Biomes: The World’s Many Communities

Biomes are the world’s major communities, which are best distinguished by their climate, animals, and plants. Scientists argue about the exact number of biomes because of all the different subcategories, however there are five major biomes in the world: aquatic, desert, forest, grasslands, and tundra. The importance of biomes is immense. All living things are closely related to their environment. Any change in one part of an environment, like an increase or decrease of a species of animal or plant, causes a ripple effect of change in other parts of the environment. The survival and well being of a biome and its organisms depends on ecological relationships throughout the world. Even changes in distant parts of the world and its atmosphere affect our environment and us. The eruption of a volcano in Mexico, or Southeast Asia can bring the temperature of the whole world down a few degrees for several years. Biomes have changed and moved many times during the history of life on Earth. More recently, human activities have drastically altered these communities. Thus, conservation and preservation of biomes should be a major concern to all.

Aquatic Biomes: Water covers about three-fourths of our planet. From oceans, to lakes, to rivers, and even streams these biomes are home to a variety of life forms. The two types of aquatic biomes are marine regions and freshwater regions. Marine regions include coral reefs, estuaries, and oceans. Oceans are the largest and most diverse of the ecosystems. Marine algae supply much of the world’s oxygen supply and take in a huge amount of atmospheric carbon dioxide. The evaporation of the seawater provides rainwater for the land. Without water, most life forms would be unable to sustain themselves and the Earth would be a barren, desert-like place. Although water temperatures can vary widely, aquatic areas tend to be more humid and the air temperature on the cooler side.
Desert Biomes: Deserts cover about one fifth of the Earth’s surface and occur where rainfall is less than 50 cm/year. There are four different types of deserts: hot and dry, semiarid, coastal, and cold. Soils in deserts often have abundant nutrients because they need only water to become very productive and have little or no organic matter. There are relatively few large mammals in deserts because most are not capable of storing sufficient water and withstanding the heat. Also, deserts don’t provide shelter from the sun for large animals. The dominant animals of warm deserts are nonmammalian vertebrates, such as reptiles. Mammals are usually small, like the kangaroo mice of North American deserts.
Forest Biomes: Forests cover one third of Earth’s land area. Forest Biomes represent the largest and most ecologically complex systems.  They contain a wide assortment of trees, plants, mammals, reptiles, amphibians, invertebrates, insects and micro-organisms which vary depending on the zone's climates. There are three major types of forests: tropical, temperate, and boreal or taiga forests. The major aspect of the forest biome is its trees. While humans and animals breathe in oxygen and exhale carbon dioxide, trees take in carbon dioxide and produce oxygen.  Deforestation represents a great threat to the future of the earth's atmosphere, and the only way this can be avoided is by careful management of this resource.
Grassland Biomes: Grassland Biomes are areas of land dominated by grasses rather than shrubs or trees. In the Miocene and Pliocene Epochs, which spanned a period of about 25 million years, mountains rose in western North America and created a continental climate favorable to grasslands. Ancient forests declined and grasslands became widespread. Following the Pleistocene Ice Ages, grasslands expanded in range as hotter and drier climates prevailed worldwide. These areas have been exploited as farming grounds or plantations by humans. Grasslands 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. Grasslands have two main categories: tropical grasslands (savannas) and temperate grasslands.
Tundra Biomes: Tundra is the coldest of all the biomes. Tundra comes from the Finnish word tunturia, meaning treeless plain. It is noted for its frost-molded landscapes, extremely low temperatures, little precipitation, poor nutrients, and short growing seasons. Still, the tundra is host to a surprising number of plants and animals, and represents a fascinating testament to nature's adaptability, and cruel beauty. Dead organic material functions as a nutrient pool. The two major nutrients are nitrogen and phosphorus. Nitrogen is created by biological fixation, and phosphorus is created by precipitation. The two types of tundra are: arctic tundra and alpine tundra.

For more information check out:

The World’s Biomes

Or

WorldBiomes.com

Page Author: Tara White

Last Modified: 2/21/06