Flying insects originated, diversified, and some species achieved large sizes during what part of the Late Paleozoic?
The correct answer and explanation is:
Flying insects originated and diversified primarily during the Carboniferous period, which spans from about 359 to 299 million years ago, a part of the Late Paleozoic era. This period saw the emergence of the first true flying insects and marked a significant point in insect evolution.
The Carboniferous was characterized by an abundance of plant life, including extensive forests of ferns, club mosses, and horsetails. These plants created a dense and oxygen-rich atmosphere, with oxygen concentrations in the air estimated to be around 35%, which is higher than present-day levels. This increased oxygen supply likely played a key role in enabling the evolution of large-bodied flying insects, as insects, being arthropods, rely on passive diffusion to transport oxygen throughout their bodies. The high oxygen levels would have allowed these insects to grow to larger sizes and develop wings capable of flight.
The first true flying insects appeared during the early Carboniferous, with species like Palaeodictyoptera and Gyrinopterida. Some of these insects were enormous by modern standards, such as the giant dragonfly-like Meganeura, which had wingspans of over 70 centimeters (about 28 inches). This period also saw the evolution of other notable groups like griffinflies and primitive mayflies.
By the end of the Carboniferous, flying insects had diversified into several ecological niches, feeding on plants, other insects, and decaying matter. The development of wings allowed insects to escape predators, explore new habitats, and colonize different parts of the environment, leading to rapid diversification. This evolutionary success continued into the Permian period, which followed the Carboniferous and saw further expansion and adaptation of flying insects.
In summary, the Carboniferous period was when flying insects first originated, diversified, and achieved larger sizes due to favorable atmospheric conditions and ecological factors that supported their evolution.