@Leadfoot,
There is no real "evidence" tht provides a good explanation re the development of complete metamorphoosis in insects. However, the concept of a metamorphism sequence is visible in the fossil record clear back to marine organisms of the Edicaran and the "Cambrian Explosion". SO the actual development of egg, free swimming polyp, and sessile adult, were observable over a 40 + million year fossil record.
First insects were seen to have incomplete metamorphosis. Theyd go through "instars" Again, though, did insects only show us their fossils of certain growth stages or do we even have any evidence of larval stages that were separate life styles as we see in many of todays ??
We know that the
ecdysis of nymphs of various Paleozoic arthropodas and crustaceans had occured in the early to mid Cmbrin (ith a "first appearance in one species of "rudist "coral may have actully occured in the late Ediacaran times. Some crustceans like early trilobites had examples of "incomplete metamorphosis" by showing severl instars in the same formational outcrop.
Insect metamorphosis did not really appear in the fossil record till the Devonian.
Several "hypotheses" of where complete and incomplete metamorphism rises from. Id say its a common ancestry thing transferred through early arthropods , annelids, coelenterates, and other families. These hypotheses, I must qpologize, are out of my pay grade and so I dont really keep up with "paleoendocrinology". The literature is full of some attempts t research but uing normal gene editing doesnt give up any secret information, it usually gives us some dead nymphs.
But, having said that, the "sudden appearance" of development stages can be followed (albeit fundamentally) through the fossil record. In order to track species development via metamorphism in the fossil record we need to be able to state definitively that e can link nymphs qnd adults. (It was easy in coleopterans nd lepidopterans because their nymphs are evolving in a fairly easily unerstood chain). Stuff like some species of insectq (like dragonflies), protochordates, graptolites etc are a "dogs breakfast" of fossils of which we hve no clue which one goes with which adult.
Im sure the Creationists/IDers are having a field day to say "See heres a group of organisms of which science has no clue"
We do, but most all our "clues" are still highly circumstantial.
Have fun with it. What you are doing though , is exactly what many of us hqve said ad nauseum. "When an IDer has an apparent roadblock in evidence he defaiults to "GOD DIDIT" followed by "MILLER TIME"
I admit to a paucity of data in this area, but no scientist, (to my knowledge), is defaulting to faith. They have ways of conducting qctual research. How about ID?