Question of the Week - Old Version

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Offline NakedScientist

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Question of the Week - Old Version
« on: 29/08/2003 00:21:58 »
A new feature, starting this week is "Question of the Week".

We'll post the question initially, everyone can have a go at answering it, then we'll hit you with the answer at the end of the week, together with the new question.

Please feel free to submit appropriate questions via our contact page :

http://www.thenakedscientists.com/html/contacts.htm

Here's the first question :

"Why do we get goosebumps"

Fire away...

TNS
« Last Edit: 03/12/2007 11:59:42 by chris »

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Offline Broca

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Re: Question of the Week - Old Version
« Reply #1 on: 29/08/2003 02:33:14 »
Our ancesters had much more hair than we do. In those days, when they became cold they would get goosebumps as a skin response which would raise the hairs on their body. By raising the hairs on their body the air could not circulate as easily thus creating a type of insulation. The air would be warmed by the body heat which in turn would warm them. We have less hair than those who came before us, we still have the same skin response however, and the goosebump is a raise in the skin where the hair protrudes and we can see it easier since we do not have the same amount of hair covering our bodies.
 

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Offline bezoar

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Re: Question of the Week - Old Version
« Reply #2 on: 29/08/2003 03:24:45 »
Do animals get goosebumps?  Or at least primates?

Bezoar
 

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Offline Broca

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Re: Question of the Week - Old Version
« Reply #3 on: 29/08/2003 03:30:47 »
Yes, animals get goosebumps as well. They get them for the same reason humans do and also animals get them to make themselves look a tad bigger when threatened. It is a survival adaptation.
 

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Offline Ians Daddy

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Re: Question of the Week - Old Version
« Reply #4 on: 29/08/2003 04:06:37 »
Do we get goosebumps when frightened for the same reason?
 

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Offline Broca

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Re: Question of the Week - Old Version
« Reply #5 on: 29/08/2003 04:15:51 »
I would guess yes, but am not certain. I would think it would again be an adaptaion for survival from when we were covered in hair.
 

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Offline NakedScientist

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Re: Question of the Week - Old Version
« Reply #6 on: 05/09/2003 22:41:32 »
ANSWER TO LAST WEEK'S QUESTION : "WHY DO WE GET GOOSEPIMPLES / GOOSEBUMPS ?"

We have inherited this rather bizarre phenomenon from our hairier ancestors. Goosepimples, or goosebumps (as the Americans prefer to call them), are elevations in the skin at the base of hairs. They occur when a tiny muscle called a piloerector muscle (from the latin word PILUS meaning a hair) contracts to lift up the hair.

In hairier animals, making the hair stand up like this helps to trap an insulating layer of air against the skin which, in turn, cuts down heat loss and hence preserves body temperature. That's why they appear when you get cold.

The more observant among you will also have noticed that goosbumps can also appear when you are nervous or frightened. This is also the origin of the saying "feeling the hairs on the back of my neck stand up" and that's because the nerves which supply the piloerector muscles are also activated by fear. The evolutionary benefit of this is that an animal which makes its fur stand on end appears larger than it really is, and hence is more likely to scare off its opponent in a challenge situation. The situation is somewhat analogous to a puffer fish expanding when frightened.

So there you have it, the cause of goosebumps.

This week's question is below.

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Offline NakedScientist

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Re: Question of the Week - Old Version
« Reply #7 on: 05/09/2003 22:43:24 »
THIS WEEK'S QUESTION : - Have a go - brownie points to the person who gets closest to the correct answer, which we'll post in a week's time.

"WHY IS THE SKY BLUE ?"

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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #8 on: 06/09/2003 11:35:44 »
Right this is a guess.

We see colours because objects absorb some wavelengths of light and reflect others. So a sensible guess is that the water particles in the atmosphere absorbs all the colours but blue. And the blue light reflects into our eyes that's why we see blue.

Angel
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Offline Exodus

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Re: Question of the Week - Old Version
« Reply #9 on: 06/09/2003 12:18:12 »
Christopher, does this have something to do with good old Lord Rayleigh?

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Offline Ians Daddy

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Re: Question of the Week - Old Version
« Reply #10 on: 06/09/2003 15:15:28 »
Reflection of the ocean.
 

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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #11 on: 07/09/2003 20:28:28 »
Ronnie, I originally thought about this answer as well but then I questioned why the ocean has that blue colour,the colour is due light that shines on it. Deeper the ocean the darker the colour, if what you said is true why doesn't the colour of the sky become a darker blue?

Another question came to my mind, why is the sky appear orange/yellow during sunset? (or may be it's the cloud?)

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Offline Ians Daddy

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Re: Question of the Week - Old Version
« Reply #12 on: 08/09/2003 01:08:57 »
I may have that backwards. Maybe the ocean is blue because it is reflecting the sky. It seems that I learned that it was reflection. I remember that it is due to the prysm effect. Diffused light through water droplets.

In fact, I believe you are correct, it would be the clouds that made it yellow / orange / red. Due to the angle of the sun i.e. morning / evening, and the density of the water of the clouds. I guess that when the sun is low, its refracting the light as reds and when the sun is high, it would be blue...less break up? What makes a gray sky?
 

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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #13 on: 08/09/2003 08:09:35 »
Air pollution?

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Offline NakedScientist

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Re: Question of the Week - Old Version
« Reply #14 on: 12/09/2003 11:44:36 »
ANSWER TO "WHY IS THE SKY BLUE ?" :

The sky is blue due to an effect of the earth's atmosphere on the light reaching us from the sun.

Although sunlight looks 'white' it is actually made up of a whole spectrum of colours which you can see in a rainbow, or with a prism. The different coloured lights have different wavelengths ranging from blue light (which has the shortest wavelength) to red light which has the longest.

The Blue light is strongly scattered by the oxygen and nitrogen in the atmosphere, whilst the other colours, with longer wavelengths, are not affected.

This means that when light waves arrive from the sun, some of the blue light is bounced about and scattered in all directions by the air so that it no longer seems to be coming just from one place - the sun - and instead the whole sky seems blue. But the rest of the light (with longer wavelengths) passes unaffected straight through the atmosphere to your eye and hence the sun looks a yellowy red colour (white minus some of the blue).

So why does the sun go red at sunset ?

This is because as the sun 'sinks' the light has to travel further through the atmosphere to reach your eye meaning that more of the blue (and shorter wavelength light) is scattered (removed) than when the sun is high in the sky, making the sun look even more red.

TNS

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Offline NakedScientist

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Re: Question of the Week - Old Version
« Reply #15 on: 12/09/2003 11:49:24 »
THIS WEEK'S QUESTION OF THE WEEK :

"WHY DON'T PENGUINS FEET FREEZE ?"

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Offline noden1

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Re: Question of the Week - Old Version
« Reply #16 on: 12/09/2003 22:55:33 »
if they did you would not be able to pick up a penguin!!!
 

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Offline Qing

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Re: Question of the Week - Old Version
« Reply #17 on: 13/09/2003 15:46:23 »
I guess they might have some kind of fat under the skin which will generate heat and provent from freezing. But as I said, it's only a guess and I've no idea.

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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #18 on: 15/09/2003 20:13:04 »
Penguin's feet are covered by its thick waterproof fur which can trap air and act as insulation. And I guess their feet are padded with ... probably fat which again acts as insulation

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Offline Ians Daddy

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Re: Question of the Week - Old Version
« Reply #19 on: 15/09/2003 23:48:36 »
THIS WEEK'S QUESTION OF THE WEEK :

"WHY DON'T PENGUINS FEET FREEZE ?"

A penguin's feet are like a duck's feet, so they don't have any protective layers of hair or fat. I would guess that it would have to do with an internal thermostat. Cold / warm blooded creatures must adapt to their surroundings. Maybe it's the lack of blood that keeps their feet from freezing up. Or, maybe their pumped full of hot blood that is heated from their little fat bodies.
Being flightless, they have no alternative but to adapt. Besides, their easier to punt when they're not stuck to the ground.

Just a thought.
 

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Offline Broca

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Re: Question of the Week - Old Version
« Reply #20 on: 16/09/2003 18:42:11 »
Ahhh another science adaptation question...critical curriculum in the 4th grade.
Penguins are able to slow the blood supply to their feet keeping the temperature of them above freezing. Their feet might be really cold, but they will not succumb to frost bite.
 

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Offline bezoar

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Re: Question of the Week - Old Version
« Reply #21 on: 16/09/2003 20:02:43 »
But it would seem like slowing the blood supply to their feet would cool the feet, making them more susceptible to freezing.
 

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Offline Donnah

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Re: Question of the Week - Old Version
« Reply #22 on: 17/09/2003 00:59:03 »
Don't they cover their feet with their pot bellies when they are not moving?  So I'm guessing their feet are kept thawed by movement and/or fat-belly cover.
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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #23 on: 17/09/2003 09:06:17 »
Now I got another theory.

May be cells of penguins feet are surrounded with networks of cappilaries and this enables oxygen to be transported to the cells in the feet. So that energy can be generated by respiration to keep their feet warm.

Angel
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Offline bezoar

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Re: Question of the Week - Old Version
« Reply #24 on: 18/09/2003 05:33:14 »
Seems like this would have to do with some type of mechanism or anatomy that keeps both the venous and arterial blood above freezing.  And obviously, the venous blood would be the greater problem.

Bezoar
 

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Offline Ians Daddy

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Re: Question of the Week - Old Version
« Reply #25 on: 18/09/2003 05:47:16 »
I'm going to stray a bit, because this is where I am. Does anyone know what happened to "Nilmot" / Tom / "The Riddler"? Haven't seen him in quite awhile.
 

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Offline Qing

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Re: Question of the Week - Old Version
« Reply #26 on: 18/09/2003 09:31:22 »
quote:
Originally posted by cuso4

Now I got another theory.

May be cells of penguins feet are surrounded with networks of cappilaries and this enables oxygen to be transported to the cells in the feet. So that energy can be generated by respiration to keep their feet warm.

Angel


I came up with this idea as well, but this might not be enough.i mean, penguins feet are in direct contact with freezing enviornment,and the tempearture is really low. so there might be other adaptations e.g. like Donnah said,"they cover their feet with their pot bellies when they are not moving". just a thought.

Qing
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Offline NakedScientist

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Re: Question of the Week - Old Version
« Reply #27 on: 19/09/2003 01:24:10 »
ANSWER TO : WHY DONíT PENGUINS FEET FREEZE ?
Part of the reason is that penguins are birds and are warm blooded so they keep their feet from freezing by pumping warm blood from their body into them. But thatís only half the story because penguins live in such a cold environment that they would very quickly lose all of their body heat if they continuously pumped hot blood around their feet. Instead they have hit upon an ingenious solution which saves heat and keeps their feet just above freezing. In the penguinís legs the arteries, which carry hot blood from the body, are wrapped around the veins bringing cold blood back from the feet. The cold blood in the veins removes most of the heat from the arteries, warming up as it does so, so that the blood entering the feet is just above freezing, but the blood in the veins, by the time it reaches the body, is back up to body temperature. So the penguins feet receive blood just warm enough to keep them from freezing, but are not so hot that the penguin melts into the ice.

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Offline NakedScientist

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Re: Question of the Week - Old Version
« Reply #28 on: 19/09/2003 01:25:54 »
HERE'S THIS WEEK'S "QUESTION OF THE WEEK" :

"HOW, AND WHY, DO CHAMELEONS CHANGE COLOUR ?"

Fire away.

TNS

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Offline Qing

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Re: Question of the Week - Old Version
« Reply #29 on: 19/09/2003 15:51:13 »
that's an interesting question. i know that chameleons change colour to protect themselves. their colour changes according to the environment. but how do they change it.

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Offline Ians Daddy

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Re: Question of the Week - Old Version
« Reply #30 on: 20/09/2003 02:47:33 »
Surely it's chemical. Maybe it detects the light rays emmiting from a surface and can balance itself to that. It's probably automatic, the same way that I turn so red when embarrassed or angry. When frightened, they "balance" themselves with their surroundings. [?]
 

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Offline Exodus

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Re: Question of the Week - Old Version
« Reply #31 on: 20/09/2003 09:45:04 »
I've always considered myself to have chameleon properties... If i drink too much i turn green too, what help that does i dont know, when your in that state you want to be found, not blend in with the grass! LOL

As for th answer, i don't really know, well i have an idea...

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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #32 on: 24/09/2003 09:05:13 »
quote:
Originally posted by NakedScientist

ANSWER TO : WHY DONíT PENGUINS FEET FREEZE ?
Part of the reason is that penguins are birds and are warm blooded so they keep their feet from freezing by pumping warm blood from their body into them. But thatís only half the story because penguins live in such a cold environment that they would very quickly lose all of their body heat if they continuously pumped hot blood around their feet. Instead they have hit upon an ingenious solution which saves heat and keeps their feet just above freezing. In the penguinís legs the arteries, which carry hot blood from the body, are wrapped around the veins bringing cold blood back from the feet. The cold blood in the veins removes most of the heat from the arteries, warming up as it does so, so that the blood entering the feet is just above freezing, but the blood in the veins, by the time it reaches the body, is back up to body temperature. So the penguins feet receive blood just warm enough to keep them from freezing, but are not so hot that the penguin melts into the ice.




Just found out that human (and other mammals) keep their hands and feet from freezing the same way as penguins. Because we are all HOMEOTHERMS.

Angel
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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #33 on: 24/09/2003 09:11:53 »
quote:
Originally posted by NakedScientist

HERE'S THIS WEEK'S "QUESTION OF THE WEEK" :

"HOW, AND WHY, DO CHAMELEONS CHANGE COLOUR ?"

Fire away.

TNS



Here's the answer. This is not purely my knowledge because I did a bit of research.

Under a chameleon°Įs outer skin are special skin cells with colour (or pigment) in them. These cells are called chromatophores. The top layer of chromatophores have red or yellow pigment. The lower layers have blue or white pigment. A chameleon changes colour when its brain sends a message to the cells. The message tells the cells to grow bigger or to shrink. When this happens, the cell pigments mix and the chameleon°Įs colour changes.

Temperature affects the chameleon°Įs colour too°™if it°Įs cold, darker skin allows the chameleon to absorb more heat from the Sun. And, light from the Sun can signal a chameleon to change to a lighter shade, to reflect the sunlight.

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Offline NakedScientist

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Re: Question of the Week - Old Version
« Reply #34 on: 29/09/2003 19:05:51 »
ANSWER TO "HOW DO CHAMELEONS CHANGE COLOUR ?"


If youíre not sure what a chameleon is, itís a kind of lizard that lives in trees, usually in Africa or Madagascar. Most people have heard of chameleons because of their amazing ability to change the colour of their entire body within seconds. But itís a myth that  chameleons change their colour to blend in with their surroundings. In fact the main reason that they change colour is so that they can communicate with each other. For example a calm chameleon is a pale green colour, an angry chameleon turns bright yellow and a chameleon who spots another chameleon it would like to mate with usually displays an explosion of different colours including reds, greens, browns, whites and blues. So how do they actually change colour. The answer lies in special cells buried in their skin called chromatophores. These cells are all wired up to the chameleonís brain and contain different coloured pigments. When the chameleon wants to change colour, signals from the brain tell the skin cells to release their coloured pigment which spreads out in the cell and changes its colour, rather like giving the cell a coat of paint. The chameleon can make a range of different colours by switching on different coloured pigment cells at the same time, a bit like mixing red and yellow paint together to make orange.

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Offline NakedScientist

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Re: Question of the Week - Old Version
« Reply #35 on: 29/09/2003 19:07:53 »
HERE IS THIS WEEK'S "QUESTION OF THE WEEK" :

"WHY DO PEOPLE HAVE DIFFERENT COLOURED SKINS ?"

Have a go, answer next week.

TNS

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Offline Ians Daddy

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Re: Question of the Week - Old Version
« Reply #36 on: 30/09/2003 00:18:14 »
Different levels of melanin?
 

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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #37 on: 30/09/2003 09:27:53 »
Yes Ronnie, I believe so.

I think different levels of melanin are due to human's adaptation to the environment. The pigment melanin can absorb UV radiation to prevent the damage to skin cells.

For example, people live in Africa are constantly exposed to strong sunlight during day time, so their ancester had evolved (not sure it's the right word to use) to have a dark skin to suit the environment.

However, people live in places like UK or Canada where the weather is colder and experience less sunlight had not adapted for exposure to sunlight but for the reduction of heat lost. Although pale colour absorb less heat they also radiate less heat.

Finally, people live in Asia especially with sub-tropical weather are adapted for medium level of sun exposure. This accounts for their tan-ish coloured skin.

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Offline Quantumcat

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Re: Question of the Week - Old Version
« Reply #38 on: 30/09/2003 09:57:03 »
darn it cuso4, that's my kind of question!![:(!] I was too late[:(] lol only kidding I'm not mad !![:)]

I can add a little bit.

When humans have little or no pigment, that is, albanism, it's because there is a mutation in the gene for tyrosinase which is an enzyme that changes tyrosine into melanin in the melanocytes.

People with darker skin have extra genes (I think, correct me if I'm wrong!!!) that increase tyrosinase production so more melanin is converted from tyrosine in the melanocytes, then let out and distributed around the skin...

When the skin is exposed to UV light, tyrosinase production is stepped up so more melanin is made. This is an emergency response designed to protect the skin from further damage from the UV light (because UV radiation can change genes, therefore cause cancer)

Tyrosinase is being made all the time, melanin isn't permanent and if you get a tan then stay is a dark room for a while you'll see that the tan wears off in a month or so.

When people get freckles it's because the melanocytes are spaced far from each other and aren't very efficent at delivering the melanin into the surrounding skin (also correct me of I'm wrong there not so sure)

Anyway I didn't copy and paste that, I wrote it from my own head ... probably why some of it is probably wrong ... lol

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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #39 on: 30/09/2003 13:33:12 »
Sorry Quantum [|)], but my bit is quite simple and can be worked out logically whereas your bit is....very scientific (good on you [:D]!) and thanks for the extra info as I didn't know melanin was made from tyrosine.

And...I'm certain that the bit about freckles is correct. People who get tan because they got even distribution of melanocytes.

Angel
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Offline Ians Daddy

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Re: Question of the Week - Old Version
« Reply #40 on: 30/09/2003 13:35:30 »
How long does the "evolution" take to adapt to the amount of sun? ie.. transplanted people from different regions. I know that a tan would fade, but how does and how long for the melocytes to alter?

Why do freckles fade with age in some people? ie... kids with freckles on their noses.[:o)]

Why do I turn deep red [:(!](not a burn)[V] as opposed to brown when I'm in the sun alot?

Just some thoughts.
« Last Edit: 30/09/2003 13:37:43 by Ians Daddy »
 

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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #41 on: 01/10/2003 08:42:10 »
May be you don't have enough melocytes to produce a tan. Instead, the capillaries near the surface of your skin expand allowing more blood flow, you therefore lose heat through radiation and convection. This is vasodilation.

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Offline Qing

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Re: Question of the Week - Old Version
« Reply #42 on: 01/10/2003 08:57:45 »
why do people get headache [xx(] after being exposed to bright sunlight for a long time perticularly if you skin colour is light?

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Offline cuso4

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Re: Question of the Week - Old Version
« Reply #43 on: 01/10/2003 13:57:19 »
Don't people get overheated and the enzymes in the body start malfunctioning?

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Offline Donnah

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Re: Question of the Week - Old Version
« Reply #44 on: 01/10/2003 22:43:26 »
Ronnie, maybe you turn red due to your Indian heritage.  

As for the geographic effect of the sun over the course of generations, why are Eskimo and Inuit people, who live in the far north, dark skinned?
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Offline Ians Daddy

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Re: Question of the Week - Old Version
« Reply #45 on: 01/10/2003 23:35:36 »
Maybe the elevation. Or, the reflective affect of the snow and sun. Actually, maybe the evolutionary adaptation period is very slow and these people are decendants from a southern race. It's fascinating to see that Eskimo, Somoan, Polinesian, Mexican, Native American Indian and Asian people have very present similarities in skin tone and features. So, maybe our "family tree" is more narrow than we thought.
 

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Offline Quantumcat

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Re: Question of the Week - Old Version
« Reply #46 on: 02/10/2003 09:44:41 »
Snow reflects more light than soil, a lot more. Either that or they haven't lived in the far north for very long.

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Offline Donnah

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Re: Question of the Week - Old Version
« Reply #47 on: 03/10/2003 01:34:09 »
There's also the issue of constant daylight in northern summers, and constant dark in winter.
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Offline bezoar

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Re: Question of the Week - Old Version
« Reply #48 on: 03/10/2003 06:02:47 »
I seem to remember, way back in high school, being taught that it isn't the number of melanocytes, but the size of the granules of melanin that makes for the differences in skin color.  Any feedback on that?

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Offline Quantumcat

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Re: Question of the Week - Old Version
« Reply #49 on: 03/10/2003 09:45:53 »
Oh, yes!! That's it. In summer their nights would be like one hour long. But, their days in winter would be like one hour long too, so it doesn't work. Bugger.

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