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Grassland Biomes
Chapter 8
8.1 GrasslandsObjectives
Describe the characteristics of grasslands Identify where grasslands are located
A grassland is an ecosystem where there is too much water to form a desert, but not
enough water to support a forest.
The land between the desert and the forest.
Grassland Climate A little wetter than the climate of a desert The desert-grassland boundary is the area
between deserts and grasslands where increased rainfall enable some grasses to grow.
This boundary shifts with long-term changes in climate patterns
Rainfall is the most significant limiting factor in grasslands
Grassland Video
Grassland Organisms Grass is the most common Most of the mass of grass is below ground Grasses not as limited by factors such as
rain and fires
Grass and Fires Natural grass fires play an important role Fires help prevent forests from
overgrowing grasslands Fires help by burning away dead grass
allowing more water and air to reach soil Fires help release valuable nutrients Germination of seeds is aided by fire
Animals Help Grasses Grazing animals help keep other vegetation
from growing without harming grass Burrowing animals help to aerate the soil
and by helping nutrients and water to reach the roots
Rainfall and Grasslands Types of grasses vary based on the amount
of rainfall Irrigation important to cultivated grass
crops When it rains is also important Some grasslands have rainy and drought
seasons Some plants have become drought-resistant
Types of Grasslands
Steppe (Chaparral)
PrairieSavanna
8.2 Steppes and PrairiesObjectives
Compare and contrast a steppe and a prairie Describe the importance of steppes and prairies in
agriculture
Steppes are grasslands that get less than 50 cm of rain a year
Prairies are grasslands characterized by rolling hills, plains, and sod-forming grasses.
Steppes and Prairies continued
Steppes have very low rainfall and sparse plant life – almost a desert
U.S. prairies are Called the Great Plains Large fertile areas where most food is grown Grains – breads and cereal Breadbasket
Steppe and Prairie Climates Steppe
25cm to 50 cm rainfall per year Rain evaporates quickly only reaching top 25 cm of
soil Temperature range from –5 oC to 30 oC
Prairie 50 cm to 75 cm of rain per year Sometimes much more rain and floods Rain usually as thunderstorms
Steppe and Prairie Organisms Prairie
soil holds water well roots of grass (sod-forming grasses) form a
mat called sod Humus is a layer of organic matter
Holds water and provides nutrients and food
Steppes Short grass prairies Mostly bunchgrasses – fine bladed grasses
that grow in clumps Clumping helps save water by holding water
in a small root area, under the shade of the grass.
Steppe and Prairie Organisms
Animal adaptations Migration Hibernation Burrowing
Plant adaptations Seeds and pollen carried by wind Spreads over a wide area
Steppe and Prairie Organisms
Buffalo
Migrating grazers do little damage But poor farming and ranching practices
cause extensive damage Overgrazing, poor farming practices
combined with droughts caused the Dust Bowl n the 30’s.
Today new techniques help reduce the impact
Steppe and Prairie Organisms
8.3 SavannasObjectives
Define savannas, and state where they are located.
Explain how savannas can support a wide range of organisms.
Savannas are tropical grasslands ranging from dry scrubland to wet open woodland.
Savanna Video
Savanna Climate Rainy seasons and long periods of drought As much as 150 cm rainfall per year Most falls heavily during thunderstorms Rest of year can be very dry Extreme climate demands a wide range of
adaptations of organisms.
Savanna Plants Grasses, shrubs and trees must be resistant to
drought, fires and grazing animals Many grow runners
long horizontal stems above or below ground Grasses grow in tufts
large clumps of tall, coarse grasses Thorns or sharp leaves
Protects from grazing animals They grow rapidly to recover quickly
Savanna Animals Reproduce during rainy season when food
is abundant Migrate to follow the rain Vertical feeding pattern
Animals eat vegetation at different heights Can feed in the same area without competing Allows more animals to live on limited
resources
TheEnd
1. Rhino2. Vertical feeding pattern3. Fire is important to health of the ecosystem4. Large areas with deep, fertile soils5. Mostly clumps of grasses with bare soil between6. Bison7. 50 cm to 75 cm of rain per year8. Climate wetter than a desert, but not as wet as a forest9. No real winter, but long dry season followed by intense
wet season10. Grazing and burrowing animals help
Quick Quiz 8QQ1. Grasslands 2. Prairie 3. Steppe 4. Savanna
1. 4
2. 4
3. 1
4. 2
5. 3
6. 2
7. 2
8. 1
9. 4
10. 1
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