Send the link below via email or IMCopy
Present to your audienceStart remote presentation
- Invited audience members will follow you as you navigate and present
- People invited to a presentation do not need a Prezi account
- This link expires 10 minutes after you close the presentation
- A maximum of 30 users can follow your presentation
- Learn more about this feature in our knowledge base article
6.3 Grassland, Desert, and Tundra Biomes
Transcript of 6.3 Grassland, Desert, and Tundra Biomes
In areas with too little precipitation or too many fires for large trees and shrubs to survive, smaller plants dominate biomes. Where there is almost no rainfall at all, few plants can grow and we find desert. Thus, warm areas with little precipitation are characterized by savannah and desert biomes. Temperate areas have grassland, chaperral, and desert biomes. Fire can play an important role in determining what biome is found in warm regions. Cold areas have desert and Tundra biomes.
Animals of the Temperate Grasslands
6.3 Grassland, Desert, and Tundra Biomes
Grasslands are highly productive because of their fertile soil. the summer is hot and the winter is cold, so plants die. The cold conditions slow the decaying process, so over time organic matter accumulates in the soil. This means the grasslands have the most fertile soil in the world. Most of this land has been converted to farms for wheat and corn.
Savannahs and Tropical Seasonal Forests
*Savannah: a tropical biome dominated by grasses, shrubs, and small trees.
*Tropical Seasonal Forests: larger growth of trees compared to Savannahs. They also have slightly wetter conditions and less frequent fires.
Parts of India, Africa, Australia, and South America are covered by savannahs. African savannahs support a wide variety of herbivores such as antelope, giraffes,and elephants, as well as the the predators that hunt them, such as cheetahs, lions, and hyenas.
Because rain only falls during the wet season, plants must be able to survive long periods of time without water. Many plants have large horizontal root systems so they can draw water from as far as possible. The coarse Savannah grasses have vertical leaves that expose less of their surface area to the hot sun to conserve water. Trees and shrubs often have thorns and sharp leaves that keep hungry herbivores away.
The giraffe is a resident of the savannah, and occupies a special niche. Because of its long neck, it can reach tree leaves 2-5.5 m from the ground. Its tongue can stretch up to 17 inches,so it can reach even taller trees. Males and females forage differently; males stretch up to reach vegetation, and females eat lower vegetation. This probably eliminates food competition between the sexes. Giraffe live in groups, who's sizes are dictated by the amount of food in the area. A male establishes dominance in a group by pushing at another male's neck, or by hitting the other males neck with its horns. Giraffe reproduction is slow; gestation is about 1 1/2 years, and produces 1 offspring, which are very vulnerable to predation .
Prairie Fires: Native Americans who inhabited the plains of North America discovered a method for avoiding prarie fires. 1st they would start a small fire near their community, then the fire would burn out a safety zone in a short time. When a large fire threatened the community, it would pass by the already burned areas. This was later used by European settlers on the plains.
Temperate grassland covers large areas of the interior of continents where there is moderate rainfall but trees and shrubs cannot be established because there is not enough rain or fires are too frequent. The Prairies in North America, the steppes in Asia, and the veldt in South America are temperate grasslands.
Mountains play a critical role in maintaining grasslands. For example, in North America, rain clouds moving from the west release most of their moisture as they pass over the Rocky Mountains. As a result, east of the Rockies receives so little rain that it looks like a desert. The amount of rain increases as you move east, which allows taller grasses and shrubs to grow.
Plants of the Temperate Grassland
Vegetation consists of grasses and wildflowers. Although there is only a single layer of vegetation, many species may be present. Shrubs and trees grow only where the soil contains extra water, such as along the banks of streams.
North American Prairie
Steppes in Asia
Veldt in South Africa
Grazing animals such as pronghorn and bison have large, flat back teeth for chewing coarse prairie grasses. Other grassland animals, such a badgers, prairie dogs, and burrowing owls live in burrows to protect them from the weather and predators.
Threats to Temperate Grasslands
Farming and overgrazing are threats to the grasslands. It also causes erosion. When grasses are constantly eaten and trampled, they cannot regenerate and hold the soil. The constant use can change fruitful grasslands into desert like biomes. The Dust Bowl Era, which affected the Great Plains in th e1930's is a dramatic example of what can happen when land is improperly managed.
*Chaparral: a temperate shrubland biome found in all parts of the world with a Mediterranean climate. These areas have moderately dry, coastal climates, with little or no rain in the summer. The hills that the HOLLYWOOD sign and old westerns are chaparral biomes.
Plants of the Chaparral
Most plants are low lying evergreen shrubs and small trees that tend to grow in dense patches. Common plants include chamise, manzanita, scrub oak, olive trees, and herbs, such as bay laurel. These plants have small leathery leaves that retain water. Chaparral plants are well adapted to fire so that they can resprout from small bits of surviving plant tissue.
Animals of the Chaparral
A common adaptation of chaparral animals is camouflage, which is shape or coloring that allows an animal to blend into its environment. Animals such as quail, lizards, chipmunks, and mule deer have a brownish-grey coloring which allows them to blend in,
Threats to the Chaparral
The greatest threat is human development. Because they get a lot of sun, are near the oceans, and have a mild climate year round, humans tend to develop it for commercial and residential use.
Many kinds of deserts are located throughout the world, but they all have 1 thing in common, they are among the driest places on Earth.
*Deserts: areas that have widely scattered vegetation and receive very little rain. In extreme cases, it never rains and there is no vegetation.
The desert has such little moisture that, it causes the temperature to change rapidly within a 24 hour period. It may go from 40 degrees C (104F) during the day to near freezing at night. Deserts are often near mountain ranges, which block the passage of rain clouds.
Plants of the Desert
All desert plants have adaptations for obtaining and conserving water. Plants called succulents, such as cactus, have thick, fleshy stems and modified leaves called spines that stored water. Their spines also have a waxy coating that prevents water loss.
the spines keep animals from eating them. Roots are just under the surface to absorb any rainfall.
Oregon's Rain Shadow
Many people think that Oregon is a state that is covered by lush forests. In fact, some of the state has an ecosystem that receives less than 25 cm of rainfall a year. This is due to an effect called a rain shadow. The Cascade Range of the Rocky Mountains (which runs from the northern to the southern edges of the state) creates a barrier that blocks ocean moisture from moving to the eastern side of the mountains. Because of this the western side of the mountains are dominated by old growth forest, while the eastern side is dominated by sagebrush.
Animals of the Desert
Reptiles, such as Gila Monsters and rattlesnakes, have thick, scaly skin that prevents water loss. Amphibians such as the spadefoot toad survive scorching desert summers by *estivating: burying themselves in the ground and sleeping through the dry season. Some animals such as the elf owl, nest in cacti to avoid predators. Insects and spiders are covered with body armor that helps them retain water. In addition, most desert animals are nocturnal, which means they are mainly active at night when it is cooler.
*Tundra: located in northern arctic regions. The winter is too cold and dry to permit the growth of trees in this biome. Many areas of the tundra are deep layers of soil called *permafrost, which are frozen throughout the year. In the summer, the tundra landscape becomes spongy and is dotted with bogs.
Vegetation of the Tundra
Over 400 species of wildflowers, such as the fireweed, grow in the Tundra during the summer. Mosses and lichens cover vast areas of rocks in this biome. The soil s thin so they have wide shallow roots to help anchor them. Most plants such as campion and gentian are short.
Animals of the Tundra
Millions o migratory birds fly to the Tundra to breed in the summer. Food is abundant in the form of plants, mollusks, worms, and especially insects. Caribou migrate in search of water and food. Wolves prey on Caribou, moose, and smaller animals, such as lemmings, mice, and hares. These animals burrow underground in the winter but are still active.
Threats to the Tundra
The tundra is one of the most fragile biomes on the planet. It's food webs are simple and easily disrupted and due to conditions it is slow to recover. It was undisturbed by humans but oil has been found in areas such as northern Alaska. Global climate is the biggest threat.