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How do we get our skin color?

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Last updated over 5 years ago
31 questions
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Question 1
1.

Before you begin, think about your skin. It covers your entire body! What questions do you
have about skin and skin color?

Watch the video once all the way through, then we'll go back through each 'stop point' in the interactive at that link.
Stop number 1: Hover over the first verticle line: "What is Skin?" and click 'more info'
Make sure you click around the interactive to explore it to answer the questions below:
Question 2
2.

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Question 3
3.

Question 4
4.

What is the connection between skin, sunlight, and Vitamin D?

Question 5
5.

Case study: you are a pediatrician and one of your young patients is at risk for rickets. Outline a treatment you would recommend to the child and their parents, and justify why:

Go back up to the interactive at the top of the page and click on the second verticle line and click "more info"

Stop Number 2: What are skin cells?

Make sure you click around the interactive to explore it!

Question 6
6.

Question 7
7.

Question 8
8.

Question 9
9.

Question 10
10.

Looking at the timeline of evolution, what else do you notice changing as hair gets less dense in populations?

Question 11
11.

What was the primary advantage of having less hair for early homo species? How do you think that helped early homo species survive to reproduce more effectively?

Go back up to the interactive at the top of the page and click on the third verticle line and click "more info"

Stop Number 3: What is Melanin?

Make sure you click around the interactive to explore it!

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Question 12
12.

Write in the word that goes with each blank:

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Question 13
13.
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Question 15
15.

What are the two primary types of melanin and how do they differ?

Question 16
16.

Explain how the amount of eumelanin and number of melanosomes differ between a
person with lighter color skin and a person with darker color skin.

Question 17
17.

Question 18
18.

Overall, human DNA on the African Continent is the most diverse of any continent, but the MC1R gene is less diverse in populations in equatorial Africa. Why might that be?

Go back up to the interactive at the top of the page and click on the fourth verticle line and click "more info"

Stop Number 4: How does Melanin protect cells?
Question 19
19.

Why does the body need to protect itself from UV light?

Question 20
20.

Explain how the body uses melanocytes to protect itself:

Note: saying how something happens involves describing all the steps

Question 21
21.

Question 22
22.

The answer to the multiple choice above is (C) - prove to me that you understand this process by describing how UV radiation causes mutations in DNA:

Last stop: Go to the final vertical white line in the animation and click "more info"

Stop Number 5: How does sunlight cause tanning?
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Question 25
25.

What are the positive and negative effects of UVB exposure?

Question 26
26.

Play with the map of the world by sliding the double-arrowed circle.

What do you notice? What do you wonder?

Question 27
27.

Question 28
28.

Question 29
29.

Explain how the relationship between skin color and UV radiation provides evidence that
this trait evolved by natural selection:

Question 30
30.

Watch the last video and answer the question: How does sunlight cause tanning?

Question 31
31.

Your friend, who tans easily, argues that it’s great to get a tan because darker skin
pigmentation offers lots more protection from damaging UV radiation, so he’s keeping
himself safe. Write a response to convince him otherwise:

Match the 'skin layer' with the description of its function:
Dermis
The layer that protects the body from most physical objects (except certain gases) and produces vitamin D.
Hypodermis
The layer that helps the body control its temperature using the vessels, glands, and nerve endings within it
Epidermis
The layer that insulates the body with fat cells that can also be used for energy when needed
Why is vitamin D important to our health? Select all that apply:
We use Vitamin D for energy
Vitamin D prevents rickets
Vitamin D is necessary for reproduction
Vitamin D deficiency can cause fatigue and depression
A lack of Vitamin D can make your bones softer
Re-order the items below into the correct life cycle of a "Keratinocyte:"
Keratinocytes form from stem cells at the bottom of the epidermis
Keratinocytes move upward while increasing keratin production
Keratinocytes stop dividing
Keratinocytes die
Keratinocytes keep the body waterproof until they fall off
Where do keratinocytes get their name?
Professor Keratin discovered them
Skin produces vitamin K using Keratinocytes
'Keratin' is a structual protein, and the suffix 'cyte' means its a cell
Select all the true statements about Melanocytes
They must be a cell since they have 'cyte' in the name
There's a melanocyte paired with each keratinocyte
Melanocytes produce melanin, which affects skin color
Melanocytes have projections that move through the skin to deliver melanosomes to different areas
Melanocytes live in the hypodermis
Approximately when did our ancestors become mostly hairless?
~7 million years ago
~3 million years ago
~2 million years ago
Started ~2 million years ago, hair faded slowly in populations of the genus homo
Just in the last 100,000 years
Question 14
14.
Which type of melanin is produced by the version of the MC1R gene (i.e., the MC1R allele) that is most prevalent among people of African ancestry??
Melanocytes
Melanosomes
Pheomelanin
Eumelanin
"Mutations" are "Errors in the DNA sequence" - this happens when...
A) UV photons hit DNA
B) pyrimidine dimers are formed
C) the cell's repair machinery removes the pyrimidine dimers
D) an individual gets cancer
Question 23
23.

Question 24
24.

Which of these is an environmental advantage to having darker skin color?
More sweat glands to cool the body
Able to absorb more Vitamin D
Less hair helps the body stay cool
Better protected from UV radiation
Which of these is an environmental advantage to having lighter skin color?
Less hair helps the body stay cool
Better protected from UV radiation
Able to absorb more Vitamin D
More sweat glands to cool the body
Fill in the blank:
longer
shorter
higher
lower
Fill in the blank:
longer
shorter
higher
lower