Earth teems with life. Plants, animals and microbes thrive in the mountains, in the oceans, even in the hot springs of Yosemite National Park. We can see some species, such as Yosemite's extremophiles, only with a microscope. Others are as big as a whale or as tall as a redwood. Without such variety, the planet would cease to exist.
Why is that? Earth is a large ecosystem, a community of living, breathing, reproducing organisms in a particular environment. The term also covers the nonliving components within a specific ecological unit, like soil, water and light. Of course, smaller ecosystems exist, such as the one in my backyard or on the city streets of Paris. Every organism within an ecosystem has a specific function, and all work as a team to keep Earth's ecology balanced [source: National Wildlife Federation].
Without all of these different habitats, species and vast gene pools, our very existence would be in jeopardy. Biodiversity provides us with different types of food and materials. Biodiversity generates income for families, businesses and governments. Without bees and other pollinators, there would be no citrus trees, no flowers, no fruits and no vegetables. Where would fishermen find their catch [sources: National Wildlife Federation, Natural History Museum]? Most of our synthetic drugs come from various plants. Cures for a variety of diseases can disappear when a native plant dies.
Moreover, a well-functioning ecosystem cleanses our air and water. It helps the planet weather extreme floods and violent forest fires. A healthy ecosystem absorbs dangerous chemicals and sustains life. Rain forests, for example, contain half of the world's plant and animal species and play a major role in regulating Earth's weather patterns. They act as a firewall against erosion and drought. The rain forests are also the world's lungs, inhaling carbon dioxide and exhaling oxygen. Biodiversity also regulates the chemistry of our atmosphere and soil while determining the growth cycle of plants and mating seasons of animals [sources: National Wildlife Federation, Natural History Museum].
Yet, removing any one species can upset an ecosystem's delicate equilibrium. When one species goes extinct, it changes the way other species interact with one another. Unfortunately, that's happening every day. Habitat loss, the introduction of alien species, pollution, climate change and overexploitation of Earth's natural resources are the main reasons why the planet is losing much of its biodiversity [source: Natural History Museum].