Ch. 8

 Ecosystem in which there is more water than in a desert  Not enough precipitation to create a forest  Tend to be located between the desert and forest biomes  In Africa, central Asia, North and South America, Australia  We live in the grasslands

 More rain than desert, but less than forests  Desert-grassland boundary: area between the deserts and grasslands where increased rainfall enables some grasses to grow. Rainfall increases: boundary becomes grassland Rainfall decrease: climate too dry to support the organisms  becomes desert

 Hot, dry summers  Limiting factor: rainfall  Not enough rain  grasslands can’t develop  Natural and man-made fires play a role in the development of the grasslands

 Abiotic and biotic factors determine the organisms in a biome  Grasses are the most common organism Most of the shrubs and trees are destroyed by fires  Grasses roots are deep so they are sometimes unaffected by fires  Rye Plant: grows to 2 m in height, but roots are up to 600 km deep

 Bison: Graze to keep grass short and help its growth Poop fertilizes the ground for further growth  Burrowing animals: Prairie dogs, earthworms, insects Aerate the soil by making tunnels/digging Helps nutrients, oxygen, and water reach roots more quickly

 Bison and antelope Run quickly  Grasshoppers Feed on seeds and leaves of grasses  Mice, gophers, prairie dogs Burrow underground Active mostly at night (avoid predators…)  Coyotes, foxes, snakes, birds Top consumers in North American Prairies

 Burn away layer of dead grass Converts to fertilizer for soil  Grasslands contain species of grass that fire actually aids in its germination

 Different rainfall amounts results in different grasses grown. United States has both tall and short grass prairies  Drier climate: shorter, fine grass  Mainly used for cattle grazing  Wetter climate: taller, thick grass  Most cleared for crop farming

 Cycles of rain Heavy period of rain (rainy season) Little or no rain (drought season)  Trees and shrubs are able to survive the drought season due to adaptations

 1. where are grasslands located in relation to deserts and forests?  2. Suggest reasons for the relationship between grass size and climate.

 Tall grasslands: have very tall grass, up to 5 feet tall get almost 30 inches of rain a year.  Mixed grasslands: grasses that grow around 2-3 feet high gets about inches of rain in a year  Short grasslands: almost a desert very short grass only receives 10 inches of rain each year

 Grasslands are becoming as extinct as the animals that are missing from them today. In Africa, national parks are being set up to preserve the grasslands. This will help the animals such as lions and elephants as well. The United States is starting to preserve the wild grasslands, too. It is even replanting grass where it has been cleared for farming.

 Steppes: short, bunched together grass Less than 50 cm of rainfall annually Located on the western edges of grassland (that nearest the desert)  Prairies: Make up most of land in United States Rolling hills and plains Fertile land provides base for crop growing  Generally a lot of wheat and grains

 Receive more than 25 cm of rainfall Prairies usually get cm of rain  High winds and high temperatures  dry environment so most of the rain evaporates quickly (doesn’t get deep in soil)  Temps: degrees fahrenheit

 Prairies Soil holds moisture very well Sod-forming grasses: form a mat of soil and roots  Example: Grass in our lawns  Holds soil together  decreases amount of evaporation Humus: layer of organic matter formed from the decomposition of plants and animals  Also helps to retain moisture and provide nutrients

 Steppes: Short grasses Bunchgrasses: short, fine-bladed grasses that grow in a clump  Clumps retain water

 Adaptations: Migrate, hibernate, or burrow Plants use the wind to aid in dispersal of seeds Colder areas:  Hibernate or migrate Warmer areas:  Burrow-nocturnal

 Overgrazing  Replacing native grasses with ones less suitable for the area

 1. Why are prairies called breadbaskets of the world?  2. How might desertification occur in steppe and prairies?

JanFebMarAprMa y Jun e JulyAugSeptOctNovdec Temp Precip

 Tropical or subtropical grasslands  Range from dry to wet, open grasslands  In Asia, Africa, and South America

 Rainy seasons As much as 150 cm of rainfall From January to April Usually falls in heavy thunderstorms  Drought seasons May to December

 Grasses, shrubs, trees Must be resistant to:  Drought, fires, grazing animals  Runners: Long stems above ground Used by some plants to reproduce  Rhizomes: Roots underground Protected from fires

 Tufts: large clumps of tall, coarse grasses  Adaptations: Trees and shrubs have thorns/sharp leaves  Protect them from predators Grow rapidly  Recover quickly from damage by animals and fire Make use of the vertical feeding pattern  Animals eat different vegetation at different heights  Decreases the competition for food  More animals can live in a smaller area

 Larger animals migrate to areas where rain has fallen  Habitat loss due to human activity has lead to disruption of some animals migrating patterns Affects the predators that feed on those animals

 1. How have plants adapted to savanna life?  2. What could happen to the migrating animals in a savanna if they were fenced in a large wildlife park for protection?