[quote=“TimothyHicks, post:39, topic:3245”]
Keep in mind I was never taught evolutionary theory in school. And when it was explained to me it was explained by people who didn’t believe it … Naturally my view of it is distorted.[/quote]
I understand.
I am not calling you a denialist. Denialists take advantage of your lack of understanding to emphasize mutation. Simple question: did Darwin know about mutations?
I agree and I’m trying to help.
Simple questions:
- Are organisms in a population different from each other?
- Are at least some of those differences heritable?
- Does every organism leave the same number of offspring?
Think about these in the context of humans.
Only those that occur in the germline are relevant to evolution, and they add very little to the variation already present (see #1 above).
My point is this: understanding evolution doesn’t start with mutations!!! Understanding evolution starts with observing heritable variation in a population.
You’re missing the simple obvious existence of heritable variation and focusing too much on mutations. New mutations contribute very, very little to the reservoir of variation already there.
If you think of them as variations, then you’re on track. Thinking of them as new mutations is the problem.
Two things: “traits” is far superior conceptually to “mutations,” but Mendel showed that much of inheritance is particulate, not “a mix.” Do you understand dominant vs. recessive alleles?
The concept that you are missing is that genetic variation is sufficient–new mutations are not required.
There are multiple mechanisms, and yes.
Absolutely zero new mutations are needed for this type of speciation (allopatric)! With a barrier, existing genetic variation in each of the now-separate populations is sufficient to allow drift, even in the absence of any difference on either side of the barrier, to lead to reproductive isolation and speciation.
Correct, even if we could shut off all new mutations.
What makes you think that our common ancestor with bacteria remained basically unchanged? How many different species of bacteria are there?