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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© Tony Craddock/SPL/Photo Researchers, Inc.

blue and gold macaw,Ara ararauna

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© 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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3

1

2

4

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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