What is the evolutionary insect history?
Insects, as well as the history of many other groups of invertebrates, is misunderstood. For many decades, it has been assumed that they have been branched from Millipedes and Centipedes, known to colonize the country 428 million years ago during the Silurian period. However, recent genetic studies suggest that insects are more likely to separate from crustaceans 410 million years ago. The circumstances of this evolutionary change are subject to the debate and much less clear than the development of lobe fish on primitive tetraps.
The oldest known specimen in the history of insects is the Devonian fossil rhyniognatha hirsti , dated between 396 and 407 million years. It was found in the formation of Rhynie Chert, a well -preserved Devonian ecosystem, which includes some of the first plants of land with vascular tissues and among the earliest and best preserved fossils of earthly arthropods. Mandibles of this insect that has already developed for years, envelops the origin of insects and other important aspects of the history of insects in TajEmstvo.
Exactly when and how the flight is to enter the history of insects is misunderstood. One researcher, Jim Marden, introduced a model where insect flight evolved from evolutionary adaptive intermediate steps involving skimming on the water. It points to Stoneflies, a group of living insects that uses its wings to spin along the water level. Skimming varieties have been found, which have less and less real water contact, each step providing considerable advantages in terms of speed, and thus the ability to avoid predators and seek food sources.
There are several well -known groups of hexapods (six -legged invertebrates), which are evolutionary basal to insects and would be separated from them before 400 million years when the first fossil insects appear. These include abundant springs, as well as less recognized proturans and diplons. It is assumed that springs, proturans and dipLorans all developed their hexapod form of locomine independently, but only insects gained the ability to fly.
over tens of millions of years were insects and other small invertebrates with the only animals that colonized the soil, at that time covered with short plants no higher than the height of the waist. As the plants grew and the fish lines have evolved to the first amphibians, joined the insects of larger tetraons that would consume them in large numbers to survive. However, due to the high oxygen level in the carbon period, about 320 million years ago, some insects have grown to huge sizes, such as griffinfly meganeura , which had a range of two legs. But when the oxygen level dropped, these insects immediately died due to the inability to circulate the oxygen through their bodies.
Other main milestones in the history of insects have appeared throughout the mesozoic when most of the modern groups, as we know them, have evolved. About 120 million years ago flowering plants developed and cooperation between insects (especiallybees) and these newcomers have led to a mutually beneficial evolutionary relationship. As a result, flowering plants are now dominant by earthly flora.