On the other hand, we have eels, manta rays, mollusks, arthropods, crustaceans, polyps, jellyfish, and plankton, all which evolved in the same “environment,” (if we’re defining the entire ocean as a single environment, which is a dicey proposal to begin with) and all of which are radically different from each other. Convergence is an interesting phenomenon, but it’s very much the exception, not the rule. Just here on Earth, we see time and again that nature finds dozens of different ways of dealing with the same hazard.
And, even in the case of convergence, we see that these similarities tend to be pretty superficial. A shark and a dolphin may have both evolved fins, but only one of them evolved lungs. They evolved similar mechanisms to deal with one aspect of their environment (how to move), but entirely different mechanisms to deal with a different, but equally vital aspect (how to breathe). And we see the same thing in almost every aspect of these creatures: there are the different methods of reproduction, the cartilaginous skeleton versus the bony skeleton, and the teeth, man, look’t the teeth!
It’s remarkable that sharks and dolphins independently evolved similar methods of locomotion. It’s astounding that humans and Vulcans evolved identical methods of locomotion. (And it’s patently ridiculous that Klingons, Andorans, Ferengi, Baajorans, and Cardassians all evolved the same method, but never mind that now). But just as one cannot assume that, because dolphins have fins like sharks, they must also have gills, you cannot assume that Vulcans use melanin the same way humans do, just because we both walk upright on two legs.
No, not at all. I was not attributing that quote to you specifically.
I appreciate many of the points you make, though I wonder why you find it remarkable that similar organisms evolved similar mechanisms of locomotion, etc.
The reason (I think) that such forms tend to evolve is that they’re good, efficient designs that suit their environment. Natural selection at work.
Of course the similarities in convergence are largely superficial; in the example I gave, there were three different classes of animals: fish, reptiles, and mammals. Just because they’re similar on the outside does not imply that their internal organs are the same, and I never said they were.
Nor does convergence imply that all organisms produced by a particular environment must be similar in form. It’s obvious that the same environment can produce a multitude of different life forms, and it would be silly to assume otherwise.
As for Vulcans having melanin… You have black-skinned Vulcans and you have yellow-skinned Vulcans. Their pigmentation quite obviously differs. Since their body chemistry is different from humans’, they of course would not have melanin, but evidently the Vulcan equivalent thereof.
On Earth, pigmentation is a mechanism for coping with a hostile environment. Why would it necessarily be different on Vulcan?
If you can present another reasonable explanation for why their skin color differs, I’ll be happy to listen to it.
There is a justification for it in the Star Trek universe. There was an ancient race of humanoids that went around the galaxy seeding their genes. This ensured that the various planets would all evolve humanoids, who have the same basic pattern, and are genetically compatible. One can imagine that the design includes melanin for all races.
Perhaps; although if it is, it is clearly not a fundamental, unchangeable part of the template.
Among the spawned species are one that is blue and one that is green. Also wasn’t there one that was half black and half white (i.e. actual black and white, not dark-brown or pinkish)?
What can we conclude about that species: that they lie on their side in a savannah?
Then what was the point in bringing up convergence in the first place, and how does it relate to your argument that humans and vulcans, both bing humanoid, would likely evolve the same defense against UV radiation?
Then why are you assuming that humans and vulcans evolved the same defense to the same environmental hazard?
It could be camouflage. It could be the result of mating preferences for dark skin. It could be the accidental byproduct of the interaction of two beneficial genes. It could be the result of deliberate genetic manipulation. It could be a reaction to an environmental hazard we don’t have on Earth. It could be the result of a bacterial infection. Or it could serve absolutely no purpose at all.
Or, yes, it could be radiation protection. There’s no reason to assume its not a defense against UV, but there’s equally no reason to think that it is.