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Insects Grouped by Type of Metamorphosis |
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Insects are the most abundant life form known to science. Approximately 1,000,000 species have been described, more than all other known organisms combined! Most of these insects are harmless to humans with only ~10,000 species ever considered to be some sort of pest. Only 1,000 are classified as serious pests. Insects as a whole are highly beneficial. Several serve as important scavengers, recycling nutrients and disposing of dead organisms. They are major components of the food chain, participating both as consumers and as those being consumed. Perhaps the single most important benefit is the service provided in pollinating plants. In general, the class Insecta can be classified by having three body regions (head, thorax, and abdomen), one pair of antennae, and three pairs of legs. Obviously, with over 1,000,000 described species, and undoubtedly millions more unknown, the morphological deviations are difficult to summarize. Furthermore, being arthropods that change form throughout their lives, an immature may look vastly different from one stage to the next. Therefore, this course will focus on using key characteristics to differentiate insect orders and selected families. |