Should at Least Make Evolutionists Consider

[Purple Knight]

Question for Debate: Why, and how, does the muntjac deer have only seven pairs of chromosomes?

Please don't look this up, at least until you've considered for a moment how weird this is. Imagine you have 20 pairs of chromosomes, and you have a baby that has sixteen pairs. He shouldn't be able to breed with the rest of your species.

Is this at least weird? A regular deer has around 40-70 chromosomes. Is it at least strange that he can even be alive having lost that much genetic information? One more halving and he'll be a fruit fly (they have 4 pairs).

[Difflugia]

"...in bed!"

AI Overview

Some gorilla-chimp similarities pose challenges to standard evolutionary models. For instance, at a significant number of genetic markers, humans and gorillas exhibit closer genetic relationships than humans and chimps. This contradicts the prediction that humans and chimps share a more recent common ancestor. Additionally, the Y chromosome of each great ape species has unique DNA sequences, further complicating the evolutionary narrative.

Two things:

First, this has absolutely nothing to do with the statement of mine that you quoted, so it's already a non sequitur, even in the broader, rhetorical sense.

Second, all this means is that humans, chimpanzees, and gorillas are all so closely related that the exact pattern of divergence is difficult to resolve. If it were the problem for evolution that you think it is, then we should have the same problem between any set of species. If the evolutionary pattern is as meaningless as you're trying to imply, then we shouldn't be able to resolve any genetic relationships, because such patterns shouldn't exist.

Your implied argument is basically that since humans, chimpanzees, and gorillas are so closely related that the exact evolutionary pattern is difficult to resolve, then evolution itself is somehow called into question. Instead, if evolution weren't responsible for both the similarities and differences between our species, "too closely related" wouldn't even be a thing.

[marke]

"...in bed!"

AI Overview

Some gorilla-chimp similarities pose challenges to standard evolutionary models. For instance, at a significant number of genetic markers, humans and gorillas exhibit closer genetic relationships than humans and chimps. This contradicts the prediction that humans and chimps share a more recent common ancestor. Additionally, the Y chromosome of each great ape species has unique DNA sequences, further complicating the evolutionary narrative.

Two things:

First, this has absolutely nothing to do with the statement of mine that you quoted, so it's already a non sequitur, even in the broader, rhetorical sense.

Second, all this means is that humans, chimpanzees, and gorillas are all so closely related that the exact pattern of divergence is difficult to resolve. If it were the problem for evolution that you think it is, then we should have the same problem between any set of species. If the evolutionary pattern is as meaningless as you're trying to imply, then we shouldn't be able to resolve any genetic relationships, because such patterns shouldn't exist.

Your implied argument is basically that since humans, chimpanzees, and gorillas are so closely related that the exact evolutionary pattern is difficult to resolve, then evolution itself is somehow called into question. Instead, if evolution weren't responsible for both the similarities and differences between our species, "too closely related" wouldn't even be a thing.

Marke: I meant by my post to point out that assumptions about evolutionary connections between humans and various animals based on chromosome counts do not adequately refute other evidence that contradicts those types of evolutionist assumptions.

[Difflugia]

I meant by my post to point out that assumptions about evolutionary connections between humans and various animals based on chromosome counts

What assumptions do you think scientists make about chromosome counts?

do not adequately refute other evidence that contradicts those types of evolutionist assumptions.

What evidence? Assuming this isn't another non sequitur, what do you think the time of divergence between humans, gorillas, and chimpanzees has to do with the improbability of hybridization? That's what we were discussing, after all.

[marke]

I meant by my post to point out that assumptions about evolutionary connections between humans and various animals based on chromosome counts

What assumptions do you think scientists make about chromosome counts?

Marke: I have reason to think that evolutionists believe DNA and chromosome count similarities must be interpreted as evidence of evolution of life forms through the ignorant accidental process of random natural selection.

do not adequately refute other evidence that contradicts those types of evolutionist assumptions.

What evidence? Assuming this isn't another non sequitur, what do you think the time of divergence between humans, gorillas, and chimpanzees has to do with the improbability of hybridization? That's what we were discussing, after all.

Marke: I have never seen any evidence that time provides the necessary missing link for believing that humans and mice evolved from the same ancestoral species.

[Difflugia]

What assumptions do you think scientists make about chromosome counts?

I have reason to think that evolutionists believe DNA and chromosome count similarities must be interpreted as evidence of evolution of life forms through the ignorant accidental process of random natural selection.

What reason is that?

What evidence? Assuming this isn't another non sequitur, what do you think the time of divergence between humans, gorillas, and chimpanzees has to do with the improbability of hybridization? That's what we were discussing, after all.

I have never seen any evidence that time provides the necessary missing link for believing that humans and mice evolved from the same ancestoral species.

Whether that's true or not, that's neither what I asked nor what we're discussing. You asserted that there is "other evidence that contradicts those types of evolutionist assumptions," by which you presumably meant something to do with humans, chimpanzees, and gorillas. Maybe not, though; you're kind of all over the place.

In case you need it spelled out for you, you keep making claims, but offer no support or justification for them. Without evidence, your statements carry as much weight as, "You will have a personal success tomorrow," or "Lucky Numbers 19 24 7 44 3 17."

In bed!

[marke]

What assumptions do you think scientists make about chromosome counts?

I have reason to think that evolutionists believe DNA and chromosome count similarities must be interpreted as evidence of evolution of life forms through the ignorant accidental process of random natural selection.

What reason is that?

Marke: Do I believe evolutionists assume similar DNA between species prove common ancestry? Yes.
AI Overview
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Yes, evolutionary biologists and scientists generally view shared DNA similarities as strong evidence for common ancestry. The more DNA similarities two species share, the closer they are believed to be related on the evolutionary timescale. This shared DNA reflects the inheritance of genetic information from a common ancestor, and is a key piece of evidence supporting the theory of evolution.

I don't think the common ancestor assumptions are right for many reasons, including the close similarity between human and mice DNA.

What evidence? Assuming this isn't another non sequitur, what do you think the time of divergence between humans, gorillas, and chimpanzees has to do with the improbability of hybridization? That's what we were discussing, after all.

Marke: I don't understand why you think my concern about gorillas is not pertinent but I still think there are kinks in certain evolutionary assumptions or theories.
AI Overview
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Gorillas present a challenge to the assumptions about chimpanzee and human common ancestry because genomic studies reveal that humans are sometimes more closely related to gorillas than to chimpanzees in certain genetic regions. This "gorilla-human closeness" is difficult to reconcile with the conventional view of chimpanzees as being the closest living relatives to humans.


I have never seen any evidence that time provides the necessary missing link for believing that humans and mice evolved from the same ancestoral species.

Whether that's true or not, that's neither what I asked nor what we're discussing. You asserted that there is "other evidence that contradicts those types of evolutionist assumptions," by which you presumably meant something to do with humans, chimpanzees, and gorillas. Maybe not, though; you're kind of all over the place.

In case you need it spelled out for you, you keep making claims, but offer no support or justification for them. Without evidence, your statements carry as much weight as, "You will have a personal success tomorrow," or "Lucky Numbers 19 24 7 44 3 17."

In bed!

[Difflugia]

Do I believe evolutionists assume similar DNA between species prove common ancestry? Yes.

Leaving aside the implications of "assume," that's true. That's not what you said, though; you were talking specifically about chromosome number. Are you abandoning that claim and moving on to "similar DNA" rather than "chromosome number?"

I don't think the common ancestor assumptions are right for many reasons,

What reasons?

including the close similarity between human and mice DNA.

We're both mammals, so why do you think they wouldn't be similar? If you're asserting that they're too similar in a way that affects evolutionary theory, how would you quantify that?

I don't understand why you think my concern about gorillas is not pertinent

I don't understand why you think it is. Gorillas, chimpanzees, and humans are all closely related and share common ancestors. Phylogenetic studies have determined that we share a more recent ancestor with chimpanzees than we do with gorillas, but because of the way things like genetic drift work in populations, there are a number of sequences that we share more closely with gorillas than we do with chimpanzees. This isn't a problem with any part of evolutionary theory and is expected with species that are very closely related. What do you think the actual problem is?

but I still think there are kinks in certain evolutionary assumptions or theories.

So you keep saying, but haven't actually supported.

I have never seen any evidence that time provides the necessary missing link for believing that humans and mice evolved from the same ancestoral species.

I bet there are a lot of things you haven't seen. You not knowing something isn't evidence of anything else, though.

[Difflugia]

I don't understand why you think my concern about gorillas is not pertinent

Here is an AI Overview. I asked ChatGPT the following question:

A creationist acquaintance is having trouble with the idea that gorillas, chimpanzees, and humans are so closely related that some human and gorilla sequences are shared with each other, but not chimpanzees. They're having difficulty reconciling that with both the idea that chimpanzees and humans share a more recent common ancestor than either does with a gorilla, and that this isn't a problem for evolutionary theory writ large. Assuming I've accurately explained their position and that mine is clear from the question, could you explain in some detail any potential flaws in each of our understandings?

ChatGPT responded with the following overview:

Yes, you've laid out a thoughtful and accurate framing of a classic point of confusion that even many scientifically literate people find initially counterintuitive. Let's carefully unpack the issue.



THE BASIC CLAIMS (summarized for clarity)

1. Your acquaintance's difficulty:
   They’re puzzled by the observation that some human DNA sequences are more similar to gorilla DNA than to chimpanzee DNA, even though the widely accepted evolutionary tree places humans and chimpanzees as closer relatives than either is to gorillas. They seem to think this observation contradicts the evolutionary model.
2. Your understanding (presumably):
   You're aware that humans and chimpanzees do share a more recent common ancestor than either does with gorillas, and you believe that the existence of shared human-gorilla sequences does not contradict that model.

Let’s break this down.



PART I: WHAT DOES EVOLUTIONARY THEORY ACTUALLY SAY?

Evolutionary theory posits that species share common ancestors and diverge over time. The closer the common ancestor, the more similar the genomes (on average). However, that’s a statistical trend, not an absolute rule for every gene or every sequence.

The current consensus phylogenetic tree, supported by morphology and genomics, shows this:

Code: Select all

      /--- Gorilla
     |
     |    /--- Chimpanzee
-----|----|
          \--- Human

Humans and chimpanzees share a more recent ancestor (~6-7 million years ago), whereas gorillas diverged earlier (~8-10 million years ago).



PART II: THE KEY CONCEPT – INCOMPLETE LINEAGE SORTING (ILS)

What is ILS?

Incomplete Lineage Sorting is a well-understood phenomenon in population genetics. When three lineages diverge in relatively quick succession, some genetic loci will not follow the "species tree".

Imagine the ancestral population of humans, chimps, and gorillas contained multiple versions (alleles) of a gene. When these lineages split, not all alleles are sorted neatly into descendant species. As a result:

• At some loci, humans and chimps will be most similar (expected).
• At some loci, humans and gorillas will be most similar (unexpected to soe).
• At others, chimps and gorillas will be closest.

This is not a flaw or contradiction; it’s a direct consequence of:

• Ancestral polymorphism (multiple alleles present before speciation)
• Short intervals between divergence events
• Random sorting of alleles into descendant lineages

How common is this?

About 70% of the genome supports the human-chimp clade. The other ~30% shows patterns like human-gorilla or chimp-gorilla similarity. This is entirely predicted by evolutionary models and has been confirmed by genome-wide analyses (e.g., Scally et al., *Nature*, 2012).



PART III: FLAW IN THE CREATIONIST’S THINKING

1. Assumption of absolute genetic hierarchy: They may believe that every part of the genome must strictly follow the species tree, but evolution predicts variation due to shared ancestry and stochastic processes like ILS.
2. Lack of understanding of population-level processes: Evolution doesn’t work by splitting single individuals into new species; it acts on populations, which often carry multiple gene variants at the time of divergence.
3. Thinking in terms of essentialism or typology: They might assume each species has a single, ideal genetic sequence, instead of understanding variation and overlap in terms of allelic diversity and probability.

PART IV: POTENTIAL MISUNDERSTANDING ON YOUR SIDE (IF ANY)

Your understanding seems broadly sound. However, one thing to watch for is:

• Overreliance on tree diagrams as absolute: The species tree (human-chimp closer than either to gorilla) reflects the majority of genetic signals, but gene trees vary, and recognizing that variation is part of how we test and confirm the evolutionary model.

You might also be cautious to not frame all human-gorilla similarity as due to ILS. Some cases can result from convergent evolution, gene loss, or horizontal gene transfer (rare in mammals, but not impossible via retroviruses). ILS is just the dominant explanation for this particular case.



TL;DR

• Human and gorilla sequences being more similar than chimpanzee ones at some loci is predicted by evolutionary theory.
• This is due to Incomplete Lineage Sorting and the short time between divergence events.
• The overall picture still supports the human-chimp closer relationship.
• Your acquaintance’s confusion stems from treating the species tree as uniformly reflected in the genome, rather than understanding gene-by-gene variation.

Would you like a metaphor or visual explanation to help explain this to your acquaintance?