An international research team on Thursday unveiled what it called the most comprehensive insect family tree ever devised, using genetic data to trace insect origins back to nearly half a billion years ago and clarify the relationships among the major insect groups. The scientists analyzed 1,478 genes from 144 species covering all the major insect groups to resolve longstanding questions about the evolution and diversification of Earth's largest and most diverse animal group. "Two-thirds of all known animal species are insects," said Bernhard Misof of the Zoological Research Museum Alexander Koenig in Germany, one of the leaders of the study published in the journal Science. "They are the important players in terrestrial ecosystems, together with plants."
The first insects appeared about 480 million years ago at about the same time as the first land plants, the scientists estimated based on the genetic data. That date is 70 million years earlier than the oldest-known insect fossil. They probably evolved from a group of venomous crustaceans called remipedia. The scientists estimated that the first winged insects appeared about 400 million years ago as land plants began to grow skyward to form forests.
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