Researchers create a phylogenetic tree of insects by comparing the sequences of 1,478 protein-coding genes among species.
Using an unprecedented quantity of genetic sequence information from insects, researchers have assembled a new phylogenetic tree showing when these invertebrates evolved and how they are related to each other. The tree suggests that insects evolved approximately 479 million years ago, around the time when plants colonized land, and that insects are most closely related to cave-dwelling crustaceans. The new study, published today (November 6) in Science, also confirms some previously suspected family groupings.
This bolsters my contention that it was the coevolution of insects and plants – because what else were insects going to eat? – that has driven much of viral evolution as well.
Because what else was there to infect? Basically, the only terrestrial organisms around some 450 million years ago were primitive green plants, insects, fungi and bacteria. So insects ate plants, fungi infected plants, viruses in insects entered plants and vice-versa; fungi got involved as well, and possibly even bacteria.
I have speculated on the possibilities here (http://www.mcb.uct.ac.za/tutorial/virorig.html), but it is pleasing to see new science that reinforces some of what I have been spreading about for some years now B-)