6-3 grasslands, desert, & tundra

6-3 Grasslands, Desert, & Tundra

Areas with too little precipitation for large trees.

Tropical Savanna

Tropical Savanna• Africa, west India, north Australia, parts of South

America (pampas)

• Grasslands and savannas found in the interior of continents, bordering on deserts and temperate forests.

• Tropical biome dominated by grasses, shrubs, & small trees

• Rain falls during wet season (only time plants can grow) which lasts for only 2-4 months

•Savannas, tropical grasslands, have very hot summers and cold winters. The temperature is usually between 10 degrees C and 35 degrees C.

•The soil in the savanna is generally a reddish color, porous, acidic, and has only a thin layer of the humus (made from the decomposition of plant and animal matter), and allows rapid water drainage.

•Large number of herbivores

Tropical Savanna

Tropical Savanna• Savannas usually receive

between 20 and 50 inches of rain annually. About 7 months of the year are rainy. Around October there are thunderstorms and drying winds, which signals the beginning of the dry season.

• Fires are expected around January at the height of the dry season.

Tropical Savanna

• Plants adapted to survive long period without water: plants lose leaves or die to ground

• Large horizontal roots• Vertical leaves to reduce water loss• Thorns to prevent being eaten

• Animals:– Grazing herbivores migrate to follow rain to water

holes– Give birth during rainy season (food most

abundant)– Graze at different heights

Temperate Grasslands

Temperate Grasslands• Interior of continents with moderate rainfall,

too little for trees• Prairies (N. America), Steppes (Asia), veldt (S.

Africa) & pampas (S. America)• Mountains play a role in maintaining

grasslands. Grasslands lie east of mountains.• Fires from thunderstorms help maintain

grasslands

Temperate Grasslands• Plants: grasses & wildflowers.• Shrubs & trees mainly on banks of streams

Temperate Grasslands

Temperate Grasslands• Plants:– Root systems form dense layers that survive

drought and fire

Temperate Grasslands• Most fertile soil – summer hot, winter cold.– Plants die back to roots– Low temperatures slow decomposition. Rate of

decay slower than rate of addition of new vegetation. Organic matter accumulates in soil

– Most grasslands converted to farmland.

Temperate Grasslands• Animals:–Herbivores:

large flat back teeth for chewing grasses

Temperate Grasslands• Animals:–Many animals

live in underground

burrows to protect them

from fire, weather, and predators

Temperate Grasslands• Threats:– Farming & overgrazing. Grain crops do not hold

soil as well as grasses, erosion occurs.– Grasslands changed to deserts.

Chaparral

Chaparral

Chaparral• Temperate shrubland found in all parts of the

world with Mediterranean climate.• Moderately dry, coastal climate in mid

lattitudes (30 degrees N & S of equator)• Little or no rain in summer

Chaparral• Plants: – Low-lying,

evergreen shrubs & small trees growing in dense patches (olive trees, scrub oak)–Herbs: sage & bay

Chaparral• Plants have small

leathery leaves that retain water.

• Leaves contain oil that promote burning

• Chaparral plants adapted to fire.

Chaparral• Animals:– Camouflage is common adaptation

Chaparral• Threats:– Human development. Near ocean, get a lot of

sun, mild climate year round = hot property (Los Angeles)

Deserts

Deserts

• Plants: adapt to less than 10 inches of water/year– Adaptations to obtain & save water• Succulents – thick, fleshy stems & leaves that

store water

Deserts• Plants: – sharp spines keep animals from eating

their juicy flesh– Roots are shallow and spread out just

under the surface–Many plants drop their leaves during dry

periods– Brief growth spurts after a rare rain.

Deserts

• Animals:– Reptiles – thick, scaly skin prevents water loss– Amphibians – estivate (bury underground & sleep through dry period)– Many are nocturnal

Tundra

Tundra

Tundra

Tundra

• Location: northern arctic regions• Winters too cold & dry for trees• Deeper layers of soil stay permanently frozen,

(permafrost)• Topsoil thin. Low productivity• In summer, topsoil thaws forming moist

spongy bogs• Free, non-frozen water scarce (limiting factor)

Tundra

• Bogs host mosquitoes & black flies, and birds.

Tundra

• Plants: low diversity– Mosses & lichens cover rocks in summer– Plants have wide shallow roots to anchor in thin

soil against icy winds– Grow close to ground to help absorb heat from

soil.– Woody plants (willow & birch) have dwarf forms

or grow flat.

Tundra

• Animals: – Migratory birds breed here in summer– Caribou & moose migrate– Lemmings, mice, hares burrow during winter– Some animals change color and fur is well

insulated

Tundra

• Threats– Most fragile biome– Foods chains simple, so easily disrupted– Conditions extreme, so land easily damaged &

slow to recover– Human disruption new – oil exploration,

extraction, transport, spills, leaks, pollution has poisoned food & water sources