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- Welcome everybody.

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My name is Gail Gasparich

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and I'm the dean of the
College of Arts and Sciences.

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And it is my great honor to welcome you

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to the 2021 annual Darwin Festival.

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2021 marks the 42nd
annual Darwin festival.

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But this year is unique in
that it is the COVID version

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and all the programming will be online.

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The event is held to celebrate
Charles Darwin's birthday

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which is February 12th.

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In 1980, two Salem State
University faculty,

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Dr. Ginny Keville, who I
believe is joining us today,

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and Dr. Phillip DePalma,

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we're teaching human and
social biology for non-majors

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and initiated the first festival.

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It has grown and developed
through the years

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to include other SSU
departments, student clubs,

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and the City of Salem, which
in part supports the event

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through the Charles
Albert Read Trust Fund.

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The Darwin Festival welcome
scientists and non scientists

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who share an interest in learning

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about the world around them.

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Some well-known speakers have presented

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at the Darwin Festival
including Lynn Margulis,

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Stephen Jay Gould, Ernst Mayr,

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E. O. Wilson, B. F.
Skinner, and Jan Pechenik,

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just to name a few.

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A full list of past speakers
and titles of their talks,

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it's available on the
website if you're interested.

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The planning committee incorporates

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an interdisciplinary and
broad definition of evolution

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to include a wide range of speakers.

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This year is no different.

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I hope you have had a chance
to look at the schedule

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as there is a wide
range of talks presented

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by a diverse group of speakers
with areas of expertise

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in the biology of cities,
the evolution of skin color,

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which you're just about to hear,

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the diversity of coral reefs,

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and the mating habits of
cannibalistic spiders,

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just to name a few.

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I would be remiss if I did not
extend my sincere gratitude

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to the members of the Darwin
Festival Planning Committee,

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as any event this large requires

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a lot of behind the scenes planning

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that starts right after the last festival

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to get the speakers lined up

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and the logistics all figured out.

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So again, I extend my warmest welcome

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to the start of the 42nd
annual Darwin Festival.

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I hope you all have an opportunity

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to learn from the amazing
speakers and films made available

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to you throughout the week.

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And now I would like to hand
it over to Dr. Jason Brown,

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to share more information to kick off

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this morning's program.

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- Great, thank you, Gail.

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So welcome to the Darwin Festival.

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First, I need to let you know

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about a few housekeeping issues.

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If you're ever dropped from a webinar

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you can reconnect from the link

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in the webinars services
email that you received.

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Your questions for the speaker

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can be submitted throughout the talk

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using the Q&A feature of Zoom.

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Your questions may be posted
anonymously if you prefer that.

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And during the last 15 minutes,

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a selection of those questions

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will be asked by our moderators,

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Dr. Ryan Fisher and Dr. Nelson Scottgale.

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Since we may not have time
to get to all the questions,

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we apologize if we don't
get to your question,

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but Dr. Jablonski has
very kindly agreed for us

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to put together any questions
that didn't get answered

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and send those to her after the talk.

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So please feel free to
post your questions here.

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So to remind Salem State students,

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each talk this week is designed to fit

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into a single class period

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and attendance lists will
be sent to your professors.

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There's also a link to the list

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of Darwin Festival streaming videos

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on the online Darwin Festival schedule.

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So now to our first speaker for
the Salem State University's

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42nd annual Darwin Festival,

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I'm pleased to introduce
Dr. Nina Jablonski,

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Dr. Jablonski is the Evan
Pugh University Professor

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of Anthropology at the
Pennsylvania State University

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where she directs

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the Center for Human
Evolution and Diversity.

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She earned her bachelor's
degree in biology

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from Bryn Mawr College and
her PhD in anthropology

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from the University of Washington.

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Her research on primate evolution

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and the evolution of human skin,
skin pigmentation and touch

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has led to the publication

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of over 170 peer reviewed
journal articles.

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Her research on STEM education

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with her collaborator
Henry Louis Gates Jr.

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led to the development of the
Finding Your Roots curriculum

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focused on fostering an
interest in health sciences

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in middle school aged children

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through personalized genomics.

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She has been honored with numerous awards

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including a prestigious
Guggenheim Fellowship

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and election to the American
Academy of Arts and Sciences.

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Her books include "Skin:
A Natural History"

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and "Living Color: The Biological

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"and Social Meaning of Skin Color"

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She also does a lot of
work on public education,

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her TED Talk and her
HHMI BioInteractive video

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together have been viewed
around 2 million times.

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And she's also written
extensively for the popular press

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including Scientific
American, New Scientists,

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and the Huffington Post.

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So now with no further
delay, Dr. Nina Jablonski.

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- Thank you very much,
Jason and greetings.

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Welcome to this wonderful Darwin Festival.

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I'm really delighted to be with you today.

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Excuse me, I'm just trying to
get the screen share working.

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Okay.

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I've been interested in skin
color for a very long time.

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The Brazilian artist, Angélica Dass,

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who's beautiful Pantone
shade skin color pictures

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you're seeing right now,

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is also interested in skin color

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from an artistic perspective.

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And because she recognized
that in her native Brazil,

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people graded in their color
from one shade to another

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with no distinct boundaries.

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I share Angelica's basic curiosity,

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but I've been interested
in why skin colors evolved

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the way they are today and why
we make of them what we do.

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So what I'm gonna try
to do very quickly today

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is take you a bit through my
own career and my own study

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and my educational projects

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on the evolution of skin pigmentation,

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so that you can share part of
my life and my own curiosity.

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I wanna talk about skin color

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as a genuine evolutionary adaptation,

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and then emphasize that color-based races

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don't exist in nature,

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but have become very durable
psycho-social templates

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that have influenced us
as people and scientists

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for hundreds of years.

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And lastly, I want to talk briefly

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about the educational
programs that we've developed

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to help kids think about their origins

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and their appearance differently.

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We know that the sun
has been very important

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to the evolution of life on earth

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and it certainly has
been extremely important

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in forging skin pigmentation,

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because humans evolved under intense sun.

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Our ancestors lived primarily
in Equatorial Africa

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and the Horn of Africa region.

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What we see in this map
are some localities,

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shown in little balloons,

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for early members of our human lineage

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and then next dot in
the pink and blue color,

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this is the range of distribution

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of our close primate
relatives, chimpanzees,

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with whom we last shared a common ancestor

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about eight or 7 million years ago.

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So there is no doubt
that the human lineage

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began in Equatorial Africa,

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all of the earliest fossils are African

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and all of our early evolution

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right up through early Homo sapiens

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occurred primarily in Africa.

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So we really need to look at
the solar situation in Africa.

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And when we begin to think
about the main characters

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who were living under the sun in Africa,

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this is a beautiful
example to start out with,

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an early member of our own genus Homo.

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This one often referred
to as Homo ergaster

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from about a million and a half years ago

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right on the equator in Kenya.

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What's key about this individual

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is that he looks remarkably
modern in his skeleton,

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although he has a
smaller brain than we do,

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his arms and his legs are in about

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the same proportions as us.

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And when we look in detail at his body,

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we can see that he basically

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had the same patterns
of movement as we do.

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He was capable of strong
bipedal striding, and running.

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In other words, he could
get hot during his exercise

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and he didn't do exercise just for fun.

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He was doing exercise
to live, to find food,

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and to escape from predators.

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What we've done as we've
tried to understand

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the evolution of skin color

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is understand how this
process was related to,

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first, the loss of most of our body hair,

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which occurred as the result of the need

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to have more unfurry skin
to help us lose heat,

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the heat that we were generating

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through all of this running and chasing.

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Basically, if you have a fur coat on,

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it's hard to keep cool.

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And so one of the key things
that we see in human evolution

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and the beginning of the genus Homo

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is the loss of most body hair.

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And the increasing density
of eccrine sweat glands

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that produce a lot of sweat
that help us keep cool.

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We'll come back to this hairy
timeline of human evolution,

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but what's critical to see

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is that by about one and a
half to 2 million years ago

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we began to get mostly hairless
and the skin color changes

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in order to help protect
us from the intense sun.

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When we reconstruct the appearance

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of this early member of the genus Homo,

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he and she have mostly naked skin,

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probably some hair on our heads

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and that mostly naked is darkly pigmented.

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When we lost our hair, we lost
a lot of our sun protection.

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And the way we compensated for this

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was through the evolution

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of permanent dark,
protective skin pigment.

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The sun feels good and is very nice,

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but at the equator,
it's very, very intense.

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And within the entire
tropics, it's very intense,

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not only with visible light,

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but a lot of ultraviolet radiation,

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which is potentially very damaging.

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And so all organisms have to
protect themselves in some way

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from these harsh effects
of ultraviolet radiation

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and other very high
energy forms of radiation

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coming from the sun.

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Ultraviolet radiation is really

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gonna be the focus of today's talk,

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because that is the
really bioactive entity

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that we're going to be dealing with

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that has specific effects on the skin.

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And when we imagine that
we're living at the equator,

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just like our distant ancestors were,

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we can think about in this simulation

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the UV coming from the sun,
the very short wave length,

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UVC being completely absorbed

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by the atmosphere surrounding the earth.

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And then UVB which we hear
a lot about these days,

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UVB is also falling to the earth surface

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penetrating the atmosphere at the equator

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and fairly strongly, but
the strongest entity is UVA,

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which travels basically
through the atmosphere

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with visible light.

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The takeaway point here is
that at the equator year round,

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the UV is strong.

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And so organisms, including our ancestors

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had to protect themselves
from the strong sunlight.

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When we look in detail at the distribution

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of this strong UV and weaker
UV, it's really telling.

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And I'll come back to
this map a few times,

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because this is really our guide

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to the evolution of skin color.

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Skin color is directly related

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00:14:16,680 --> 00:14:20,100
to ultraviolet radiation intensity.

260
00:14:20,100 --> 00:14:22,750
And really we could end the lecture here,

261
00:14:22,750 --> 00:14:26,170
because the rest is just sort of details.

262
00:14:26,170 --> 00:14:30,830
The most protective skin coloration.

263
00:14:30,830 --> 00:14:34,180
The darkest skin occurs in areas

264
00:14:34,180 --> 00:14:36,680
where ultraviolet radiation is highest,

265
00:14:36,680 --> 00:14:40,050
shown here in red and hot pink.

266
00:14:40,050 --> 00:14:43,350
And then we have incrementally lower

267
00:14:43,350 --> 00:14:47,320
and more seasonal amounts
of ultraviolet radiation

268
00:14:47,320 --> 00:14:49,253
as we get closer to the poles.

269
00:14:50,380 --> 00:14:55,380
These maps have been created
from NASA remotely sensed data

270
00:14:56,580 --> 00:15:00,340
that have been rendered into map form

271
00:15:00,340 --> 00:15:03,710
by my collaborator and
husband George Chaplin.

272
00:15:03,710 --> 00:15:05,780
And he's made a variety of such maps.

273
00:15:05,780 --> 00:15:08,660
I'll only use this annual average map

274
00:15:08,660 --> 00:15:10,920
by way of illustration today.

275
00:15:10,920 --> 00:15:13,940
But the other thing that
I wanted you to take away

276
00:15:13,940 --> 00:15:18,140
from this map is okay,
it's very, very strong.

277
00:15:18,140 --> 00:15:20,680
The UV is very strong around the equator,

278
00:15:20,680 --> 00:15:23,540
but in areas where
there's a lot of humidity

279
00:15:23,540 --> 00:15:26,490
like Amazonia here in South America,

280
00:15:26,490 --> 00:15:31,490
or Equatorial West Africa,
the UV levels are lower.

281
00:15:31,910 --> 00:15:34,920
Similarly, as we get out of the tropics

282
00:15:34,920 --> 00:15:38,120
and begin going into
the Northern Hemisphere,

283
00:15:38,120 --> 00:15:41,810
whoa, look at Northern North
America, Northern Eurasia,

284
00:15:41,810 --> 00:15:45,600
very, very low levels of
ultraviolet radiation.

285
00:15:45,600 --> 00:15:49,640
This is the roadmap for understanding

286
00:15:49,640 --> 00:15:52,330
the evolution of human pigmentation

287
00:15:52,330 --> 00:15:54,880
as humans begin to disperse

288
00:15:54,880 --> 00:15:59,113
into these different zones millennia ago.

289
00:16:00,290 --> 00:16:03,610
So in early Homo, we've
got this handsome guy

290
00:16:03,610 --> 00:16:05,760
with his beautiful dark skin

291
00:16:05,760 --> 00:16:07,820
capable of doing a lot of sweating.

292
00:16:07,820 --> 00:16:09,930
And the dark skin is made dark

293
00:16:09,930 --> 00:16:12,670
by this remarkable eumelanin pigment,

294
00:16:12,670 --> 00:16:17,670
which absorbs ultraviolet
radiation and visible radiation.

295
00:16:17,760 --> 00:16:20,580
It's dark because it absorbs
all these wavelengths.

296
00:16:20,580 --> 00:16:22,480
It's a remarkable molecule,

297
00:16:22,480 --> 00:16:25,650
and it's used by thousands, millions

298
00:16:25,650 --> 00:16:29,480
of different vertebrates
and invertebrates species

299
00:16:29,480 --> 00:16:32,250
to protect from ultraviolet radiation,

300
00:16:32,250 --> 00:16:34,513
as well as to impart color.

301
00:16:37,350 --> 00:16:39,360
In our work, we've identified

302
00:16:39,360 --> 00:16:42,810
that the most important selective force,

303
00:16:42,810 --> 00:16:47,810
the most important reason
in evolutionary theory

304
00:16:47,900 --> 00:16:51,350
for the evolution of
dark skin pigmentation

305
00:16:51,350 --> 00:16:56,350
has been to protect foliate availability.

306
00:16:56,710 --> 00:17:01,710
Foliate is a B vitamin that
is absolutely essential

307
00:17:01,750 --> 00:17:05,780
for making and regulating DNA.

308
00:17:05,780 --> 00:17:10,150
Basically, if you can't make
and regulate and repair DNA

309
00:17:10,150 --> 00:17:12,880
you can't make new cells,
you can't repair cells,

310
00:17:12,880 --> 00:17:14,730
you're sunk basically,

311
00:17:14,730 --> 00:17:19,693
and you can't make an early
embryo and you can't make sperm.

312
00:17:20,950 --> 00:17:25,950
We came to this realization
when we realized that foliate,

313
00:17:29,300 --> 00:17:32,650
which we get from a
variety of dietary sources

314
00:17:32,650 --> 00:17:34,950
like green vegetable and citrus fruits,

315
00:17:34,950 --> 00:17:38,570
is actually sensitive to
ultraviolet radiation.

316
00:17:38,570 --> 00:17:40,590
So when you've got something sensitive

317
00:17:40,590 --> 00:17:43,020
to both ultraviolet radiation

318
00:17:43,020 --> 00:17:46,000
and processes that depend upon it,

319
00:17:46,000 --> 00:17:50,423
you've got to protect that
light sensitive entity.

320
00:17:52,010 --> 00:17:54,950
Folate as I said, is derived

321
00:17:54,950 --> 00:17:58,520
from a variety of green leafy vegetables,

322
00:17:58,520 --> 00:18:03,520
citrus fruits, whole grains and
it's really super important.

323
00:18:04,774 --> 00:18:07,200
All the women in the audience

324
00:18:07,200 --> 00:18:10,240
will certainly sort of understand

325
00:18:10,240 --> 00:18:14,050
why there's so much
foliate supplementation

326
00:18:14,050 --> 00:18:17,820
that they are encouraged to ingest

327
00:18:17,820 --> 00:18:20,390
when they're thinking of being pregnant,

328
00:18:20,390 --> 00:18:23,160
because folate is so important

329
00:18:23,160 --> 00:18:25,390
to a normal, healthy pregnancy,

330
00:18:25,390 --> 00:18:27,780
because there's all this
cell division going on.

331
00:18:27,780 --> 00:18:30,810
You have to have folate to fuel that.

332
00:18:30,810 --> 00:18:34,433
And if you have any processes
that interrupt folate,

333
00:18:35,336 --> 00:18:40,336
or cause it to be depleted or
destroyed you're in trouble,

334
00:18:41,010 --> 00:18:45,120
hence a lot eumelanin pigmentation

335
00:18:45,120 --> 00:18:48,300
that forms a natural sunscreen in the skin

336
00:18:48,300 --> 00:18:52,730
to help protect the
integrity of the bioactive

337
00:18:52,730 --> 00:18:55,723
and important foliates in the circulation.

338
00:18:56,810 --> 00:19:00,850
So here we are with our
hairy timeline again.

339
00:19:00,850 --> 00:19:04,490
There's the evolution of
the genus Homo approximately

340
00:19:04,490 --> 00:19:08,880
and the evolution of
Homo sapiens in Africa

341
00:19:08,880 --> 00:19:12,560
beginning around 300,000 years ago.

342
00:19:12,560 --> 00:19:15,360
Basically our lineage,

343
00:19:15,360 --> 00:19:18,430
although we do have some representatives

344
00:19:18,430 --> 00:19:21,670
who leave Africa at various times,

345
00:19:21,670 --> 00:19:25,830
this Homo erectus, for
instance, going into Eurasia

346
00:19:25,830 --> 00:19:29,520
about a million and a
million and a half years ago,

347
00:19:29,520 --> 00:19:33,130
most of those populations become extinct.

348
00:19:33,130 --> 00:19:36,910
What we're concerned with is Homo sapiens

349
00:19:36,910 --> 00:19:40,100
that continues to evolve in Africa

350
00:19:40,100 --> 00:19:45,100
and basically our Homo
sapiens, our species,

351
00:19:45,810 --> 00:19:49,893
the first skeletal evidence
around 300,000 years ago,

352
00:19:51,120 --> 00:19:54,850
we become modern in every respect,

353
00:19:54,850 --> 00:19:57,860
with respect to our culture,

354
00:19:57,860 --> 00:20:02,210
our capacity for language
and symbolic behavior,

355
00:20:02,210 --> 00:20:06,510
very sophisticated
technologies, art, you name it.

356
00:20:06,510 --> 00:20:08,350
All of these things evolved

357
00:20:08,350 --> 00:20:13,350
when we were in our early days
of Homo sapiens in Africa,

358
00:20:14,110 --> 00:20:16,650
exclusively in Africa between

359
00:20:16,650 --> 00:20:20,463
about 300,000 and 80,000 years ago.

360
00:20:23,760 --> 00:20:27,080
So when we think about the evolution

361
00:20:27,080 --> 00:20:30,170
of early African Homo sapiens

362
00:20:30,170 --> 00:20:35,170
and the populations in Africa
that remain there today,

363
00:20:36,520 --> 00:20:41,520
we can think easily of this
continuity of selective forces

364
00:20:43,740 --> 00:20:46,780
and the evolution of dark pigmentation

365
00:20:46,780 --> 00:20:51,780
to protect people from
intense ultraviolet radiation.

366
00:20:52,260 --> 00:20:55,530
But we know that there are lots of people

367
00:20:55,530 --> 00:20:59,530
with more lightly pigmented
skin that exist in the world.

368
00:20:59,530 --> 00:21:02,710
So really we have to figure
out, well, what's going on?

369
00:21:02,710 --> 00:21:03,940
What happened?

370
00:21:03,940 --> 00:21:05,973
How did this,

371
00:21:07,000 --> 00:21:10,150
I would argue, loss of pigmentation,

372
00:21:10,150 --> 00:21:11,493
or depigmentation occur?

373
00:21:14,150 --> 00:21:18,780
Well, let's look at our UV
map and think just generally

374
00:21:18,780 --> 00:21:21,420
about the pattern of dispersals,

375
00:21:21,420 --> 00:21:26,420
movement of people that
occurred at periods

376
00:21:26,440 --> 00:21:31,200
after around 80,000
years ago, out of Africa.

377
00:21:31,200 --> 00:21:34,220
Remember most people over this time

378
00:21:34,220 --> 00:21:37,733
are living and moving within Africa.

379
00:21:38,740 --> 00:21:42,570
So what we're talking
about here are small groups

380
00:21:42,570 --> 00:21:45,770
that are leaving Africa
in pursuit of food,

381
00:21:45,770 --> 00:21:49,100
usually prey animals of various kinds.

382
00:21:49,100 --> 00:21:53,610
We know that people started moving

383
00:21:53,610 --> 00:21:55,990
into the Afro-Arabian Peninsula,

384
00:21:55,990 --> 00:21:58,640
as well as along the coast of East Asia,

385
00:21:58,640 --> 00:22:02,163
probably 60 to 70,000 years ago.

386
00:22:03,060 --> 00:22:05,690
These arrows just give you a general idea

387
00:22:05,690 --> 00:22:07,670
of where these dispersals are going,

388
00:22:07,670 --> 00:22:09,620
but I want you to watch the arrows

389
00:22:09,620 --> 00:22:12,690
relative to the UV zones.

390
00:22:12,690 --> 00:22:14,350
So here we have people going

391
00:22:14,350 --> 00:22:19,350
into Southern and Southeast
Asia, an island, Melanesia

392
00:22:22,730 --> 00:22:25,910
from a hinterland position

393
00:22:25,910 --> 00:22:28,610
in between the Caspian and the Black Sea,

394
00:22:28,610 --> 00:22:33,120
we have people going
northwestward into Europe

395
00:22:33,120 --> 00:22:36,020
and northeastward into Northeast Asia,

396
00:22:36,020 --> 00:22:38,620
and then considerably later beginning

397
00:22:38,620 --> 00:22:43,620
probably around 15,000 years
ago into the new world.

398
00:22:43,630 --> 00:22:47,540
Now what's important here is
that not only are people going

399
00:22:47,540 --> 00:22:51,450
or dispersing into these
zones of different UV,

400
00:22:51,450 --> 00:22:54,870
especially into these very low UV zones

401
00:22:54,870 --> 00:22:57,230
in the Northern Hemisphere,

402
00:22:57,230 --> 00:23:01,570
But also we know from
genetic and genomic studies

403
00:23:01,570 --> 00:23:05,310
that these populations
of people are small.

404
00:23:05,310 --> 00:23:08,600
And so these populations have experienced

405
00:23:08,600 --> 00:23:12,410
what geneticists call
population bottlenecks,

406
00:23:12,410 --> 00:23:15,093
restrictions of genetic variability.

407
00:23:16,200 --> 00:23:18,720
The combination of bottlenecks

408
00:23:18,720 --> 00:23:22,040
plus intense natural selection

409
00:23:22,040 --> 00:23:27,040
really is the story of human
skin pigmentation evolution.

410
00:23:29,130 --> 00:23:31,230
It's important to remember

411
00:23:31,230 --> 00:23:35,340
even though humans are dispersing
over thousands of years,

412
00:23:35,340 --> 00:23:37,880
that during individual human lifetimes

413
00:23:37,880 --> 00:23:39,370
people didn't travel much.

414
00:23:39,370 --> 00:23:42,010
There were no vacations per se.

415
00:23:42,010 --> 00:23:46,160
There was not a lot of sort
of commuting that went on.

416
00:23:46,160 --> 00:23:48,710
They spent most of their time outdoors

417
00:23:48,710 --> 00:23:53,710
and there really wasn't until
about 20 to 30,000 years ago,

418
00:23:54,140 --> 00:23:57,340
there wasn't much in
the way of sewn clothing

419
00:23:57,340 --> 00:24:00,360
or built environment, shelters.

420
00:24:00,360 --> 00:24:03,800
People took shelter in
rock shelters and caves,

421
00:24:03,800 --> 00:24:06,670
but they spent most of their time outdoors

422
00:24:06,670 --> 00:24:08,270
without sewn closing.

423
00:24:08,270 --> 00:24:12,800
The point is, is that skin
was the primary interface

424
00:24:12,800 --> 00:24:15,893
between our bodies and the environment.

425
00:24:17,500 --> 00:24:21,040
And so we adapted to the UV regimes

426
00:24:21,040 --> 00:24:24,300
that were outside at any particular time,

427
00:24:24,300 --> 00:24:27,410
whether they were intense
or not so intense,

428
00:24:27,410 --> 00:24:31,090
the skin was the primary interface.

429
00:24:31,090 --> 00:24:33,190
So what was it like?

430
00:24:33,190 --> 00:24:35,890
What were the sun's rays like,

431
00:24:35,890 --> 00:24:38,740
let's say in the extreme
Northern Hemisphere

432
00:24:38,740 --> 00:24:40,600
during the winter time?

433
00:24:40,600 --> 00:24:42,590
Let's look at this simulation,

434
00:24:42,590 --> 00:24:47,590
again, UVC is gonna be completely
absorbed by the atmosphere

435
00:24:47,750 --> 00:24:49,960
as is the UVB.

436
00:24:49,960 --> 00:24:54,960
Now, I dwell on UVB here
because it turns out,

437
00:24:55,070 --> 00:24:57,920
although, it's monumentally destructive

438
00:24:57,920 --> 00:25:01,050
in terms of its effects
on biological systems

439
00:25:01,050 --> 00:25:03,110
including the human body,

440
00:25:03,110 --> 00:25:07,290
UVB does one positive important thing,

441
00:25:07,290 --> 00:25:10,520
which is to begin the process

442
00:25:10,520 --> 00:25:12,893
of making vitamin D in the skin.

443
00:25:15,270 --> 00:25:19,740
UVA also comes to the earth
surface with visible light,

444
00:25:19,740 --> 00:25:22,890
just like it did in
the earlier simulation.

445
00:25:22,890 --> 00:25:26,290
But the key point here is that UVB

446
00:25:26,290 --> 00:25:30,510
isn't missing in the
sunlight during the winter

447
00:25:30,510 --> 00:25:32,723
outside of the tropics.

448
00:25:34,760 --> 00:25:39,420
So when we think about these two guys,

449
00:25:39,420 --> 00:25:40,580
we need to think about

450
00:25:40,580 --> 00:25:45,040
well, how is their skin
reacting to sunlight?

451
00:25:45,040 --> 00:25:47,590
Now, if this is mid-summer,

452
00:25:47,590 --> 00:25:50,240
judging by the intensity of the sunlight

453
00:25:50,240 --> 00:25:52,250
and their sunglasses,

454
00:25:52,250 --> 00:25:54,710
what we know is that the man on the right

455
00:25:54,710 --> 00:25:59,070
who has more eumelanin
natural sunscreen in his skin

456
00:25:59,070 --> 00:26:00,960
will be well-protected,

457
00:26:00,960 --> 00:26:05,380
but he'll also make vitamin D in his skin

458
00:26:05,380 --> 00:26:09,540
at a slower rate than the man on the left.

459
00:26:09,540 --> 00:26:12,670
And this is really where the next phase

460
00:26:12,670 --> 00:26:17,380
of this evolution pigmentation
timeline is going.

461
00:26:17,380 --> 00:26:22,380
When populations are dispersing
into higher latitudes,

462
00:26:23,010 --> 00:26:27,100
the only way that they're
gonna stay healthy

463
00:26:27,100 --> 00:26:28,970
year in and year out

464
00:26:28,970 --> 00:26:33,970
is to lose some of their
protective sunscreen pigment.

465
00:26:35,980 --> 00:26:39,550
So what we really have
to think about here is

466
00:26:39,550 --> 00:26:44,550
light skin being depigmented
skin having lost its eumelanin,

467
00:26:45,120 --> 00:26:48,370
and the less eumelanin you have

468
00:26:48,370 --> 00:26:52,763
the easier it is to make
vitamin D in the skin.

469
00:26:54,110 --> 00:26:57,780
So here we are thinking about

470
00:26:57,780 --> 00:27:02,400
what's going on as people
go into these high latitudes

471
00:27:02,400 --> 00:27:05,660
first in Eurasia and then in the Americas?

472
00:27:05,660 --> 00:27:08,610
It's salutary to remember too that

473
00:27:08,610 --> 00:27:12,590
that there are no really
high latitude environments

474
00:27:12,590 --> 00:27:14,140
in the Southern Hemisphere,

475
00:27:14,140 --> 00:27:18,000
apart from the lower
portion of South America,

476
00:27:18,000 --> 00:27:20,170
there's very little in the way

477
00:27:20,170 --> 00:27:23,090
of extreme high latitude
environments there.

478
00:27:23,090 --> 00:27:24,977
So we're talking about primarily

479
00:27:24,977 --> 00:27:27,940
a Northern Hemisphere phenomenon.

480
00:27:27,940 --> 00:27:32,940
And what we see as people
are dispersing over time

481
00:27:32,950 --> 00:27:37,950
into the Northern Hemisphere
is a combination of biologic

482
00:27:38,020 --> 00:27:42,460
i.e. genetic and cultural adaptations

483
00:27:42,460 --> 00:27:45,663
that allow them to live healthy lives.

484
00:27:47,370 --> 00:27:49,830
And this is really what we want to look at

485
00:27:49,830 --> 00:27:54,623
in a bit more detail, is these
just how this all worked out.

486
00:27:57,560 --> 00:28:02,210
In a variety of excellent genetic studies

487
00:28:02,210 --> 00:28:05,320
that have been conducted
in the last 15 years,

488
00:28:05,320 --> 00:28:08,860
we've been able to look at
the genetic architecture,

489
00:28:08,860 --> 00:28:11,760
so to speak, for pigmentation

490
00:28:11,760 --> 00:28:14,430
in many populations of the world.

491
00:28:14,430 --> 00:28:17,400
And there's been great attention focused

492
00:28:17,400 --> 00:28:20,950
on Western Europeans and Eastern Asians,

493
00:28:20,950 --> 00:28:24,420
because both of them have
lightly pigmented skin.

494
00:28:24,420 --> 00:28:28,420
And it was quite surprising
when it became evident

495
00:28:28,420 --> 00:28:30,860
a little bit more than 10 years ago

496
00:28:30,860 --> 00:28:34,760
that these two populations

497
00:28:34,760 --> 00:28:38,420
who have roughly very similar looking skin

498
00:28:38,420 --> 00:28:43,420
actually evolved the same
skin tones independently

499
00:28:44,660 --> 00:28:48,453
via independent genetic means.

500
00:28:49,360 --> 00:28:53,800
This is one of the most
remarkable examples

501
00:28:53,800 --> 00:28:58,120
of natural selection
occurring independently

502
00:28:58,120 --> 00:29:03,120
in these recently split
lineages of modern humans.

503
00:29:04,020 --> 00:29:08,980
They split apart completely
around 40,000 years ago.

504
00:29:08,980 --> 00:29:12,230
And they underwent
increased depigmentation

505
00:29:13,910 --> 00:29:17,340
from 40,000 years ago to the present time,

506
00:29:17,340 --> 00:29:21,997
largely on the basis of
different genetic mutations.

507
00:29:25,380 --> 00:29:28,840
Remember, mutations aren't all bad.

508
00:29:28,840 --> 00:29:32,070
So you can have mutations
that are favorable

509
00:29:32,070 --> 00:29:34,450
under certain environmental conditions.

510
00:29:34,450 --> 00:29:37,440
And what we're talking
about here are mutations

511
00:29:37,440 --> 00:29:41,830
that are favorable
under low UV conditions,

512
00:29:41,830 --> 00:29:45,030
that allow the skin to have less eumelanin

513
00:29:45,030 --> 00:29:50,030
so that it can absorb more
UVB to make more vitamin D

514
00:29:50,470 --> 00:29:52,400
out of available sunlight.

515
00:29:52,400 --> 00:29:55,733
This is such a beautiful
example of natural selection.

516
00:29:57,710 --> 00:30:00,583
So really what we can identify here

517
00:30:00,583 --> 00:30:03,100
is that the primary selective force

518
00:30:03,100 --> 00:30:08,040
for loss of eumelanin
pigmentation for depigmented skin

519
00:30:08,040 --> 00:30:12,623
is the promotion of UV
induced vitamin D production.

520
00:30:15,180 --> 00:30:20,120
And we see these at higher latitudes

521
00:30:20,120 --> 00:30:22,490
with not only less intense,

522
00:30:22,490 --> 00:30:25,390
but much more highly seasonal UV.

523
00:30:25,390 --> 00:30:30,390
We have just tremendous amounts
of depigmentation occurring

524
00:30:30,480 --> 00:30:34,670
plus a lot of sort of cultural buffering.

525
00:30:34,670 --> 00:30:38,130
In addition to depigmented skin,

526
00:30:38,130 --> 00:30:40,940
we see people using a lot

527
00:30:40,940 --> 00:30:45,620
and making use of a lot of
vitamin D rich food sources

528
00:30:45,620 --> 00:30:49,820
like oily fish, marine
mammals, caribou reindeer,

529
00:30:49,820 --> 00:30:51,320
this kind of thing,

530
00:30:51,320 --> 00:30:55,120
because they need to replenish their diet

531
00:30:55,120 --> 00:30:57,200
with as much vitamin D as possible

532
00:30:57,200 --> 00:31:02,200
because the UVB is so weak at
these extreme high latitudes,

533
00:31:02,480 --> 00:31:06,023
they can't make enough
vitamin D in their skin.

534
00:31:07,840 --> 00:31:09,870
Vitamin D is really important

535
00:31:09,870 --> 00:31:13,690
for the absorption of
calcium from the diet

536
00:31:13,690 --> 00:31:18,030
and in the absence of
normal calcium absorption

537
00:31:19,323 --> 00:31:22,440
and the absence of sufficient vitamin D,

538
00:31:22,440 --> 00:31:25,963
we see kids developing
nutritional rickets,

539
00:31:26,950 --> 00:31:30,400
probably very common in much of the world

540
00:31:31,330 --> 00:31:32,980
during historical periods,

541
00:31:32,980 --> 00:31:36,260
certainly in the United
States, this is true.

542
00:31:36,260 --> 00:31:40,430
And it is particularly serious

543
00:31:40,430 --> 00:31:43,490
with respect to its
evolutionary consequences

544
00:31:43,490 --> 00:31:45,530
when it affects normal birth,

545
00:31:45,530 --> 00:31:50,290
as it does in the case of
this young woman's pelvis.

546
00:31:50,290 --> 00:31:52,800
The outlet of which is very constricted

547
00:31:52,800 --> 00:31:56,693
as the result of rickets
during her early development.

548
00:31:58,560 --> 00:32:01,510
But equally important we now recognize,

549
00:32:01,510 --> 00:32:05,160
and this is something
that physicians emphasize

550
00:32:05,160 --> 00:32:08,540
to us simile every day during the winter,

551
00:32:08,540 --> 00:32:11,182
is that vitamin D is really important

552
00:32:11,182 --> 00:32:15,400
to help keep our immune
systems in good condition.

553
00:32:15,400 --> 00:32:17,850
So having enough vitamin D in the diet,

554
00:32:17,850 --> 00:32:21,310
or taking vitamin D to
maintain healthy levels

555
00:32:21,310 --> 00:32:26,150
is really important for
the health of our innate

556
00:32:26,150 --> 00:32:28,703
and adaptive immune systems.

557
00:32:30,100 --> 00:32:33,820
So when we think about
what's going on here,

558
00:32:33,820 --> 00:32:38,390
again, I wanna think
now about what happens

559
00:32:38,390 --> 00:32:42,290
when people are dispersing
not only into high latitudes,

560
00:32:42,290 --> 00:32:44,610
but then back into lower latitudes.

561
00:32:44,610 --> 00:32:49,570
For instance, when we think
about people who dispersed

562
00:32:49,570 --> 00:32:52,490
into the Indian subcontinent,

563
00:32:52,490 --> 00:32:57,350
many populations went into lower UV areas

564
00:32:57,350 --> 00:33:00,950
and then came back into higher UV areas.

565
00:33:00,950 --> 00:33:04,150
What happened to those populations?

566
00:33:04,150 --> 00:33:07,510
And again, what we see is a combination

567
00:33:07,510 --> 00:33:12,510
of biological and cultural adaptations.

568
00:33:12,520 --> 00:33:15,280
When we look at these three men,

569
00:33:15,280 --> 00:33:18,640
all of whom have darkly pigmented skin,

570
00:33:18,640 --> 00:33:21,490
one of the things that we now appreciate

571
00:33:21,490 --> 00:33:25,530
is that the genetic architecture

572
00:33:25,530 --> 00:33:30,530
for dark and highly tangible
skin is actually distinct,

573
00:33:31,730 --> 00:33:34,990
is different in these three major groups

574
00:33:34,990 --> 00:33:39,700
from East Africa,
Australia, and Melanesia,

575
00:33:39,700 --> 00:33:42,063
and Southern India.

576
00:33:42,980 --> 00:33:46,310
Again, this is a beautiful example

577
00:33:46,310 --> 00:33:49,043
of natural selection in action.

578
00:33:50,900 --> 00:33:54,630
Having the same skin colors

579
00:33:54,630 --> 00:33:57,910
evolved multiple times independently

580
00:33:57,910 --> 00:34:02,910
and from a distinct pools
of genetic mutation.

581
00:34:05,480 --> 00:34:09,800
It turns out in our studies
of skin pigmentation genes

582
00:34:09,800 --> 00:34:13,350
that there are dozens and dozens of genes

583
00:34:13,350 --> 00:34:16,580
that have effect on skin pigmentation.

584
00:34:16,580 --> 00:34:20,300
There are probably a large
handful that have a major effect,

585
00:34:20,300 --> 00:34:22,710
but there are many that
have smaller effects.

586
00:34:22,710 --> 00:34:27,710
And often in genetically
restricted populations

587
00:34:28,740 --> 00:34:30,593
that have undergone bottlenecks,

588
00:34:31,702 --> 00:34:35,720
these genes of minor effect have been used

589
00:34:35,720 --> 00:34:39,930
to enhance tanning
mechanisms for instance.

590
00:34:39,930 --> 00:34:43,690
So the research in this
area is still ongoing.

591
00:34:43,690 --> 00:34:47,020
It's very exciting,
but it's so interesting

592
00:34:47,020 --> 00:34:50,000
because we have natural
selection being played out

593
00:34:50,000 --> 00:34:52,070
on our own bodies.

594
00:34:52,070 --> 00:34:54,780
So there are many genetic loci

595
00:34:54,780 --> 00:34:58,240
that are associated with both
depigmentation and tanning,

596
00:34:58,240 --> 00:35:00,720
and these processes occurred

597
00:35:00,720 --> 00:35:03,323
under strong positive selection.

598
00:35:04,490 --> 00:35:07,170
So we could really think
about skin pigmentation

599
00:35:07,170 --> 00:35:11,160
being a beautiful evolutionary compromise

600
00:35:11,160 --> 00:35:14,250
between the demands of photoprotection,

601
00:35:14,250 --> 00:35:18,170
especially under the extreme UV conditions

602
00:35:18,170 --> 00:35:22,960
in drier parts of the
world near the equator

603
00:35:22,960 --> 00:35:27,850
and closer to the poles incline

604
00:35:27,850 --> 00:35:32,037
or gradient favoring
photosynthesis of vitamin D.

605
00:35:32,037 --> 00:35:35,120
And in-between these two zones,

606
00:35:35,120 --> 00:35:40,120
we have people adapting to seasonal levels

607
00:35:40,370 --> 00:35:42,170
of seasonal changes in UV

608
00:35:42,170 --> 00:35:46,640
and often with different
tanning mechanisms

609
00:35:46,640 --> 00:35:50,500
so that they can gain and
lose eumelanin pigment

610
00:35:50,500 --> 00:35:51,743
throughout the year.

611
00:35:53,620 --> 00:35:57,320
This really warrants some
Darwinian celebration,

612
00:35:57,320 --> 00:36:01,760
because this is one of the best examples

613
00:36:01,760 --> 00:36:04,450
of natural selection on the human body.

614
00:36:04,450 --> 00:36:07,650
And so when you're talking
to your friends about this,

615
00:36:07,650 --> 00:36:09,550
or teaching your classes

616
00:36:09,550 --> 00:36:13,120
you can think about this
being one of the best examples

617
00:36:13,120 --> 00:36:16,163
that you can bring it to
your classes and students.

618
00:36:17,820 --> 00:36:22,480
Another important point is that
these features of the skin,

619
00:36:22,480 --> 00:36:25,990
this highly tangible dark pigmentation

620
00:36:25,990 --> 00:36:30,640
is not associated necessarily
with other physical features.

621
00:36:30,640 --> 00:36:34,100
So when we look at the hair
texture of these people,

622
00:36:34,100 --> 00:36:37,810
the skeletal proportions, the skull shape,

623
00:36:37,810 --> 00:36:39,880
this shape of the physical features,

624
00:36:39,880 --> 00:36:42,480
these are all very different
in these individuals

625
00:36:42,480 --> 00:36:44,360
with darkly pigmented skin.

626
00:36:44,360 --> 00:36:48,170
And this is important that skin color,

627
00:36:48,170 --> 00:36:52,420
whether we're talking about
darkly or depigmented skin

628
00:36:52,420 --> 00:36:57,050
is determined by genes that
travel for the most part

629
00:36:57,050 --> 00:37:00,410
entirely independently of the genes

630
00:37:00,410 --> 00:37:04,240
that determine the form
of these other traits

631
00:37:04,240 --> 00:37:06,760
that are physically evident.

632
00:37:06,760 --> 00:37:10,663
So this again is an important point.

633
00:37:12,950 --> 00:37:17,080
A big takeaway, similar skin
colors evolved independently

634
00:37:17,080 --> 00:37:19,590
under the same UV conditions,

635
00:37:19,590 --> 00:37:24,370
and that means that we
can't use skin color

636
00:37:24,370 --> 00:37:29,370
as any kind of marker of
unique group identity,

637
00:37:30,380 --> 00:37:35,380
or as a classification entity
to create a race of humans.

638
00:37:39,830 --> 00:37:43,590
Skin color is simply to label

639
00:37:44,564 --> 00:37:47,350
a beautifully adaptive characteristic,

640
00:37:47,350 --> 00:37:52,350
but totally useless for
purposes of classifying people.

641
00:37:53,920 --> 00:37:58,330
So when we think about this
beautiful, beautiful CP

642
00:37:58,330 --> 00:38:00,830
or rainbow of skin colors,

643
00:38:00,830 --> 00:38:05,230
such as produced by
Angelica Dass here again.

644
00:38:05,230 --> 00:38:10,230
We don't see any sharp
differences between people.

645
00:38:11,760 --> 00:38:16,760
So why did we end up with
various schemes around the world

646
00:38:17,610 --> 00:38:20,130
in which people are grouped

647
00:38:20,130 --> 00:38:24,150
by seemingly well demarcated skin colors?

648
00:38:24,150 --> 00:38:27,540
Well, the origin of human races

649
00:38:27,540 --> 00:38:32,100
is all about the origin of human bias,

650
00:38:34,160 --> 00:38:37,600
the origin of inadequate information

651
00:38:37,600 --> 00:38:41,960
and the origin of really the ability

652
00:38:41,960 --> 00:38:46,960
to promote certain ideas under
certain social circumstances,

653
00:38:47,380 --> 00:38:48,550
this is a long story.

654
00:38:48,550 --> 00:38:50,763
So you're gonna get
the very short version.

655
00:38:51,610 --> 00:38:56,610
Two of the important
characters here to mention are

656
00:38:56,690 --> 00:39:01,360
Linnaeus the systematist,
the person who first thought

657
00:39:01,360 --> 00:39:05,230
about putting species
of plants and animals

658
00:39:05,230 --> 00:39:09,300
into a system of binomial nomenclature.

659
00:39:09,300 --> 00:39:12,800
He thought about humans deeply,

660
00:39:12,800 --> 00:39:16,100
and Kant, Immanuel Kant the philosopher

661
00:39:16,100 --> 00:39:20,020
who also thought deeply about
humans and human diversity

662
00:39:20,020 --> 00:39:24,200
as he ruminated over what made

663
00:39:24,200 --> 00:39:28,300
for a civilized, moral human being.

664
00:39:28,300 --> 00:39:33,030
Now, what's key about these guys

665
00:39:33,030 --> 00:39:35,070
is that they used skin color.

666
00:39:35,070 --> 00:39:39,690
And first Linnaeus used skin
color to define human groups.

667
00:39:39,690 --> 00:39:43,260
And this is important
because Linnaeus thought

668
00:39:43,260 --> 00:39:44,340
a lot about color.

669
00:39:44,340 --> 00:39:45,640
He was a botanist.

670
00:39:45,640 --> 00:39:49,320
And for him being able
to distinguish flowers,

671
00:39:49,320 --> 00:39:52,210
for instance, by skin
color was really important.

672
00:39:52,210 --> 00:39:55,260
And so when he became aware of the fact

673
00:39:55,260 --> 00:39:57,570
that people came in different colors,

674
00:39:57,570 --> 00:40:00,050
he never traveled very
much outside of Europe.

675
00:40:00,050 --> 00:40:04,310
So he wouldn't have seen
people, but he heard about them.

676
00:40:04,310 --> 00:40:06,430
He defined

677
00:40:08,612 --> 00:40:11,370
those groups of people by color,

678
00:40:11,370 --> 00:40:15,170
just as he would with the
plants that he studied.

679
00:40:15,170 --> 00:40:18,580
So in his earliest classification,

680
00:40:18,580 --> 00:40:22,950
we see humans according to continent

681
00:40:22,950 --> 00:40:25,713
classified only by their color.

682
00:40:26,550 --> 00:40:30,740
Later he classifies things
a little differently,

683
00:40:30,740 --> 00:40:35,740
but he only sort of adds
to those classifications

684
00:40:36,430 --> 00:40:39,693
with some other attributes,
which I won't go into now.

685
00:40:40,670 --> 00:40:45,670
Kant takes this one step further.

686
00:40:45,840 --> 00:40:48,380
We have Linnaeus working in 1740,

687
00:40:48,380 --> 00:40:52,370
Kant is deliberating about
the nature of human diversity,

688
00:40:52,370 --> 00:40:55,540
physical diversity in the 1770s.

689
00:40:55,540 --> 00:40:59,500
And he writes an important
treatise in 1775,

690
00:40:59,500 --> 00:41:04,330
in which he articulates
this scheme of four races.

691
00:41:04,330 --> 00:41:08,223
And he calls them races,
in Germany, Rassen.

692
00:41:09,760 --> 00:41:14,330
The key thing here is
that he does distinguishes

693
00:41:14,330 --> 00:41:18,700
these four groups as a hierarchy.

694
00:41:18,700 --> 00:41:23,440
Linnaeus hadn't put these
people in any kind of order,

695
00:41:23,440 --> 00:41:28,440
Kant did as did Kant's contemporary
in Scotland, David Hume.

696
00:41:31,620 --> 00:41:36,620
Both of them importantly put
the race of the whites on top.

697
00:41:38,520 --> 00:41:41,270
Again, these men didn't travel,

698
00:41:41,270 --> 00:41:44,650
they had access to very limited data,

699
00:41:44,650 --> 00:41:48,140
but important for the rest of our story

700
00:41:48,140 --> 00:41:52,420
is that they had enormous influence

701
00:41:52,420 --> 00:41:54,830
on the history of scholarly thought,

702
00:41:54,830 --> 00:41:57,467
but also on the history of political

703
00:41:57,467 --> 00:42:00,573
throughout Europe and North America.

704
00:42:02,530 --> 00:42:04,880
So according to the Kantian view,

705
00:42:04,880 --> 00:42:09,250
which we can also say it was
championed by David Hume,

706
00:42:09,250 --> 00:42:13,010
races were physically
and culturally distinct

707
00:42:13,010 --> 00:42:14,080
from one another.

708
00:42:14,080 --> 00:42:17,640
Kant felt that the intensity of the sun

709
00:42:17,640 --> 00:42:21,520
affected one's ability to reason,

710
00:42:21,520 --> 00:42:26,520
ability to work creatively,
to have moral judgment

711
00:42:26,640 --> 00:42:29,183
and develop civilization.

712
00:42:30,990 --> 00:42:32,620
And in these attributes

713
00:42:32,620 --> 00:42:36,933
he felt that the white
race was entirely superior.

714
00:42:40,840 --> 00:42:45,570
What we see in the 1780s and '90s

715
00:42:45,570 --> 00:42:50,570
is this racial hierarchy,
a framework of named races,

716
00:42:51,910 --> 00:42:56,910
in order becoming a durable template

717
00:42:57,960 --> 00:43:00,270
that describes variation.

718
00:43:00,270 --> 00:43:03,850
There are all sorts of
economic reasons for this too,

719
00:43:03,850 --> 00:43:07,440
because in the late 1700s,

720
00:43:07,440 --> 00:43:11,660
there is increasing pressure
to end the slave trade,

721
00:43:11,660 --> 00:43:13,563
the transatlantic slave trade,

722
00:43:14,500 --> 00:43:18,890
but in a way and a terrible irony

723
00:43:18,890 --> 00:43:23,890
is that science rescues the slave trade

724
00:43:24,030 --> 00:43:29,030
by giving this framework,
this hierarchy of races,

725
00:43:30,760 --> 00:43:34,973
whites followed by blacks and others.

726
00:43:36,160 --> 00:43:40,320
According to this hierarchical scheme,

727
00:43:40,320 --> 00:43:44,910
if blacks, so-called, from Africa

728
00:43:44,910 --> 00:43:48,230
are biologically inferior to whites,

729
00:43:48,230 --> 00:43:51,233
then it is okay to enslave them.

730
00:43:52,200 --> 00:43:57,020
And this sadly and ironically turns out

731
00:43:57,020 --> 00:44:00,340
to be one of the major justifications

732
00:44:00,340 --> 00:44:04,330
that was embraced not only
by European slave traders,

733
00:44:04,330 --> 00:44:09,330
but by avid slave owners who
wanted to acquire more slaves

734
00:44:12,250 --> 00:44:14,610
through the transatlantic slave trade

735
00:44:14,610 --> 00:44:19,610
through the late 1700s and into
the 1800s in North America.

736
00:44:23,345 --> 00:44:27,440
This hierarchical framework
decisively affects

737
00:44:27,440 --> 00:44:31,780
the way human variation
is considered and studied

738
00:44:31,780 --> 00:44:36,780
in science and in politics,
basically to this very day.

739
00:44:38,330 --> 00:44:43,330
We really have to scrutinize
this as a historical process

740
00:44:43,350 --> 00:44:48,140
and say how can we begin
to better understand

741
00:44:48,140 --> 00:44:51,370
and undo this in light
of the better knowledge

742
00:44:51,370 --> 00:44:52,830
that we have today?

743
00:44:52,830 --> 00:44:55,930
Why use an 18th century compass

744
00:44:55,930 --> 00:44:59,313
when you have a 21st century GPS?

745
00:45:00,930 --> 00:45:05,930
Because what we see is that
these racial stereotypes

746
00:45:06,260 --> 00:45:10,060
lead to what I would call color memes

747
00:45:10,060 --> 00:45:14,440
from which developed the
psychosocial templates

748
00:45:14,440 --> 00:45:16,670
of racism as they developed

749
00:45:16,670 --> 00:45:21,670
in the late 19th, 20th,
and early 21st century.

750
00:45:22,230 --> 00:45:27,230
We can see now this clear progression,

751
00:45:27,800 --> 00:45:32,103
a tragic progression in human history.

752
00:45:34,490 --> 00:45:36,500
But we can think about
these things differently.

753
00:45:36,500 --> 00:45:38,100
And in the last few minutes,

754
00:45:38,100 --> 00:45:40,850
I just want to share with you a program

755
00:45:40,850 --> 00:45:43,690
that I've developed with
Henry Louis Gates, Jr.

756
00:45:43,690 --> 00:45:45,820
to try to get at this,

757
00:45:45,820 --> 00:45:49,540
to try to change the way that we think,

758
00:45:49,540 --> 00:45:53,310
and not geared at old
folks or older students,

759
00:45:53,310 --> 00:45:56,250
but geared primarily at young people

760
00:45:56,250 --> 00:45:59,500
who are interested and not jaded,

761
00:45:59,500 --> 00:46:02,340
who want to figure out what
the world is all about.

762
00:46:02,340 --> 00:46:04,660
And we want to get them more interested

763
00:46:04,660 --> 00:46:09,208
in understanding science,
in understanding facts,

764
00:46:09,208 --> 00:46:11,160
so that they can make observations

765
00:46:11,160 --> 00:46:12,470
and make sense of the world

766
00:46:12,470 --> 00:46:14,270
and make sense of their place in it.

767
00:46:15,120 --> 00:46:18,530
To make a long story short,
we created a working group

768
00:46:18,530 --> 00:46:21,250
and we started to create a curriculum

769
00:46:21,250 --> 00:46:25,460
that we thought would work
to help kids get interested

770
00:46:25,460 --> 00:46:29,513
in science and the world
through studying themselves.

771
00:46:30,350 --> 00:46:33,540
We got some great financial support

772
00:46:33,540 --> 00:46:36,730
and we started developing summer camps

773
00:46:36,730 --> 00:46:41,110
for middle school aged kids,
genetics and genealogy modules

774
00:46:41,110 --> 00:46:43,520
and undergraduate biology classes,

775
00:46:43,520 --> 00:46:47,490
as well as developed a series
of outreach documentaries

776
00:46:47,490 --> 00:46:49,223
and online materials.

777
00:46:50,850 --> 00:46:53,010
Starting with our camps,

778
00:46:53,010 --> 00:46:55,960
we were really gratified when these things

779
00:46:55,960 --> 00:46:59,553
finally came together
and we had kids doing it.

780
00:47:00,390 --> 00:47:04,280
They were investigating
their own personal DNA,

781
00:47:04,280 --> 00:47:06,520
ancestry and genealogy,

782
00:47:06,520 --> 00:47:10,763
and studying the nature of
human variation on themselves.

783
00:47:12,060 --> 00:47:15,740
They extracted DNA on
strawberries and kiwifruit.

784
00:47:15,740 --> 00:47:19,090
They extracted their own
DNA from cheek swabs.

785
00:47:19,090 --> 00:47:22,030
They basically were in charge

786
00:47:22,030 --> 00:47:26,013
as young scientists of
the process of discovery.

787
00:47:27,210 --> 00:47:32,210
They discovered details
of their own genealogies.

788
00:47:32,280 --> 00:47:35,250
Some kids had more success
than others, of course,

789
00:47:35,250 --> 00:47:39,283
because of their individual
family histories.

790
00:47:40,670 --> 00:47:44,470
They looked at variation in
human physical attributes,

791
00:47:44,470 --> 00:47:47,530
like skin color, and tried
to make sense of them

792
00:47:47,530 --> 00:47:49,440
with respect to evolution,

793
00:47:49,440 --> 00:47:52,220
just like I did in the
beginning of this lecture

794
00:47:53,640 --> 00:47:55,500
They did projects.

795
00:47:55,500 --> 00:47:57,020
Some of them on skin color,

796
00:47:57,020 --> 00:47:59,820
some of them on entirely different things.

797
00:47:59,820 --> 00:48:03,760
They were autonomous young scientists,

798
00:48:03,760 --> 00:48:08,760
self-empowered and motivated
to study the world themselves.

799
00:48:09,830 --> 00:48:12,730
And to recognize that they
could make observations

800
00:48:12,730 --> 00:48:14,673
just as well as anyone else.

801
00:48:15,830 --> 00:48:19,817
We partnered with our public
broadcasting station WPSU.

802
00:48:21,720 --> 00:48:26,290
And here are the two key
producers with Skip Gates.

803
00:48:26,290 --> 00:48:31,190
We created a series of webisode modules

804
00:48:31,190 --> 00:48:33,730
about one of our camps

805
00:48:33,730 --> 00:48:38,730
in which we developed in
a series of nine episodes,

806
00:48:39,680 --> 00:48:43,720
basically the key foundations
of our curriculum.

807
00:48:43,720 --> 00:48:47,100
And you can find this on the web

808
00:48:47,100 --> 00:48:50,973
easily Finding Your Roots:
The Seedlings nine webisodes.

809
00:48:52,440 --> 00:48:56,760
When you get to our
www.fyrclassroom.org website,

810
00:49:01,720 --> 00:49:05,910
what you'll see is this lovely
screen with some of our kids.

811
00:49:05,910 --> 00:49:09,450
You can look at the series
of webisodes, the curriculum,

812
00:49:09,450 --> 00:49:14,040
and there's a whole bunch
of new at home resources,

813
00:49:14,040 --> 00:49:16,833
especially for at homeschoolers.

814
00:49:18,540 --> 00:49:20,803
Here's the website again.

815
00:49:22,240 --> 00:49:25,670
And one of the wonderful
things that we saw

816
00:49:25,670 --> 00:49:30,210
is that when our young
people left the camp

817
00:49:30,210 --> 00:49:34,670
they didn't just sort of
zone out and not do stuff.

818
00:49:34,670 --> 00:49:39,670
They were really excited in
their own lives to do this,

819
00:49:39,670 --> 00:49:42,630
to carry on observing the world,

820
00:49:42,630 --> 00:49:44,900
thinking about their place in it,

821
00:49:44,900 --> 00:49:47,890
thinking about learning science.

822
00:49:47,890 --> 00:49:52,720
And one of our campers,
when she got to high school,

823
00:49:52,720 --> 00:49:55,870
she not only continued studying science,

824
00:49:55,870 --> 00:49:58,170
but also went back to her middle school

825
00:49:58,170 --> 00:50:00,160
to introduce some of the same lessons

826
00:50:00,160 --> 00:50:03,273
to her middle school young colleagues.

827
00:50:04,530 --> 00:50:09,530
So we had this framing
question of who am I?

828
00:50:09,790 --> 00:50:12,830
Being transformed to who I am,

829
00:50:12,830 --> 00:50:17,830
in these empowered
self-actualized young scientists.

830
00:50:19,980 --> 00:50:22,710
Thank you, thank you for your attention.

831
00:50:22,710 --> 00:50:25,740
And I hope we have time
for some questions.

832
00:50:25,740 --> 00:50:30,120
This is a wonderful time
to think about evolution,

833
00:50:30,120 --> 00:50:34,800
human history and how we can do better

834
00:50:34,800 --> 00:50:39,590
in teaching our children
about how the world came to be

835
00:50:39,590 --> 00:50:40,973
and how we think about it.

836
00:50:46,530 --> 00:50:48,370
- [Nelson] Dr. Jablonski I
wanna thank you very much.

837
00:50:48,370 --> 00:50:51,910
This is Nelson Scottgale,
I'm one of the moderators.

838
00:50:51,910 --> 00:50:53,713
We really appreciate this.

839
00:50:54,810 --> 00:50:58,393
And I would like to start by asking

840
00:51:00,370 --> 00:51:02,040
actually two questions, if I may,

841
00:51:02,040 --> 00:51:04,680
one is to clear something up

842
00:51:04,680 --> 00:51:07,210
and then the other is a
more involved question.

843
00:51:07,210 --> 00:51:12,010
The first is, can you
explain the relationship

844
00:51:12,010 --> 00:51:14,210
between folate and folic acid?

845
00:51:14,210 --> 00:51:15,720
- Ah, yes.

846
00:51:15,720 --> 00:51:19,750
Folic acid is sort of the
non-biological form of folate.

847
00:51:19,750 --> 00:51:22,590
So you have this vitamin B9

848
00:51:22,590 --> 00:51:27,560
and when you buy it in
a little vitamin pill,

849
00:51:27,560 --> 00:51:29,090
let's say in the pharmacy,

850
00:51:29,090 --> 00:51:33,130
you're buying folic acid
which is the synthesized form.

851
00:51:33,130 --> 00:51:36,450
But when you ingest folic acid

852
00:51:36,450 --> 00:51:39,400
is quickly converted in your body

853
00:51:39,400 --> 00:51:43,143
to different forms of foliate.

854
00:51:43,143 --> 00:51:47,263
And so the real bioactive form is folate

855
00:51:48,970 --> 00:51:50,513
as opposed to folic acid.

856
00:51:51,360 --> 00:51:54,540
- [Nelson] Thank you, and then
I wanna follow that up with,

857
00:51:54,540 --> 00:51:57,080
this is from a participant,

858
00:51:57,080 --> 00:51:59,240
regarding human skin pigment

859
00:51:59,240 --> 00:52:01,140
during the transatlantic slave trade,

860
00:52:01,140 --> 00:52:03,580
many of the members of the
Negro peoples were enslaved

861
00:52:03,580 --> 00:52:05,580
and transported to
climates vastly different

862
00:52:05,580 --> 00:52:07,960
than their ancestral home.

863
00:52:07,960 --> 00:52:09,520
Disregarding interracial breeding

864
00:52:09,520 --> 00:52:12,660
over centuries of enslavement
in colder climates,

865
00:52:12,660 --> 00:52:15,770
did the generations of slaves
adapt to the relative extremes

866
00:52:15,770 --> 00:52:17,530
with their new climate?

867
00:52:17,530 --> 00:52:20,240
- This is a really important question.

868
00:52:20,240 --> 00:52:23,690
There actually was no change

869
00:52:23,690 --> 00:52:27,340
in genetically determined
skin pigmentation,

870
00:52:27,340 --> 00:52:32,340
but what we did see in many
enslaved African people,

871
00:52:32,750 --> 00:52:35,410
especially those people who were living

872
00:52:35,410 --> 00:52:39,820
at higher latitudes in the
North American colonies

873
00:52:40,830 --> 00:52:42,900
and who lived indoors

874
00:52:42,900 --> 00:52:46,420
is that they're excellent sunscreen

875
00:52:46,420 --> 00:52:48,760
worked to their disadvantage,

876
00:52:48,760 --> 00:52:52,110
because they couldn't make
enough vitamin D in their skin

877
00:52:52,110 --> 00:52:53,800
from available sunlight.

878
00:52:53,800 --> 00:52:58,800
So nutritional rickets
was extremely common

879
00:53:01,485 --> 00:53:03,450
during the years of the slave trade,

880
00:53:03,450 --> 00:53:07,070
but also throughout the rest of the 19th

881
00:53:07,070 --> 00:53:09,020
and early 20th century.

882
00:53:09,020 --> 00:53:12,760
it was in some places almost considered,

883
00:53:12,760 --> 00:53:14,100
and I use the quote here

884
00:53:14,100 --> 00:53:19,100
from a previous historian of
science "The Negro disease"

885
00:53:19,650 --> 00:53:24,060
because vitamin D
deficiency caused rickets

886
00:53:24,060 --> 00:53:25,890
was so common.

887
00:53:25,890 --> 00:53:28,610
So we don't see actually a change

888
00:53:28,610 --> 00:53:31,750
in the genetically
determined skin pigmentation.

889
00:53:31,750 --> 00:53:34,760
This would have taken
quite a few generations

890
00:53:34,760 --> 00:53:37,730
and much stronger selective pressures.

891
00:53:37,730 --> 00:53:42,230
What we do see is that many
people developed rickets

892
00:53:42,230 --> 00:53:43,683
early in their lives.

893
00:53:44,889 --> 00:53:45,963
(coughing) Excuse me.

894
00:53:51,050 --> 00:53:53,580
- [Ryan] Thank you for a
lovely talk, Dr. Jablonski.

895
00:53:53,580 --> 00:53:55,083
This is Ryan Fisher.

896
00:53:55,940 --> 00:53:58,660
Also one of your question moderators.

897
00:53:58,660 --> 00:54:00,780
I have two questions.

898
00:54:00,780 --> 00:54:05,020
The first is compiling a
number of different questions,

899
00:54:05,020 --> 00:54:09,130
you mentioned in your talk
that the genes for skin color

900
00:54:09,130 --> 00:54:11,453
and other attributes are separate.

901
00:54:12,810 --> 00:54:14,750
That is indeed the case, correct?

902
00:54:14,750 --> 00:54:16,090
- Yes, that's correct.

903
00:54:16,090 --> 00:54:19,700
So for instance, the genes
that determine skin color

904
00:54:19,700 --> 00:54:22,270
in any one of us are different from those

905
00:54:22,270 --> 00:54:24,610
that determine the shape of our ears,

906
00:54:24,610 --> 00:54:27,050
or in most cases the color of our hair,

907
00:54:27,050 --> 00:54:28,620
or the shape of our lips.

908
00:54:28,620 --> 00:54:30,880
And that's really important,

909
00:54:30,880 --> 00:54:34,330
because often there's this thought

910
00:54:34,330 --> 00:54:39,330
that we have these groups of
so-called racial features,

911
00:54:39,430 --> 00:54:41,540
that sort of travel together.

912
00:54:41,540 --> 00:54:44,450
Genetically, they do not travel together.

913
00:54:44,450 --> 00:54:48,050
What we see is, in modern humans today,

914
00:54:48,050 --> 00:54:53,050
are sort of this sort of
frozen in time picture

915
00:54:53,240 --> 00:54:58,240
of a clump of genes working to
create a beautiful organism.

916
00:54:58,280 --> 00:55:01,900
But the way that people
have looked over the years

917
00:55:01,900 --> 00:55:04,540
has depended very much on where they are,

918
00:55:04,540 --> 00:55:08,760
who they have admixed
with at any one time,

919
00:55:08,760 --> 00:55:12,140
and how isolated they've been.

920
00:55:12,140 --> 00:55:16,070
So humans in the past have
probably looked very different

921
00:55:16,070 --> 00:55:17,543
from how they look today.

922
00:55:19,050 --> 00:55:20,927
- [Ryan] Thank you, and
then a different question

923
00:55:20,927 --> 00:55:23,870
a sort of medical associated question,

924
00:55:23,870 --> 00:55:26,610
and I quote are people with darker skin

925
00:55:26,610 --> 00:55:29,960
kinda are less likely
to develop skin cancer.

926
00:55:29,960 --> 00:55:31,610
And additionally if medical science

927
00:55:31,610 --> 00:55:34,290
did not exist to treat such conditions,

928
00:55:34,290 --> 00:55:35,910
would natural selection favor

929
00:55:35,910 --> 00:55:38,243
traits of more pigment over less pigment?

930
00:55:39,550 --> 00:55:43,004
- It is true that people with very dark,

931
00:55:43,004 --> 00:55:44,163
(coughing) excuse me,

932
00:55:45,050 --> 00:55:46,850
very dark skin pigmentation

933
00:55:46,850 --> 00:55:50,710
are less susceptible to skin cancers.

934
00:55:50,710 --> 00:55:55,360
But when people live,
regardless of their skin color,

935
00:55:55,360 --> 00:55:58,810
when they live under very
sort of indoor conditions,

936
00:55:58,810 --> 00:56:03,580
normal sort of American
conditions, let's say,

937
00:56:03,580 --> 00:56:08,530
and we don't have much
exposure to outdoor sunlight,

938
00:56:08,530 --> 00:56:11,490
even people with darkly pigmented skin

939
00:56:11,490 --> 00:56:14,540
can experience severe sunburns

940
00:56:14,540 --> 00:56:17,110
when they go out into intense sunlight,

941
00:56:17,110 --> 00:56:18,890
let's say on vacation.

942
00:56:18,890 --> 00:56:22,010
So dark skin is less susceptible

943
00:56:22,010 --> 00:56:24,400
to skin cancer and to damage,

944
00:56:24,400 --> 00:56:27,290
but it is still potentially damageable.

945
00:56:29,360 --> 00:56:33,810
Dark skin is extremely good

946
00:56:33,810 --> 00:56:37,403
under conditions of intense
or changeable sunlight.

947
00:56:42,500 --> 00:56:46,400
It's less adapted to extremely

948
00:56:46,400 --> 00:56:49,030
low levels of ultraviolet radiation

949
00:56:49,030 --> 00:56:51,970
and seasonal levels of
ultraviolet radiation.

950
00:56:51,970 --> 00:56:56,030
Under those conditions, people
with darkly pigmented skin

951
00:56:56,030 --> 00:56:57,230
really have to make sure

952
00:56:57,230 --> 00:56:59,370
that they're getting enough vitamin D.

953
00:56:59,370 --> 00:57:02,630
So it isn't a case of
one skin pigmentation

954
00:57:02,630 --> 00:57:04,960
being superior to another,

955
00:57:04,960 --> 00:57:09,960
it's just that these different
levels of skin pigmentation

956
00:57:10,400 --> 00:57:15,000
work under certain
environmental conditions.

957
00:57:15,000 --> 00:57:18,470
And when we live under different
environmental conditions

958
00:57:18,470 --> 00:57:20,010
we have to compensate.

959
00:57:20,010 --> 00:57:25,010
And everything about modern
culture is about compensating.

960
00:57:25,110 --> 00:57:27,050
and we do a lot of this,

961
00:57:27,050 --> 00:57:30,640
naturally we keep ourselves
warm in the winter

962
00:57:30,640 --> 00:57:33,200
by compensating for the lack of fur

963
00:57:33,200 --> 00:57:35,770
by wearing clothing and so forth.

964
00:57:35,770 --> 00:57:39,580
So we have to make new compensations

965
00:57:39,580 --> 00:57:43,250
for having dark skin in high latitudes,

966
00:57:43,250 --> 00:57:47,253
or light skin in low latitudes
and everything in between.

967
00:57:48,810 --> 00:57:50,350
- [Ryan] Thank you, I'll pass it over

968
00:57:50,350 --> 00:57:51,927
to my colleague, Dr. Scottgale,

969
00:57:51,927 --> 00:57:56,380
and just to remind our
participants in the audience,

970
00:57:56,380 --> 00:57:58,777
we'll try to get to another
handful of questions,

971
00:57:58,777 --> 00:58:00,850
but we have about five more minutes.

972
00:58:00,850 --> 00:58:02,483
Nelson I'll pass it back to you.

973
00:58:03,690 --> 00:58:05,770
- Thank you very much, Ryan.

974
00:58:05,770 --> 00:58:08,890
I wanted to ask you a
very important question.

975
00:58:08,890 --> 00:58:10,800
You've mentioned about seeing

976
00:58:15,965 --> 00:58:20,330
your different types
of programs for people,

977
00:58:20,330 --> 00:58:21,630
but there's a question,

978
00:58:21,630 --> 00:58:24,010
can we get involved in
the camps as volunteers?

979
00:58:24,010 --> 00:58:25,550
And I wanted to make sure to give you

980
00:58:25,550 --> 00:58:28,443
a chance to ask them.
- Well, absolutely.

981
00:58:30,040 --> 00:58:33,850
What we've done, if you go to our website,

982
00:58:33,850 --> 00:58:36,610
you can download all of these materials

983
00:58:36,610 --> 00:58:40,450
and you can make any of these lessons

984
00:58:40,450 --> 00:58:45,450
into afterschool programs,
lessons, for homeschooling,

985
00:58:46,090 --> 00:58:48,720
or create your own summer camps.

986
00:58:48,720 --> 00:58:52,120
If your university or your high school

987
00:58:52,120 --> 00:58:54,040
has a summer camp program,

988
00:58:54,040 --> 00:58:59,040
you can actually use our
materials to create summer camps.

989
00:58:59,190 --> 00:59:03,030
And you can take a few
bits and not all of it,

990
00:59:03,030 --> 00:59:05,980
or all of it and modify it.

991
00:59:05,980 --> 00:59:09,880
We encourage people to sort of modify this

992
00:59:09,880 --> 00:59:14,280
and I'm happy to say that we
have a new injection of funds.

993
00:59:14,280 --> 00:59:16,270
And so for the next two years,

994
00:59:16,270 --> 00:59:20,310
we're going to be making more
of these modules available,

995
00:59:20,310 --> 00:59:24,350
especially for high school
and undergraduate audiences.

996
00:59:24,350 --> 00:59:26,050
So watch our website

997
00:59:27,008 --> 00:59:31,610
and we'll be keeping lots
of materials up to date

998
00:59:31,610 --> 00:59:33,943
and completely freely available.

999
00:59:36,770 --> 00:59:38,370
- [Nelson] Thank you very much.

1000
00:59:38,370 --> 00:59:40,683
And I'm gonna ask one more question,

1001
00:59:42,120 --> 00:59:44,610
if less melanin means more vitamin D,

1002
00:59:44,610 --> 00:59:47,660
how would we explain higher propensity

1003
00:59:47,660 --> 00:59:49,960
of bone density problems like osteoporosis

1004
00:59:49,960 --> 00:59:51,483
in lighter skinned people.

1005
00:59:52,510 --> 00:59:57,490
- It turns out that vitamin
D levels in the body

1006
00:59:57,490 --> 01:00:02,490
and vitamin D that works on
bone density and bone deposition

1007
01:00:05,684 --> 01:00:09,863
is again controlled by
a wide variety of genes.

1008
01:00:10,940 --> 01:00:14,530
And so what we see in people

1009
01:00:14,530 --> 01:00:18,030
with lightly or depigmented skin

1010
01:00:18,030 --> 01:00:21,560
is that if they have a calcium rich diet

1011
01:00:21,560 --> 01:00:23,780
and get plenty of vitamin D,

1012
01:00:23,780 --> 01:00:27,810
and if they undertake lots of exercise,

1013
01:00:27,810 --> 01:00:29,970
like our ancestors did,

1014
01:00:29,970 --> 01:00:33,310
they have good strong bones
throughout their lifespan.

1015
01:00:33,310 --> 01:00:38,310
However, modern life on the
couch and in the office,

1016
01:00:38,950 --> 01:00:43,250
doesn't necessarily make that easy.

1017
01:00:43,250 --> 01:00:46,670
And so there are many people

1018
01:00:46,670 --> 01:00:50,140
who live, especially in
the Northern Hemisphere

1019
01:00:51,470 --> 01:00:54,620
with lightly pigmented, depigmented skin

1020
01:00:54,620 --> 01:00:58,380
under conditions, indoor
conditions most of the time,

1021
01:00:58,380 --> 01:01:01,150
they may not have a vitamin D rich diet,

1022
01:01:01,150 --> 01:01:03,940
their calcium levels
might not be very good.

1023
01:01:03,940 --> 01:01:08,940
And so there are some 20th
and 21st century bones

1024
01:01:09,570 --> 01:01:10,880
aren't doing very well

1025
01:01:10,880 --> 01:01:14,450
under these modern cultural conditions.

1026
01:01:14,450 --> 01:01:19,410
What we see is that many of our genes

1027
01:01:19,410 --> 01:01:23,160
were sort of designed or evolved

1028
01:01:23,160 --> 01:01:27,590
under conditions of our
early history as a species.

1029
01:01:27,590 --> 01:01:32,590
When we work outdoor active
Homo sapiens at high latitudes

1030
01:01:33,120 --> 01:01:38,120
doing all sorts of stuff,
not sitting in an office.

1031
01:01:38,560 --> 01:01:41,660
So I think we just need
to sort of bring ourselves

1032
01:01:41,660 --> 01:01:44,400
back to, okay, what was it like,

1033
01:01:44,400 --> 01:01:49,050
let's say 10,000 or 15,000
years ago for our ancestors?

1034
01:01:49,050 --> 01:01:51,960
Okay, I don't want you to
become a hunter or gatherer,

1035
01:01:51,960 --> 01:01:54,830
but what you have to do is try to

1036
01:01:55,910 --> 01:02:00,460
include more calcium and
vitamin D in your diet

1037
01:02:00,460 --> 01:02:02,660
and undertake more exercise

1038
01:02:02,660 --> 01:02:07,260
so you can keep normal,
healthy bone density

1039
01:02:07,260 --> 01:02:08,510
throughout your lifetime.

1040
01:02:12,560 --> 01:02:14,550
- [Ryan] Dr. Jablonski I have a question

1041
01:02:14,550 --> 01:02:18,330
from a seventh grade
student here in Salem.

1042
01:02:18,330 --> 01:02:20,800
What do you would have
happened to the early humans

1043
01:02:20,800 --> 01:02:23,723
without their natural ways
to protect them from the sun?

1044
01:02:25,120 --> 01:02:30,120
- Well, I mean, what we have
in most of our evolution

1045
01:02:30,780 --> 01:02:35,350
is that we have minimal levels of culture.

1046
01:02:35,350 --> 01:02:37,540
We were able to seek some shelter,

1047
01:02:37,540 --> 01:02:40,750
but we didn't have anything
like sewn clothing,

1048
01:02:40,750 --> 01:02:44,600
or built shelters until
about 30,000 years ago.

1049
01:02:44,600 --> 01:02:49,600
And so basically our
skin, as I said earlier,

1050
01:02:49,920 --> 01:02:52,010
was the primary interface

1051
01:02:52,010 --> 01:02:55,560
between the environment and
the insides of our bodies.

1052
01:02:55,560 --> 01:02:58,820
So the skin underwent a lot of changes

1053
01:02:58,820 --> 01:03:01,870
and including in skin color.

1054
01:03:01,870 --> 01:03:06,850
And what we see as in
more recent human history

1055
01:03:06,850 --> 01:03:09,200
is that our cultural adaptations

1056
01:03:09,200 --> 01:03:11,060
become more and more sophisticated.

1057
01:03:11,060 --> 01:03:14,060
We get really good at
making clothes and shelter,

1058
01:03:14,060 --> 01:03:17,880
basically whether we're
living under extreme cold

1059
01:03:17,880 --> 01:03:20,220
or extreme heat conditions.

1060
01:03:20,220 --> 01:03:23,870
So what we see in modern
peoples, we look around us today

1061
01:03:23,870 --> 01:03:27,430
and we see people with all
these bewildering varieties

1062
01:03:27,430 --> 01:03:31,130
of different kinds of
clothing, protective clothing,

1063
01:03:31,130 --> 01:03:34,820
ways to keep themselves warm and cool,

1064
01:03:34,820 --> 01:03:36,493
different kinds of buildings.

1065
01:03:37,380 --> 01:03:42,380
Basically, we played out
this natural experiment

1066
01:03:42,610 --> 01:03:46,960
throughout the early millennia
of our species existence

1067
01:03:46,960 --> 01:03:50,420
from our origin 300,000 years ago,

1068
01:03:50,420 --> 01:03:53,100
basically until about 30,000 years ago,

1069
01:03:53,100 --> 01:03:57,610
when populations started
adopting more sophisticated means

1070
01:03:57,610 --> 01:04:02,070
of bodily protection
and building protection.

1071
01:04:02,070 --> 01:04:05,903
Basically the skin did most of the work.

1072
01:04:08,160 --> 01:04:09,570
- [Ryan] Thank you, I think perhaps,

1073
01:04:09,570 --> 01:04:11,210
if Dr. Scottgale agrees with me

1074
01:04:11,210 --> 01:04:12,597
this would be the final question

1075
01:04:12,597 --> 01:04:17,597
and to our audience we've had
over, or around 40 questions,

1076
01:04:17,600 --> 01:04:20,480
we'll collate them and
perhaps Dr. Jablonski

1077
01:04:20,480 --> 01:04:22,546
if we could pass some--
- Yes please.

1078
01:04:22,546 --> 01:04:25,483
- [Ryan] And check back with
the Dawn Festival Committee.

1079
01:04:26,550 --> 01:04:28,260
So the final question, with the climate

1080
01:04:28,260 --> 01:04:31,060
getting exponentially
warmer around the world,

1081
01:04:31,060 --> 01:04:33,670
you expect to see a
microevolution of skin color,

1082
01:04:33,670 --> 01:04:37,193
where humans, especially Northern
Hemisphere become darker.

1083
01:04:38,210 --> 01:04:43,210
- Well, what we see happening
now in human evolution

1084
01:04:43,400 --> 01:04:45,460
is cultural evolution.

1085
01:04:45,460 --> 01:04:48,380
People are changing their position.

1086
01:04:48,380 --> 01:04:53,010
Sometimes they might move,
or they get a better fan,

1087
01:04:53,010 --> 01:04:54,723
or a better air conditioner.

1088
01:04:55,620 --> 01:04:57,140
I'm not being flippant here.

1089
01:04:57,140 --> 01:05:02,140
We see humans engaging than
ever more cultural buffering

1090
01:05:03,090 --> 01:05:07,130
in using sophisticated
means to protect themselves

1091
01:05:07,130 --> 01:05:09,810
from fluctuations in the environment

1092
01:05:09,810 --> 01:05:14,030
including higher temperatures.

1093
01:05:14,030 --> 01:05:19,030
In places where people can't
afford these added protections

1094
01:05:20,410 --> 01:05:24,640
we will see greater
mortality, there's no doubt,

1095
01:05:24,640 --> 01:05:27,830
but probably there will
be cultural corrections

1096
01:05:27,830 --> 01:05:31,630
that occur quite quickly
so that this mortality

1097
01:05:31,630 --> 01:05:35,393
is not associated with a
natural selection event.

1098
01:05:37,000 --> 01:05:37,833
- [Ryan] Thank you very much.

1099
01:05:37,833 --> 01:05:39,140
I'll now pause the microphone

1100
01:05:39,140 --> 01:05:41,060
and back to my colleague, Jason Brown

1101
01:05:41,060 --> 01:05:44,730
to formally thank you and end the webinar.

1102
01:05:44,730 --> 01:05:45,730
Thank you very much.

1103
01:05:48,400 --> 01:05:52,453
- Thank you so much, Dr.
Jablonski for a wonderful talk.

1104
01:05:53,700 --> 01:05:57,860
And thank you all for
attending the webinar.

1105
01:05:57,860 --> 01:06:02,010
We're excited to kick off
our Darwin Festival this year

1106
01:06:02,010 --> 01:06:04,510
with this wonderful talk by Dr. Jablonski.

1107
01:06:04,510 --> 01:06:05,343
Thank you all.