So which do scientists think came first, the snake or the serpent/reptile/whatever you want to call it?
If the legged creature, what would have caused it to lose its legs, then? It certainly would not have provided any evolutionary advantage and it couldn't be classified as *not needing it* (like the old appendix argument). Legs are a bit more critical than that.
I assume what you meant was something along the lines of "did snakes evolve from legged animals"? The answer is obviously "yes", because snakes are reptiles, and the earliest reptiles had legs.
If the legged creature, what would have caused it to lose its legs, then? It certainly would not have provided any evolutionary advantage
Certainly, huh? From the above article:
One long-held theory is that snakes are closely related to some group of terrestrial lizards and lost their limbs on land. Many burrowing animals, from weasels to worm lizards, have smaller limbs today. "For animals wiggling around in small holes and crevices, it makes sense that limbs would get in the way," Hedges said.(bolding added)
What's a worm lizard? Amphisbaeniae
Elongate, slender, fossorial reptiles with scales arranged in annular rings, short robust forelimbs, hindlimbs absent. Hindlimbs absent, front ones present.(bolding added)
Kinda like a transitional would look, eh? (these are not transitional between lizards and snakes, what we have here is convergence). More about amphisbaeniae.
Legs are a bit more critical than that.
Depends where you live and what you're doing. The above references reduction in limb size in weasels (also platypuses, moles, and others), absence of limbs (snakes, some amphisbaenians) partial absence (other amphisbaenians). So loss of limbs is unusual and counterintuitive, but happened several times independently. Loss of flight in birds is also counterintuitive, but is found worldwide and is common on islands.