Earth: a Living Planet

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Earth: A Living Planet
To care for our planet we must understand how it opperates. Ecology is the study of interactions of organisms with one another and with their physical surroundings. Scientists who study ecology are called ecologists. Earts is a biosphere, or a living globe. The biosphere is that part of the Earth in which life exists. Biospheres include all the areas of land, air, and water on the planet. The biosphere goes about eight kilometers above the Earth's surface to as far as eight kilometers below the surface of the ocean.

Since the biosphere is way too large and complex for scientists to study as a whole, so they separate it into smaller units call ecosystems. There are two things that make up an ecosystem, the areas physical features (abiotic factors) and living organisms (biotic factors). The organisms living together in an ecosystem are called a community. Sometimes things in one ecosystem are affected from another ecosystems, so ecosystems are not self contained.

Ecological Succession
Ecosystems change over time. This process is called ecological succession. Sometimes ecological succession occurs where there were no living organisms before. but over time it obtains them. Lichens are organisms that produce acids that breakdown rocks and turn them into soil. Sucession can dramatically change an ecosystem. Like it might start out as a pond, but then over a period of time silt will fill it up and turn it into a into a marshland and then the marshland will dry up turning into a forest. Succession often leads to a faily stable collection of organisms called a climax community.

Land Biomes
A biome is an environment
that has a charcteristic climax community. The Earth is made up of two main biomes: land biomes and aquatic biomes. The major biomes are the tundra, taiga, temperate decidous forest, grassland, tropical rainforest, and desert.

Tundras are the northermost biomes. They have nearly no tress and are covered with mosses, lichens, and grasses. Organisms such as caribou, reaindeer, wovles, foxes, and mosquitoes live there. The most characteristic feature of tundras is the layer of permanently frozen subsoil.

Taiga biomes are dominated by coniferous tress, such as fir, pine, and spruce. Although winters in the taiga are cold, summers are mild enough to support a variety of organisms such as: black bears, grizzlies, wolves, moose, elk, voles, wolverines, and grouse.

Temperate Decidous Rainforest
These biomes are characterized by changing seasons and leaf fall. They are covered with forests of oak, maple, beech, and birch. This biome goes through striking seasonal changes. Alot of the organisms that live there have been hunted to the point of near extinction. Many organisms such as deer, moose, gray foxes, chipmunks, racoons, opossums, sqirrels, and a variety of birds.

This biome is characterized by it's many grasses and small leafy plants. This biome receives a significant amount of rainfall, but the majority is in one season, so they are usually dry. They have hot summers and cold winters. There is little temperature change in seasons thought. Oragnisms in grasslands of Africa include impala, gazelles, wildebeasts, and elephants. When properly supported the deep rich soul of grasslands make great farming areas.

Tropical Rainforests
Tropical rainforest receive 200 to 400 centimeters of rainfall a year. There are no drastic changes in temperature. Tropical rainforest have more organisms that all the other biomes combined. Trees there can grow up to 70 meters Organisms there include insects, birds, reptiles, small mammals, and amphibians. The floor of this biome is filled with danger. Many animals that live here produce chemicaal which can be used to fight diseases.

Deserts usually occur in areas with
less than 25 centimeters of rain a year. Desert climate is hot and dry. Oragnisms here includes many species of...
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