn global temps. Which will result in rising
  sea levels and change weather patterns world
  wide.
• To properly feed world human pop. More
• efficient farming techniques are needed
• along w/ slowing pop. Increases and
• saving the forests in general.

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http//www.paphrag.com/PeaceCorps/Occupationspages
/BurnForest.html
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