1
00:00:01,000 --> 00:00:03,900
We are all apes.

2
00:00:03,900 --> 00:00:06,940
All of you are apes.
Every single one of you.

3
00:00:06,940 --> 00:00:08,700
If we look in the animal kingdom,

4
00:00:08,700 --> 00:00:12,060
our closest living relatives
are chimpanzees,

5
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bonobos, and gorillas.

6
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So, here's one of my cousins.

7
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We look very different.

8
00:00:20,260 --> 00:00:24,380
So, when did our family trees
split apart from each other?

9
00:00:24,380 --> 00:00:26,220
What makes him a gorilla?

10
00:00:26,220 --> 00:00:28,660
What makes me a human?

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This is Albert the gorilla.
I'm Professor Alice Roberts.

12
00:01:02,260 --> 00:01:04,500
Welcome to the second of this year's

13
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Royal Institution
Christmas Lectures.

14
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Now, Albert is going to come
and say hello to some of you.

15
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He's very interested in you.

16
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I'm sure you're interested in him
as well.

17
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On the surface, he looks
really different, but maybe

18
00:01:17,180 --> 00:01:20,660
when you get a bit closer,
you can see some similarities.

19
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If you hold up your hand, so...

20
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He's looking right at...

21
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He's looking right at you there,
in the hoodie.

22
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If you hold up your hand,
he should hold up his hand as well,

23
00:01:31,340 --> 00:01:33,940
and you can compare your hand
to his. You can see that his hand

24
00:01:33,940 --> 00:01:36,340
is very large, but he's got
four fingers and a thumb.

25
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He's got fingernails.

26
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Try smiling at him, show your teeth.

27
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He'll recognise that as a smile,
he knows that you're

28
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being submissive.
He's baring his teeth as well.

29
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I think he quite likes you.
Do you want to say hello?

30
00:01:47,900 --> 00:01:50,620
Hi.
LAUGHTER

31
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It's all right, he's harmless.

32
00:01:52,820 --> 00:01:55,620
He does like you! Awww!

33
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He's found a friend -
a cousin and a friend.

34
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Albert, come back down here, though.

35
00:02:00,580 --> 00:02:02,620
Come on. Come down.

36
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Albert is a great ape.

37
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We are part of this family
of great apes as well.

38
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And so those great apes include
gorillas and chimpanzees

39
00:02:13,540 --> 00:02:16,740
and bonobos and orangutans.

40
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And then our family of great apes
is part of an even bigger group

41
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of animals called primates,

42
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and all primates have
various things in common.

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So...
SHE LAUGHS

44
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We're all very good with our hands.
We've got grasping hands.

45
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All primates have clavicles.
You've got collarbones,

46
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haven't you? That's one thing
that makes you a primate.

47
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And also, all primates are really,
really good at climbing.

48
00:02:43,420 --> 00:02:46,460
ATMOSPHERIC MUSIC PLAYS

49
00:03:51,660 --> 00:03:55,260
Alex and Dane, that was
absolutely amazing!

50
00:03:55,260 --> 00:03:59,540
How wonderful to see people who can
use their bodies in that way,

51
00:03:59,540 --> 00:04:02,780
and move around in 3-D space
like that.

52
00:04:02,780 --> 00:04:07,700
It reminds us just how flexible
the human body really is.

53
00:04:07,700 --> 00:04:10,460
I think a lot of us move
around in a really boring way

54
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in comparison.

55
00:04:11,700 --> 00:04:16,740
Which one of you here has ever tried
to climb a climbing frame or a tree?

56
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You've all done it.

57
00:04:19,140 --> 00:04:21,620
So we are primates at heart.

58
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Thank you very much.

59
00:04:23,020 --> 00:04:26,100
And Alex and Dane,
what an amazing performance.

60
00:04:26,100 --> 00:04:27,780
I thought you were
absolutely brilliant.

61
00:04:27,780 --> 00:04:30,780
Let's ask Albert what he thinks,
though. What do you think, Albert,

62
00:04:30,780 --> 00:04:33,580
for their parkour performance?

63
00:04:33,580 --> 00:04:36,900
Awww!

64
00:04:36,900 --> 00:04:39,940
Oh, I think it was
better than that.

65
00:04:39,940 --> 00:04:43,180
Oh, well. A big round of applause
for our great apes.

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00:04:43,180 --> 00:04:45,620
APPLAUSE

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Alex and Dane showed us brilliantly
how we can still move around

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in 3-D space as primates do, if we
want to, and if we train at it.

69
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But in fact there are other clues
to our primate connections,

70
00:05:04,300 --> 00:05:06,620
and there's one clue
I'd like to show you now,

71
00:05:06,620 --> 00:05:09,260
which is only there for a
fleeting moment in our lives

72
00:05:09,260 --> 00:05:10,980
when we're very, very young.

73
00:05:10,980 --> 00:05:14,380
So, I'd like you to do a very gentle
round of applause now

74
00:05:14,380 --> 00:05:16,500
for Vicki and Aria.

75
00:05:19,260 --> 00:05:21,980
Hello, Vicki. Hello.
Hello, Aria.

76
00:05:21,980 --> 00:05:25,220
So, Aria is very, very small.
She's a very new person.

77
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How old is she? She's six weeks.
She's six weeks? Yes.

78
00:05:28,380 --> 00:05:30,900
You're gorgeous! Aren't you lovely?

79
00:05:30,900 --> 00:05:34,460
Now, Aria is so small
that she still has a reflex

80
00:05:34,460 --> 00:05:36,900
that all of you
will have lost long ago,

81
00:05:36,900 --> 00:05:38,540
but I might be able
to show it to you.

82
00:05:38,540 --> 00:05:41,660
I want to look at her hand, is this
all right with you? Yes, of course.

83
00:05:41,660 --> 00:05:44,740
And what I'm trying to do
is put my finger in her hand,

84
00:05:44,740 --> 00:05:47,620
and she closes her fingers...
ARIA MOANS

85
00:05:47,620 --> 00:05:50,020
She doesn't like it. Oh, no, Aria!

86
00:05:50,020 --> 00:05:53,620
I'm sorry, poppet! Oh, oh. It's OK.

87
00:05:53,620 --> 00:05:57,180
She's really gripping my finger,
really strongly.

88
00:05:57,180 --> 00:05:59,980
She's got this incredible reflex
which is elicited,

89
00:05:59,980 --> 00:06:02,820
I'm making it happen
just by slightly tickling the palm

90
00:06:02,820 --> 00:06:05,900
of her hand, and she grabs on.

91
00:06:05,900 --> 00:06:08,820
ARIA CRIES
Aw, baby! Good girl.

92
00:06:08,820 --> 00:06:12,620
So, this reflex disappears
by about six weeks of age,

93
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but it's something that we think
is left over

94
00:06:15,060 --> 00:06:18,060
from our ancient primate ancestors.

95
00:06:18,060 --> 00:06:21,740
And, Vicki and Aria,
I've got a little video here...

96
00:06:21,740 --> 00:06:24,900
..to show you some cousins.
So, these are chimpanzees.

97
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And what you can see
here is the chimpanzee baby

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on its mother's back,

99
00:06:28,740 --> 00:06:31,260
and you can see how the mum's
moving pretty swiftly,

100
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and that chimp baby, even though
it's tiny, has to cling on

101
00:06:34,220 --> 00:06:37,260
for dear life, so it's really
gripping with its hands.

102
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So this is where we think
this grasp reflex is

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00:06:39,660 --> 00:06:41,900
left over from in our babies.

104
00:06:41,900 --> 00:06:44,580
But by about six months,
she'll have forgotten how to do it.

105
00:06:44,580 --> 00:06:47,020
Thank you so much, Vicki.
Thank you. Thank you, Aria.

106
00:06:47,020 --> 00:06:51,820
Thanks. Another gentle round of
applause. Thank you!

107
00:06:51,820 --> 00:06:55,860
So, we've seen now evidence
of primate connections in the way

108
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that we CAN move with our bodies,
if we want to.

109
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We've seen primate connections
and this amazing grasp reflex

110
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that we're all born with
but then we then lose,

111
00:07:04,820 --> 00:07:08,060
and there are other signs
of these connections

112
00:07:08,060 --> 00:07:09,540
when we look at anatomy.

113
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I'm an anatomist, so I go
under the skin and I start looking

114
00:07:12,100 --> 00:07:14,620
at the structure of the body,

115
00:07:14,620 --> 00:07:18,780
and what I've got here are two bones
from two different species.

116
00:07:18,780 --> 00:07:23,460
One of them is from a human, and
one of them is from a chimpanzee.

117
00:07:23,460 --> 00:07:27,700
First of all, there's this very,
very narrow groove at the top

118
00:07:27,700 --> 00:07:30,140
of this bone. If we look at
the bottoms of the bones,

119
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there are some differences as well.

120
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So both of these bones have got
a ball shape at the bottom.

121
00:07:34,340 --> 00:07:37,740
And on this bone, you can see
that there's a much more prominent

122
00:07:37,740 --> 00:07:41,260
lip on it. So, there are really
subtle differences that tell me

123
00:07:41,260 --> 00:07:46,180
that this bone is the chimpanzee
humerus, and this one

124
00:07:46,180 --> 00:07:49,820
is the human humerus, but they're
kind of shockingly similar.

125
00:07:49,820 --> 00:07:52,780
Now, we're going to put them
in context and bring in two complete

126
00:07:52,780 --> 00:07:57,820
skeletons - a human skeleton
and a chimpanzee skeleton.

127
00:07:58,140 --> 00:08:00,300
And when you look at a whole
skeleton like this,

128
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I think you notice the differences
more than the similarities at first,

129
00:08:03,260 --> 00:08:07,100
especially because the human
has been hung like this, so he looks

130
00:08:07,100 --> 00:08:08,540
like he's walking on two feet.

131
00:08:08,540 --> 00:08:11,060
And the chimpanzee's arranged
like this, so he looks

132
00:08:11,060 --> 00:08:13,380
like he's just getting ready
to go knuckle walking,

133
00:08:13,380 --> 00:08:16,820
which is what chimpanzees tend to do
when they drop down to the ground.

134
00:08:16,820 --> 00:08:19,220
So that was the humerus
that we were looking at

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00:08:19,220 --> 00:08:20,540
in both of these animals.

136
00:08:20,540 --> 00:08:22,860
That's a very similar bone
in the chimp and the human.

137
00:08:22,860 --> 00:08:25,220
There are other bones
which are much more different.

138
00:08:25,220 --> 00:08:28,580
So, if you look at the pelvis here,
that's a completely different shape.

139
00:08:28,580 --> 00:08:32,420
It's got a very long, flat blade,

140
00:08:32,420 --> 00:08:35,980
whereas our pelvis is kind of a
basin shape, and it's adapted to

141
00:08:35,980 --> 00:08:37,900
us walking upright on two legs.

142
00:08:37,900 --> 00:08:40,380
But there are other bits
that are quite similar still,

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00:08:40,380 --> 00:08:43,500
and our hands are a great
example of that.

144
00:08:43,500 --> 00:08:46,340
So, if I hold up the chimp
hand and the human hand,

145
00:08:46,340 --> 00:08:48,700
you can see that the chimp thumb
is a bit weedy

146
00:08:48,700 --> 00:08:50,260
compared to the human thumb.

147
00:08:50,260 --> 00:08:53,380
But still both of those hands
are capable of doing something

148
00:08:53,380 --> 00:08:55,260
that you can all do.

149
00:08:55,260 --> 00:08:57,660
Those thumbs can move
in a very special way.

150
00:08:57,660 --> 00:08:59,740
The thumb can move
right across the palm,

151
00:08:59,740 --> 00:09:03,740
and you can touch the tip of your
thumb to your little finger.

152
00:09:03,740 --> 00:09:06,860
It may not feel like a really
special thing to be able to do,

153
00:09:06,860 --> 00:09:11,100
but this opposable thumb
is really important in grasping.

154
00:09:11,100 --> 00:09:13,540
It's something that other
primates have as well,

155
00:09:13,540 --> 00:09:16,660
but our opposable thumbs
are exceptional.

156
00:09:16,660 --> 00:09:20,860
So, they're really great
when you're making and using tools.

157
00:09:20,860 --> 00:09:25,260
But I want to demonstrate just how
useful they are with two volunteers.

158
00:09:25,260 --> 00:09:28,460
So, can I have two volunteers
from the audience, please?

159
00:09:28,460 --> 00:09:32,860
So, I'd like you in
the mustard jumper and...

160
00:09:32,860 --> 00:09:36,100
..yes, in the grey hoodie.
Come down, come down.

161
00:09:36,100 --> 00:09:38,660
And we've got a little
challenge for you.

162
00:09:38,660 --> 00:09:41,500
As you can see, it involves grapes.
What's your name? Esme.

163
00:09:41,500 --> 00:09:44,300
Esme, so, you're over there
with the green grapes, Esme.

164
00:09:44,300 --> 00:09:46,660
Are you right or left-handed?
I'm right-handed.

165
00:09:46,660 --> 00:09:48,860
OK, can you put your left
hand behind your back? Sure.

166
00:09:48,860 --> 00:09:52,140
Lovely. And what's your name?
Lehner. Lehner.

167
00:09:52,140 --> 00:09:57,020
So, Esme and Lehner, you're going to
be pitted against each other

168
00:09:57,020 --> 00:09:59,660
in a grape-picking challenge.

169
00:09:59,660 --> 00:10:02,700
You're both right-handed, so,
Lehner, if you put your left hand

170
00:10:02,700 --> 00:10:05,940
behind your back as well, so you're
not tempted to use it at all.

171
00:10:05,940 --> 00:10:10,020
What I want you to do, when I say
go, is pluck grapes from that bunch,

172
00:10:10,020 --> 00:10:13,620
just using one hand, and put
the grapes in this empty bowl.

173
00:10:13,620 --> 00:10:15,420
So, that's the challenge. All right?

174
00:10:15,420 --> 00:10:18,500
So, taking, taking grapes... I'll
put the bowls round that way

175
00:10:18,500 --> 00:10:20,340
for you as well,
so it might be a bit easier.

176
00:10:20,340 --> 00:10:22,980
So, you pluck the grapes off,
you put them in the bowl

177
00:10:22,980 --> 00:10:24,900
and you've got 15 seconds to do it.

178
00:10:24,900 --> 00:10:27,380
I'm going to give you a countdown.

179
00:10:27,380 --> 00:10:31,540
One, two, three, four,
I declare...

180
00:10:31,540 --> 00:10:34,020
..a thumb war. Go!

181
00:10:34,020 --> 00:10:35,700
15 seconds.

182
00:10:40,220 --> 00:10:42,340
Who's going to do better at this?
LAUGHTER

183
00:10:42,340 --> 00:10:45,700
I think that might be cheating!
LAUGHTER

184
00:10:48,980 --> 00:10:53,180
Right, stop! Stop, stop, stop!
Drop the grapes.

185
00:10:53,180 --> 00:10:55,700
Now, the really amazing thing
about this demonstration

186
00:10:55,700 --> 00:10:58,500
is it's meant to show how, if you
don't have your opposable thumb...

187
00:10:58,500 --> 00:10:59,820
LAUGHTER

188
00:10:59,820 --> 00:11:02,700
I was just taking it up...! ..you're
much worse at plucking grapes!

189
00:11:02,700 --> 00:11:05,140
Do you know what, Lehner?
We've done it with so many people

190
00:11:05,140 --> 00:11:07,500
this afternoon in rehearsals,
and we always end up with a

191
00:11:07,500 --> 00:11:10,340
great pile of grapes over here and a
very small pile of grapes over here.

192
00:11:10,340 --> 00:11:11,580
LAUGHTER

193
00:11:11,580 --> 00:11:14,420
I think possibly you cheated by
picking up the bunch and shaking it.

194
00:11:14,420 --> 00:11:16,980
Maybe.
LAUGHTER

195
00:11:16,980 --> 00:11:19,300
But this does show
something really important.

196
00:11:19,300 --> 00:11:22,700
So, if you don't pick up the bunch
and shake it,

197
00:11:22,700 --> 00:11:25,100
then you're going to end up
with fewer grapes in here.

198
00:11:25,100 --> 00:11:28,820
Humans are also rather ingenious
and very good at problem-solving.

199
00:11:28,820 --> 00:11:32,100
So, thank you very much to Lehner
and Esme

200
00:11:32,100 --> 00:11:34,940
for testing out their thumbs.
Thank you.

201
00:11:39,340 --> 00:11:41,780
So, lots of things, then,
that we've got in common

202
00:11:41,780 --> 00:11:45,860
with our primate cousins
- anatomy, behaviour -

203
00:11:45,860 --> 00:11:49,100
but actually the similarities
go down to the level

204
00:11:49,100 --> 00:11:50,780
of molecules inside yourselves.

205
00:11:50,780 --> 00:11:53,500
You can actually look for
similarities like this

206
00:11:53,500 --> 00:11:55,940
when you get down to the level
of DNA.

207
00:11:55,940 --> 00:11:58,820
So, this is when I'd like
to introduce my friend,

208
00:11:58,820 --> 00:12:01,740
the geneticist,
Professor Aoife McLysaght.

209
00:12:01,740 --> 00:12:04,420
APPLAUSE

210
00:12:10,340 --> 00:12:12,100
OK, thank you so much.

211
00:12:12,100 --> 00:12:16,420
Well, one of the really useful
things about genetics and DNA

212
00:12:16,420 --> 00:12:20,260
analysis is that we can actually put
a number on these similarities

213
00:12:20,260 --> 00:12:22,460
that Alice has already
been describing.

214
00:12:22,460 --> 00:12:25,900
So, the people in row five
all have a very special ribbon

215
00:12:25,900 --> 00:12:27,420
in front of you, all around there.

216
00:12:27,420 --> 00:12:29,540
So, could you just take
hold of that ribbon?

217
00:12:29,540 --> 00:12:31,740
I'm going to tell you to stand up.
So, are you ready?

218
00:12:31,740 --> 00:12:33,540
OK, can you stand up, please?

219
00:12:33,540 --> 00:12:35,820
And we're going to show
this ribbon to everybody.

220
00:12:35,820 --> 00:12:39,620
OK, great. So, what you can see
here across the room,

221
00:12:39,620 --> 00:12:41,500
that's a DNA sequence.

222
00:12:41,500 --> 00:12:44,540
And that's not just any old DNA
sequence, that's real DNA sequence.

223
00:12:44,540 --> 00:12:48,860
The top ribbon is showing you DNA
sequence from the human genome,

224
00:12:48,860 --> 00:12:52,900
and the bottom ribbon is DNA
sequence from the chimpanzee genome.

225
00:12:52,900 --> 00:12:54,420
It's a real sequence.

226
00:12:54,420 --> 00:12:57,580
This actually comes from a gene
called Factor IX, which makes

227
00:12:57,580 --> 00:12:59,460
part of your blood clotting system.

228
00:12:59,460 --> 00:13:02,340
So the first thing you might notice
when you look at these

229
00:13:02,340 --> 00:13:04,740
is that the top and the bottom
are mostly the same,

230
00:13:04,740 --> 00:13:07,380
and this is what we see -
the human and the chimpanzee

231
00:13:07,380 --> 00:13:09,660
DNA sequences are really,
really similar,

232
00:13:09,660 --> 00:13:12,660
but there are a few differences.
So I would like the people

233
00:13:12,660 --> 00:13:15,140
in row four to help me out
here. If you could just have a look,

234
00:13:15,140 --> 00:13:17,700
and I just want to see
letter differences.

235
00:13:17,700 --> 00:13:20,140
So, raise your hand
and show me if you've got one.

236
00:13:20,140 --> 00:13:22,860
So, yeah, we've got one up here.
Thank you.

237
00:13:22,860 --> 00:13:27,860
So, what we see here is, in the
human sequence on the top, we have a

238
00:13:27,940 --> 00:13:31,660
C and a G, and in the chimpanzee
sequence on the bottom,

239
00:13:31,660 --> 00:13:34,340
we've got a T and an A, so we've
got two letter differences there.

240
00:13:34,340 --> 00:13:36,980
Have we got somewhere else?
Got a difference? Give me a wave.

241
00:13:36,980 --> 00:13:38,620
Yeah, over there.

242
00:13:38,620 --> 00:13:42,420
So, yeah, so this one here,
just one letter

243
00:13:42,420 --> 00:13:46,140
that's different here. So, we've got
a T in human and a C in chimpanzee,

244
00:13:46,140 --> 00:13:48,620
but the rest,
they're all pretty much the same.

245
00:13:48,620 --> 00:13:51,220
So, that's just one kind
of difference that we can look at.

246
00:13:51,220 --> 00:13:55,380
And if we looked over the whole
genome, we find that this amount

247
00:13:55,380 --> 00:13:58,540
of difference is actually quite
representative of what we see

248
00:13:58,540 --> 00:14:00,980
over the whole DNA comparison.

249
00:14:00,980 --> 00:14:04,060
So, that's about 1% different,
or 99% the same,

250
00:14:04,060 --> 00:14:08,700
you could say. But that's just one
way of counting the differences.

251
00:14:08,700 --> 00:14:10,700
There are actually other
kind of differences.

252
00:14:10,700 --> 00:14:13,380
So, somewhere in this ribbon,
we've got a loop that's

253
00:14:13,380 --> 00:14:15,380
sticking out. Give me a wave
if you can see the loop.

254
00:14:15,380 --> 00:14:16,740
OK, over here, yeah.

255
00:14:16,740 --> 00:14:20,980
So, in this loop here,
that's the human sequence

256
00:14:20,980 --> 00:14:24,180
going across the top. Chimpanzee
sequence across the bottom.

257
00:14:24,180 --> 00:14:26,340
And there's this bit that's
looping out in human,

258
00:14:26,340 --> 00:14:29,540
there's nothing to match
it against on the other side.

259
00:14:29,540 --> 00:14:33,220
So this is...there's a piece of
DNA that's either been inserted

260
00:14:33,220 --> 00:14:37,820
into the human genome or deleted
from the chimpanzee genome.

261
00:14:37,820 --> 00:14:39,980
But we just,
we can't match those up.

262
00:14:39,980 --> 00:14:42,300
And there are other bits
like that around the genome,

263
00:14:42,300 --> 00:14:44,140
if we were to do
the whole comparison,

264
00:14:44,140 --> 00:14:47,900
and that adds about
another 3% different.

265
00:14:47,900 --> 00:14:51,940
So, if we put these together,
we get it to about 4% different,

266
00:14:51,940 --> 00:14:53,420
or 96% the same.

267
00:14:53,420 --> 00:14:55,620
It's the kind of thing
you might like to see on a T-shirt

268
00:14:55,620 --> 00:14:58,580
or something, don't you think?
Alice, I'd like it on a T-shirt.

269
00:14:58,580 --> 00:15:00,180
ALICE LAUGHS

270
00:15:00,180 --> 00:15:02,140
OK. OK, then. Yeah.

271
00:15:02,140 --> 00:15:03,940
We'd better do a countdown,
hadn't we?

272
00:15:03,940 --> 00:15:09,060
OK, yeah, we should do a countdown
for this. Three, two, one!

273
00:15:09,060 --> 00:15:11,940
Boom! Woo!
LAUGHTER

274
00:15:11,940 --> 00:15:14,620
OK, so, thank you so much.

275
00:15:14,620 --> 00:15:17,020
So, the people in row
five can sit down.

276
00:15:17,020 --> 00:15:19,900
Who got the T-shirts?
Can we have a look at them?

277
00:15:19,900 --> 00:15:23,460
"99% chimp," yeah, great.

278
00:15:23,460 --> 00:15:25,300
What does your one say?

279
00:15:25,300 --> 00:15:28,940
"96% chimp, including
insertions and deletions."

280
00:15:28,940 --> 00:15:32,300
Very good!
Who's going to wear those T-shirts?

281
00:15:32,300 --> 00:15:36,260
Yeah? Wear them with pride.
96% chimp and proud.

282
00:15:36,260 --> 00:15:38,940
We made that comparison
kind of easy for you.

283
00:15:38,940 --> 00:15:40,460
We just showed it to you.

284
00:15:40,460 --> 00:15:42,780
Now I'm actually going to test
you on something

285
00:15:42,780 --> 00:15:44,580
we're not telling you in advance.

286
00:15:44,580 --> 00:15:47,700
So, we've got some other
species we want to compare.

287
00:15:47,700 --> 00:15:50,460
So, what we have here...

288
00:15:50,460 --> 00:15:53,820
So, Alice has a human
and a chimpanzee,

289
00:15:53,820 --> 00:15:56,780
and I have a mouse and a rat.

290
00:15:56,780 --> 00:15:59,460
They're very cute, aren't they?
They're very sweet. Yes.

291
00:15:59,460 --> 00:16:04,460
So, I'm going to ask you to tell me
which pair you think is more similar

292
00:16:05,100 --> 00:16:06,740
at the genetic level.

293
00:16:06,740 --> 00:16:10,980
So, hands up if you think that human
and chimpanzee are most similar

294
00:16:10,980 --> 00:16:12,900
at the genetic level.

295
00:16:12,900 --> 00:16:15,180
So, good few hands.

296
00:16:15,180 --> 00:16:17,660
Hands up who thinks mouse
and rat are most similar

297
00:16:17,660 --> 00:16:19,300
at the genetic level.

298
00:16:19,300 --> 00:16:21,780
Oh, not as many, OK.
This is interesting.

299
00:16:21,780 --> 00:16:26,020
So, even though mouse and rat
look much more similar,

300
00:16:26,020 --> 00:16:28,100
they're actually very
similar-looking

301
00:16:28,100 --> 00:16:31,100
- at least they are to me - they are
much more different genetically

302
00:16:31,100 --> 00:16:33,740
than human and chimpanzee are.

303
00:16:33,740 --> 00:16:38,220
So, we have 99%, or 96 taking
into consideration the insertions

304
00:16:38,220 --> 00:16:42,540
and deletions, but in rat and mouse,
when we compare them,

305
00:16:42,540 --> 00:16:45,900
just the genes we can align,
it's about 93%.

306
00:16:45,900 --> 00:16:47,980
And then there's lots
and lots of those loops.

307
00:16:47,980 --> 00:16:50,180
So, lots more that we can't compare.

308
00:16:50,180 --> 00:16:52,020
These animals look
very, very similar.

309
00:16:52,020 --> 00:16:54,460
I mean, you've got DNA here
making a very similar body -

310
00:16:54,460 --> 00:16:57,060
little ears,
little paws, little tail.

311
00:16:57,060 --> 00:17:00,220
These animals look much, much
more different from each other,

312
00:17:00,220 --> 00:17:03,660
so that small percentage difference
translates into a big difference

313
00:17:03,660 --> 00:17:06,500
in actual body. A huge difference,
a huge difference. Yeah.

314
00:17:06,500 --> 00:17:09,420
But what we've done now, anyway,
is we've learned how to count

315
00:17:09,420 --> 00:17:12,540
those differences and describe
those differences, but the thing

316
00:17:12,540 --> 00:17:15,020
we really want to know
is how the genetic differences

317
00:17:15,020 --> 00:17:17,260
make those physical differences
that you see.

318
00:17:17,260 --> 00:17:21,060
Because, despite the similarities,
there are these big differences,

319
00:17:21,060 --> 00:17:24,180
aren't there? There's a big gulf
between us and our closest

320
00:17:24,180 --> 00:17:29,180
relatives. I mean, chimpanzees
don't go to school.

321
00:17:29,620 --> 00:17:32,980
Chimpanzees don't go
to Christmas lectures.

322
00:17:32,980 --> 00:17:37,940
And I don't think Father Christmas
even knows that chimpanzees exist.

323
00:17:37,940 --> 00:17:40,780
Very sad indeed.

324
00:17:40,780 --> 00:17:44,220
There's another big difference,
and that's when chimpanzees

325
00:17:44,220 --> 00:17:47,100
stop climbing around in trees
and come down to the ground,

326
00:17:47,100 --> 00:17:51,100
they don't do what we tend to do,
which is walking on our two feet.

327
00:17:51,100 --> 00:17:53,940
They tend to walk on all fours.

328
00:17:53,940 --> 00:17:55,700
They knuckle-walk.

329
00:17:55,700 --> 00:17:59,060
So, when did we start
walking on two feet?

330
00:17:59,060 --> 00:18:02,780
In order to answer that, I'm going
to need a very brave volunteer,

331
00:18:02,780 --> 00:18:05,620
and somebody who's brilliant
at balancing.

332
00:18:05,620 --> 00:18:08,980
Er, Christmas jumper in the
second row back, please come down.

333
00:18:08,980 --> 00:18:11,180
That's a fantastic jumper!

334
00:18:13,820 --> 00:18:16,300
Thank you very much
for volunteering, you're very brave.

335
00:18:16,300 --> 00:18:18,100
What's your name? Stephen.

336
00:18:18,100 --> 00:18:19,860
Stephen, right.

337
00:18:19,860 --> 00:18:23,620
Now, Stephen, you can see exactly
what you volunteered for.

338
00:18:23,620 --> 00:18:26,380
So, this is a tightrope challenge.

339
00:18:26,380 --> 00:18:28,700
So, I'd like you to go
and stand on there.

340
00:18:28,700 --> 00:18:30,420
I'll help you get up.

341
00:18:30,420 --> 00:18:34,620
And before you start doing
this tightrope challenge,

342
00:18:34,620 --> 00:18:37,660
let me just show you what I want
you to start doing, because I'd like

343
00:18:37,660 --> 00:18:42,740
you to behave a little bit like
one of your primate cousins.

344
00:18:47,620 --> 00:18:52,060
making its way across a tightrope.
LAUGHTER

345
00:18:52,060 --> 00:18:55,540
So Stephen, what I'd like you to do
is bring your hands down to

346
00:18:55,540 --> 00:18:58,580
the cable here, bring your hands
down to the tightrope.

347
00:18:58,580 --> 00:19:00,740
Can you go across on all fours?

348
00:19:00,740 --> 00:19:03,620
Are you going to be able to make it?

349
00:19:03,620 --> 00:19:06,420
Is he going to be able to do it,
ladies and gentlemen?

350
00:19:06,420 --> 00:19:10,340
No! I'm sorry, Stephen. I don't
think anybody in the audience

351
00:19:10,340 --> 00:19:12,340
could do it either.
I don't think you can do it.

352
00:19:12,340 --> 00:19:14,100
There's plenty of people
that are keen.

353
00:19:14,100 --> 00:19:16,740
We've tried it with lots of people.
Nobody can do it.

354
00:19:16,740 --> 00:19:18,940
Nobody can get all the way
from there to there.

355
00:19:18,940 --> 00:19:20,820
We are apes.

356
00:19:20,820 --> 00:19:24,340
We've got quite big bodies
compared with the capuchin monkey

357
00:19:24,340 --> 00:19:25,740
that you just saw.

358
00:19:25,740 --> 00:19:29,500
He's a little, tiny
small-bodied monkey.

359
00:19:29,500 --> 00:19:32,260
He can run along,
he can keep his body weight

360
00:19:32,260 --> 00:19:37,300
above quite a narrow branch,
or even a tightrope.

361
00:19:37,300 --> 00:19:39,620
How would you prefer
to travel across that?

362
00:19:39,620 --> 00:19:42,740
Standing on two legs
with weights on my either side.

363
00:19:42,740 --> 00:19:45,620
OK, I'm not going to give
you weights, but if you pop back

364
00:19:45,620 --> 00:19:47,900
up there, shall I give
you a hand, you all right?

365
00:19:47,900 --> 00:19:49,900
Yeah, I'm good. You can do it on
two feet, then.

366
00:19:49,900 --> 00:19:53,140
Have a go then, let's be nice and
quiet, let's give him some...

367
00:19:53,140 --> 00:19:56,180
That's it! Yeah. Try that.

368
00:19:56,180 --> 00:19:58,100
I'm going to let you go now,
Stephen.

369
00:19:58,100 --> 00:19:59,900
You all right?

370
00:19:59,900 --> 00:20:01,540
LAUGHTER

371
00:20:02,940 --> 00:20:04,940
It's really difficult.

372
00:20:04,940 --> 00:20:08,220
It's really difficult,
and it's also quite terrifying,

373
00:20:08,220 --> 00:20:10,780
even though you're only a foot
or two above the ground.

374
00:20:10,780 --> 00:20:13,700
I'm going to do something now
which I think will make it

375
00:20:13,700 --> 00:20:17,460
an awful lot easier for you.
So, you see that rope going up?

376
00:20:17,460 --> 00:20:22,500
So if you walk underneath that rope,
and back up on the pedestal,

377
00:20:23,060 --> 00:20:25,300
now you can use this to help you.

378
00:20:25,300 --> 00:20:28,020
Don't pull on it hard,
and just use one hand.

379
00:20:28,020 --> 00:20:30,580
But I think it will
give you a lot of help.

380
00:20:30,580 --> 00:20:34,020
So, let's see how
Stephen does this time.

381
00:20:34,020 --> 00:20:36,220
He's using the rope
just to help him balance,

382
00:20:36,220 --> 00:20:38,780
he's not putting much weight on it
at all, you can see.

383
00:20:38,780 --> 00:20:40,180
He's weight-bearing on his feet.

384
00:20:40,180 --> 00:20:42,380
Well done! Well done!

385
00:20:46,660 --> 00:20:48,660
Stephen, that was
absolutely brilliant.

386
00:20:48,660 --> 00:20:51,700
And I now want to show you an ape
doing something very similar,

387
00:20:51,700 --> 00:20:53,940
shot from a slightly strange
angle, I must say.

388
00:20:53,940 --> 00:20:56,980
But let's have a look at
an orangutan doing the same thing.

389
00:20:59,420 --> 00:21:03,060
So, what that orang is doing
is walking along that rope

390
00:21:03,060 --> 00:21:05,740
on his feet like you walked
along the tightrope,

391
00:21:05,740 --> 00:21:08,380
and using his hands
to stabilise him.

392
00:21:08,380 --> 00:21:10,460
So, you were doing
exactly the same thing.

393
00:21:10,460 --> 00:21:12,860
Thank you very much. Thank you.

394
00:21:18,100 --> 00:21:21,380
We can do this thing of walking
along a tightrope and

395
00:21:21,380 --> 00:21:23,780
suspending ourselves, or at least
stabilising ourselves,

396
00:21:23,780 --> 00:21:25,260
by holding on to other things.

397
00:21:25,260 --> 00:21:27,500
And as we've seen
with the orangutan,

398
00:21:27,500 --> 00:21:29,180
other apes do this as well.

399
00:21:29,180 --> 00:21:32,780
So, what we think happened
deep back in our ancestry...

400
00:21:32,780 --> 00:21:34,620
Oh, hello.

401
00:21:34,620 --> 00:21:39,140
What we think happened deep back
in our ancestry is that our ancient

402
00:21:39,140 --> 00:21:42,700
tree-living ancestors were doing
this, were walking around in trees,

403
00:21:42,700 --> 00:21:45,340
and then when they started
walking on the ground more,

404
00:21:45,340 --> 00:21:47,460
it was quite a simple thing
for them to do,

405
00:21:47,460 --> 00:21:51,020
to drop out of the tree
and just continue walking

406
00:21:51,020 --> 00:21:54,900
on two legs, on two feet,
on the ground.

407
00:21:54,900 --> 00:21:59,180
So we don't have to explain
how you go from being a four-legged

408
00:21:59,180 --> 00:22:02,180
quadrupedal animal
to being an upright animal.

409
00:22:02,180 --> 00:22:04,420
We think our ancestors
always were upright,

410
00:22:04,420 --> 00:22:06,860
and then they just swapped walking
in the trees

411
00:22:06,860 --> 00:22:09,100
for walking on the ground.

412
00:22:09,100 --> 00:22:12,060
And then, by the time
we get to about four,

413
00:22:12,060 --> 00:22:17,100
to three million years ago, we find
ancestors who have started to adapt

414
00:22:17,100 --> 00:22:19,820
in their bodies to this new way
of getting around.

415
00:22:19,820 --> 00:22:21,900
So, their skeletons have started
to change,

416
00:22:21,900 --> 00:22:24,500
so they're getting better
and better at walking.

417
00:22:24,500 --> 00:22:28,140
And I want to introduce you
to one of these ancestors.

418
00:22:28,140 --> 00:22:32,260
So this is a reconstruction
of the fossil of a very,

419
00:22:32,260 --> 00:22:34,700
very famous fossil discovery.

420
00:22:34,700 --> 00:22:39,780
She's called Lucy,
and she was discovered in Ethiopia.

421
00:22:39,860 --> 00:22:44,580
She belongs to a species called
Australopithecus afarensis.

422
00:22:44,580 --> 00:22:47,300
Australopithecus means southern ape,

423
00:22:47,300 --> 00:22:51,140
and afarensis means she comes from
the Afar region of Ethiopia.

424
00:22:51,140 --> 00:22:55,260
And this is a reconstruction of Lucy
here, so we can imagine

425
00:22:55,260 --> 00:22:57,900
what she would have looked like
in the flesh.

426
00:22:57,900 --> 00:23:01,100
So we can see from her skeleton
that she's got adaptations

427
00:23:01,100 --> 00:23:02,700
to walking on two legs.

428
00:23:02,700 --> 00:23:07,020
Her pelvis has changed,
it's become adapted to bipedalism,

429
00:23:07,020 --> 00:23:08,580
to two-legged walking.

430
00:23:08,580 --> 00:23:12,060
Her femur, her thigh bone,
is curving in to bring her knees

431
00:23:12,060 --> 00:23:15,700
and her feet underneath
her centre of mass.

432
00:23:15,700 --> 00:23:18,260
She's still got some
adaptations to climbing

433
00:23:18,260 --> 00:23:22,780
left in her skeleton, though,
including quite curved finger bones.

434
00:23:22,780 --> 00:23:24,620
And we're not quite sure
if she was still doing

435
00:23:24,620 --> 00:23:26,180
a lot of climbing,

436
00:23:26,180 --> 00:23:30,140
or whether these are just left over
from HER ancestors.

437
00:23:30,140 --> 00:23:32,420
But she's quite small.

438
00:23:32,420 --> 00:23:35,180
There are some other individuals
from her species who are a bit

439
00:23:35,180 --> 00:23:37,780
bigger than her. But there's
something else that's

440
00:23:37,780 --> 00:23:40,300
quite striking, I think,
about her limb proportions.

441
00:23:40,300 --> 00:23:42,620
She's got longish arms
and short legs,

442
00:23:42,620 --> 00:23:44,980
so she doesn't really
look like us yet.

443
00:23:44,980 --> 00:23:47,620
And there's a change to long legs
that happens about

444
00:23:47,620 --> 00:23:52,500
two million years ago,
with a new species appearing.

445
00:23:52,500 --> 00:23:55,940
And this species is
called Homo erectus.

446
00:23:55,940 --> 00:23:59,300
And Homo erectus appears
about two million years ago.

447
00:23:59,300 --> 00:24:01,940
This particular reconstruction
is based on a fossil

448
00:24:01,940 --> 00:24:06,340
from 1.5 million years ago,
and he's called Nariokotome Boy,

449
00:24:06,340 --> 00:24:08,820
because his fossilised
remains were found

450
00:24:08,820 --> 00:24:11,420
near the Nariokotome River in Kenya.

451
00:24:12,580 --> 00:24:14,820
And he's quite interesting
when you look at his bones,

452
00:24:14,820 --> 00:24:17,180
because he looks like he's 15.

453
00:24:17,180 --> 00:24:19,500
Have we got any 15-year-olds
in the audience tonight?

454
00:24:19,500 --> 00:24:21,940
If I were to do an X-ray and look at
your bones, I'd see that

455
00:24:21,940 --> 00:24:24,500
some of your bones would
still have gaps at the ends.

456
00:24:24,500 --> 00:24:26,740
They haven't fused yet,
cos you're still growing.

457
00:24:26,740 --> 00:24:28,780
And his skeleton looks a bit
like that,

458
00:24:28,780 --> 00:24:30,420
but you're nearly fully grown.

459
00:24:30,420 --> 00:24:34,340
So he's got the skeleton of a
15-year-old, almost fully grown,

460
00:24:34,340 --> 00:24:36,900
but then if we look carefully
at his bones and his teeth,

461
00:24:36,900 --> 00:24:39,140
it turns out that he was only 8.

462
00:24:39,140 --> 00:24:42,060
So he's only 8,
but with the body of a 15-year-old.

463
00:24:42,060 --> 00:24:45,740
He grew up really, really fast.

464
00:24:45,740 --> 00:24:50,220
He didn't have the long childhoods
that we have,

465
00:24:50,220 --> 00:24:52,460
and those childhoods
are really important.

466
00:24:52,460 --> 00:24:54,380
Important to us as humans.

467
00:24:54,380 --> 00:24:58,780
They allow us time to learn
before we grow up into adults.

468
00:24:58,780 --> 00:25:00,820
We can see other things
in his skeleton.

469
00:25:00,820 --> 00:25:03,740
In his back here,
he's got strong back muscles,

470
00:25:03,740 --> 00:25:06,620
and then moving down to his legs,
he's got strong leg muscles,

471
00:25:06,620 --> 00:25:09,620
and he's got really springy tendons,
particularly this one here,

472
00:25:09,620 --> 00:25:12,340
the Achilles tendon,
that attaches at the heel.

473
00:25:12,340 --> 00:25:16,020
We can see from the bones
that he had a really lovely

474
00:25:16,020 --> 00:25:19,180
big springy Achilles tendon,
and that's why we've reconstructed

475
00:25:19,180 --> 00:25:24,180
him like this, because we think
Nariokotome Boy was a runner.

476
00:25:24,460 --> 00:25:28,140
But in order to see just how good
the human body is at running,

477
00:25:28,140 --> 00:25:31,300
we're going to look at it in action,
and Aoife's in the library

478
00:25:31,300 --> 00:25:32,980
with a runner.

479
00:25:34,340 --> 00:25:37,100
Hi, Alice. Yeah, I'm here in the
library, and I'm with Marcus

480
00:25:37,100 --> 00:25:41,100
from Sheffield Hallam University,
and also our very wonderful

481
00:25:41,100 --> 00:25:42,700
volunteer Tom who's been running

482
00:25:42,700 --> 00:25:44,820
here on the treadmill for
quite a few minutes.

483
00:25:44,820 --> 00:25:47,980
So, Marcus, you've been
capturing his movements.

484
00:25:47,980 --> 00:25:51,380
Yeah, exactly. So, you might see
that Tom's covered

485
00:25:51,380 --> 00:25:53,740
in all of these spherical markers,

486
00:25:53,740 --> 00:25:56,580
and what we can do is use
these motion capture cameras

487
00:25:56,580 --> 00:26:00,460
that you can see dotted around in
the red cameras, and they can

488
00:26:00,460 --> 00:26:03,100
really accurately measure
the position of those markers.

489
00:26:03,100 --> 00:26:06,020
Yeah, and we see his head
is staying quite steady,

490
00:26:06,020 --> 00:26:10,220
and we also see that his shoulders
are moving back and forth.

491
00:26:10,220 --> 00:26:13,940
So motion capture is a technology
which people like Marcus

492
00:26:13,940 --> 00:26:18,740
who are sport scientists can use
to analyse how the human body moves,

493
00:26:18,740 --> 00:26:21,380
but also to help athletes
improve their performance.

494
00:26:21,380 --> 00:26:24,820
And we can see, looking
at that little stick man

495
00:26:24,820 --> 00:26:27,380
there of Tom,
his shoulders are moving.

496
00:26:27,380 --> 00:26:30,060
So by the point in time
we've got Nariokotome Boy,

497
00:26:30,060 --> 00:26:32,900
we've got a nice long waist,
and that enables your shoulders

498
00:26:32,900 --> 00:26:35,340
to rotate, and that helps
you to balance and it makes

499
00:26:35,340 --> 00:26:37,140
running more efficient.

500
00:26:37,140 --> 00:26:40,140
And we've also got his head
staying quite still,

501
00:26:40,140 --> 00:26:42,540
so, like Nariokotome Boy,
he's got nice strong muscles

502
00:26:42,540 --> 00:26:45,940
and that strong ligament in the back
of the head, and strong back muscles

503
00:26:45,940 --> 00:26:47,580
to stop his body pitching forward.

504
00:26:47,580 --> 00:26:50,620
Cos actually when you're running,
you're pretty much falling over

505
00:26:50,620 --> 00:26:53,780
almost at every step, and you've
got to stop yourself doing that.

506
00:26:53,780 --> 00:26:56,500
So we're seeing those
adaptations in action.

507
00:26:56,500 --> 00:27:01,540
But actually, there's something else
that would stop you in your tracks

508
00:27:01,620 --> 00:27:05,060
with running, and I think, Aoife,
you're measuring that as well.

509
00:27:05,060 --> 00:27:09,060
Yeah, so Tom is a pretty wonderful
volunteer because he's also

510
00:27:09,060 --> 00:27:10,540
swallowed one of these.

511
00:27:10,540 --> 00:27:12,780
This is a really small thermometer.

512
00:27:12,780 --> 00:27:16,060
And he was asked to do
this by Dr Danny Longman

513
00:27:16,060 --> 00:27:18,660
from Cambridge University,
who's also joining us here.

514
00:27:18,660 --> 00:27:20,460
So what have you been measuring?

515
00:27:20,460 --> 00:27:23,540
Sure, so the pill that Tom swallowed
earlier is transmitting data

516
00:27:23,540 --> 00:27:25,260
wirelessly to this laptop here.

517
00:27:25,260 --> 00:27:28,100
And that's giving us information
about Tom's deep core

518
00:27:28,100 --> 00:27:30,660
body temperature, letting us know
how warm he really is.

519
00:27:30,660 --> 00:27:34,180
And what do you see here? So, we've
got a graph of his temperature?

520
00:27:34,180 --> 00:27:35,700
We do indeed.

521
00:27:35,700 --> 00:27:39,140
So, we see here at rest,
Tom had a core body temperature of

522
00:27:39,140 --> 00:27:41,660
37 degrees, which is that
of a healthy human.

523
00:27:41,660 --> 00:27:43,660
However, when he started
to run about here,

524
00:27:43,660 --> 00:27:46,180
we see that his core body
temperature started to rise,

525
00:27:46,180 --> 00:27:49,180
and that was because his muscles
were activated and muscle activation

526
00:27:49,180 --> 00:27:50,980
generates a lot of heat.

527
00:27:50,980 --> 00:27:53,380
He looks quite hot!
He does indeed.

528
00:27:53,380 --> 00:27:56,500
So, when Tom started to warm up,
his evolved heat loss mechanisms

529
00:27:56,500 --> 00:27:59,500
began to kick in, and he was able
to lose heat at the same rate

530
00:27:59,500 --> 00:28:01,260
as his muscles were producing them.

531
00:28:01,260 --> 00:28:04,860
And we can see here we actually get
a plateau in core body temperature.

532
00:28:04,860 --> 00:28:06,980
And is this the same, then,
for other animals?

533
00:28:06,980 --> 00:28:10,700
Well, if we were to have a gazelle
or a cheetah doing this experiment

534
00:28:10,700 --> 00:28:13,020
in place of Tom, we would see
that the core body temperature

535
00:28:13,020 --> 00:28:14,780
would continue to increase.

536
00:28:14,780 --> 00:28:17,060
They don't have the mechanisms
to lose heat that we do.

537
00:28:17,060 --> 00:28:19,580
So a cheetah would have to stop,
despite being so fast?

538
00:28:19,580 --> 00:28:23,380
Absolutely. Yeah, yeah. So Tom here
is better than a tom cat!

539
00:28:23,380 --> 00:28:26,500
So there's obviously something
that our bodies are doing in order

540
00:28:26,500 --> 00:28:30,380
to regulate that temperature
and to try to keep us cool

541
00:28:30,380 --> 00:28:33,220
whilst everything we're doing
is trying to make us hotter

542
00:28:33,220 --> 00:28:34,620
and hotter and hotter.

543
00:28:34,620 --> 00:28:36,860
And the amazing thing
about being able to regulate our

544
00:28:36,860 --> 00:28:39,820
temperature like this is it means
we can just carry on running.

545
00:28:39,820 --> 00:28:41,740
We're really good
at endurance running.

546
00:28:41,740 --> 00:28:46,500
We can even outrun horses and dogs,
and there's a particular secret

547
00:28:46,500 --> 00:28:48,500
to how we do it.
That was good, wasn't it?

548
00:28:48,500 --> 00:28:51,780
And, Aoife, you happen
to be back in the theatre. Uh-huh.

549
00:28:51,780 --> 00:28:55,140
So, you're going to demonstrate for
me, Aoife... Yeah.

550
00:28:55,140 --> 00:28:58,900
..what our superpower is, how we
manage to keep our temperature down.

551
00:28:58,900 --> 00:29:02,540
OK, yeah. There's a spike. Uh-huh.
And we've got these balloons.

552
00:29:02,540 --> 00:29:03,940
And we've got these balloons.

553
00:29:03,940 --> 00:29:09,020
So this balloon represents
the amount of sweat that a 70kg dog

554
00:29:09,420 --> 00:29:12,420
sweats out during
an hour of exercise.

555
00:29:12,420 --> 00:29:16,700
70kg is bigger than me. Yeah.
That's a big dog. Yeah.

556
00:29:16,700 --> 00:29:18,300
I'm going to go and stand over here.
OK.

557
00:29:18,300 --> 00:29:20,140
You're making me worried, Alice.

558
00:29:20,140 --> 00:29:22,780
I'm wearing my good shoes!

559
00:29:22,780 --> 00:29:24,460
OK. Well, I need a countdown.

560
00:29:24,460 --> 00:29:26,420
I'm not doing this by myself, OK?

561
00:29:26,420 --> 00:29:28,540
Three, two, one...

562
00:29:31,500 --> 00:29:32,940
OK!

563
00:29:32,940 --> 00:29:35,140
It wasn't as bad as I expected,
so that's a 70kg...

564
00:29:35,140 --> 00:29:37,020
That was a 70kg dog.

565
00:29:37,020 --> 00:29:38,820
Dogs don't sweat that much.

566
00:29:38,820 --> 00:29:41,820
They have to stop, and they have
to bring their temperature down

567
00:29:41,820 --> 00:29:44,660
by panting. OK.
But humans sweat quite a bit.

568
00:29:44,660 --> 00:29:49,660
So this balloon contains the amount
of sweat that a human sweats out

569
00:29:50,580 --> 00:29:52,660
during an hour of exercise.

570
00:29:52,660 --> 00:29:54,340
So, we probably need
a countdown again.

571
00:29:54,340 --> 00:29:56,820
Three, two, one...

572
00:29:56,820 --> 00:29:58,660
AOIFE SCREAMS

573
00:30:00,420 --> 00:30:02,180
That was two litres!
Oh, yeah!

574
00:30:02,180 --> 00:30:04,860
Two litres of sweat.
I think I felt it, yeah.

575
00:30:04,860 --> 00:30:06,940
Are you a bit wet?
I'm a bit wet!

576
00:30:06,940 --> 00:30:09,300
I'm sorry, Aoife. You're not
really sorry though, are you?

577
00:30:09,300 --> 00:30:10,740
Not really, no. Not really.

578
00:30:10,740 --> 00:30:13,260
So, Aoife has magnificently...
I'm so sorry, Aoife.

579
00:30:13,260 --> 00:30:16,100
She's going to get me back now
in lecture three, isn't she?

580
00:30:16,100 --> 00:30:18,820
She's going to be thinking
of something to do to me.

581
00:30:18,820 --> 00:30:23,220
Aoife's demonstrated - brilliantly,
I thought, absolutely brilliantly -

582
00:30:23,220 --> 00:30:25,060
the secret of sweat.

583
00:30:25,060 --> 00:30:28,220
This is how we humans manage
to keep our temperature down,

584
00:30:28,220 --> 00:30:30,300
and there's something
about us that's very,

585
00:30:30,300 --> 00:30:33,420
very different from our closest
living ape relatives,

586
00:30:33,420 --> 00:30:37,340
and that is it looks as though we've
lost the fur over our bodies.

587
00:30:37,340 --> 00:30:40,300
In fact, that's not quite true,
because over the surface

588
00:30:40,300 --> 00:30:43,740
of the human body, we've got
five million hair follicles,

589
00:30:43,740 --> 00:30:46,260
and that's actually the same
as a chimpanzee has.

590
00:30:46,260 --> 00:30:50,060
It's just that our hairs are
so much finer over our bodies,

591
00:30:50,060 --> 00:30:51,340
and that's really important,

592
00:30:51,340 --> 00:30:53,380
because it means those hairs
don't trap sweat.

593
00:30:53,380 --> 00:30:56,420
The sweat spreads out
on the surface of the skin,

594
00:30:56,420 --> 00:31:00,180
and then it can evaporate off,
and as it evaporates off,

595
00:31:00,180 --> 00:31:01,660
it takes heat with it.

596
00:31:01,660 --> 00:31:04,340
So we're really, really good
at sweating.

597
00:31:04,340 --> 00:31:08,260
And so we are able to run long
distances, and we think

598
00:31:08,260 --> 00:31:11,660
this was incredibly important
to our ancient ancestors,

599
00:31:11,660 --> 00:31:13,660
people like Nariokotome Boy.

600
00:31:13,660 --> 00:31:16,940
So going back two million years ago,

601
00:31:16,940 --> 00:31:20,820
we've got the expansion of
grasslands in Africa, Savannah.

602
00:31:20,820 --> 00:31:23,660
And with the expansion
of those grasslands, we've got

603
00:31:23,660 --> 00:31:26,500
the expansion of populations of
animals who are eating that grass,

604
00:31:26,500 --> 00:31:30,740
so grazers. And then the predators
are eating the grazers.

605
00:31:30,740 --> 00:31:35,220
And if you could run fast, and get
to a carcass that a predator

606
00:31:35,220 --> 00:31:39,260
had taken down, perhaps those lions
have gone off to sleep in the shade,

607
00:31:39,260 --> 00:31:41,260
you can steal some of that meat.

608
00:31:41,260 --> 00:31:43,140
So our ancestors were
certainly scavenging,

609
00:31:43,140 --> 00:31:45,980
they may have been hunting as well,
and we also know that they were

610
00:31:45,980 --> 00:31:50,660
making stone tools that can cut
through flesh and sinew.

611
00:31:50,660 --> 00:31:55,500
And now I want to introduce to you
two people who make stone tools

612
00:31:55,500 --> 00:31:58,380
today, and they make stone tools
that are very much

613
00:31:58,380 --> 00:32:00,540
like those of our ancestors -

614
00:32:00,540 --> 00:32:04,820
Antony and Nada from the
Ancient Technology Centre in Dorset.

615
00:32:04,820 --> 00:32:08,100
Let's give them a round of applause.

616
00:32:10,500 --> 00:32:14,740
Now, before they get started,
some very sharp flakes can fly

617
00:32:14,740 --> 00:32:16,500
from this, so I'm going
to put goggles on,

618
00:32:16,500 --> 00:32:19,180
and those of you in the front row
have got goggles.

619
00:32:19,180 --> 00:32:21,340
I think, yeah, front and second row.

620
00:32:21,340 --> 00:32:25,260
We may get some flakes flying off,
so let's just be careful about it.

621
00:32:25,260 --> 00:32:28,660
So, Antony and Nada are going
to start making stone tools,

622
00:32:28,660 --> 00:32:31,060
and they do it by
bashing rocks together.

623
00:32:31,060 --> 00:32:33,700
It's actually quite complicated,
isn't it? I've had a go

624
00:32:33,700 --> 00:32:35,620
at doing it,
and it IS difficult to do it.

625
00:32:35,620 --> 00:32:38,220
There's quite a lot to it, yeah,
it's quite a technical process.

626
00:32:38,220 --> 00:32:41,340
Bash a couple of flakes off,
and let's see what happens. OK.

627
00:32:41,340 --> 00:32:44,020
And he's using a cobble to
break those flakes off.

628
00:32:44,020 --> 00:32:46,700
That's quite a big one.
That's amazing, look at that.

629
00:32:46,700 --> 00:32:49,380
As soon as you do this, as soon as
you start breaking flakes off,

630
00:32:49,380 --> 00:32:51,740
you end up with things
that have got very sharp edges.

631
00:32:51,740 --> 00:32:54,340
It's a cutting edge.
I mean, this is a stone knife.

632
00:32:54,340 --> 00:32:56,500
Absolutely brilliant.

633
00:32:56,500 --> 00:33:01,540
So, you can actually see how thin
that flake is just there,

634
00:33:02,660 --> 00:33:04,980
especially if I shine
a light through it.

635
00:33:04,980 --> 00:33:07,420
You should be able to see
quite nicely

636
00:33:07,420 --> 00:33:10,020
that it's incredibly thin
at the edges.

637
00:33:10,020 --> 00:33:12,740
That's a really,
really sharp cutting edge,

638
00:33:12,740 --> 00:33:14,900
so you'd be able to
cut up your Christmas turkey

639
00:33:14,900 --> 00:33:16,740
with that very easily indeed.

640
00:33:16,740 --> 00:33:18,420
Thank you.

641
00:33:18,420 --> 00:33:22,460
So, Antony's making
fairly basic flake tools,

642
00:33:22,460 --> 00:33:25,180
and over here, Nada is making
something a little bit

643
00:33:25,180 --> 00:33:27,220
more sophisticated.

644
00:33:27,220 --> 00:33:29,940
The kind of tool that Nariokotome
Boy might have made, actually.

645
00:33:29,940 --> 00:33:32,220
Nada, would you mind holding it up?
Not at all.

646
00:33:32,220 --> 00:33:35,660
So, this is a hand axe. She's making
flakes which are useful as knives,

647
00:33:35,660 --> 00:33:37,220
but this is useful too, isn't it?

648
00:33:37,220 --> 00:33:40,780
Yes, absolutely.
It's a multipurpose tool.

649
00:33:40,780 --> 00:33:43,620
Yeah, so you could use
it for chopping, maybe,

650
00:33:43,620 --> 00:33:45,620
smashing bones to get marrow out of.

651
00:33:45,620 --> 00:33:48,100
Absolutely, yes.
Yeah, all sorts of things.

652
00:33:48,100 --> 00:33:50,900
The other really interesting thing
about this particular shape

653
00:33:50,900 --> 00:33:53,660
is it's a shape that gets copied
and copied and copied,

654
00:33:53,660 --> 00:33:55,980
and passed on down
through the generations.

655
00:33:55,980 --> 00:34:00,420
And I think this tells us something
really important about the minds

656
00:34:00,420 --> 00:34:03,380
of these toolmakers,
because it's not just simply

657
00:34:03,380 --> 00:34:05,100
a question of bashing away at it,
is it?

658
00:34:05,100 --> 00:34:06,740
You've got a shape in your mind.

659
00:34:06,740 --> 00:34:09,380
No, you have to visualise
what you want to get out of a rock,

660
00:34:09,380 --> 00:34:11,700
and work towards that shape,
absolutely.

661
00:34:11,700 --> 00:34:14,500
Yeah. So you are like a sculptor,
you're making the shape.

662
00:34:14,500 --> 00:34:18,020
So that means our ancestors,
even as long ago as Nariokotome Boy,

663
00:34:18,020 --> 00:34:20,140
were capable of abstract thought
like this.

664
00:34:20,140 --> 00:34:22,620
They could hold the idea
of a shape in their heads.

665
00:34:22,620 --> 00:34:24,620
It's quite a special
thing to be able to do.

666
00:34:24,620 --> 00:34:27,140
And not only that,
they could make it real,

667
00:34:27,140 --> 00:34:28,820
which is even more special.

668
00:34:28,820 --> 00:34:31,300
Thank you ever so much,
Nada and Antony.

669
00:34:31,300 --> 00:34:33,860
That was brilliant. Thank you.

670
00:34:43,100 --> 00:34:47,740
Now, stone tools tend to stick
around in the archaeological record.

671
00:34:47,740 --> 00:34:51,180
They're the kinds of things
that archaeologists can easily find

672
00:34:51,180 --> 00:34:52,500
and dig up.

673
00:34:52,500 --> 00:34:55,540
They are, after all, stone.
It doesn't really rot away.

674
00:34:55,540 --> 00:34:58,300
Things we don't find so often
in archaeology

675
00:34:58,300 --> 00:35:00,780
are made of organic materials.

676
00:35:00,780 --> 00:35:04,580
So, anything made out of leaves
or grass or wood

677
00:35:04,580 --> 00:35:07,540
is usually going to rot away.

678
00:35:07,540 --> 00:35:10,660
And so it's very difficult to know
exactly what our ancestors

679
00:35:10,660 --> 00:35:14,380
were using in terms of wooden tools
at this point in time,

680
00:35:14,380 --> 00:35:18,340
but we do know that lots of hunter
gatherers use very simple

681
00:35:18,340 --> 00:35:20,100
wooden tools like this.

682
00:35:20,100 --> 00:35:23,940
And you can imagine making this,
just taking a stick, and then using

683
00:35:23,940 --> 00:35:27,180
one of those stone flakes to sharpen
the end of it until you get a point.

684
00:35:27,180 --> 00:35:28,940
And then perhaps what you're
thinking is

685
00:35:28,940 --> 00:35:30,460
I'm going to use that as a spear.

686
00:35:30,460 --> 00:35:34,220
Well, I could, but actually
you can use it for something else

687
00:35:34,220 --> 00:35:36,620
as well. Something very important.

688
00:35:36,620 --> 00:35:40,580
Lots of modern day hunter gatherers
use sticks like this to dig food

689
00:35:40,580 --> 00:35:42,300
out of the ground.

690
00:35:42,300 --> 00:35:46,620
And there's a really important clue
as to what that underground food

691
00:35:46,620 --> 00:35:50,540
might be when we delve
into genetics.

692
00:35:50,540 --> 00:35:51,980
That sounds like my part!

693
00:35:51,980 --> 00:35:55,660
Yeah, so we can actually learn
something very interesting

694
00:35:55,660 --> 00:35:58,260
about our adaptations
by looking at our genes.

695
00:35:58,260 --> 00:36:02,780
So, in your mouth you have spit,
of course, and in your saliva,

696
00:36:02,780 --> 00:36:07,500
there is an enzyme called amylase
that helps you digest starch

697
00:36:07,500 --> 00:36:10,660
in your mouth, start breaking down
the starch in your mouth.

698
00:36:10,660 --> 00:36:14,460
And the amount of amylase
you have in your saliva

699
00:36:14,460 --> 00:36:16,180
depends on your genes.

700
00:36:16,180 --> 00:36:18,540
So, all of you will have noticed
you have a little packet

701
00:36:18,540 --> 00:36:21,020
of crackers, so you can get
your packet of crackers out.

702
00:36:21,020 --> 00:36:24,060
Yeah, so you're not to start eating
them yet, because I need to

703
00:36:24,060 --> 00:36:26,700
tell you what to do first,
but you can just quickly

704
00:36:26,700 --> 00:36:28,540
take them out of the wrapper.

705
00:36:28,540 --> 00:36:31,460
OK, what I want you to do is I want
you to start chewing the cracker,

706
00:36:31,460 --> 00:36:33,420
but you're not to swallow it, OK?

707
00:36:33,420 --> 00:36:35,940
You have to keep it in your mouth
and keep chewing.

708
00:36:35,940 --> 00:36:37,180
Not yet, not yet.

709
00:36:37,180 --> 00:36:39,460
It's going to get all mushy,
and it's going to go all gooey

710
00:36:39,460 --> 00:36:40,940
and whatever, but that's fine.

711
00:36:40,940 --> 00:36:43,580
Just keep it in your mouth
and keep chewing, chewing, chewing.

712
00:36:43,580 --> 00:36:46,540
And at some point,
the flavour is going to change,

713
00:36:46,540 --> 00:36:49,660
so when the flavour changes,
I want you to stand up.

714
00:36:49,660 --> 00:36:52,980
OK, so is everybody ready?
Steady? Go.

715
00:36:52,980 --> 00:36:54,300
Just chew, chew, chew.

716
00:36:54,300 --> 00:36:55,740
Don't swallow it.

717
00:36:55,740 --> 00:36:59,820
And then let me know
when the flavour changes.

718
00:36:59,820 --> 00:37:02,580
We've got one already, very good.

719
00:37:02,580 --> 00:37:03,620
Yeah.

720
00:37:04,740 --> 00:37:06,940
More. And this is totally normal.

721
00:37:06,940 --> 00:37:10,540
It's actually expected
that different people stand up

722
00:37:10,540 --> 00:37:12,020
at different times.

723
00:37:12,020 --> 00:37:14,500
This is amazing, everybody's
starting to stand up! So...

724
00:37:16,140 --> 00:37:18,420
I'm running around the stairs...

725
00:37:18,420 --> 00:37:20,780
What was the flavour change for you?

726
00:37:20,780 --> 00:37:23,580
Boring.
Boring! OK.

727
00:37:23,580 --> 00:37:26,220
It changed to boring.
did it start out interesting?

728
00:37:26,220 --> 00:37:27,460
What did you think?
Sweet.

729
00:37:27,460 --> 00:37:29,940
It changed to sweet.
What did you think? Sweet.

730
00:37:29,940 --> 00:37:32,140
Interesting. This is very good.

731
00:37:32,140 --> 00:37:33,740
What did you think?

732
00:37:33,740 --> 00:37:35,420
It got sweeter.
It got sweeter.

733
00:37:35,420 --> 00:37:38,140
It's interesting that we have
people saying sweet,

734
00:37:38,140 --> 00:37:39,860
because that's what I expected.

735
00:37:39,860 --> 00:37:43,700
So the amylase enzyme
in your saliva, what it does

736
00:37:43,700 --> 00:37:46,580
is it breaks the starch down
into simple sugars.

737
00:37:46,580 --> 00:37:50,380
So it's what we expect, is that it
starts to feel sweet for you.

738
00:37:50,380 --> 00:37:53,860
And the reason different people
stood up at different times

739
00:37:53,860 --> 00:37:56,860
is because actually we know that
humans have different numbers

740
00:37:56,860 --> 00:37:59,420
of copies of this gene
that makes the amylase.

741
00:37:59,420 --> 00:38:02,540
So, some people have two copies,
but some people have as many as

742
00:38:02,540 --> 00:38:04,220
18 copies of this gene.

743
00:38:04,220 --> 00:38:06,500
So if you have more copies
of the gene,

744
00:38:06,500 --> 00:38:09,780
we expect that the flavour would
change to sweet sooner.

745
00:38:09,780 --> 00:38:14,340
And in parts of the world
where there is a traditional diet

746
00:38:14,340 --> 00:38:18,100
that's very starch rich,
so things like rice and potatoes

747
00:38:18,100 --> 00:38:21,460
and yams, we see that people
who come from that part of the world

748
00:38:21,460 --> 00:38:23,940
tend to have more copies
of the amylase gene.

749
00:38:23,940 --> 00:38:28,300
So it's an adaptation to diet
that's written in our genes.

750
00:38:29,980 --> 00:38:33,100
Yes, but our ancient ancestors
also had another way of unlocking

751
00:38:33,100 --> 00:38:35,100
the energy from their food.

752
00:38:38,460 --> 00:38:43,460
By a million years ago,
our ancestors had controlled fire.

753
00:38:44,220 --> 00:38:47,300
And with fire,
they could do all sorts of things.

754
00:38:47,300 --> 00:38:50,580
They could obviously
keep themselves warm,

755
00:38:50,580 --> 00:38:54,060
they could ward off predators,
and they could do something

756
00:38:54,060 --> 00:38:57,740
really important when it came
to food - they could cook it.

757
00:38:57,740 --> 00:39:01,340
So things start to taste
a bit nicer, perhaps.

758
00:39:01,340 --> 00:39:05,380
But even more importantly,
if you can cook food,

759
00:39:05,380 --> 00:39:09,780
then it means you're doing some of
the work in unlocking the energy

760
00:39:09,780 --> 00:39:13,100
from that food before you get it
anywhere near your mouth.

761
00:39:13,100 --> 00:39:17,140
So you're effectively getting
more energy from your food.

762
00:39:17,140 --> 00:39:21,260
And we think that this is
reflected in a change

763
00:39:21,260 --> 00:39:23,620
in our ancestors' anatomy.

764
00:39:23,620 --> 00:39:27,580
So, over time what happened
is that our ancestors

765
00:39:27,580 --> 00:39:31,740
- thank you very much -
who started off with teeth

766
00:39:31,740 --> 00:39:36,820
as big as this, huge gnashers,
over time, those teeth diminished

767
00:39:38,020 --> 00:39:42,500
in size, and got a lot more like
the teeth in your mouth.

768
00:39:42,500 --> 00:39:45,260
So modern human teeth
are tiny in comparison

769
00:39:45,260 --> 00:39:48,660
to this australopithecine jaw
with its teeth.

770
00:39:48,660 --> 00:39:52,020
So, if you can make your food softer
- you can do that by pounding it,

771
00:39:52,020 --> 00:39:54,620
you can do it by cooking it -
it means there's no longer

772
00:39:54,620 --> 00:39:58,140
any advantage in having
great big teeth like this,

773
00:39:58,140 --> 00:39:59,740
and your teeth can grow smaller.

774
00:39:59,740 --> 00:40:04,380
And then something else that happens
is that brains are getting larger.

775
00:40:04,380 --> 00:40:08,100
And if I compare these two skulls
by showing you the skulls like that,

776
00:40:08,100 --> 00:40:11,660
you can see that this modern human
skull is much bigger

777
00:40:11,660 --> 00:40:13,180
compared with this one.

778
00:40:13,180 --> 00:40:16,260
The brain cavity, especially
at the front just above the eyes,

779
00:40:16,260 --> 00:40:18,460
is much, much bigger.

780
00:40:18,460 --> 00:40:22,980
Now, the brain is a really important
organ, and making a change

781
00:40:22,980 --> 00:40:26,980
to a brain is something
that's quite difficult to do,

782
00:40:26,980 --> 00:40:29,500
as we can see from genetics.

783
00:40:29,500 --> 00:40:30,860
Yes, we do.

784
00:40:30,860 --> 00:40:34,500
And so there's something really,
really amazing that we can do

785
00:40:34,500 --> 00:40:38,020
with DNA sequence analysis
which allows us to actually

786
00:40:38,020 --> 00:40:40,540
figure out which are the important
genes.

787
00:40:40,540 --> 00:40:44,580
And so, to explain this to you, I'm
going to tell you a story.

788
00:40:44,580 --> 00:40:48,460
And it's a true story,
and it takes place in World War II.

789
00:40:48,460 --> 00:40:51,380
So, the Air Force wanted
to reinforce their planes,

790
00:40:51,380 --> 00:40:54,100
so they had this idea
but they would reinforce the parts

791
00:40:54,100 --> 00:40:56,220
of the planes that get
lots of bullet holes.

792
00:40:56,220 --> 00:40:59,300
So they brought in a statistician
to help them, they wanted him

793
00:40:59,300 --> 00:41:01,620
to count the bullet holes
and figure out where they are.

794
00:41:01,620 --> 00:41:03,940
But in order to picture this,
and to figure out the kind of

795
00:41:03,940 --> 00:41:05,980
challenge this was,
we're going to do something.

796
00:41:05,980 --> 00:41:09,460
So you all have paper aeroplanes
under your seat.

797
00:41:09,460 --> 00:41:12,300
So just take them,
don't do anything with them yet.

798
00:41:12,300 --> 00:41:13,700
OK.

799
00:41:13,700 --> 00:41:15,580
So if you just take a quick
look at those,

800
00:41:15,580 --> 00:41:17,380
you'll see that they have holes
punched in them.

801
00:41:17,380 --> 00:41:19,300
So that's like a bullet hole.

802
00:41:19,300 --> 00:41:22,660
And so what I want you to do,
when I give you the word

803
00:41:22,660 --> 00:41:25,660
- don't anybody go early - I want
you to throw those aeroplanes,

804
00:41:25,660 --> 00:41:28,220
and I want you to aim for me.
Not yet, not yet, please!

805
00:41:28,220 --> 00:41:31,500
You aim for me because basically
I'm on home base, OK?

806
00:41:31,500 --> 00:41:33,220
Are you ready?

807
00:41:33,220 --> 00:41:34,620
Steady?

808
00:41:34,620 --> 00:41:35,940
Go!

809
00:41:35,940 --> 00:41:37,900
SHE SCREAMS

810
00:41:37,900 --> 00:41:39,580
SHE LAUGHS

811
00:41:40,940 --> 00:41:42,340
OK!

812
00:41:44,700 --> 00:41:46,020
Well, that worked!

813
00:41:46,020 --> 00:41:49,660
OK, so the job the statistician
had then, these are all the planes

814
00:41:49,660 --> 00:41:52,940
that made it back to home base,
and he wanted to look at these.

815
00:41:52,940 --> 00:41:55,580
So, I need to mark, I need to
keep track of what's happening.

816
00:41:55,580 --> 00:41:58,420
OK, I'll mark them on this. Alice,
you can give me a little hand here.

817
00:41:58,420 --> 00:42:01,100
So this one has a bullet hole there.

818
00:42:01,100 --> 00:42:02,900
So you can take that from me.
Yeah.

819
00:42:02,900 --> 00:42:06,100
What I'm going to do
is I'm going to make little marks

820
00:42:06,100 --> 00:42:08,780
on this plane. So there's one
there... There's one on the wing.

821
00:42:08,780 --> 00:42:12,020
One on that little bit of the wing.
Yeah.

822
00:42:12,020 --> 00:42:16,220
OK, this is going to take forever.
We need a bigger plane!

823
00:42:16,220 --> 00:42:19,020
Thank you! OK.

824
00:42:19,020 --> 00:42:22,380
So, this plane, we've already
collected all these data.

825
00:42:22,380 --> 00:42:24,420
So this is what the
statistician had to do.

826
00:42:24,420 --> 00:42:27,460
He had to collect the information
from all the different planes

827
00:42:27,460 --> 00:42:32,140
that came back, and he mapped them
onto a picture of the plane.

828
00:42:32,140 --> 00:42:36,860
And the legend is that the
Air Force's first instinct was,

829
00:42:36,860 --> 00:42:39,540
"Well, we're going to patch
up those bits of the plane

830
00:42:39,540 --> 00:42:41,460
"that have loads of
bullet holes in them".

831
00:42:41,460 --> 00:42:44,540
But the statistician said to them,
"No, you've got it wrong,

832
00:42:44,540 --> 00:42:47,780
"really, because actually we notice
these parts of the plane

833
00:42:47,780 --> 00:42:51,060
"that have no bullet holes in them,"
so what's happening there?

834
00:42:51,060 --> 00:42:53,780
Well, they're the planes
that didn't come home.

835
00:42:53,780 --> 00:42:57,340
They're the ones that had really
bad damage they couldn't fly with.

836
00:42:57,340 --> 00:43:00,980
These are the bullet holes
that allowed the plane to fly,

837
00:43:00,980 --> 00:43:03,220
despite the damage.

838
00:43:03,220 --> 00:43:06,820
So, these parts of the plane
are things like the engine,

839
00:43:06,820 --> 00:43:10,060
or the cockpit,
or the steering gear.

840
00:43:10,060 --> 00:43:12,940
So by looking at the pattern
of bullet holes, you can see

841
00:43:12,940 --> 00:43:16,340
the important parts
and the less important parts.

842
00:43:16,340 --> 00:43:19,700
And it turns out we can do
this same kind of analysis

843
00:43:19,700 --> 00:43:21,100
with gene sequences.

844
00:43:21,100 --> 00:43:25,100
So, if you imagine for a moment
that this is a genome.

845
00:43:25,100 --> 00:43:29,420
Then we had some genes in the genome
where lots of mutations happen.

846
00:43:29,420 --> 00:43:32,460
So, the DNA changes,
but it doesn't really matter.

847
00:43:32,460 --> 00:43:34,820
So, there's a change,
but it's not a significant change.

848
00:43:34,820 --> 00:43:37,060
And then there are other
parts of the genome,

849
00:43:37,060 --> 00:43:41,460
other genes, that they really
matter, and when you get a change

850
00:43:41,460 --> 00:43:43,220
in them, it really affects
the individual.

851
00:43:43,220 --> 00:43:46,100
So they can't survive
and thrive as well.

852
00:43:46,100 --> 00:43:48,060
And if we look across
mammals and we say,

853
00:43:48,060 --> 00:43:51,140
"Which are the genes in these
really important areas?",

854
00:43:51,140 --> 00:43:53,980
We find that there's especially,
in these parts of the genome,

855
00:43:53,980 --> 00:43:57,620
it's especially genes
that are involved in your brain.

856
00:43:57,620 --> 00:44:00,140
So genes that work in your brain.

857
00:44:00,140 --> 00:44:03,500
But something really changed
in human evolution.

858
00:44:05,420 --> 00:44:10,260
So, in early human evolution,
these brain genes started

859
00:44:10,260 --> 00:44:13,300
changing quicker.
They started evolving faster.

860
00:44:13,300 --> 00:44:17,900
So this is a really unusual pattern,
and this tells us that something

861
00:44:17,900 --> 00:44:22,900
was driving that change, something
really important had happened.

862
00:44:22,900 --> 00:44:27,900
So, in order for those mutations
to start appearing and then building

863
00:44:28,420 --> 00:44:31,940
up and creating this big difference
in brains and getting brains to grow

864
00:44:31,940 --> 00:44:36,900
larger, there must have been
a significant advantage in growing

865
00:44:36,900 --> 00:44:40,540
a bigger brain. And anthropologists
have racked their brains

866
00:44:40,540 --> 00:44:44,340
about what that could possibly
be that was driving this increase

867
00:44:44,340 --> 00:44:46,100
in brain size in human evolution.

868
00:44:46,100 --> 00:44:50,460
They said, "Our ancestors must
have been working together in teams

869
00:44:50,460 --> 00:44:54,540
"on the African plains, as hunters,
so maybe it's cooperative hunting,

870
00:44:54,540 --> 00:44:57,580
"maybe that's what's driving
this increase in brain size".

871
00:44:57,580 --> 00:45:02,180
But then, hunting dogs and lions are
great at cooperating in hunting,

872
00:45:02,180 --> 00:45:04,420
and their brains aren't very big
at all.

873
00:45:04,420 --> 00:45:07,140
So then apologists said, "Well,
maybe there's something else.

874
00:45:07,140 --> 00:45:10,820
"Maybe it's stone tools,
maybe you need a big brain

875
00:45:10,820 --> 00:45:12,940
"in order to be able
to make stone tools."

876
00:45:12,940 --> 00:45:16,060
But actually, that turns out
not to be likely either

877
00:45:16,060 --> 00:45:19,660
because our ancestors started making
stone tools more than three million

878
00:45:19,660 --> 00:45:22,780
years ago, when again,
their brains were pretty small.

879
00:45:22,780 --> 00:45:25,340
There's another group
of anthropologists

880
00:45:25,340 --> 00:45:28,860
who think they've got a hypothesis
which stacks up when it comes

881
00:45:28,860 --> 00:45:32,220
to brain size, and I need
a volunteer now to help me

882
00:45:32,220 --> 00:45:33,980
explore that hypothesis.

883
00:45:33,980 --> 00:45:36,820
I'm particularly drawn by Christmas
jumpers, so I'm going to pick

884
00:45:36,820 --> 00:45:41,460
you with a fantastic reindeer
Christmas jumper. Come on down.

885
00:45:41,460 --> 00:45:44,020
APPLAUSE
Jasmine, right.

886
00:45:44,020 --> 00:45:46,820
OK, I've got a bit of a challenge
here for you, Jasmine.

887
00:45:49,860 --> 00:45:53,700
What we've got here are some cubes,
and the cubes represent brain size.

888
00:45:53,700 --> 00:45:56,740
In fact, they represent
a very special bit of the brain,

889
00:45:56,740 --> 00:45:59,900
they represent the grey matter
on the outside that we call

890
00:45:59,900 --> 00:46:03,500
the neocortex, and we've
scaled it to body size,

891
00:46:03,500 --> 00:46:07,020
so this must be an animal with a
very small amount of neocortex,

892
00:46:07,020 --> 00:46:10,940
and this must be an animal with a
large amount of neocortex.

893
00:46:10,940 --> 00:46:14,740
Underneath these cubes, that
represent that different brain size,

894
00:46:14,740 --> 00:46:18,540
we've got a clue as to what it is
that's driving brain size increases,

895
00:46:18,540 --> 00:46:20,700
or explaining brain size increases.

896
00:46:20,700 --> 00:46:23,420
So what I'd like you to do
is lift up each of these cubes,

897
00:46:23,420 --> 00:46:27,780
and we'll reveal a score
for each species.

898
00:46:27,780 --> 00:46:31,060
Here we go, then,
what's the score for this one?

899
00:46:32,020 --> 00:46:33,860
Oh! The score is one.

900
00:46:33,860 --> 00:46:36,820
And this species is...

901
00:46:36,820 --> 00:46:39,140
..a slow loris.

902
00:46:39,140 --> 00:46:41,340
A very cute type of primate.

903
00:46:41,340 --> 00:46:43,180
OK, what about this species here?

904
00:46:43,180 --> 00:46:45,660
Let's reveal a score for this one.

905
00:46:45,660 --> 00:46:47,500
Oh, that's a lot.

906
00:46:47,500 --> 00:46:51,540
That's 17... I can count very
quickly! ..small cubes.

907
00:46:51,540 --> 00:46:54,380
And this species is a spider monkey.

908
00:46:55,460 --> 00:46:58,460
What about this one?
What's the score for that one?

909
00:46:58,460 --> 00:47:00,660
Oh, 54 small cubes!

910
00:47:00,660 --> 00:47:02,020
LAUGHTER

911
00:47:02,020 --> 00:47:04,900
This one is a chimpanzee.

912
00:47:04,900 --> 00:47:07,660
And then finally, would you like to
lift that big cube?

913
00:47:07,660 --> 00:47:10,420
Ah! There's a pile of
people underneath it.

914
00:47:10,420 --> 00:47:13,460
This is a human...
LAUGHTER

915
00:47:15,420 --> 00:47:17,940
..and what these scores...

916
00:47:17,940 --> 00:47:19,740
LAUGHTER

917
00:47:19,740 --> 00:47:21,260
What these scores represent,

918
00:47:21,260 --> 00:47:25,940
Jasmine, is the size of social group
that these animals normally live in.

919
00:47:25,940 --> 00:47:28,780
So the slow loris is
a very solitary creature.

920
00:47:28,780 --> 00:47:32,020
It doesn't have any friends.
It just lives on its own.

921
00:47:32,020 --> 00:47:34,860
Spider monkeys are a little bit
more gregarious.

922
00:47:34,860 --> 00:47:38,260
They live in a social group
which averages 17,

923
00:47:38,260 --> 00:47:40,580
chimpanzees, even more.

924
00:47:40,580 --> 00:47:43,060
Average group size of 54.

925
00:47:43,060 --> 00:47:47,020
Humans, on average,
we have 150 friends,

926
00:47:47,020 --> 00:47:50,620
and that's not just acquaintances,
that's people we know pretty well.

927
00:47:50,620 --> 00:47:54,380
Jasmine, thank you for revealing
the secret of big human brains.

928
00:47:54,380 --> 00:47:56,780
Thank you very much.
APPLAUSE

929
00:48:01,660 --> 00:48:03,940
So, it turns out, then,
that it's most likely

930
00:48:03,940 --> 00:48:06,860
that our big brains are
all about making friends,

931
00:48:06,860 --> 00:48:10,540
making friends and keeping friends,
making those connections.

932
00:48:10,540 --> 00:48:15,100
After all, we are quite puny apes,
and we've done ever so well

933
00:48:15,100 --> 00:48:19,860
for ourselves as a species,
and we've managed to expand

934
00:48:19,860 --> 00:48:23,460
across the whole world,
and what we're going to do now

935
00:48:23,460 --> 00:48:28,380
is map out those expansions,
and I need two volunteers to come

936
00:48:28,380 --> 00:48:30,580
and help me colonise the world.

937
00:48:30,580 --> 00:48:33,580
There's somebody in a blue T-shirt,
second row to the back.

938
00:48:33,580 --> 00:48:35,980
Yes, you! Come down.

939
00:48:35,980 --> 00:48:39,700
Aoife, have you got a volunteer
your side? Yes.

940
00:48:39,700 --> 00:48:42,620
Hello. I've got Tessa here.

941
00:48:42,620 --> 00:48:45,420
Come on down. Come on down.
APPLAUSE

942
00:48:46,700 --> 00:48:49,780
Wonderful. Come here, turn around.

943
00:48:49,780 --> 00:48:51,500
So, what's your name? Shareen.

944
00:48:51,500 --> 00:48:53,100
Shareen, lovely to meet you.

945
00:48:53,100 --> 00:48:57,580
So, Tessa and... Shareen. Shareen,
what we're going to ask you to do

946
00:48:57,580 --> 00:49:01,140
is start in Africa, because
that's where our species starts,

947
00:49:01,140 --> 00:49:03,460
so can you find Africa on the map?

948
00:49:03,460 --> 00:49:06,580
Plant your feet on it, occupy it.

949
00:49:06,580 --> 00:49:10,700
That's where our species starts,
and our species originated in Africa

950
00:49:10,700 --> 00:49:15,540
about 300,000 years ago,
so you can each put a pair of feet

951
00:49:15,540 --> 00:49:17,980
firmly on Africa.

952
00:49:17,980 --> 00:49:21,260
We might need to reload these
as we go. We might. OK.

953
00:49:21,260 --> 00:49:23,660
So, we start in Africa,
plant them on the map.

954
00:49:23,660 --> 00:49:26,700
You can walk around in Africa a bit,
you're all over Africa.

955
00:49:26,700 --> 00:49:30,180
So, our species was just an African
species for a few hundred thousand

956
00:49:30,180 --> 00:49:33,020
years, and then about
100,000 years ago...

957
00:49:33,020 --> 00:49:36,020
Tessa, if I move you backwards,
you can start to come out of Africa.

958
00:49:36,020 --> 00:49:39,020
Make a little trail of footprints,
and you can come all the way

959
00:49:39,020 --> 00:49:42,500
along here into Asia.
Do you need a bit more paint?

960
00:49:42,500 --> 00:49:46,500
And you can come along here,
through south Asia...

961
00:49:46,500 --> 00:49:50,500
Do you want to come all the way
down into Australia?

962
00:49:50,500 --> 00:49:55,500
By 65,000 years ago,
modern humans had reached Australia!

963
00:49:56,180 --> 00:49:59,860
Yay! Fantastic!
APPLAUSE

964
00:49:59,860 --> 00:50:03,460
I'll move you back over here.
And now, Shareen, if you...

965
00:50:03,460 --> 00:50:05,380
Are you nicely loaded up with paint?

966
00:50:05,380 --> 00:50:07,740
You can start making your way
into Europe, if you like.

967
00:50:07,740 --> 00:50:10,700
So From about 50,000 years ago,
and you can walk all the way

968
00:50:10,700 --> 00:50:13,020
over to Britain...
Can you see Britain on the map?

969
00:50:13,020 --> 00:50:16,540
By 40,000 years ago,
modern humans, Homo sapiens

970
00:50:16,540 --> 00:50:20,660
like us had reached Britain. Lovely.
APPLAUSE

971
00:50:24,180 --> 00:50:26,540
Tessa, I've got a bit
more work for you to do.

972
00:50:26,540 --> 00:50:29,900
Start from here in South Asia,
and you can walk all the way

973
00:50:29,900 --> 00:50:33,740
up to the north, up to the coast
of the Arctic Ocean by 30,000 years

974
00:50:33,740 --> 00:50:36,180
ago, come over here.
You can walk across here.

975
00:50:36,180 --> 00:50:39,060
Actually, there's a land bridge
here, because the sea level is low,

976
00:50:39,060 --> 00:50:42,140
and you can pop across into Alaska,
and now the ice is melting

977
00:50:42,140 --> 00:50:45,100
in Alaska, and you can walk
all the way down to South America.

978
00:50:45,100 --> 00:50:46,940
We've colonised North America.

979
00:50:46,940 --> 00:50:50,220
That's the Clovis hunters of
North America, and we've got people

980
00:50:50,220 --> 00:50:53,660
going all the way down
into South America

981
00:50:53,660 --> 00:50:55,860
and we have colonised the world!
Yay!

982
00:50:55,860 --> 00:50:57,060
APPLAUSE

983
00:50:57,060 --> 00:50:59,700
Fantastic! Well done, Shareen!

984
00:50:59,700 --> 00:51:02,780
Brilliant handiwork,
I think there, Shareen and Tessa.

985
00:51:02,780 --> 00:51:04,340
Or I should say, footwork.

986
00:51:04,340 --> 00:51:07,260
We've colonised the globe,
good work!

987
00:51:07,260 --> 00:51:10,180
Thank you very much. Well done!
APPLAUSE

988
00:51:13,980 --> 00:51:16,580
It took a while to get
into Europe, didn't it?

989
00:51:16,580 --> 00:51:18,740
It did, there was a little
bit of hanging around.

990
00:51:18,740 --> 00:51:22,140
I think they might have
met some friends around here.

991
00:51:22,140 --> 00:51:24,540
Oh, indigenous European people.

992
00:51:24,540 --> 00:51:28,900
Well, these earlier humans
who were already there

993
00:51:28,900 --> 00:51:32,540
before the modern humans
got there, Neanderthals.

994
00:51:32,540 --> 00:51:35,140
So the Neanderthals
where the inhabitants of Europe

995
00:51:35,140 --> 00:51:40,140
before our lot got there, and we
used to think they were entirely

996
00:51:40,140 --> 00:51:44,820
separate. Looking at their bones,
we thought there was never any real

997
00:51:44,820 --> 00:51:47,380
interaction between modern
humans and Neanderthals,

998
00:51:47,380 --> 00:51:49,180
but genetics has changed
all of that.

999
00:51:49,180 --> 00:51:52,540
Yes, so what we can do now,
we can actually get DNA

1000
00:51:52,540 --> 00:51:54,140
out of these really old bones.

1001
00:51:54,140 --> 00:51:57,420
So, we've been able to get DNA
out of Neanderthal bones,

1002
00:51:57,420 --> 00:52:00,300
and this revealed some really
interesting surprises, because

1003
00:52:00,300 --> 00:52:03,740
when we look at the Neanderthal DNA,
you could see that it didn't look

1004
00:52:03,740 --> 00:52:06,780
actually totally different
from human DNA.

1005
00:52:06,780 --> 00:52:09,860
So, as you know, you got
half your DNA from your mum

1006
00:52:09,860 --> 00:52:11,380
and half from your dad,

1007
00:52:11,380 --> 00:52:14,860
so 50-50, and then you've got
about 25% of your DNA from

1008
00:52:14,860 --> 00:52:17,460
each of your grandparents,
and then different amounts

1009
00:52:17,460 --> 00:52:21,220
from other ancestors,
and when we look at people today,

1010
00:52:21,220 --> 00:52:25,300
we find we have chunks of DNA that
are from a Neanderthal ancestor.

1011
00:52:25,300 --> 00:52:27,540
I've got a bit in my genome.
Me, too.

1012
00:52:27,540 --> 00:52:30,540
There's only one way to get a chunk
of DNA from somebody else.

1013
00:52:30,540 --> 00:52:33,180
Yes, shenanigans.
Shenanigans. Something went on!

1014
00:52:33,180 --> 00:52:36,860
There was some serious interaction
between modern humans

1015
00:52:36,860 --> 00:52:39,580
and Neanderthals.
You're shocking the parents.

1016
00:52:39,580 --> 00:52:42,940
And it's not just Neanderthals,
there's these other species

1017
00:52:42,940 --> 00:52:47,180
who were around over here in Asia,
and we met up with them as well.

1018
00:52:47,180 --> 00:52:49,420
We don't...
Well, they may be a species,

1019
00:52:49,420 --> 00:52:52,220
they may just be a slightly
different set of people.

1020
00:52:52,220 --> 00:52:55,500
They're called the Denisovans.
My view is that they are

1021
00:52:55,500 --> 00:52:59,380
the same species. We're all the same
species because of all this mixing.

1022
00:52:59,380 --> 00:53:01,940
Do you think? Yeah.
That's something we disagree on.

1023
00:53:01,940 --> 00:53:04,300
I say from bones, Neanderthals
are a different species,

1024
00:53:04,300 --> 00:53:06,500
but genetically,
you're saying they're the same.

1025
00:53:06,500 --> 00:53:08,940
See, scientist don't always agree.
No.

1026
00:53:08,940 --> 00:53:11,940
But with the Denisovan, there's
so little you can say, anyway.

1027
00:53:11,940 --> 00:53:14,100
There's so little,
in terms of bones.

1028
00:53:14,100 --> 00:53:16,460
A finger bone and three teeth,
I think.

1029
00:53:16,460 --> 00:53:18,820
Mm-hm.
But we can get really good DNA...

1030
00:53:18,820 --> 00:53:22,580
Even though it's just a tiny bone,
the DNA inside it was really well

1031
00:53:22,580 --> 00:53:26,300
preserved, so it's really good DNA
sequence, and if we look at people,

1032
00:53:26,300 --> 00:53:28,860
especially people from around
this part of the world,

1033
00:53:28,860 --> 00:53:32,060
we see that they have chunks
of DNA from Denisovans.

1034
00:53:32,060 --> 00:53:35,100
But we've got quite a lot of
Neanderthal DNA hanging around,

1035
00:53:35,100 --> 00:53:38,380
haven't we? Yes. We all have
chunks of Neanderthal DNA.

1036
00:53:38,380 --> 00:53:40,300
But we have different chunks of DNA.

1037
00:53:40,300 --> 00:53:43,660
So if I were to take all the
different chunks and tile them

1038
00:53:43,660 --> 00:53:47,740
together, we would get about
70% of the Neanderthal Genome

1039
00:53:47,740 --> 00:53:50,380
is in people walking around today.

1040
00:53:50,380 --> 00:53:52,540
I can do better than that, Aoife.
Can you?

1041
00:53:52,540 --> 00:53:56,020
I can show you a whole Neanderthal.

1042
00:53:56,020 --> 00:53:58,180
APPLAUSE

1043
00:54:04,740 --> 00:54:08,460
So, with the help of some
quite amazing prosthetics,

1044
00:54:08,460 --> 00:54:13,340
we have transformed a modern human
into an ancient Neanderthal

1045
00:54:13,340 --> 00:54:16,740
and we can see that there
are differences in the face shape.

1046
00:54:16,740 --> 00:54:21,460
She's got a very big brow ridge
compared with us modern humans,

1047
00:54:21,460 --> 00:54:24,660
and actually, she has a lump
at the back of her skull as well,

1048
00:54:24,660 --> 00:54:27,580
which you can't see under all
this hair, but the skull shape

1049
00:54:27,580 --> 00:54:29,700
is also different shape to ours,
too.

1050
00:54:29,700 --> 00:54:33,900
A bit long and low, compared with
our more globular face shapes,

1051
00:54:33,900 --> 00:54:35,100
or head shapes.

1052
00:54:35,100 --> 00:54:40,140
She's got a very chunky jaw, but
actually, she looks similar enough

1053
00:54:40,220 --> 00:54:42,580
to us that I don't think
you'd really notice

1054
00:54:42,580 --> 00:54:45,020
if she was walking down
the street, would you?

1055
00:54:45,020 --> 00:54:47,660
And we keep on finding
more clues that Neanderthals

1056
00:54:47,660 --> 00:54:50,500
were more like modern humans
than we thought,

1057
00:54:50,500 --> 00:54:53,780
and one of those clues is in
what she's holding in hand.

1058
00:54:53,780 --> 00:54:57,620
So, this is a shell, and it's
a replica based on one that was

1059
00:54:57,620 --> 00:55:00,900
dug out of a cave in Spain,
and it's a scallop shell

1060
00:55:00,900 --> 00:55:04,340
that's been pierced,
so perhaps used as a pendant,

1061
00:55:04,340 --> 00:55:07,340
and also painted with red ochre.

1062
00:55:07,340 --> 00:55:11,060
So it seems that Neanderthals
were interested in decoration

1063
00:55:11,060 --> 00:55:14,540
and art in the way that we know
our own modern human ancestors

1064
00:55:14,540 --> 00:55:15,860
were as well.

1065
00:55:15,860 --> 00:55:19,300
So perhaps a lot more similar
to us than we previously expected.

1066
00:55:19,300 --> 00:55:22,740
Anthropologists for a long time
have wondered whether Neanderthals

1067
00:55:22,740 --> 00:55:26,580
had language like we do, and that's
something we may not ever know.

1068
00:55:26,580 --> 00:55:28,060
I mean, can you speak?

1069
00:55:28,060 --> 00:55:30,180
Of course I can speak!

1070
00:55:30,180 --> 00:55:33,100
We've solved the riddle.
APPLAUSE

1071
00:55:33,100 --> 00:55:34,820
Thank you.

1072
00:55:37,540 --> 00:55:41,060
Although Neanderthals have left
a little bit of themselves behind

1073
00:55:41,060 --> 00:55:44,340
and still alive in the form of
fragments of their DNA

1074
00:55:44,340 --> 00:55:47,180
in our genomes,
as a group of people,

1075
00:55:47,180 --> 00:55:49,540
they had died out
by 20,000 years ago.

1076
00:55:49,540 --> 00:55:54,540
We don't find their fossils any
more, but modern humans survived

1077
00:55:54,980 --> 00:55:58,620
through the peak of the last ice
age when the ice sheets descended

1078
00:55:58,620 --> 00:56:01,540
over northern Europe
and over North America,

1079
00:56:01,540 --> 00:56:04,220
and it's at this particular
time that we see an amazing

1080
00:56:04,220 --> 00:56:06,900
explosion in art.

1081
00:56:06,900 --> 00:56:11,140
We see our ancestors making
fantastic sculptures out of bone

1082
00:56:11,140 --> 00:56:16,140
and ivory, and they also painted
the caves that they lived in,

1083
00:56:16,340 --> 00:56:21,380
and here's a wonderful painting
of an ancient human in a cave,

1084
00:56:21,660 --> 00:56:25,220
painting some of the animals
that are in her environment

1085
00:56:25,220 --> 00:56:29,580
and there's a child holding a lamp
there, which has properly got some

1086
00:56:29,580 --> 00:56:33,700
animal fat in it, burning away, so
that she can see what she's doing.

1087
00:56:33,700 --> 00:56:36,340
And you might think that this seems
really frivolous,

1088
00:56:36,340 --> 00:56:40,020
that these are people surviving
through the depths of the Ice Age

1089
00:56:40,020 --> 00:56:42,580
and shouldn't they be out,
hunting and gathering

1090
00:56:42,580 --> 00:56:44,900
and keeping their families alive?

1091
00:56:44,900 --> 00:56:48,620
What are they doing
painting caves and making art?

1092
00:56:48,620 --> 00:56:50,500
But it's not frivolous.

1093
00:56:50,500 --> 00:56:53,700
Art is a really important part
of the way that we communicate

1094
00:56:53,700 --> 00:56:58,660
with each other, and this really
underpins our success as a species.

1095
00:56:59,500 --> 00:57:03,780
We carry on expanding,
we carry on making culture.

1096
00:57:03,780 --> 00:57:08,020
And what we see from the genetics
is that, throughout our history,

1097
00:57:08,020 --> 00:57:11,500
we've been moving and mixing
with archaic humans

1098
00:57:11,500 --> 00:57:15,900
and with modern humans,
and we see this continuing today.

1099
00:57:15,900 --> 00:57:18,980
The ethnic groups and the
populations that we recognise today

1100
00:57:18,980 --> 00:57:21,740
are just a mix of lots
and lots of people.

1101
00:57:21,740 --> 00:57:26,740
In the third lecture, we're going to
look at human diversity today,

1102
00:57:27,140 --> 00:57:31,780
and we're going to find out how
those ancient migrations contributed

1103
00:57:31,780 --> 00:57:34,620
to the patterns that we see
around us today.

1104
00:57:34,620 --> 00:57:38,780
And we're going to look at how
our DNA influences who we are.

1105
00:57:38,780 --> 00:57:43,180
But for now, we're going to close
this lecture with a celebration

1106
00:57:43,180 --> 00:57:46,540
of all of our ancient
hominin ancestors,

1107
00:57:46,540 --> 00:57:51,220
everything that they've given us,
our love of art, our language,

1108
00:57:51,220 --> 00:57:55,580
all of those secrets and gifts
tucked away in our DNA,

1109
00:57:55,580 --> 00:58:00,620
and we're going to celebrate them
all with a little musical number.

1110
00:58:01,620 --> 00:58:04,900
Ta-da!
APPLAUSE

1111
00:58:04,900 --> 00:58:07,380
You can help me here, Alice. Really?

1112
00:58:07,380 --> 00:58:10,300
Yeah, I'll just leave you in charge
of one. OK? Everybody ready?

1113
00:58:10,300 --> 00:58:11,980
See if you recognise this.

1114
00:58:11,980 --> 00:58:15,540
SHE PLAYS JINGLE BELLS

1115
00:58:33,940 --> 00:58:36,860
CHEERING AND APPLAUSE

1116
00:58:40,980 --> 00:58:44,500
The Christmas lectures
have been filmed for 82 years,

1117
00:58:44,500 --> 00:58:47,820
but a few are missing
from the Royal Institution archives.

1118
00:58:47,820 --> 00:58:50,820
If you think you might have
any recordings hidden away

1119
00:58:50,820 --> 00:58:54,140
in your attic, please dig
them out and let us know.

1120
00:58:54,140 --> 00:58:58,060
The missing lectures are listed
on the Royal Institution website.

1121
00:58:58,060 --> 00:58:59,940
Thank you.