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Grassland Biomes
Grassland are generally semi-arid areas with little or no trees, and are inhabited by grazing mammals, ground-nesting birds, insects, and a few species of reptiles.
Grasses first appeared during the Eocene Era, and their success supported the development of the communities of grazers that inhabit the great grassy plains of our planet. There are perhaps 11,000 species of grasses, each one adapted to survive under particular environmental conditions. 
Some grasses are annuals, and survive the winters as seeds: other species are perennials, and sprout again each year from a well-developed network of roots. Another adaptive characteristic of grasses is that they grow up from where the stems join the roots. Other plants grow from the tips of shoots, twigs, and branches, but grasses grows from the bottom up. This allows animals to eat grass without slowing its growth.
Grasses are wind pollinated flowering plants. The tiny flowers form at the top of the stalks where the wind can pick up and deliver the pollen. Later the seed heads form at the top of the stalks. Grasses are monocotyledons, so that when the seeds germinate each one sends up a single leaf. Grasslands fauna is diverse, with antelopes, groundhogs or prairie dogs, burrowing mammals, snakes, and ground nesting birds. Predators range from grizzly bears to foxes and include hawks and owls. Each grassland has its own animals, and they tend to live in similar ecological niches. Grassland are found around the world and fall within the following categories: 
PrairiesPrairies are generally humid and are densely covered in tall grass. There are very few trees on prairies, most of them usually found on hill slopes or more humid near springs and rivulets. The prairie soil is rich in nutrients and is ideal for the growth of plant life, which is why prairie regions have been exploited by farmers for centuries. Grazing animals such as oxen and bison who fed on the prairie grass were also exploited by humans, with the bison being driven to near extinction by hunters. Steppe The steppe grassland is usually found in areas of the world which are less prone to moisture. Steppe vegetation is well suited to this drier climate, and the grass is generally shorter than that which is found on prairie grasslands. 
Animal life on the steppe is comprised of grazing mammals such as the antelope, and a wide variety of burrowing mammals such as ground squirrels and ferrets. Steppes are virtually semi-arid deserts in the making, and are highly threatened by overgrazing.
SavannaSavanna biomes are distinguished by their warmer drier climates, and their seasonal droughts. Savanna plant life is highly adapted to the hot and dry climate, with trunks that can store water for days, or special built-in mechanisms allowing the plant to lie dormant during periods of drought. Another variant of this grassland biome is the Tropical Savanna, which is perhaps the most ecologically diverse of the grasslands; here, several species of animals including birds, mammals, reptiles, and insects congregate and feed upon the trees and grass or each other. One good example of the tropical savanna is found in Africa, where lions, elephants and warthogs make their home. 
Humans have exploited many of the animals of the savanna biome, either for sport, fur, or illegal poaching. Rhinos and elephants are now endangered species due to the illegal trading of their horns and tusks. Frequent fires have also contributed to the diminishing savanna biome, and though most occur because of the dry heat, they are more frequent in areas populated by humans.
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