Freethought & Rationalism Archive

scombrid · 09-19-2002, 05:25 AM

I'm in a debate about the evo/creat and church/state separation all roled into one thread. Someone even threw in pascal's wager.

Anyway, I thought you'd get a chuckle out of the latest anti-evolution post.

Quote:

Statement: Evolution is the process of a less-complicated organism evolving into a more-complicated structure through selectivity and mutation, right?

If this is true, how did the female organism (which is much more complicated physically) evolve at the same rate as the male organism?

Also, why do men have nipples?

It seems to me that fossils are simply evidence of the elimination of species, rather than the evolution of species. Evolution is a fancy theory, but there is really no scientific evidence for it.

But just answer the two questions above, if you will.

<img src="graemlins/banghead.gif" border="0" alt="[Bang Head]" /> Our public education really is that bad isn't it.

Hopefully I'll find the time to respond. There are a suprising number of poorly educated fundies on that forum.

tgamble · 09-19-2002, 10:02 AM

Quote:

Originally posted by scombrid:
<strong>Also, why do men have nipples?
</strong>

Maybe HE could provide a good explanation for that. Just why DO men have nipples?

scigirl · 09-19-2002, 04:17 PM

The correct question is "Why do WOMEN have nipples?"

We all know the answer to that!

It was just simply easier for evolution to keep them around than to figure out how to get rid of them in the men.

scigirl

Doubting Didymus · 09-19-2002, 04:25 PM

I am interested in this. I know that all foetuses develop as females and male type kicks in later, so are nipples just a side effect of embryology co-opted into stimulatory functions?

GeoTheo · 09-19-2002, 04:30 PM

Scigirl, Not to hijack this post but I was getting to busy to continue with the formal debate also.
I am working full time and taking 14 credits which includes molecular genetics. It was fun though.
BTW just to stay on topic:
Could a mutation in the "Y" chromosome eliminate male nipples?

scigirl · 09-19-2002, 04:44 PM

Geo, the nipples are not encoded on the Y, so no.

In order for sex-specific organs to develop, the hormones need to be expressed first. I don't think the Y chromosome codes for much of anything except some male-specific factors that turn on more testosterone (which is NOT on the Y). Then the other non-Y genes know to make a male, or a female, organ. Sometimes they malfunction and you get none, or both. Especially if there's two or more Y's or too many X's.

To stop male nipples from being formed, you would have to figure out a way for the nipple development to be under female hormone control, or something like that.

scigirl

scigirl · 09-19-2002, 04:46 PM

Quote:

Originally posted by GeoTheo:
I am working full time and taking 14 credits which includes molecular genetics. It was fun though.

Good, you can help me argue with Vanderzyden about chromosomes!

scigirl

Doubting Didymus · 09-19-2002, 04:52 PM

How many other animal species have male nipples? How far back can male nipples be traced?

Jesus Tap-Dancin' Christ · 09-19-2002, 08:24 PM

I think dog males have nipples, but I'm not too sure.

lpetrich · 09-19-2002, 09:26 PM

I think that one must be careful to avoid an atomistic view of genetics here, that of one gene makes one feature. It works fine with proteins, but not nearly as well for overall features.

An example is the gene Pax6, which induces the development of eyes where it is expressed. It has cross-phylum homology -- mouse Pax6 will induce fruit flies to develop eyes, even out-of-place eyes. However, the eyes are fruit-fly-style eyes rather than mouse-style eyes, meaning that most eye features are not directly specified by Pax6.

Which means that Pax6 simply induces other genes to go into action to form eyes.

And sex differentiation most likely works in the same way, with both sexes sharing development-control genes that are controlled by some "which sex am I" factor.

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09-19-2002, 04:17 PM	#3
scigirl Veteran Member Join Date: Jul 2001 Location: Seattle Posts: 4,261	The correct question is "Why do WOMEN have nipples?" We all know the answer to that! It was just simply easier for evolution to keep them around than to figure out how to get rid of them in the men. scigirl

09-19-2002, 04:25 PM	#4
Doubting Didymus Veteran Member Join Date: Jul 2002 Location: East Coast. Australia. Posts: 5,455	I am interested in this. I know that all foetuses develop as females and male type kicks in later, so are nipples just a side effect of embryology co-opted into stimulatory functions?

09-19-2002, 04:30 PM	#5
GeoTheo Veteran Member Join Date: May 2002 Location: Bemidji Posts: 1,197	Scigirl, Not to hijack this post but I was getting to busy to continue with the formal debate also. I am working full time and taking 14 credits which includes molecular genetics. It was fun though. BTW just to stay on topic: Could a mutation in the "Y" chromosome eliminate male nipples?

09-19-2002, 04:44 PM	#6
scigirl Veteran Member Join Date: Jul 2001 Location: Seattle Posts: 4,261	Geo, the nipples are not encoded on the Y, so no. In order for sex-specific organs to develop, the hormones need to be expressed first. I don't think the Y chromosome codes for much of anything except some male-specific factors that turn on more testosterone (which is NOT on the Y). Then the other non-Y genes know to make a male, or a female, organ. Sometimes they malfunction and you get none, or both. Especially if there's two or more Y's or too many X's. To stop male nipples from being formed, you would have to figure out a way for the nipple development to be under female hormone control, or something like that. scigirl

09-19-2002, 04:52 PM	#8
Doubting Didymus Veteran Member Join Date: Jul 2002 Location: East Coast. Australia. Posts: 5,455	How many other animal species have male nipples? How far back can male nipples be traced?

09-19-2002, 08:24 PM	#9
Jesus Tap-Dancin' Christ Veteran Member Join Date: Apr 2001 Location: Heaven Posts: 6,980	I think dog males have nipples, but I'm not too sure.

09-19-2002, 09:26 PM	#10
lpetrich Contributor Join Date: Jul 2000 Location: Lebanon, OR, USA Posts: 16,829	I think that one must be careful to avoid an atomistic view of genetics here, that of one gene makes one feature. It works fine with proteins, but not nearly as well for overall features. An example is the gene Pax6, which induces the development of eyes where it is expressed. It has cross-phylum homology -- mouse Pax6 will induce fruit flies to develop eyes, even out-of-place eyes. However, the eyes are fruit-fly-style eyes rather than mouse-style eyes, meaning that most eye features are not directly specified by Pax6. Which means that Pax6 simply induces other genes to go into action to form eyes. And sex differentiation most likely works in the same way, with both sexes sharing development-control genes that are controlled by some "which sex am I" factor.

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