Macroevolution?

Question

Hi, folks. I was just discussing evolution with a very intelligent Creationist over on the Religion and Spirituality board & then through private emails and s/he made me really examine my belief in evolution. So I'm coming to learn a bit more about what I profess to believe.

Is the primary driving force behind macroevolution mutations? And in primates, since we only give birth to one every 9 months per fertile female, the mutation would have to be either dominant - and thus, wouldn't it eventually eclipse the non-mutated creature, or there would have to be a mass mutation with a sudden spike in births with the mutation, right? Can that - in primates that produce offspring so slowly - actually result in divergent evolution?

Sorry if this is a really stupid question. Please put it in terms that an English major will understand! Thanks!

Wow... I don't recall asking anything religious in nature. I was asking about the mechanisms of macroevolution. I'm sorry I bothered to tell ou why I was asking, but if I wish to contine my argument, I need more knowledge. I'm sorry if that offends you.

Thank you, Joe!! That makes sense.

Yoda, I emailed you because I think you probably have some intelligent things to bring to the conversation.

Answer 1

First, forgive some others here who appear to be a bit overdefensive. I'm taking it it at face value that you are asking a sincere question, and therefore deserve a sincere answer.

Whatever drives microevolution drives macroevolution as well. They are not fundamentally different processes as far as people who understand the theory of natural selection are concered. If two populations of the same species get genetically separated for a long time (say, a few thousand generations), and both experience microevolution then they will eventually lose the ability to interbreed with each other (the definition of speciation) and will be *permanently* genetically isolated. I.e. enough microevolution produces macroevolution.

This is why only creationists use that false distinction 'micro-' vs. 'macro-' evolution. There is a difference in *scale* between the two, but not a difference in *kind* (they don't require different mechanisms).

W.r.t. mutations, almost all mutations are indeed recessive. But recessive genes are neither helpful nor harmful and can therefore propagate at random through a population ... it is "hidden" from natural selection. Eventually, however, two carriers of that recessive gene will mate and produce offspring that express it. If the gene confers some benefits, then that individual will produce slightly more offspring than others in the population ... if harmful, that individual will produce slightly fewer. The gene has become "visible" to natural selection. In this way, beneficial genes will propagate faster *on average* in the population. That is the mechanism that drives 'microevolution', as well as 'macroevolution'.

Answer 2

It's a noble reason to ask as knowing more helps you make more informed decisions. Macroevolution is change between gene pools so the genes that make up a population. This occurs amongst two or more isolated gene pools of the same species. The isolated populations (all individuals of a species in one area) are acted differently on by natural selection (survival of the fittest as new genetic combinations occur producing favorable traits). It slowly occurs with the changes accumulating producing two different species as they can no longer interbreed and produce fertile offspring. Mutations only need to occur in the sex cells to get passed on. Macroevolution occurs over many years with the main driving force being genetic recombination. Mutations only play a part in the new combinations as whenever two individuals randomly mate, they produce a unique combination. There are other things that cause new combinations of genes but it requires some biology terminology.
Hope that helps.

Answer 3

"Is the primary driving force behind macroevolution mutations?"

Well, not exactly. Mutations are the source of variation in the gene pool, not a "driving force" in and of themselves. Everyone is born with several (on average) mutations (gene sequences not present in either parent.)

The mutation would NOT have to be dominant. Recessive genes get passed on just as dominant ones do. They may not express right away, but as they would be neutral in effect at first, there would be no reason for them not to be passed on at first, even if harmful. Nor would there have to be a "spike" of mutations. There are many mutations present in every generation of every population. Some may disappear and some may get passed on.

Your problem seems to be that you are thinking in terms of a single specific mutation in a single specific individual. Remember that mutations are the source of variation in a large, reproducing, population of organisms.

It's non-intuitive to think in terms of populations - it's much easier to think in terms of specific individuals. But the key to truly understanding evolution is to approach it in terms of populations. Populations evolve, individuals don't.

Answer 4

You're a liar.
No one who has more than a teaspoon full of brain matter "questions" evolution. No one.
And there is NO such thing as an "intelligent creationist". Creationism is the ultimate is intellectual failure.
To reject literally hundreds of thousands of pages of research and facts that surround Evolution in favor of an outdated and irrelevant book of bronze-age jewish mythology, is the biggest cop-out there is.
So please, take your pious fraud elsewhere, this is a SCIENCE board. Religious crap belongs elsewhere. Think of this as a science class ok?
The fact is, you don't want knowledge, you want a quick, simple and childish answer like "god did it". Well you know what? Science does not work that way. There are no easy answers, only more questions. You want brainless absolutes? Stick to religion. You want ideas, facts and hypothesis? Stick to science. But do try and learn the difference between reality and fantasy first ok?

Oh and for the record, I'll make it really easy for you;
Micro + micro + micro + micro + micro + micro = Macro. Pretty simple huh?

Answer 5

This is not only off topic but it's blatently religious in nature. If you are going to take the word of some born again about Evolution, then why are you studying the science of Biology?