[Applause]
our species Homo sapiens is about two
hundred thousand years old by
evolutionary standards that makes us
relatively young but based on what we
know from the fossil record of all the
species that have ever lived almost all
of them more than 99% eventually became
extinct
how much longer will our species survive
another two hundred thousand years 500
thousand a million years our ultimate
fate depends in part on what happens to
our planet eventually another asteroid
like the one that killed the dinosaurs
will come crashing down from space
darkening the sky with debris a big
enough impact would make it impossible
for plants to grow leading to a cascade
of extinctions that would take our
species out along with many others or
perhaps our demise will come from the
eruption of a supervolcano
like the one lurking beneath Yellowstone
fueling its geysers and hot springs or
maybe our continued population growth
will simply overwhelm the finite
resources of our planet life on Earth
will go on no doubt but not necessarily
for us humans one way to avoid such a
fate would be to spread out beyond Earth
venturing out into the galaxy the way
our ancestors spread from our birthplace
in Africa colonizing other planets would
make it more likely that at least some
of us would survive should there be a
catastrophic disaster here on earth and
the more places we occupy the better the
chances that our species will survive
for a long time to come
science fiction is filled with stories
of people traveling on rockets and
living on other planets as an
evolutionary biologist I approached this
idea not a science fiction but as a real
possibility for the future with
technological challenges and biological
consequences
as we speak the first steps towards
creating a human colony on Mars are
already underway there are a number of
reasons why Mars might be a good place
to begin our efforts at becoming a
multiplanetary species for one thing as
planets go it’s not too far away it’ll
take about seven months to get there we
also now know that there’s ice trapped
in the soil so we’d have a source of
water some aspects of Mars make it
familiar for people coming from Earth a
day on Mars is about the same length as
a day on earth only 41 minutes longer
Mars even has seasons much like on earth
it does get a bit chilly though the
poles can reach minus 280 degrees
Fahrenheit but a nice summer day near
the equator the temperatures could be in
the 80s the first manned missions to
Mars could come sooner than you might
think NASA is planning a manned mission
to Mars in the 2030s Elon Musk’s company
SpaceX is aiming for 2020 for these
first expeditions will be round-trip
journeys so astronauts will spend some
time on Mars and then travel back to
Earth but if our goal is to create a
colony that can sustain the human
species eventually people will need to
spend their entire lives there and
perhaps most importantly they will need
to reproduce living on Mars is going to
be challenging enough without bringing
babies children and pregnancy into the
mix for one thing Mars says about 1/3
the gravity of Earth that means that a
person that weighs 150 pounds on earth
would weigh just 57 pounds on Mars we
also know from experiments on pregnant
mice exposed to simulated microgravity
that pregnancy complications are likely
to be a lot more common for women living
on Mars
pregnant women also experience bone
density loss as calcium
their bodies is transferred to the
growing babies skeleton astronauts
experience bone density loss as well as
the reduced force of gravity means
there’s less force on the body weakening
the bones having brittle bones would be
dangerous for anyone on Mars but for
pregnant women having brittle bones
might make it less likely that they’d
even survive childbirth but perhaps the
most challenging part of living on Mars
will be exposure to radiation space is
filled with all different sorts of
radiation from ultraviolet rays to
x-rays cosmic rays and high-energy solar
particles which thankfully we don’t have
to worry about much on earth because we
have a thick atmosphere and a
magnetosphere that together form a
protective barrier around our planet
Mars has neither so radiation from space
hits its surface at nearly full strength
a person who’s born on Mars grows up
there and lives an average human
lifespan of about 80 years would be
exposed to more than 5,000 times the
amount of radiation during their
lifetime as would a person who lives the
same amount of time on earth all this
radiation is a big concern for anybody
but people living on Mars they’ll have
to find a way to deal with it in ways
that we’re not having to you worry about
here on earth at all for context the US
Department of Energy sets maximum limits
on the amount of exposure that a person
who can be exposed to every year as a
part of their job one year of living on
Mars would expose a person to ten times
that annual limit now there might be
some ways to minimize the radiation
exposure for people on Mars we can
create underground structures and make
sure that you always wear a spacesuit if
you do have to venture out onto the
surface but even still the radiation
people
exposed to on Mars will be far greater
than anything we’re used to here on
earth imagine being a kid growing up on
Mars you can never really play outside
at least not without a spacesuit you’d
always have to eat your vegetables
because the only food options would be
Hardy crop plants that can grow into
thin Martian soil think space kale at
least sports would be interesting you
could kick a soccer ball a pretty good
distance and reduced gravity and they’ll
probably have to raise the height of
basketball hoops because everyone can
easily dunk but there are some serious
concerns about living and reproducing on
Mars
radiation causes damage to DNA which is
why you have to wear those lead aprons
when you get an x-ray that radiation
damage to DNA can cause mutations which
can lead to cancer that’ll be a much
bigger problem on Mars but mutations in
the cells that make sperm and eggs
well those mutations can be passed on to
your children and we tend to think of
mutations as a bad thing but actually
they’re an important part of evolution
all of the great diversity of life we
see here on earth can be traced back to
a mutation that made an individual
survive a little bit longer or have more
offspring than their neighbours that
made those mutations more common in
later generations mutations are a normal
part of life here on earth
every baby that is born has about 60 new
mutations in its genes because of all
the radiation babies born on Mars will
have far more mutations perhaps
thousands many of those mutations will
lead to problems so miscarriages will
probably be much more common for people
living on Mars but for those that
survive they’ll be providing natural
selection with a lot more raw material
to work with the chances are good that
some of the mutations that will arise on
Mars will make life a little bit easier
for the people living there perhaps a
mutation will arise that allows the body
to cope with a little bit less oxygen
something similar has happened here on
earth for people who live in mountainous
regions like the Andes or the Himalaya
on the Tibetan Plateau for example
there’s 40% less oxygen in the air than
there is at sea level yet native
Tibetans do just fine in part that’s
because they evolved to have denser beds
of capillaries the blood vessels that
deliver oxygen through the blood to the
muscles brain and other organs they can
also dilate their blood vessels
expanding them so more blood reaches the
tissues with every heartbeat perhaps a
similar mutation will arise on Mars
allowing people to cope with less oxygen
there it’ll be a valuable commodity
maybe a mutation will occur on Mars that
allows people to cope a little bit
better with having to live in those
underground structures here on earth
organisms that live underground have
adapted in all kinds of interesting ways
many of them have lost their eyes like
blind cavefish if we have artificial
lights in our underground structures we
may still have need for our eyes but
perhaps we’ll lose the ability to see
long distances if we rarely venture out
from those subterranean chambers and are
mostly in confined spaces experiments on
children suggest that those who spend
more time indoors are actually more
likely to become nearsighted another
possible mutation that could be
beneficial on Mars would be to have
denser bones at birth because we’ll lose
bone density as we age on Mars thanks to
there being less gravity starting off
life with denser bones would be a real
advantage especially for women it might
make it more likely that by the time
they reach the age that they
start having children they make it
through childbirth without fracturing a
pelvis
perhaps the mutation would arise that
would help the body to cope with all the
damage from radiation and our bodies we
use a pigment called you melanin to help
protect our skin from ultraviolet
radiation other species use different
pigments like carotenoids which give
carrots their orange color some aphids a
kind of insect that’s normally green
evolved the ability to produce
carotenoids and in the process they
became orange perhaps a new pigment will
arise on Mars that helps people deal
with the radiation exposure and gives
them a lovely new skin tone – but
mutations occur randomly so people
living on Mars may choose to edit their
own DNA directly the technology to do so
already exists using a technique called
CRISPR caste 9 we can take one of the
DNA letters the a’s t’s g’s and C’s that
make up the alphabet of the human genome
and swap it out for a different letter
why wait around for a new skin pigment
that can protect you from radiation when
you can design one yourself and the best
part is if you edit the DNA of a sperm
or egg cell
well those changes will be passed on to
your children who will pass it on to
their children
and so on any change whether it’s from a
mutation or an edited gene that is
beneficial will become more common in
each generation that’s how natural
selection works and we tend to think of
evolution as being a slow process
because it occurs over generations but
because of all the radiation causing
mutations on Mars not to mention the
possibility of making changes to those
genes directly evolution on Mars will be
much faster than what we’re used to in
just a few generations we might see
changes among people living on Mars that
would take thousands of years here on
earth
eventually if we have people living on
Mars they may evolve to become different
from the people living on earth one of
the changes that could happen relatively
quickly would be to lose the immune
system this could make the changes
happen even faster the reason is that
there are no microorganisms on Mars to
cause disease so if we make an effort to
try to prevent introducing
microorganisms from Earth we could
create a place where no one ever gets
the flu you don’t have to use sterile
technique to perform surgeries and
deadly diseases like cholera and malaria
would become distant memories to do that
we could treat the journey from Earth to
Mars as a sort of quarantine period
anyone who shows symptoms of a disease
could be treated before they arrive or
not allowed to leave the spacecraft now
here on earth we’re constantly facing
new types of diseases whether it’s a new
strain of flu or entirely new diseases
like Zika that’s because there are
microorganisms that were infecting an
animal hosts that switch and start
infecting humans that won’t be a problem
on Mars as long as we choose not to
bring any animal pets or livestock so
unfortunately that means no dogs or cats
or hamburgers on Mars but it’s a small
price to pay for completely eliminating
all infectious disease if people on Mars
lose their immune system it would be
very dangerous if not impossible for
them to ever survive a journey back to
earth at the same time contact between
people from Earth and people on Mars
could be deadly for the Martians
enforced separation of people on Mars
and people on earth
would mean that each population would
evolve independently accumulating
differences over time something similar
happens here on earth for plants and
animals that live on Islands Charles
Darwin was inspired to develop his
theory of evolution based in part on
observations he made of finches and
tortoises living on the Galapagos
Islands he realized that the ancestors
of the species we see today had arrived
on an island become stranded there and
accumulated differences over time
adapting to the local conditions thanks
to the powerful combination of mutation
and natural selection any individuals of
the species that are isolated from one
another will eventually evolve into
distinct species the planets in our
solar system are much like the Galapagos
Islands and like tortoises and finches
people living on Earth and Mars will
evolve differences as well eventually
becoming multiple distinct species we
may not stop at Mars there are other
places in our solar system that might be
possible to colonize some of them
include some of the moons of Jupiter and
Saturn now these are further away than
Mars making it more difficult to send
people and supplies but at least two of
them Europa and Enceladus are thought to
have water beneath their surfaces a key
ingredient for a human colony the recent
discoveries of exoplanets planets
orbiting stars other than our Sun
suggest that habitable conditions may
exist outside of our solar system if we
eventually come to inhabit multiple
worlds scattered across the galaxy over
time we may see the evolution of a
plethora of new human species so with
all this in mind should we go ahead and
start establishing human colonies on
other planets perhaps but if we do we
should recognize that there could be
unintended consequences for who our
descendants become many generations from
now
it’s ironic isn’t it perhaps the only
way to ensure the long-term survival of
our species is to establish colonies on
planets or moons yet doing so will cause
us to evolve in ways that could change
us forever
thank you
[Applause]
our species Homo sapiens is about two
hundred thousand years old by
evolutionary standards that makes us
relatively young but based on what we
know from the fossil record of all the
species that have ever lived almost all
of them more than 99% eventually became
extinct
how much longer will our species survive
another two hundred thousand years 500
thousand a million years our ultimate
fate depends in part on what happens to
our planet eventually another asteroid
like the one that killed the dinosaurs
will come crashing down from space
darkening the sky with debris a big
enough impact would make it impossible
for plants to grow leading to a cascade
of extinctions that would take our
species out along with many others or
perhaps our demise will come from the
eruption of a supervolcano
like the one lurking beneath Yellowstone
fueling its geysers and hot springs or
maybe our continued population growth
will simply overwhelm the finite
resources of our planet life on Earth
will go on no doubt but not necessarily
for us humans one way to avoid such a
fate would be to spread out beyond Earth
venturing out into the galaxy the way
our ancestors spread from our birthplace
in Africa colonizing other planets would
make it more likely that at least some
of us would survive should there be a
catastrophic disaster here on earth and
the more places we occupy the better the
chances that our species will survive
for a long time to come
science fiction is filled with stories
of people traveling on rockets and
living on other planets as an
evolutionary biologist I approached this
idea not a science fiction but as a real
possibility for the future with
technological challenges and biological
consequences
as we speak the first steps towards
creating a human colony on Mars are
already underway there are a number of
reasons why Mars might be a good place
to begin our efforts at becoming a
multiplanetary species for one thing as
planets go it’s not too far away it’ll
take about seven months to get there we
also now know that there’s ice trapped
in the soil so we’d have a source of
water some aspects of Mars make it
familiar for people coming from Earth a
day on Mars is about the same length as
a day on earth only 41 minutes longer
Mars even has seasons much like on earth
it does get a bit chilly though the
poles can reach minus 280 degrees
Fahrenheit but a nice summer day near
the equator the temperatures could be in
the 80s the first manned missions to
Mars could come sooner than you might
think NASA is planning a manned mission
to Mars in the 2030s Elon Musk’s company
SpaceX is aiming for 2020 for these
first expeditions will be round-trip
journeys so astronauts will spend some
time on Mars and then travel back to
Earth but if our goal is to create a
colony that can sustain the human
species eventually people will need to
spend their entire lives there and
perhaps most importantly they will need
to reproduce living on Mars is going to
be challenging enough without bringing
babies children and pregnancy into the
mix for one thing Mars says about 1/3
the gravity of Earth that means that a
person that weighs 150 pounds on earth
would weigh just 57 pounds on Mars we
also know from experiments on pregnant
mice exposed to simulated microgravity
that pregnancy complications are likely
to be a lot more common for women living
on Mars
pregnant women also experience bone
density loss as calcium
their bodies is transferred to the
growing babies skeleton astronauts
experience bone density loss as well as
the reduced force of gravity means
there’s less force on the body weakening
the bones having brittle bones would be
dangerous for anyone on Mars but for
pregnant women having brittle bones
might make it less likely that they’d
even survive childbirth but perhaps the
most challenging part of living on Mars
will be exposure to radiation space is
filled with all different sorts of
radiation from ultraviolet rays to
x-rays cosmic rays and high-energy solar
particles which thankfully we don’t have
to worry about much on earth because we
have a thick atmosphere and a
magnetosphere that together form a
protective barrier around our planet
Mars has neither so radiation from space
hits its surface at nearly full strength
a person who’s born on Mars grows up
there and lives an average human
lifespan of about 80 years would be
exposed to more than 5,000 times the
amount of radiation during their
lifetime as would a person who lives the
same amount of time on earth all this
radiation is a big concern for anybody
but people living on Mars they’ll have
to find a way to deal with it in ways
that we’re not having to you worry about
here on earth at all for context the US
Department of Energy sets maximum limits
on the amount of exposure that a person
who can be exposed to every year as a
part of their job one year of living on
Mars would expose a person to ten times
that annual limit now there might be
some ways to minimize the radiation
exposure for people on Mars we can
create underground structures and make
sure that you always wear a spacesuit if
you do have to venture out onto the
surface but even still the radiation
people
exposed to on Mars will be far greater
than anything we’re used to here on
earth imagine being a kid growing up on
Mars you can never really play outside
at least not without a spacesuit you’d
always have to eat your vegetables
because the only food options would be
Hardy crop plants that can grow into
thin Martian soil think space kale at
least sports would be interesting you
could kick a soccer ball a pretty good
distance and reduced gravity and they’ll
probably have to raise the height of
basketball hoops because everyone can
easily dunk but there are some serious
concerns about living and reproducing on
Mars
radiation causes damage to DNA which is
why you have to wear those lead aprons
when you get an x-ray that radiation
damage to DNA can cause mutations which
can lead to cancer that’ll be a much
bigger problem on Mars but mutations in
the cells that make sperm and eggs
well those mutations can be passed on to
your children and we tend to think of
mutations as a bad thing but actually
they’re an important part of evolution
all of the great diversity of life we
see here on earth can be traced back to
a mutation that made an individual
survive a little bit longer or have more
offspring than their neighbours that
made those mutations more common in
later generations mutations are a normal
part of life here on earth
every baby that is born has about 60 new
mutations in its genes because of all
the radiation babies born on Mars will
have far more mutations perhaps
thousands many of those mutations will
lead to problems so miscarriages will
probably be much more common for people
living on Mars but for those that
survive they’ll be providing natural
selection with a lot more raw material
to work with the chances are good that
some of the mutations that will arise on
Mars will make life a little bit easier
for the people living there perhaps a
mutation will arise that allows the body
to cope with a little bit less oxygen
something similar has happened here on
earth for people who live in mountainous
regions like the Andes or the Himalaya
on the Tibetan Plateau for example
there’s 40% less oxygen in the air than
there is at sea level yet native
Tibetans do just fine in part that’s
because they evolved to have denser beds
of capillaries the blood vessels that
deliver oxygen through the blood to the
muscles brain and other organs they can
also dilate their blood vessels
expanding them so more blood reaches the
tissues with every heartbeat perhaps a
similar mutation will arise on Mars
allowing people to cope with less oxygen
there it’ll be a valuable commodity
maybe a mutation will occur on Mars that
allows people to cope a little bit
better with having to live in those
underground structures here on earth
organisms that live underground have
adapted in all kinds of interesting ways
many of them have lost their eyes like
blind cavefish if we have artificial
lights in our underground structures we
may still have need for our eyes but
perhaps we’ll lose the ability to see
long distances if we rarely venture out
from those subterranean chambers and are
mostly in confined spaces experiments on
children suggest that those who spend
more time indoors are actually more
likely to become nearsighted another
possible mutation that could be
beneficial on Mars would be to have
denser bones at birth because we’ll lose
bone density as we age on Mars thanks to
there being less gravity starting off
life with denser bones would be a real
advantage especially for women it might
make it more likely that by the time
they reach the age that they
start having children they make it
through childbirth without fracturing a
pelvis
perhaps the mutation would arise that
would help the body to cope with all the
damage from radiation and our bodies we
use a pigment called you melanin to help
protect our skin from ultraviolet
radiation other species use different
pigments like carotenoids which give
carrots their orange color some aphids a
kind of insect that’s normally green
evolved the ability to produce
carotenoids and in the process they
became orange perhaps a new pigment will
arise on Mars that helps people deal
with the radiation exposure and gives
them a lovely new skin tone – but
mutations occur randomly so people
living on Mars may choose to edit their
own DNA directly the technology to do so
already exists using a technique called
CRISPR caste 9 we can take one of the
DNA letters the a’s t’s g’s and C’s that
make up the alphabet of the human genome
and swap it out for a different letter
why wait around for a new skin pigment
that can protect you from radiation when
you can design one yourself and the best
part is if you edit the DNA of a sperm
or egg cell
well those changes will be passed on to
your children who will pass it on to
their children
and so on any change whether it’s from a
mutation or an edited gene that is
beneficial will become more common in
each generation that’s how natural
selection works and we tend to think of
evolution as being a slow process
because it occurs over generations but
because of all the radiation causing
mutations on Mars not to mention the
possibility of making changes to those
genes directly evolution on Mars will be
much faster than what we’re used to in
just a few generations we might see
changes among people living on Mars that
would take thousands of years here on
earth
eventually if we have people living on
Mars they may evolve to become different
from the people living on earth one of
the changes that could happen relatively
quickly would be to lose the immune
system this could make the changes
happen even faster the reason is that
there are no microorganisms on Mars to
cause disease so if we make an effort to
try to prevent introducing
microorganisms from Earth we could
create a place where no one ever gets
the flu you don’t have to use sterile
technique to perform surgeries and
deadly diseases like cholera and malaria
would become distant memories to do that
we could treat the journey from Earth to
Mars as a sort of quarantine period
anyone who shows symptoms of a disease
could be treated before they arrive or
not allowed to leave the spacecraft now
here on earth we’re constantly facing
new types of diseases whether it’s a new
strain of flu or entirely new diseases
like Zika that’s because there are
microorganisms that were infecting an
animal hosts that switch and start
infecting humans that won’t be a problem
on Mars as long as we choose not to
bring any animal pets or livestock so
unfortunately that means no dogs or cats
or hamburgers on Mars but it’s a small
price to pay for completely eliminating
all infectious disease if people on Mars
lose their immune system it would be
very dangerous if not impossible for
them to ever survive a journey back to
earth at the same time contact between
people from Earth and people on Mars
could be deadly for the Martians
enforced separation of people on Mars
and people on earth
would mean that each population would
evolve independently accumulating
differences over time something similar
happens here on earth for plants and
animals that live on Islands Charles
Darwin was inspired to develop his
theory of evolution based in part on
observations he made of finches and
tortoises living on the Galapagos
Islands he realized that the ancestors
of the species we see today had arrived
on an island become stranded there and
accumulated differences over time
adapting to the local conditions thanks
to the powerful combination of mutation
and natural selection any individuals of
the species that are isolated from one
another will eventually evolve into
distinct species the planets in our
solar system are much like the Galapagos
Islands and like tortoises and finches
people living on Earth and Mars will
evolve differences as well eventually
becoming multiple distinct species we
may not stop at Mars there are other
places in our solar system that might be
possible to colonize some of them
include some of the moons of Jupiter and
Saturn now these are further away than
Mars making it more difficult to send
people and supplies but at least two of
them Europa and Enceladus are thought to
have water beneath their surfaces a key
ingredient for a human colony the recent
discoveries of exoplanets planets
orbiting stars other than our Sun
suggest that habitable conditions may
exist outside of our solar system if we
eventually come to inhabit multiple
worlds scattered across the galaxy over
time we may see the evolution of a
plethora of new human species so with
all this in mind should we go ahead and
start establishing human colonies on
other planets perhaps but if we do we
should recognize that there could be
unintended consequences for who our
descendants become many generations from
now
it’s ironic isn’t it perhaps the only
way to ensure the long-term survival of
our species is to establish colonies on
planets or moons yet doing so will cause
us to evolve in ways that could change
us forever
thank you
[Applause]
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