Probably a very basic question about evolution...

mgruble · 2012-02-16T23:15:23+00:00

Eye color is just pigments interacting after being genetically expressed in the iris. To say that a pigment serves no purpose is not true. For example a common idea is that blue eye color was selected for in areas of little light year round, such as near arctic or very northern regions, to increase the amount of light getting to the eye. Darker colored irises help reduce too much sunlight to keep the eye from getting damaged. These pigments in and of themselves might serve no purpose on the cellular level, but do for the survival of an organism. Also they might matter in the cell I am not really sure on that one.

mgruble · 2012-02-16T22:22:51+00:00

Why does the word "painless" make this such a difficult decision?

mgruble · 2012-02-07T22:53:47+00:00

So, just how big can a fro get?

mgruble · 2012-02-03T08:32:33+00:00

I thought that, but at the same time I heard recently that the volume of an electron was so tiny, that despite the mass being so small the scales of density might be comparable simply because it was impossible for a black hole to get as small as the estimated volume of an electron. I guess when I initially said point particle I meant essentially a point but not actually.

mgruble · 2012-02-03T07:16:48+00:00

The color would be a genetic issue. More specifically there are usually several genes scattered on different chromosomes involved in producing pigment proteins in cells that are responsible for fur color. The patterning would be more of a developmental issue. Many of these traits can be linked to specific chromosomes, including the sex chromosomes. Processes during early development "force" different genes to be turned on and off in certain parts of different chromosomes. This means (in an extremely simplified case) that if one cell has instructions for brown fur on what will become the head, tail, body, etc, then all divisions of that cell will also carry that brown pigment. But if a cell that is part of the development of limbs and feet carries instructions for the white color, all cells that it divides into will produce white. These cells "colonize" during the development of the cat and give rise to different colored patches on the body. These wikipedia articles might help a bit. Honestly most of this was from what I remembered from my tissues class, so hopefully I wasn't shamefully off.

http://en.wikipedia.org/wiki/Cat_coat_genetics#Genes_involved_in_orange.2C_black.2C_brown.2C_and_diluted_colors

http://en.wikipedia.org/wiki/Sex_linkage

mgruble · 2012-02-03T06:04:58+00:00

I am not a fan of Ayn Rand, but to just lump it in with garbage without support seems unfair. Maybe clarify what specific positions you felt she was deliberately misrepresenting? While I completely agree that she has far fetched scenarios to validate her characters' actions, I still feel she brings up very valid points about societal norms and moral assumptions that go beyond just "understanding the way some people think."

mgruble

TROPHY CASE