What is the mechanism that stops genetic differences from accumulating to the point of speciation?

A common creationist fallacy when presented with evidence for evolution is "That is adaptation/microevolution, not [macro]evolution". However, genetic change is genetic change. The only difference between the (supposed) micro and macroevolution (terms that only creationists seem to use) is the amount of genetic change in a population. Furthermore, "species" is nothing more than a man-made construct. It's not a tangible "thing". We could define species in any way we please so this barrier that stops genetic change in populations from accumulating to the arbitrary point of speciation needs to be defined and supported with evidence. Otherwise, the argument is baseless.

So, the question for creationists is:

Can you describe and present evidence for the mechanism that stops genetic differences in populations from accumulating to the point of speciation?

Please describe, biologically, what this mechanism is and present evidence for said mechanism. How does this barrier work? What is the empirical evidence for this barrier?

PSA: This is not a thread for discussing any other aspect of creationism or evolution, it's a thread that's asking a very specific question so please do not derail this thread by dragging the discussion away from the topic outlined above.

a reply to: GetHyped

The same thing that prevents the accumulation of stones into a pile from becoming a mountain. Nothing.

a reply to: GetHyped

Jesus!! the Bible and 6000 year old earth thats what.

Wheres tinsheep?.

a reply to: GetHyped

That depends; are you Micah Hanks?

It's one thing to pose a question, it's another to pose a question that no one that can possibly know the answer to without making someone feel inferior in one way or another.

Keep it simple; there is no point being superior if no one knows what you are talking about.

I'm sure there's a biological code that doesn't let ones genetics color outside the lines as a career choice

a reply to: Thecakeisalie

A common creationist fallacy when presented with evidence for evolution is "That is adaptation/microevolution, not [macro]evolution". However, genetic change is genetic change. The only difference between the (supposed) micro and macroevolution (terms that only creationists seem to use) is the amount of genetic change in a population. Furthermore, "species" is nothing more than a man-made construct. It's not a tangible "thing". We could define species in any way we please so this barrier that stops genetic change in populations from accumulating to the arbitrary point of speciation needs to be defined and supported with evidence. Otherwise, the argument is baseless.

a reply to: hknudzkknexnt

What is this code? Where are these lines?

As you've stated, we do not currently have a clearly defined outline of what amounts to a new "species". For example, an american bison and a domestic cow could be crossed to produce hybrids (beefalo), which are viable and fertile. Therefore, could one classify bison and cow as belonging to the same species? Of course not. Therefore, without a clearly defined meaning of what counts as a "species", the question you are imploring is moot.

Due to heritablity of genes, it is possible to conclude with reasonable certainty that with enough genetic variation speciation would occur. However, without a well established definition of "species", the specific question you are exploring cannot be accurately studied and/or debated. Perhaps with developments in gene sequencing and other techniques, the scientific community could reach a consensus on the exact boundaries between two similar species and this topic could be re-explored.

a reply to: Thecakeisalie

I know what he is talking about. Anyone who is well studied in evolutionary theory would know what he is talking about. Now, NATURALLY, the Creationists he is talking to probably don't know what he is talking about, but that's because they are largely poorly studied in Evolutionary theory.

a reply to: Pistoche

Actually you raise a very good point. The definition of a species is, to some extent, still arbitrary, however most scientists agree that it has to do with infertility between the two populations. As you point out though sometimes species that are still related but would seem on the surface to be quite different can produce hybrids such as the beefalo or liger.

I think the point of this thread, though, is that there is no built-in mechanism that would STOP animals from crossing the species boundary and thus no mechanism that would prevent the tree of life from expanding out further and further branches given long enough. Even if we don't agree 100% on what a species is there is no genetic boundary built in to stop incremental changes from adding up over generations to produce something new and, if that new population is driven far enough it will become a new species.

The fact that we can disagree on where that species line lies shows how long evolution often takes. For example dogs are now a subspecies of wolves while some used to think they were a separate species but either way the variety of breeds is evidence of evolution.

Creationists often reference the Biblical passage that says God created animals after their "kind" which some argue means that animals can evolve but not outside their Genus, they had to admit this after it was shown that new species could emerge. The goalposts of creationism are constantly moving.

a reply to: GetHyped

However you forget that the initial evidence is dubious at best and requires further scrutiny. But don't let said scrutiny stop you, there needs to a homogeneous defunct proletariat to stop the inevitable deluge of hate that will follow.

Say what you think because a thesaurus won't think for you.

a reply to: Thecakeisalie

What "initial" evidence is dubious at best exactly? There are TONS of evidence in favor of evolution that could be considered "initial" evidence. So what exactly are you talking about?

a reply to: GetHyped

Can I remind everyone this from the OP.


PSA: This is not a thread for discussing any other aspect of creationism or evolution, it's a thread that's asking a very specific question so please do not derail this thread by dragging the discussion away from the topic outlined above.


So can anyone answer his question?.

Well if a creationist thinks the Earth is only 6,000 years old, then there hasn't been enough time for things to evolve. Also, the Bible basically says that God created the plants and animals all at once as they are today, and the dinosaurs were too big to fit on Noah's Ark.

a reply to: Krazysh0t

You know what? it's my bad. I am not a creationist.

I am just tired. Tired of people reaching for the thesaurus to make their argument seem more plausible then it truly is.

I just want people to make sense.

a reply to: Krazysh0t

I think you misunderstood me, or I screwed up.

I agree with the sentiments but I don't agree with the delivery, what many people want is something they can relate to instead of big words. K.I.S.S.

a reply to: Thecakeisalie

This thread is about the specific creationist claim: "That is adaptation/microevolution, not [macro]evolution".

Thus, the question posed is: Can you describe and present evidence for the mechanism that stops genetic differences in populations from accumulating to the point of speciation?

The entire creationist argument hinges on this supposed barrier. The purpose of this thread is to try and get creationists to support this claim in some scientific way.

Do you have anything to add that is on-topic?

a reply to: darkbake

Unfortunately, that's not what this thread is about. Creationists will (usually) concede that small genetic change is "adaptation", and that large genetic change is somehow impossible. Why? What stops genetic change in a population from accumulating beyond some arbitrary point? What is this arbitrary point? What is the biological mechanism that stops too much genetic change from accumulating?

a reply to: GetHyped

Just a shot in the dark here but I "THINK" it would take time and sufficient genetic adaptation to branch off the mother or host species to justify being a new species. Kinda like the new fossils found in Africa of the little hominids, while they may technically be hominids they are not human. We are related but not the same species. Was I even close to an answer here???

originally posted by: Pistoche
As you've stated, we do not currently have a clearly defined outline of what amounts to a new "species".

I agree that the definition of "species" can be ambiguous and, ultimately, it's an arbitrary line in the sand. However, creationists will often treat species as this tangible thing, and that genetic change can't diversify a population beyond this barrier.

Therefore, without a clearly defined meaning of what counts as a "species", the question you are imploring is moot.

My point is that ultimately any definition of species is moot to the argument that genetic change can't accumulate beyond whatever line in the sand you draw. Why? What stops genetic change from accumulating beyond any line in the sand anyone cares to draw?

Again, this is to address the common creationist claim that "That is adaptation/microevolution, not [macro]evolution".