R
rossum
Guest
It is a crayfish, so it evolved from earlier crayfish, as the article said.What did this creature evolve from?
Correct.It needs it’s hard shell and claws to protect itself and feed.
If you go far back, its ancestors were not crayfish, but more generalised arthopods. They already had shells and claws. Crayfish have always had shells and claws.What was this animal using while it was waiting millions of years for evolution to make it fit for survival ?
Going back to the Cambrian, well before the first crayfish, a lot of clades developed shells and claws. For example, trilobites, euteryptids, ur-arthopods and others. The hypothesis is that a change in the chemistry of the oceans allowed the construction of hard shells and teeth at around that time.
Before then all animals were soft bodied, none of them had hard shells or teeth. In the absence of toothed predators, hard shells were not so essential a requirement. For example, we have fossils of early sort-bodied trilobites from before they developed hard shells.
As the environment changes, the requirements for surviving in that environment change.
rossum