Pearson Assessments



Texas GrasslandsEcosystem Description??There are three types of prairies; tall grass, short grass and mixed grass. Once 400,000 square miles of tall grass prairie covered North America. Now a very small amount is left. The rest has been plowed under for farms and buildings. Grasslands have mostly grasses. However, a few trees, such as cottonwoods, oaks, and willows grow in river valleys, and a few hundred species of flowers grow among the grasses. The various grasses include purple needlegrass, blue grama, buffalo grass, and bluestem. Flowers include asters, blazing stars, coneflowers, goldenrods, sunflowers, clovers, and wild indigos. Brightly colored flowers attract pollinators such as bees, wasps, and birds.Precipitation in the grasslands usually occurs in the late spring and early summer. The annual average of rainfall is about 51 to 89 cm. Summer temperatures can be well over 100 degrees Fahrenheit, while winter temperatures can be as low as -40 degrees Fahrenheit.Plant Adaptations??Prairie plants have roots that grow downward for as much as 3.5 meters and form networks to absorb (take in) moisture during dry periods. The deep roots hold the soil together. Soil here is deep and dark. It gets nutrients from the decomposition of so many roots. Prairie fires move quickly, so the soil acts as a buffer protecting prairie plants' underground growing structures. Many prairie plants grow stronger after fires. For some plants with hard seed-coats, fire burns some of the seed-coat off the seeds and actually helps the seed germinate (start to grow) faster.Prairie grasses also have narrow leaves that lose less water to evaporation than broad, flat leaves lose.48040390303The roots of so many plants grow together to form a network, much like the strings in a net are connected.00The roots of so many plants grow together to form a network, much like the strings in a net are connected.Animals of the grasslandsBecause there are few trees, animals living in grasslands must cope with extreme weather and temperature. To do so, many animals have strong front legs and paws to dig tunnels or burrows that provide shelter from poor weather, and relief from temperature extremes. Prairie dogs are excellent diggers, and create elaborate tunnels. This burrowing behavior gives grassland animals some protection from predators. Jackrabbits, burrowing owls, and snakes also live in burrows.With few trees or rocks to hide behind, many grassland animals have highly effective camouflage, which allows them to hide while in plain sight. Most antelope, deer, and birds are covered in colors that match the grass and surroundings of their wide-open habitats.Lacking trees, birds that live in grasslands must nest on or under the ground. Most grassland birds try to hide their eggs as much as possible, laying them in thick grasses. Burrowing owls steal a convenient burrow, or make their own in which they lay 2 to 12 eggs. Prairie Chickens nest in the tall grasses, but feed in short grass areas.In a forest, animals must be able to run around trees and objects, so they usually cannot run as fast as possible. This is not the case in grasslands, where many animals -- predators and prey alike -- are capable of reaching incredible speeds. Jackrabbits can reach 40 miles an hour. Pronghorn antelopes can go nearly 60 miles an hour.Plant eaters must escape the attention of predators. Some species have become social, and form large groups, sometimes with other animal groups. By grazing, drinking and sleeping in the company of many others, they increase the chances that one of the herd’s members will detect a predator and alert the rest of the group. Bison, pronghorn antelopes, and prairie dogs belong in this category. Bison form a circle around their young and lower their heads and horns to face a predator. Prairie dogs always have members on watch duty. These prairie dogs stay alert and call out if a predator is sighted.Adapted from:“The Grassland Biome” “North American Prairie” “Prairie Ecosystems” “Example of Animal Adaptations in Grassland Environments” ................
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