When did holometaboly evolve?

When did holometaboly evolve?

• A. 450-500 million years ago.
• B. 10-20 million years ago.
• C. 280-300 million years ago, during the late Carboniferous to early Permian.
• D. 600-700 million years ago.

Answer: (C)

Complete metamorphosis appeared when insects first developed a distinct larval stage, a pupal phase, and an adult that look different from the larva. This developmental strategy likely arose once within the Endopterygota and then diversified. The fossil record shows the earliest clear holometabolous insects in the late Carboniferous to early Permian, about 280–300 million years ago, which fits with the appearance of the distinctive larval-adult life histories and pupation seen in fossils from that interval. If holometaboly had evolved much earlier, we’d expect older, well-preserved fossils showing those features; if it evolved later, we wouldn’t see the broad diversification of major holometabolous groups by the Permian. So the best-supported timing is roughly 280–300 million years ago.

Complete metamorphosis appeared when insects first developed a distinct larval stage, a pupal phase, and an adult that look different from the larva. This developmental strategy likely arose once within the Endopterygota and then diversified. The fossil record shows the earliest clear holometabolous insects in the late Carboniferous to early Permian, about 280–300 million years ago, which fits with the appearance of the distinctive larval-adult life histories and pupation seen in fossils from that interval. If holometaboly had evolved much earlier, we’d expect older, well-preserved fossils showing those features; if it evolved later, we wouldn’t see the broad diversification of major holometabolous groups by the Permian. So the best-supported timing is roughly 280–300 million years ago.