[thedoc (OP)]

Science gets under your skin on this week's Naked Scientists, where we find out how human skin colour evolved to make the best of our sunlight.  We explain why albino people have no skin pigment at all and how to heal wounds without leaving scars.  Also, the nano-scale media storage that will last a billion years, the toxic bite of the komodo dragon and the biological link between cancer and depression.  Plus, we shine a light on jaundice phototherapy, with the help of a urinating glass baby!
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If you want to discuss this show, or ask a question, this is the place to do it.

[Tom Whitelaw]

Tom Whitelaw asked the Naked Scientists:
   
I booked into a hotel in Pakistan opened my room window only to be attacked by a hawk (who had a nest on the airconditioner).

Later, at a buffet on the roof, it recognised me and attacked me on sight!

Tom

What do you think?

[Chemistry4me]

Well, hopefully, it didn't claw your eyes out.

Later, at a buffet on the roof, it recognised me and attacked me on sight!

What...!

[Bob Person]

Bob Person asked the Naked Scientists:
   So, I have been noticing on the several science shows I've listened to including "The Naked Scientists" a tendency toward sort of Lamarkian explanations of evolved features. One example was the recent discussion of why flowers have cone-shaped cells. Another is reflected in this back and forth between Chris and a guest:

"Chris Smith: But as I move away from Africa and go to climes like Britain where we have much less sun exposure, what's the point of going white? Why don't I just stay dark, because then I won't break down my folate and I won't get skin cancer?         

Nina Jablonski: The reason that your ancestors underwent loss of pigmentation is that you still need to make vitamin-D in your skin. Your skin not only protects you from a lot of stuff but it's a vitamin factory, it makes vitamin-D. As you get farther north, the farther away from the equator, up where you are living, you get about two months during the year when you have ultraviolet-B radiation in the atmosphere that can cause vitamin-D production, you'd need to lose as much pigment as possible to take advantage of that very rare UVB; and that's why you and your ancestors look the way you do."

I don't believe there really was purposeful evolution toward being white. Are we all Lamarkian at the core, do we just need to be more careful how we express ourselves, or both? What do you think?

What do you think?

[BenV]

Hi Bob,

I think you're quite right, this is just a convenient way of expressing ourselves but it could easily be misconstrued as Lamarkian.  I think that it's easier and quicker to refer to a population as "I change" or "we changed" rather than the more accurate discussion of selective pressures acting on a population, and the resulting change in future generations of that population.

It's something we will try to look out for in the future, as we don't want to lead people into misunderstanding our coverage of evolution!

[Kevan Gelling]

Bob Person asked the Naked Scientists:
I don't believe there really was purposeful evolution toward being white. Are we all Lamarkian at the core, do we just need to be more careful how we express ourselves, or both?

Unless epigenetics can affect our skin colour.

My own anecdotal experience is that Brits of Afro-Caribbean descent tend to be lighter than Africans living in the UK.