A5.22S
Student
Activity 5.22 Debunking the myth of
polar bear hair
Purpose
 To recall ideas about adaptation and natural selection
 To consider the role of the scientific community in validating new evidence
For this activity you should work in small groups. Look at each of the cards in turn and discuss the ideas and
questions. Consider the cards in the numbered order. Once all of the cards have been discussed reflect on
your discussions by completing the questions below.
Card 1
Card 2


Polar bears appear white
What is the advantage to the polar bear
in appearing white?
Polar bear hair contains no
pigment. Their hairs are
transparent.
What might be the disadvantage to the
bear in being white?
Suggest why polar bears look white,
although their hairs are transparent.
Card 3
Card 4


Polar bear hairs are hollow.
Polar bear skin is black
Suggest any advantages and
disadvantages of hollow hair structure.
Suggest why this feature might have
been a selective advantage for the polar
bear.
Card 5
Card 6


The rough inner surface of the
polar bear hair scatters visible
light, making it appear white.
Researchers have published
results of experiments showing
that polar bear fur absorbs UV
light. The researchers suggested
that the hollow hairs may be
acting as ‘optic fibres’,
transmitting the UV light to the
skin.
Comment on these results and ideas,
including any advantages and
disadvantages of hairs acting as optical
fibres.
Published experimental results
show that the polar bear hairs do
absorb UV light, but it is not
transmitted down the hair. The
researchers suggest that it might
be the hair protein keratin
absorbing the UV light. But they
have not investigated this
experimentally.
Comment on these findings. How does
this information influence your
discussions of Card 5?
Salters-Nuffield Advanced Biology, Pearson Education Ltd 2009. © University of York Science Education Group.
This sheet may have been altered from the original.
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A5.22S
Activity 5.22 Debunking the myth of
polar bear hair
Student
Q1 For each adaptive feature mentioned on the cards, summarise why it might be a selective advantage.
Q2 The findings about absorption of UV light by polar bears were published in the peer-reviewed journal
Applied optics. The idea that hairs might funnel light to the skin was taken up by many other scientific
journals and the popular press, reporting it as a ‘fact’. Was this justified? (Read the wording on the cards
carefully.) Explain your answer.
Q3 The suggestion that keratin absorbs UV light needs to be experimentally investigated to determine
whether it is true. What role would the scientific community have in validating evidence produced to
support the idea?
Read the article ‘Debunking the myth of polar bear hair’ and see the weblinks associated with this article.
These will tell you more about the urban myth that developed about fibre optic hairs.
Salters-Nuffield Advanced Biology, Pearson Education Ltd 2009. © University of York Science Education Group.
This sheet may have been altered from the original.
2 of 2