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Author Topic:   Proving Evolution in the Age of Genetics
commike37
Inactive Member


Message 1 of 50 (176331)
01-12-2005 6:24 PM


One of the key components of evolutions is the changing of species. A man is not the same species as an ape. In the age of genetics, we have discovered that the code for each species is contained in the DNA. Man and ape are not the same species because their DNA is different. Now although evolutionists claim that certain species exhibit characteristics of natural selection, do any of these examples involve the modification of the actual DNA structure? Natural selection can occur if the alleles of the genes change, but has the actual composure of the DNA and its genes changed so that a different species has evolved? I think this issue raises three main questions:
1. Is there evidence for natural selection through changing DNA (to the point where the DNA evolves into that of a different species)?
2. Darwin says that evolution occurs in small, successive steps. What sort of change in DNA would qualify as one of these steps?
3. What two species have DNA that have the closest relation to each other?

Replies to this message:
 Message 3 by crashfrog, posted 01-13-2005 1:32 AM commike37 has not replied
 Message 6 by DrJones*, posted 01-13-2005 1:59 AM commike37 has replied
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commike37
Inactive Member


Message 7 of 50 (176670)
01-13-2005 6:04 PM
Reply to: Message 5 by crashfrog
01-13-2005 1:44 AM


But changing alleles doesn't change the species. Dogs come in many different varieties, but a dog can only still mate with a dog. Has natural selection changed the DNA of a dog to the point where it can't mate with another dog because they're two different species. In order to make the jump from the earliest single-celled life forms to the species we have today, the DNA would have to change to describe a different species.

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 Message 5 by crashfrog, posted 01-13-2005 1:44 AM crashfrog has replied

Replies to this message:
 Message 9 by Jazzns, posted 01-13-2005 6:35 PM commike37 has replied
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commike37
Inactive Member


Message 8 of 50 (176672)
01-13-2005 6:07 PM
Reply to: Message 6 by DrJones*
01-13-2005 1:59 AM


Also man and ape aren't the same species because "ape" isn't a species. There are 4 genera and 3 species in what we call apes.
Gorilla gorilla
Pongo pygmaeus
Pan troglodytes
Pan paniscus
OK, we can nitpick, but all of those species are still not the same as the species of a man.

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commike37
Inactive Member


Message 10 of 50 (176695)
01-13-2005 7:05 PM
Reply to: Message 9 by Jazzns
01-13-2005 6:35 PM


Old Style of Proving Evolution
Right now, you're looking at the external features of the animals. I'm looking internally, at the DNA. A dog and man can't mate. Why can't they mate? They are different species with different DNA. We're not talking about alleles changing, we're talking about the compostion of genes changing (ie: a different number of chromosomes [excepting genetic defects], adding the DNA for another leg, etc).

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Replies to this message:
 Message 12 by crashfrog, posted 01-13-2005 7:50 PM commike37 has replied
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commike37
Inactive Member


Message 13 of 50 (176719)
01-13-2005 8:01 PM
Reply to: Message 12 by crashfrog
01-13-2005 7:50 PM


after a few generations they'd no longer be genetically compatible, either.
But the alleles of these dogs don't change (or to clarify, the genotypes of these alleles change, but the alleles don't). How about the quantum leap where the DNA changes in this way to a different species?
This message has been edited by commike37, 01-13-2005 20:02 AM

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commike37
Inactive Member


Message 26 of 50 (176776)
01-13-2005 10:17 PM
Reply to: Message 20 by crashfrog
01-13-2005 9:35 PM


All right, my knowledge of genetic terms has wined since I took Molecular Biology has waned, and I don't exactly have the best definition of a species. Nonetheless, I'll try to show this argument.
Different species/animals/(whatever term you wish to use) have different DNA. For example, humans have 46, and fruit flies have 8. Now for a fruit fly to eventually evolve into a human, certain changes have to occur in a DNA. To go from a human to a fruit fly, you need to add sets of genes that describe a certain organ/part/(insert your term here). What evidence is there for evolution on the genetic level?

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Replies to this message:
 Message 27 by crashfrog, posted 01-13-2005 10:21 PM commike37 has replied
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commike37
Inactive Member


Message 31 of 50 (176790)
01-13-2005 10:42 PM
Reply to: Message 27 by crashfrog
01-13-2005 10:21 PM


OK, chromosomes isn't the best way to put it, but fruit flies still 3-4 as many genes as a human. So you had to do something to add all those genes.
All DNA contains is descriptions of proteins.
So in order to make evolutionary changes, you would need to add DNA segments (bingo, there's a good enough term) that represent these proteins.
I always knew I was better in physics than in biology, so excuse any mistakes

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 Message 34 by crashfrog, posted 01-13-2005 10:50 PM commike37 has replied

  
commike37
Inactive Member


Message 35 of 50 (176797)
01-13-2005 10:57 PM
Reply to: Message 34 by crashfrog
01-13-2005 10:50 PM


Er, wait now, more chromosomes doesn't mean more genes.
And that's why chromosome isn't the best way to put it
And humans only have about 25,000 genes to the fruit fly's 13,000, so that's nowhere near the 3-4 times you suggested.
There's still an obvious difference in the number of genes between a fruit fly and human.
Mutation and natural selection can do this. I'm pretty sure examples have been given, but there's literally thousands of examples in the literature.
On the subject of mutation, the following question is raised:
How many proteins must be added so that they give an organism an advantage that can allow it to thrive through natural selection.
This message has been edited by commike37, 01-13-2005 22:57 AM

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Replies to this message:
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commike37
Inactive Member


Message 41 of 50 (177146)
01-14-2005 9:06 PM
Reply to: Message 37 by crashfrog
01-14-2005 1:42 AM


Well that just made answering my question much much harder. If I can't precisely (or somewhat precisely) determine what kind of genetic steps need to be taken to make an evolutionary transition, then I don't have much to work with.
But it doesn't bother me...not all questions can be answered.

This message is a reply to:
 Message 37 by crashfrog, posted 01-14-2005 1:42 AM crashfrog has replied

Replies to this message:
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