From a population standpoint, insects rule our planet. Scientists have gotten around to naming almost 900,000 different species of insects, but some experts suggest that there may be as many as 30 million more species that haven't yet been christened [source: Smithsonian]. These same scientists estimate that about 10 quintillionthat's 10 with 18 zeroes behind itinsects are alive on Earth at this very minute. 

With numbers this staggering, it's no wonder that insects affect our lives and civilization, influencing everything from religion to agriculture to technology. Sometimes the insects' actions are what we perceive as helpful, such as the dung beetle, the sewer worker of the insect world. Sometimes the insects seem to cause harm, such as mosquito that bite you every time you walk outside, harmful pesticides and other bug killers such as toxaphene, dieldrin, and aldrin that affect your reproductive, nervous, endocrine, and immune system, and insect-borne diseases such as Malaria and Yellow Fever or  the deer tick, whose bite can inflict Lyme disease. Other times, the purpose of the insect is more ambiguous. It's all part of the world's biodiversity, where the actions of one species often complement another. Each species depends on the other to ensure survival, sometimes in ways we don't yet know.