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Author Topic:   Micro v. Macro Creationist Challenge
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


Message 181 of 252 (816616)
08-08-2017 7:47 AM
Reply to: Message 180 by CRR
08-07-2017 9:28 PM


Re: Non homologous genes
CRR writes:

However if you go back to my past posts you will find that I disagree with equating macroevolution to speciation. I have said that speciation could be the result of either microevolution or macroevolution; where the critical difference is whether the mutation adds a significant amount of new genetic information.

Fruitful discussion requires agreement on definitions. As a starting point, here's the definition of macroevolution from Wikipedia:

quote:
Macroevolution is evolution on a scale at or above the level of species, in contrast with microevolution, which refers to smaller evolutionary changes of allele frequencies within a species or population.
Macroevolution and microevolution describe fundamentally identical processes on different time scales.

In your view, what's wrong with that definition?

--Percy


This message is a reply to:
 Message 180 by CRR, posted 08-07-2017 9:28 PM CRR has responded

Replies to this message:
 Message 183 by CRR, posted 08-09-2017 3:52 AM Percy has responded

  
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


Message 185 of 252 (816666)
08-09-2017 9:08 AM
Reply to: Message 183 by CRR
08-09-2017 3:52 AM


Re: micro/macro definitions
CRR writes:

The issue remains unresolved.

How can fruitful discussion about micro and macroevolution take place while disagreement about their definitions remains?

--Percy


This message is a reply to:
 Message 183 by CRR, posted 08-09-2017 3:52 AM CRR has not yet responded

  
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


(1)
Message 204 of 252 (817032)
08-15-2017 7:23 AM
Reply to: Message 202 by CRR
08-13-2017 2:23 AM


Re: Non homologous genes between humans and chimps
CRR writes:

That would depend on what changes were required to produce the differences and how you define micro/macro evolution....
...
This is why I originally said that you had arranged a "no win" challenge since you can make any assumptions you want and your definition of "microevolution" is so broad that such a scenario is permissible. From Message 1:

Taq writes:

...Just for clarity, I am defining a microevolutionary change as a single mutational event (e.g. base substitution, insertion, deletion, transposon insertion, retroviral insertion, or genetic recombination) that is passed on to descendants.

From the above it can be seen that your statement that Taq defined microevolution broadly is contradicted by his very words that you quote, which describe a rather narrow definition.

These are the definitions of micro and macroevolution you offered in Message 183:

microevolution = changes in gene frequencies and trait distributions that occur within populations and species
macroevolution = large evolutionary change, usually in morphology, typically refers to evolution of differences among populations that would warrant their plaecment in different genera or higher-level taxa

(from the flashcard website http://www.cram.com/flashcards/evolution-2013900)

Yours and Taq's definitions seem well within the realm of reconciliation. I continue to encourage you to reach agreement on the definitions.

Taq writes:

If humans did evolve from a common ancestor shared with chimps, would you accept that as an example of macroevolution?

That would depend on what changes were required to produce the differences and how you define micro/macro evolution. As I've said before IF the common ancestor had all the human genes that chimps lack (and vice versa) and IF you define genetic loss as microevolution THEN it could be entirely microevolution.

No one's defining microevolution as genetic loss, and no one's calling human/chimp evolution from a common ancestor microevolution. Chimps have genes humans don't have, and humans have genes chimps don't have. That would seem the very definition of the accumulation of microevolutionary changes into macroevolution.

--Percy


This message is a reply to:
 Message 202 by CRR, posted 08-13-2017 2:23 AM CRR has responded

Replies to this message:
 Message 205 by CRR, posted 08-16-2017 7:34 AM Percy has responded

  
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


Message 206 of 252 (817268)
08-16-2017 10:10 AM
Reply to: Message 205 by CRR
08-16-2017 7:34 AM


Re: Non homologous genes between humans and chimps
CRR writes:

What I was trying to point out is that there is no single agreed definition for micro/macroevolution.

All you've done is demonstrated a fact of life, that different people use different words and ways to define the same things.

Both the definitions I gave disagreed with your quoted definition for macroevolution.

Not in any substantive way. If you think there are meaningful disagreements then point them out.

In message 1 Taq is trying to define microevolution as a single mutation event including almost any possible change, including an insertion of any size. The de novo appearance of a fully functional orphan gene as a single insertion would therefore be counted as microevolution.

Technically yes it would, but that's an impossibly unlikely event.

Basically Taq allows himself a magic wand to accomplish any imaginable change in an arbitrary time.

Taq has never said anything like this.

--Percy


This message is a reply to:
 Message 205 by CRR, posted 08-16-2017 7:34 AM CRR has not yet responded

  
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


Message 209 of 252 (817364)
08-17-2017 7:35 AM
Reply to: Message 208 by CRR
08-16-2017 6:37 PM


Re: Non homologous genes between humans and chimps
CRR writes:

I am defining macroevolution as a gain of a statistically significant amount of genetic information.

Macroevolution should constitute gains, losses and changes of genetic information.

What do you consider a "statistically significant amount of genetic information"? Chimp and human genomes are percentagely similar in the high 90's.

--Percy


This message is a reply to:
 Message 208 by CRR, posted 08-16-2017 6:37 PM CRR has responded

Replies to this message:
 Message 211 by CRR, posted 08-18-2017 6:12 PM Percy has responded

  
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


Message 212 of 252 (817669)
08-19-2017 9:41 AM
Reply to: Message 211 by CRR
08-18-2017 6:12 PM


Re: Non homologous genes between humans and chimps
CRR writes:

Microevolution: genetic variation that requires no statistically significant increase in functional information.

This is just a bunch of weasel words. If a mutation causes a new allele to be added to the gene pool of a population, then that is an increase in information. If via selection an allele disappears from the gene pool of a population, then that is a decrease in information.

--Percy

Edited by Percy, : "a mutation" => "an allele" in last sentence.


This message is a reply to:
 Message 211 by CRR, posted 08-18-2017 6:12 PM CRR has acknowledged this reply

  
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


Message 216 of 252 (818353)
08-27-2017 12:31 PM
Reply to: Message 215 by CRR
08-27-2017 3:48 AM


Re: Non homologous genes between humans and chimps
CRR writes:

Did this gene evolve independently in 4 species but not in the other; or is it a gene that comes from a common ancestor and was lost in the chimp species?

The latter.

Similarly there are genes in the chimp that have no homologue in humans but does have homologues in Orangutan, Gorilla, and Macaque. How would you explain this?

Same way.

It seems that you find many genes that appear to be shared across several species but are missing from some. What does this indicate for how you view primate evolution?

Primate evolution is an unremarkable example of evolution in action.

--Percy


This message is a reply to:
 Message 215 by CRR, posted 08-27-2017 3:48 AM CRR has not yet responded

  
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


Message 223 of 252 (818550)
08-30-2017 8:56 AM
Reply to: Message 218 by CRR
08-30-2017 12:04 AM


Re: Non homologous genes between humans and chimps
CRR writes:

So the hypothetical common ancestor of humans and chimps would have had a few hundred more genes that either humans or chimps.

That's how you've decided to measure amount of information in a genome? By counting the genes? The more genes the more information? Probably not valid.

Anyway, you've made the error of paying attention to only one side of ledger, namely losing genes. Humans and chips have also acquired genes. Here's a chart that provides some gains and losses in number of genes:

So the hypothetical common ancestor of humans and chimps would have had a few hundred more genes that either humans or chimps.

The chart says the opposite, that the common ancestor had fewer genes.

So this would be clear evidence of devolution.

More genes doesn't mean better. The amoeba genome is a hundred times larger than the human genome, though I don't know how many genes it has. And the water flea Daphnia has 31,000 genes, exceeding the human count of 19,000 by quite a bit. And does the Daphnia genome contain more information than the human genome? At the rate you're figuring out how to measure information, you'll never be able to answer that question.

Creationists have been saying for some time that devolution, rather than evolution, is what we observe in nature.

What we observe in nature is the process of evolution, which includes gaining and losing chromosomes, genes and alleles. The term "devolution" has no defined meaning within biology.

--Percy


This message is a reply to:
 Message 218 by CRR, posted 08-30-2017 12:04 AM CRR has not yet responded

  
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


Message 228 of 252 (819049)
09-05-2017 1:56 PM
Reply to: Message 226 by Meddle
08-31-2017 11:01 PM


Re: Non homologous genes between humans and chimps
Meddle writes:

I would agree with Taq, Percy and others that these were examples of gene loss in the ancestors of Chimpanzees since they branched off from a common ancestor with Humans.

Actually, I didn't say that. It seems to me that other things being equal that something more symmetric should have happened, that humans and chimps should both have acquired and lost alleles and genes since the common ancestor. Here's some information I thought significant from the paper Comparing the human and chimpanzee genomes: Searching for needles in a haystack says:

quote:
∼50 known or predicted human genes were found to be missing partially or entirely in the chimpanzee genome, and some of these differences were confirmed by PCR or Southern blotting (The Chimpanzee Sequencing and Analysis Consortium 2005).
...
Alu elements (duplications) are the most abundant class of SINEs in humans, making up ∼10% of the genome (Lander et al. 2001), where they apparently expanded up to three times more than in the chimpanzee genome (The Chimpanzee Sequencing and Analysis Consortium 2005).
...
However, given the relatively few protein-sequence differences between human and chimpanzees, differential regulation of gene and protein expression is a likely mechanism for explaining human:chimpanzee differences.

In other words, chimps may have lost genes that humans did not; duplications were 10 times more common in the human genome; and gene regulation by non-coding regions is a large unexplored area. There's a lot more in the paper.

--Percy


This message is a reply to:
 Message 226 by Meddle, posted 08-31-2017 11:01 PM Meddle has responded

Replies to this message:
 Message 240 by Meddle, posted 09-09-2017 10:22 AM Percy has acknowledged this reply

  
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


Message 236 of 252 (819188)
09-07-2017 6:01 PM
Reply to: Message 233 by CRR
09-07-2017 5:34 PM


Re: Genetic Differences
I've been trying to track down more details about this chart:

I originally assumed the obvious, that the number in the right hand column is the number of genes, and that the red/blue numbers are the number of genes added/subtracted from the common ancestor. But now I'm not sure I trust this chart, for these reasons:

  • For humans:

    19619+276-1439 = 18456

    For chimps:

    17811+933-274 = 18470

    That number on the right should be the number of genes for the common ancestor, and it should be the same number whether you calculate backwards from human or chimp, but it isn't. There may be a good explanation, but I don't know what that is, and I couldn't find an explanation anywhere.

  • The number of genes for humans is estimated to be 19,000-20,000, but that chart places it at 19,619, which is far more precision than we currently have.

  • The number of genes for chimps is estimated to be 20,000-25,000, but the chart places it at 17,811, again, too much precision, and far different than the estimate.

  • We haven't studied the genomes of the other animals in the table to anywhere near the extent of humans and chimps and so could not possibly know the number of genes to the precision in the table.

  • If the numbers in the chart *are* genes, then as you noted the mutation rate is very, very high. Far too high. Not possible.

  • I can't find the webpage that the chart comes from.

For these reasons, I'm disavowing this chart.

But the original point made back in my Message 223 still stands. It's not valid to pay attention to "only one side of the ledger, namely losing genes."

--Percy


This message is a reply to:
 Message 233 by CRR, posted 09-07-2017 5:34 PM CRR has not yet responded

  
Percy
Member
Posts: 20334
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.1


Message 251 of 252 (819504)
09-11-2017 9:11 PM
Reply to: Message 249 by CRR
09-11-2017 5:47 PM


Re: Genetic Differences
CRR writes:

I've already said I'm not interested in answering the original topic because it is set up as a no win proposition.

It was not a "no win proposition." Message 1 posed a simple question: why aren't two SNPs just nothing more than two microevolutionary events?

I don't know what you're afraid of. An SNP is the most basic of microevolutionary events. Two SNPs would be two basic microevolutionary events. What is the problem with simply acknowledging this?

--Percy


This message is a reply to:
 Message 249 by CRR, posted 09-11-2017 5:47 PM CRR has not yet responded

  
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