How It Works - UK (2020-02)

THE

SECRETS

OF SKIN

Professor Ben Garrod is a TV presenter

and professor of evolutionar y biolog y

and science engagement at the

University of East Anglia. He explores

the evolution of skin and scales in a

new BBC documentary series

in particular exploring the secretsofskin?
I like the st yle of this series, because it’s not
purely a stand back and look at the grandeur of
nature, it gets deep dow n and dirt y w ith the
science and explores how different things
operate. We wanted to look at skin in particular
because you often see documentaries on big
sex y topics, like bones and blood vessels and
hearts, but skin seems to get overlooked and
taken for granted. When you look at skin quite
analytically and then through the magnifying
glass, it really transforms and becomes not just
this barrier bet ween us and the outside world,
but this whole stor y in itself. I thought that stor y
needed to be told from a scientific perspective
and in a fun, engaging way.

How versatile is skin? How has it evolved as
a result of changing environments?
In terms of versatilit y, skin can accommodate
ever y thingfrompolar temperatures to sur v iv ing

inplus-40degreesCelsiusandthenever y thing

in bet ween. We have animals that can shed their

skins, shed their tails, change colour in a second

and then back again. We know that cuttlefish

can change colour and the texture of their skin

from one that’s beautifully smooth to one that’s

full of [hair-like] filaments instantly. Skin

enables animals to fit into ever y env ironment

imaginable. A nd that’s why it’s one of those sex y

topics. It’s not just this passive barrier; it’s an

interacting organ bet ween us and the outside

world. It’s exploiting and interacting w ith the

env ironment itself and others liv ing in it. In

terms of versatilit y: imagine a situation or an

env ironment or a habitat and there is a skin to

accommodate that.

The environment plays a massive part in

how a species evolves and adapts, but what

are other driving forces in skin evolution?

This is probably why skin is so diverse in terms

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ofitsformandfunction,becauseit’ssubject

to all different things, like predator-prey

relationships. That’s easy to see when we can

look at species like armadillos and tortoises. On

the predator side, sharks, for example, have

these dermal denticles, these tiny back ward-

facing teeth. Basically the shark is covered in

millions upon millions of teeth all over its body,

and they are able to sw im in these ver y fast

dy namic behav iours because they’ve got this

ver y streamlined hydrody namic covering over

their body. That allows fast-sw imming sharks,

like makos, to car ve through the water.

We’ve seen predator-prey as a selective

evolutionar y pressure for skin – also anti-

parasite. Poison dart frogs, for example: we

think part of the reason for them being so toxic

isn’t solely for anti-predation, but [the poison]

also works as anti-fungal and antibacterial

chemicals. So they’re basically a little self-

cleaning hand wash thing, jumping around the

046 How It Works

A lemon shark’s skin viewed through a

scanning electron microscope

Garrod visits the National Museum of Ireland

to explore species’ form and function

Some vertebrates

have transformed

their skins from

shields into weapons Source: WIki/ Pascal Deynat/Odontobase