you don't evolve from something that still exists...
"That's exactly how evolution works. It's been observed in action."
A controlled experiment?...did you observe it? .how complex was the species? what were the conditions under which this "evolution" took place? And no, that is not how evolution works...so now evolution is selective within one species? Is evolution a disease and is only susceptible by some within one species and not others within the same species? This can't be your argument....I mean really...where's the proof?
Either there was a phenomenonal mutation (which wipes out the previous species) or an implementation of a new a species all together.
"That's exactly the opposite of how evolution works."
An evolution is a change, gradually. A mutation is a change, albeit a drastic one. Once the change has occurred, the previous entity no longer exists.
Fish are still here..and if only some species of fish "evolved", why not all species of fish?
"Back up. Explain why you think all fish would evolve into a new species at the same time?"
I don't purport to say anything about fish evolving...I'm merely phrasing a question...which you did not answer....
More importantly, why was there a need to evolve? A message like the one presented provides no insight into this fundamental question. Darwin failed miserably at it. And I challenge any evolutionist to show proof of a NEED for humans to have evolved from any other species that lived on this planet.
"To survive under changing environmental conditions, for one. But, in any event, populations change over time, regardless, that's a fact. It just IS. Need may not have anything to do with it."
What environmental conditions? Water is now 2/3 of this planet. I'm quite sure millions of years ago it was more. What would cause a fish to come out from an environment that encompassed nearly the entire planet? Nature was never and will never be "Just IS". Nature is purposeful. If there is no need, Nature doesn't and will not ever alter because it wants to...that's man way of thinking.
Maat