Thread: Let's discuss evolution from a scientific perspective -not for Creationist, anti-scientific argument

Originally Posted by Darkmatters

Ok, that clears things up a lot - especially the last part, thanks for that.

Here's the thing that always kind of bugged me about evolution via natural selection (as a complete layman who's only exposure was to read Dawkins' Mount Improbable and a bunch of Sagan books) -

It just seems to strain credibility that almost any species at all manage to generate viable mutations when environmental conditions threaten their existence.

I mean - how does that work?

Are there constantly mutations happening and the vast majority of them never lead to new species because the environment doesn't necessitate it (not that I'm expecting you to know this Blueline… just conjecturing)? Punctuated equilibrium is a thing, isn't it? Meaning that evolutionary changes generally don't happen for long periods of time, until environmental changes make it necessary to change or die out, and suddenly wham! New species pop up.

It just seems to me (again, as a layman) that it would make sense if somehow the genes are actually responding to environmental pressure. I'm not saying that's definitely what happens - of course nobody knows. But it seems like if evolution really happened only through random mutations that happened to coincide with environmental changes that select in favor of those exact changes - it sort of seems like new species would almost never happen. Or am I sounding like a Creationist? I absolutely don't mean to imply any Creator who's pulling the strings, just to make that clear! Just some hitherto unknown mechanism that causes genes to respond to changing conditions and generate new mutations of specific types. Not because that's what an animal or species WANTS to happen consciously of course - like some species of dinosaur thinking "Wow, wouldn't it be cool if we could grow wings and fly around, and maybe our scales could change into feathers… ". Or "Let's change into banandas". I don't mean to propose any particular mechanism, just saying…

Your post is a little confusing, so I'm not exactly sure what you're asking. But here is quick overview of mutations and natural selection, and a link to a page that describes punctuated equilibrium.

Most mutations are neutral; they neither help nor hurt the organism. Imagine you have a codon in a DNA template that codes for the amino acid alanine, which will then go on to be part of a protein/enzyme. There are four sets of codons that can code for alanine: GCU, GCC, GCA, and GCG. If you have a DNA template that reads CGA, then if the RNA polymerase (which transcribes DNA into mRNA) is working correctly, you will get GCU, which codes for alanine. But if the RNA pol. makes a mistake, it can transcribe CGA incorrectly, perhaps as GCA. But that won't have any effect on the final protein, since GCA also codes for alanine.

Mutations happen all the time, and as I just explained, most are neutral. But whether a mutation is beneficial or deleterious depends on the organism's environment. A mutation that is beneficial for one organism may be harmful to another. Whether a mutation (or group of mutations) is selected for in an environment is where the randomness stops. The mutations are random (i.e we cannot predict them, AFAIK), but their continued existence is not (if they are beneficial).

Punctuated equilibrium: Evolution 101: The Big Issues