Freethought & Rationalism Archive

KnightWhoSaysNi · 10-08-2002, 07:38 PM

Hi sciteach,

Here's a question we often like to challenge new creationists with in the E/C forum, originally proposed by scigirl. I also challenge you to show this to your students, and let them decide for themselves whether common ancestry or common design makes more sense:

(scigirl, I hope you don't mind if I usurp you a little

)

Quote:

Here's a question for you, about some evidence for evolution of humans.
<a href="http://www.gate.net/~rwms/EvoEvidence.html" target="_blank">http://www.gate.net/~rwms/EvoEvidence.html</a>
Chimps have 24 chromosomes in their sperm/eggs, we only have 23. According to the site above, scientists speculated that perhaps two of the chromosomes fused in our chimp-like ancestor, giving us 23 chromosomes. If this theory is true, than we should see two things: two extra telomeres in our chromosome 2 (we have them), and an extra non-functioning centromere (we have it).

Keep in mind, the evolutionary tree (the one that says we share a common ancestor with chimps) was hypothesized by scientists before we had the genetic data (before we even knew what DNA looked like!)

The theory of evolution predicted that we should have the same, or nearly the same, chromosome number as chimps. We do.

Furthermore, the chromosome fusion theory predicts that we would find extra centromeres and telomeres. We did.

How does this evidence not support evolution? Do you have an alternate theory that explains this fusion evidence better? Let's hear it.

Here's a picture:

H = human (note there's only one), C = chimp, G = gorillla, O = orangutan. Note the three other primates have two chromosomes.

scigirl

[ October 08, 2002: Message edited by: Nightshade ]

Neruda · 10-08-2002, 08:13 PM

ooh, I like this! kudos to scigirl on this one.

KnightWhoSaysNi · 10-08-2002, 08:26 PM

Here's some addition explanation of the challenge from scigirl, if you're not clear on the terminology, sciteach:

Quote:

Basically, here�s the story. After Darwin formulated his theory of evolution, scientists went to work categorizing evolutionary trees. That is � they tried to figure out what evolved from what, based on morphology and the fossil record. Keep in mind that this was all done before we even knew what DNA or chromosomes were (although the theory of evolution did predict �heritable units.�) After the field of genetics developed, many scientists re-analyzed these trees with this new evidence. By and large, the trees still held true.

One of the trees that was re-analyzed speculated that humans and chimps shared a common ancestor. Now that we have it, does the chromosome data support or refute this tree? Let�s go over what evolutionary theory predicts:

Prediction 1. Humans and chimps should have the same number, or a very similar number, of chromosomes. Similar is of course a relative term, but the number of human chromosomes should match up better with a chimp, than say, a mouse, if evolution theory is correct. If the number is different, there should be a feasible natural explanation as to why they are different.

Well it was discovered that humans have 23 chromosomes in their gamete cells (sperm and egg cells that is). Chimps have 24. And there is evidence of a fusion event. If two chromosomes fused together, you would now have 23. Fusion events can be, and are, observed in nature, so this is a plausible explanation. So far, the tree still holds. I�ll explain more about evidence for a fusion later on.

Prediction 2. The chromosome patterns should look fairly similar to each other, when you compare patterns such as G banding and size.

Look at the picture above. G banding is a unique characteristic of each chromosome, much like a fingerprint. The G banding patterns of human and chimp chromosomes look similar or the same for the two sets of chromosomes. Chromosome 2 of humans looks like two of the chimp chromosomes put together.

You may argue here that, well, since genetics determines our morphology, than morphologically similar animals should have similar genetics patterns, right? That�s only true for some parts of our DNA, such as the genes. We would expect two similar-functioning proteins to have similar sequences. However, if evolution is not true, than it would be very surprising to find that the patterns of genes, and pseudogenes, and introns, and all that other genetics stuff is consistent with evolutionary trees.

Why would this be surprising? Because it appears that the patterns of genes themselves (which can be inferred by G banding) do not appear to be significant. In fact, genes seem to be all scattered around haphazardly if you analyze them according to their function. For instance, I used to work in a lab that studied an enzyme called �NADPH oxidase.� This important host defense enzyme is composed of five subunits. The genes for these subunits are all over the genome � which doesn�t make much sense if you buy into the �intelligent design� or �special creation� theory. However, if you buy into the theory that each subunit used to do something else, and became adapted over time for a new function but was still stuck in the same place in the genome (i.e. if you accept evolution) than this �haphazardness� makes a lot more sense. Another piece of evidence that genes do not need to be in their exact spots in order to function is that you can transfect genes in on a plasmid into a cell or an animal, and by and large, they work ok.

So, if genes don't need to be in a particular order (as evidenced by genetic engineering AND just common sense observations about proteins), than why are so many genes from so many different organisms lined up in a pattern that is consistent with evolution?

What I am trying to impress upon you is this:

1) Genes do not appear to need a particular location in order to function.

2) Genes appear to have a �haphazard� order if you analyze them according to what they do in a given organism.

3) These same exact genes are in that same weird haphazard order in related organisms. For example, the NADPH subunit gp91 is on the X chromosome in humans, and lo and behold, it's also on the X in all the animals that evolution says are our relatives.

Prediction 3. If there was indeed a chromosome fusion event, there would be evidence of that fusion.

Every chromosome has two telomeres (one on each end) and a centromere in the middle. These telomeres and centromeres have characteristic DNA sequences to them. So, if indeed two of the chimp chromosomes fused in our ancestor, there should be evidence of 2 extra telomeres and 1 extra centromere in our chromosome # 2 (the one that matches the G banding patterns of two of the chimp chromosomes.

We indeed find just that evidence, as provided by nightshade in the original post. Here is the link again if you need it:

<a href="http://www.gate.net/~rwms/EvoEvidence.html" target="_blank">http://www.gate.net/~rwms/EvoEvidence.html</a>

As far as scientists can tell, the extra telomeres and centromere are not doing anything. They appear to simply be evidence of the fusion.
Many creationists have used the argument, �Well God made both humans and chimps so of course there would be similarities, just like a robot designer would make two similar robots.� In anticipation of that type of argument, let�s look at the robot analogy closer.

Suppose we are watching a junkyard wars marathon, and we tune in to find the following robot had been constructed:

1. A robot with a one-piece arm. This part had a hook on it that attached it to the main frame, and also had a characteristic blemish on it--say, a big red stain.

Now, let's say that the old creations get left in the junkyard, and can be used in future shows.
Next week we find this robot:

2. This robot body is much different from last week's robot. The arm is composed of two pieces this time. The piece that attaches to the main frame (the "upper arm) has a different hook from the first robot arm. But then we notice that there's a piece that was welded by the team to the upper arm (i.e. the "forearm) that, strangely enough, looks just like the main arm from the first robot. In fact, the hook is still there, but is not hooking to anything. Also, this forearm has the same red stain, and is the same size.

Would you conclude the following?

A. The junkyard wars team constructed the second robot arm de novo, they stuck a hook on the forearm even though it wasn't hooking to anything, and also purposely put a red stain on it.

B. The team found the first robot in the junkyard, took the arm, and stuck it on their new robot.

That, I believe is a better analogy. Robot A's arm represents one of the chimp chromosomes (how about 2q), robot B's arm represents human chromosome 2. A piece of chromosome 2 looks just like 2q - same size, same blemishes, same non-functioning hook. The centromere does actually function as a hook--the microtubules attach to it to pull chromosomes apart during meiosis and mitosis. Chromosomes only need one. We have not observed any known function for the extra centromere in the human chromosome, but yet, there it is, looking just like the centromere from 2q, blemishes and all.

Any questions?

scigirl

[ October 08, 2002: Message edited by: Nightshade ]

Albion · 10-08-2002, 09:48 PM

No fair! He doesn't know anything about biology, remember? He just knows in his heart that however it happened, it didn't evolve. Goddidit! Goddidit! Goddidit!

Non-praying Mantis · 10-08-2002, 10:39 PM

Quote:

Originally posted by Albion:
No fair! He doesn't know anything about biology, remember? He just knows in his heart that however it happened, it didn't evolve. Goddidit! Goddidit! Goddidit!

And Sciteach, just some advice from a collegue:

Please, if you do not accept (which you probably won't since your mind appears to be closed on this subject) the above evidence as proof that evolution happened, then at least read the above challenge, and be able to understand the underlying biology, so that you can teach the genetics unit more effectively!

And, BTW, spelling it evilution will NOT go over well at all if MPHS is a public school!

NPM

scigirl · 10-09-2002, 03:18 PM

Any comments or questions, sciteach?

scigirl

Bubba · 10-09-2002, 06:14 PM

A comment not directly related to Sciteach...this should be posted by someone like Rufus over on Christian Forums.

Bubba

GeoTheo · 10-10-2002, 07:18 AM

I think there are some special Creationist hold overs in my comparative invert. anatomy class. We are studying cestoda (tapeworms) of which we humans have our own unique species. It is starting to look pretty obvious they co-evolved with us. I can see some wheels turning in some of the creationsists heads.
Did God create human tapeworms?
Did they change from some other form after the fall?
What would a tapeworm eat before the fall?

dk · 10-10-2002, 08:35 AM

The Swami knows: The Swami before his audience was handed a sealed envelope that contained a question. He taped the envelope upon his turbine, chanted a silent mantra that telepathically registered the answer in his mind. The swami said �two of the chromosomes fused�, then hands the envelope to an impartial judge who read the question, �How did people and chimps evolve from a common ancestor?�. The audience muttered in unison a hushed �aweeeee�, amazed that chimps and people evolved from the same mythical creature, and being convinced faithfully registered the information as a scientific fact. Now is this science, or did the Swami fashion the answer with foreknowledge of the question. Was the evidence persuasive, or was the dubious presentation designed to persuade the audience with slight of hand. Lets examine the facts.

Chimps exist and people exist, this much is apparent. Chimps look a lot like people in many respects, and so by virtue of appearances alone were catalogued on the same branch of the evolutionary tree. This is quite logical, but not science. As scigirl pointed out the evolutionary tree was ordered upon evolutionary theory absent empirical evidence. When Mendel�s genetics were published people looked for patterns to explain the evolutionary tree, and when genetics lead to the discovery of DNA, people interpreted the context from the evolutionary tree. Where similarities existed, evolutionary science found evidence for evolution, and simply discarded the rest of the DNA chain as useless junk. Was this science, or mining answers to fit a preconceived question , then presenting a drama to convince the public, just like the Swami. For example....

Quote:

<a href="http://www.rae.org/introns.html" target="_blank"> Abstract </a>
The research on functions for introns in the cell is reviewed. Darwinists once generally argued that non-protein coding DNA are relics of once-functioning genes or useless "junk" DNA that strongly argued against design of the genome. The fact that an enormous quantity of cell resources and energy is invested in these putative vestigial structures, especially in the complex intron splicing mechanism, argues that introns have important biological functions including a means of facilitating genetic diversification. Evidence now exists that introns have many functions, including for regulation and structural purposes, and that many of the roles now hypothesized for introns are plausible but need further elucidation. The author concluded that the new knowledge related to introns supports the intelligent design worldview.
----- Jerry Bergman teaches biology, chemistry, and physics at Northwest State College in Archbold, Ohio and is a research associate and adjunct professor at Medical College of Ohio in Toledo. He has over 400 publications in scholarly and popular science journals and has written 20 books and monographs. His work has been translated into twelve languages. To discuss his research, Bergman has been a featured speaker on many college campuses throughout the United States and Europe, and a frequent guest on radio and television programs. Dr. Bergman has earned seven college degrees, including three masters degrees and two doctorates. His last Ph.D. is in biology. A resident of Montpelier, Ohio since 1986, he and his wife, Dianne, have four children, Aeron and Mishalea, Chistine and Scott; and two granddaughters, Kearstin and Bryn.

I think that explains the problem with evolutionary science, and leaves the answer open to debate. Absent context, science can easily be confused with pretext.

[ October 10, 2002: Message edited by: dk ]

Xixax · 10-10-2002, 09:19 AM

dk, I watched a very similar discussion on this same topic last month.

Are you aware that chromosomes DO fuse?
Are you aware that the additional telomere and centromere portions of that particular chromosome are indicative of a fusion?

If they do fuse, and those are indicative of a fusion, if we were to find them 'unfused' in another species ( especially a species predicted to be our nearest living relative ), would that then not indicate common heredity -before- the fusion occured?

You're saying that people just assumed 'they fused', and then use that to infer in a circular argument that it is proof of common heredity ( since to you, the only proof of their fusion is that we share a common ancestor ).

That is -not- the case. The proof of their being a fused version of those two is the additional telomeres and centromere, and the near perfect matching of the banding sequences of the two when compared. The evidence of the fusion stands on it's own apart from common heredity.

I'll let the experts here deal in the details ( again, as they have so graciously done over and over for those like you who have emotional and philosophical problems with something that involvs neither emotion or philosophy ). I just hate to see you waste so much straw making little men out of them to pummel.

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10-08-2002, 08:13 PM	#2
Neruda Junior Member Join Date: Sep 2002 Location: Portland, OR, USA Posts: 80	ooh, I like this! kudos to scigirl on this one.

10-08-2002, 09:48 PM	#4
Albion Veteran Member Join Date: Jul 2002 Location: US east coast. And www.theroyalforums.com Posts: 2,829	No fair! He doesn't know anything about biology, remember? He just knows in his heart that however it happened, it didn't evolve. Goddidit! Goddidit! Goddidit!

10-09-2002, 03:18 PM	#6
scigirl Veteran Member Join Date: Jul 2001 Location: Seattle Posts: 4,261	Any comments or questions, sciteach? scigirl

10-09-2002, 06:14 PM	#7
Bubba Veteran Member Join Date: Mar 2001 Location: Orient, OH USA Posts: 1,501	A comment not directly related to Sciteach...this should be posted by someone like Rufus over on Christian Forums. Bubba

10-10-2002, 07:18 AM	#8
GeoTheo Veteran Member Join Date: May 2002 Location: Bemidji Posts: 1,197	I think there are some special Creationist hold overs in my comparative invert. anatomy class. We are studying cestoda (tapeworms) of which we humans have our own unique species. It is starting to look pretty obvious they co-evolved with us. I can see some wheels turning in some of the creationsists heads. Did God create human tapeworms? Did they change from some other form after the fall? What would a tapeworm eat before the fall?

10-10-2002, 09:19 AM	#10
Xixax Veteran Member Join Date: May 2001 Location: Seattle, WA Posts: 2,101	dk, I watched a very similar discussion on this same topic last month. Are you aware that chromosomes DO fuse? Are you aware that the additional telomere and centromere portions of that particular chromosome are indicative of a fusion? If they do fuse, and those are indicative of a fusion, if we were to find them 'unfused' in another species ( especially a species predicted to be our nearest living relative ), would that then not indicate common heredity -before- the fusion occured? You're saying that people just assumed 'they fused', and then use that to infer in a circular argument that it is proof of common heredity ( since to you, the only proof of their fusion is that we share a common ancestor ). That is -not- the case. The proof of their being a fused version of those two is the additional telomeres and centromere, and the near perfect matching of the banding sequences of the two when compared. The evidence of the fusion stands on it's own apart from common heredity. I'll let the experts here deal in the details ( again, as they have so graciously done over and over for those like you who have emotional and philosophical problems with something that involvs neither emotion or philosophy ). I just hate to see you waste so much straw making little men out of them to pummel.

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