bio 100 chapter 39
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Chapter 39Major Ecosystems of the BiosphereLecture Outline
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Solar radiation and winds determine climate
The sun’s rays are more direct at the equator and more spread out at the polar regions
The tilt of the earth can cause one hemisphere to be warmer than the other
Air currents have a direct affect on rainfall.
Topography influences climate
Topography – surface features of land Mountains affect climate
Leeward side is in a rain shadow
Bodies of Water influence the climate
Ex: Ocean water gains & loses heat slower than land
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Figure 39.2A Elevation affects the distribution of terrestrial ecosystems
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ice
tundra ice
Increasing Latitude
alpinetundra
montaneconiferousforest
deciduousforest
tropicalforest
coniferousforest
temperatedeciduousforest
Incr
easi
ng
Alt
itu
de
Figure 39.2B Formation of a rain shadow
Ocean currents affect climate
Water tends to be warmest at the equator and coldest near the poles
Figure 39.4 Pattern of ecosystem distribution on land
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Equator
Tropic of Capricorn
Tropic of Cancer
polar ice
tundrataigamountain zonetemperate deciduous forest
temperate rain forest
tropical deciduous forest
tropical seasonal forest
tropical rain forestshrubland
temperate grasslandsavanna
semidesert
desert
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39.5 The tundra is cold & dark much of the year
Arctic tundra encircles the Earth just south of the ice-covered polar seas in the Northern Hemisphere
Because rainfall amounts to only about 20 cm a year, the tundra could possibly be considered a desert
Only the topmost layer of soil thaws, permafrost beneath this layer is always frozen
Trees are not found in the tundra
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Figure 39.5 Tundra, the northern-most ecosystem
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39.6 Coniferous forests are dominated by gymnosperms
Taiga (called boreal or northern forest), exists south of the tundra and covers approximately 11% of the Earth’s landmasses
Temperate rain forest – coniferous forest that runs along the west coasts of Canada and the United States
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Figure 39.6 Taiga, a northern coniferous forest
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39.7 Temperate deciduous forests have abundant life
Temperate deciduous forests
Climate in these areas is moderate, with relatively high rainfall
Seasons are well defined
Trees (oak, beech, sycamore, and maple) have broad leaves and are deciduous – lose their leaves in fall and grow them in spring
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Figure 39.7 Temperate deciduous forest in the fall
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39.8 Temperate grasslands have extreme seasons
Temperate grasslands
Very cold winters and hot and dry summers (Ex: praries)
Small mammals, (mice, prairie dogs, and rabbits) live below ground, but usually feed aboveground
Virtually all grasslands have been converted into agricultural lands because of their fertile soils
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Figure 39.8 Temperate grassland in the summer
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39.9 Savannas have wet-dry seasons
Savannas – in regions where a cool dry season is followed by hot rainy season
Largest savannas are in central and southern Africa
African savanna supports the greatest variety and number of large herbivores of all the biomes
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Figure 39.9 The African savanna
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39.10 Deserts have very low annual rainfall
Deserts usually found at latitudes of about 30° in both the Northern and Southern Hemispheres
Most have plants highly adapted to survive long droughts, extreme heat, and extreme cold
Some animals are adapted to the desert environment
Exs: Camels and sidewinders
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Figure 39.10 Desert with some vegetation
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39.11 Tropical rain forests
Tropical rain forests
Diversity of species is enormous
Complex structure, with many levels of life, including the forest floor, the understory, and the canopy
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Figure 39.11B Representative animals of the tropical rain forests of the world
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
© Tony Craddock/SPL/Photo Researchers, Inc.
blue and gold macaw,Ara ararauna
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
© M. Fogden/OSF/Animals Animals
cone-heated katydid,Panacanthus cuspidatus
39.12 Fresh water Ecosystems
Fresh water ecosystems include streams, lakes, rivers & ponds
Wetlands absorb storm water Protect from effects of floods
Purify water by filtering it
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Figure 39.12A Freshwater ecosystems (e.g., stream, lake, and river) often adjoin wetland ecosystems (e.g., delta and salt marsh)
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stream
river
carp, Cyprinus carpio
lake
stonefly larva, Plecoptera sp.
rainbow trout, Salmo gairdneri
salt marsh
delta
blue crab, Callinectes sapidus
(stonefly): © Kim Taylor/Bruce Coleman,Inc.; (trout): © William H. Mullins/Photo Researchers, Inc.; (carp):© Robert Maier/Animals Animals;(crab): © Gerlach NaturePhotography/Animals Animals; (oligotrophic): © Roger Evans/PhotoResearchers, Inc
Classification of Lakes
Lakes are often classified by nutrient status Oligotrophic lakes are nutrient-poor, having a small
amount of organic matter and low productivity
Eutrophic lakes are nutrient-rich, having plentiful organic matter and high productivity
Eutrophication: “over fertilization” too much phosphorous = algae growth in lakes
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Figure 39.12B (top) Oligotrophic lakes are nutrient poor and have limited algal growth (bottom) Eutrophic lakes are nutrient rich and have much algal growth
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(oligotrophic): © Roger Evans/Photo Researchers, Inc.; (eutrophic): © Michael Gadomski/Animals Animals
Oligotrophic lake
Eutrophic lake
39.13 Marine ecosystems include those of the coast and the ocean
Coastal Ecosystems Border the Oceans
Salt marshes, mudflats and mangrove swamps are ecosystems that occur at a delta
Estuary – where fresh water & sea water mix as a river enters the ocean
Ecologically important areas Large amount of nutrients support a wide variety of species
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Figure 39.13A Coastal
ecosystems
39-31(mudflat): © John Eastcott/Yva Momatiuk/Animals; (mangrove swamp): © Theo Allofs/Visuals Unlimited
Mudflat
Mangrove swamp
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39.13 Marine ecosystems: The Ocean
Oceans
Phytoplankton (algae) is food for the entire ocean
Coral reefs
Areas of biological abundance just below the surface in shallow, warm, tropical waters
Densely populated with life
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Figure 39.13C Ocean inhabitants in
divisions of the pelagic zone
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sea turtle
dolphin
shark
ocean bonito
mackerel
tuna
prawn
barracuda
midshipman
viperfish
hagfish
anglerfish
gulper
baleenwhale
EpipelagicZone
lanternfish
giantsquidMesopelagic
Zone
spermwhale
BathypelagicZone
deep-seashrimp
Connecting the Concepts:Chapter 39
Topography influences climate There are several different land-based
ecosystems on the earth, each with unique characteristics.
There are several fresh-water ecosystems Coastal ecosystems include Estuaries Marine ecosystems cover most of the surface of
the earth
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