from the howard hughes medical institute
the two thousand five holiday lectures
on science
this year's lectures evolution
constant change and common threads
will be given by doctor shaundy carol
howard hughes medical institute
investigator at the university of
wisconsin madison
and doctor david m kingsley
howard hughes medical institute
investigators at stanford university
school of medicine
the first lectured is titled
endless forms most beautiful
and now it to introduce our program
the president of the howard hughes
medical institute
doctor thomas check
welcome to the howard hughes medical
institute
and to our two thousand and five holiday
lectures on science the thirteenth in
our annual series
where webcasting here live
uh... from our
h_ h_ m_ i_ headquarters and chevy chase
maryland and with us in the audience are
two hundred high school students from
throughout the greater washington d_c_
area
the mission of h h m i is to make
discoveries in biomedical sciences and
to foster uh... vibrant science
education and nothing brings these two
activities together as well as having
argues investigator speaking to a local
high school students
to learn more about the institute go to
our website h h_m_o_ i dot pork
are important topic for these lectures
is evolution it's safe to say that all
of the h h_m_o_ eyes
research activities
depend on the central unifying concept
of evolution
evolution is as fundamental
and its central to modern biology as the
law of gravity or the law of
conservation of energy is to physics
in the year two thousand
i had the opportunity to travel through
the galapagos islands and to see the
sparse landscape in the exotic
plants and animals
that inspired are charles darwin's great
idea
and similarly a lot of researchers who
are particularly drawn to evolution tend
to enjoy natural history and feel
biology our lecturers for this series
sean carroll and david kingsley are no
exception although they are in their
bread and butter
in the research laboratory
they also spent time in the field
hunting fossils chasing animals studying
habitats
our first speaker sean carroll
is in a trait shammai investigator at
the university of wisconsin in madison
sean trained
in molecular biology
and became interested in how genes
control embryonic development
as shawn's work and developmental
genetics progressed he began to
appreciate the key role
that the same genes played in the
evolution of species and he became one
of the
main contributors to a new field called
evoke devo
which stands for evolutionary
developmental
biology his passion forty vote devo
let him recently
too right
a popular book
endless forms most beautiful
and in fact this is the title
that he's chosen for his first lecture
here to introduce our speaker is a short
video
i think my interest in science started
as a little kid
i would like to stroll out into the
backyard and flip over lawns
and i just like
looking for critters
and i love the vessel thrill you got
flipping over a longer turning over a
rock and seeing and we had never seen
before
and
depreciating how they live their
patterns their body forms is that i
always had the sense that i was going to
be interested in biology
and as i started to learn about how
biologist worked
and then as i entered college and had
the opportunity working nights and all
that i knew i was
on the right path
ait was clearly interested in
understanding
machinery of how major works
uh... how cells were calgene's work
and so the first phase of my career was
devoted towards understanding some of
the
mysteries and going in
field called developmental biology which
is the study of how
adults developed
uh... but i understood also there's a
deep connection between that area
and the evolution
because all four levels by changes in
the bells
some interesting development
you understand something about them
i'd been working at that interface
all of the ideas about evolution at work
human health
because we are living species
we are variable we have been and are
subject to
forces like natural selection
part of our genetic makeup has been
sculpted by battles in the past with the
pathogens that we've encountered as
human spread across the globe so we are
involved in still evolving
species
in the most practical aspects
uh... our medical
lives are intertwined revolution because
reconnaissance arms race with the
pathogens
affect us michael for the holiday
lectures is too
arouse interest
natural history
evolution is the big ideas
in biology
lifeless course to be experiment on
so there's really no bigger idea to get
your head
and for those of us who spend a couple
of decades
trying to understand
what individual organisms dealing with
species are how they change
found one of the relationships to each
other
very march
and still extending subject
good morning
journey here a lot about evolution
for next two days
i think you hear a lot of new things
about evolution next two days
in doctor king's denied agreed that
perhaps
the vast majority of what you hear is
not even text books yet
and it's a sign
of the figure an evolutionary science in
two thousand five
but all of the five has deep roots
improves that started
you know very dramatic way in the
nineteenth century
and so our discussion of evolution
today's going to begin with charles
darwin
for as we'll see is contributions
were announced
and they've endured
and then expanded upon now for a hundred
and fifty years
i think his contributions
scientists
don't realize the scope of his work
until you actually dig into the many
books many contributions at uni
over life's work
so in this first lecture
i would tell you about
darwin's key ideas and how he arrived at
them
and in the following lectures dr king's
and i are going to focus on
the expanding understanding of how
evolution works
so let's start
with charles darwin
i'll say perhaps in the mist undead most
misunderstood characters in the history
of science i hope the next fifteen or
twenty minutes you gain a better
appreciation of just who this person was
was this greatest of all naturalists
always destined for greatness
now among the high school students here
in the audience how do you work
pondering a medical career some sort
show here
very high percentage of k
so was charles darwin
in till he saw surgery for the first
time
and surgery in the early nineteenth
century was
not the very sterile process that you
see on television two thousand five
it was in very our rapid process because
without the anesthesia the idea was to
uh... get it over with quickly before
the patient uh... rejected too
strenuously
so are
darwin now he wasn't covered with
surgery he was a couple of the site of
blood he had a fairly queasy stomach
so after two years of medical school
that he started at age sixteen
he washed out
and it was clearly not going to be the
thing for him
any change colleges he moved to the
university of cambridge
and he took up
some of his passions
which were natural history
beetle collecting
running around the countryside he was a
good shot
is a good horsemen
he enjoyed a lot of hobbies
he was brought up in a fairly wealthy
household the son of a physician
he enjoyed certain advantages
he likes reading
and he read about specifically earlier
british nationalists who had explored
the tropics
and being in danger
graying dreary cold windy
unheeded
he wanted to go to some warmer more
vibrant places
his wealthy father fearing
his son was amounting to nothing
uh... just enjoying himself and that
setting his talents to anything serious
his options were relatively limited
netday nations he wasn't gonna be a
physician and the more respectable
option would be
for example for charles to join the
clergy
and so that's what
darwin's father chose for him that he
would enter divinity school at cambridge
study divinity
and become for example a country parson
and he would be able to then
uh... take his national history pursuits
living out in the country sort of as a
hobby
so that was the plan yes the clergy
that's for darman his head
fate intervened
and darwin while he's preparing a study
divinity
was unexpectedly offered the chance
to avoid jazz as ships naturalist with
the british navy
being only twenty-two
financially dependent
fresh out of college
he had to ask a stance permission
anne was turned down
his father had many reasons and i went
out of these reasons down and this is a
copy of it than original document
darwin's notes
of his father's objections to this
voyage
louise your to redeem in this version
so what were his father's objections
with his voyage would be disreputable to
his character is a clergyman hereafter
that it was a wild scheme
that made the navy must have offered the
job too many others before him
the place naturalist this was true
darwin was not the first choice
because it was not accepted there must
be something wrong with the vessel
or the expedition
that he would never settle down to a
study life here after
that his accommodations would be most
uncomfortable this was definitely true
that he doctor darwin would consider it
things again changing his profession
blitz which ones from medicine to the
clergy
and they would be about early useless
undertaking
and darwin
in a systematic manner that was sort of
the his whole approach to life that it
as well as science believe in marriage
he worked on a rebuttal a point-by-point
rebuttal of each of these injections
consulted with his own corn with able to
finally persuade his father to let him
go
so it just aged twenty two
he set off on a voyage that was claim to
be a two-year voyage around the world
it wound up
taking five
so he left england and never saw his
family for five full years
most of that time spent on a rickety
wooden boat called the h_m_s_ beagle
in cramped quarters
experiencing
storms at sea
earthquakes imports
and for darling
sea sickness for the entire forage
queasy stomach haunted him not only
for medical school through this wage but
his entire adult life
so off they went
and on board
with these relatively limited amount of
space
darwin had to figure carefully what was
going to take on this voyage
well he brought supplies it a natural
sweden and he brought
pickle jars and he brought notebooks and
he brought all sorts of
uh... pens and pencils and things to
draw specimens and
other supplies you need to ship
specimens home because he was gonna
carry all this stuff
for this multi year voyage with him he
was going to ship some back on british
ships we're going home that they passed
on the sea routes
well among the things he had won the
most important were couple books one
book
charles lyle's principles of geology
a brand new book at the time that
offered a pretty dramatically new vision
of geology from
of the wisdom of the recent decades
and darwin
uh... was very keenan geology he had a
lot of experience that while at
cambridge of going across the english
countryside which has lots of
interesting geological formations in
darwin took
extra care to learn about them
second bookie had with him was the holy
bible
who's gonna study for the clergy
considered this book
his authoritative reference on all
matters of morality
and he would quote
onboard ship
literally directly from the bible and
and read through that some of the
sailors
the geological background aren't having
his grasp of geology
was absolutely critical
to his future success is a naturalist
this is one element that he had running
through his brain
that other naturalists of the time
perhaps did not
what darling
understood from reading while from some
of his personal experiences
that landforms change
that was a relatively new idea at the
time
secondly
he began to understand the immensity of
time
at the earth was much bolder
than he'd been first led to think
so just those ideas were percolating in
his mind as he started
to voyage around the world
one of the topics he first started to
think about
prompted by the my scene interestingly
informs us they passed by indigenous
people
was how to some of these forms actually
uh... develop
and i'm showing you here a picture from
the pacific ocean
of a series of islands
uh... the fuel in the background are act
also they're just a little dunes
surrounded by reams of coral
in the foreground ec pretty familiar
looking island again surrounded by coral
ring
now at the time
and reading while the fought on how
coral reefs formed
was that every core we can use our adat
ho like that that that that was choral
that had been built on the edge of a
volcanic crater
but are we thought this was really
unlikely
you know underneath the seat on his just
walking away after talking with the
volcano just pack right up against each
other
he just didn't think that was right
and so we thought about this more and he
knew that
major landforms would sink
under their weight
land
winforms would change over time
he thought no i don't think that
coral reefs are all built on the ridges
of volcanic craters that when i look at
the different types of coral reefs that
exist in the world i see this is all
different
stages of the same process
and darlings first great theory
wasn't about animals and organisms and
all it was about
the formation of coral reefs
and this was his model
his idea was that
when for example of all can a guy who
was tossed up out of the ocean
and the corals would grow around the
shallow water surrounding that island
that would form what would be called a
fringe in grief
and then as the women started to sink
shown here in the center of the slide
overblown would form
between
outside reef and land
and that outside reef would be barrier
reef
and that is the lansing completely out
of sight
that's when you have
these apples formed
so different stages of the same process
so long before the book for which he's
most famous
darwin road an entire book on the
structure and distribution of coral
reefs putting forth
his first great theory
and this
turned out that i was very contentious
for decades
to be right
what this demonstrated wistar one's
ability
the theorized on a grand scale
to take a few observations ruminate on
them
stretches line a little bit more go out
of the boundaries of conventional
thinking
and come up with a grand explanation
in this case
for the four entire
range of coral reefs that we see in the
world
now what do you see in terms of living
forms
well darwin's voyage to come to a lots
of interesting places and as soon as he
got the opportunity get off that boat he
went
they got on horseback by whatever way
necessary he proved a deep
jungles of south america
in these generals he whispered
absolutely delighted absolutely uh... in
heaven
to be studying all these
if i were the colored and diverse forms
but there were some strange things
things that started to
making think about
nature in a different way
when you see
he saw flightless birds
that's peculiar
every bird he'd seen in england could
fly
a good fully functional wings
he saw flightless birds
he also found in the rocks
looks very carefully at the geology very
area
he found fossils
in this case for example giant fossil
grounds law
now he knew the worse loss in south
america he saw the slots but these
fossils box they were huge they were
catholic sides
much bigger
and stone started depreciate alder
than anything he saw around south
america time
so this is starting to plant some seeds
and of course he continued on
west coast of south america
to the galapagos islands
and he saw some very unusual creatures
their the prompted a lot of his thinking
and we have a little video
about those animals
swimming lizards
the famous marine iguanas
giant tortoises large enough for darling
to ride
there also a good source of meat
seals seal that were so tame you cook
the sailors could walk right up to them
they had no predators so they have no
fear of man
and of course
the finches
so as darling sorted piece this together
he started to develop the notion that
may be contrary to what you've been
taught
purchase landforms change
that species change
and so is he returned home to end it
with thoughts of
flightless birds and
giant ancient ground swamps and streams
wizards
he started to connect the dots
of what he'd seen over the course of
five years
and really
from that voyage of five years he had
enough questions the last in five
decades and it was five incredible
decades of work that followed
darwinian return england
started a phase it he refers to his own
autobiography is mental writing
what was the meaning of all these things
he'd seen he'd seen many more things
in any naturalist beforehand
he had to study these things very
carefully had five years to think about
them
all that time on the ship for example
but he knew that this idea about species
changing
was dangerous
it was heresy
it was absolutely contrary to the
doctrine of the anglican church at the
time
sardar when u
he fear eyes
at great risk
he kept his thoughts private
he started writing
in secret notebooks
he letter these notebooks that he
finished when he went on to the next so
we see police these are actual specimens
of organs original notebooks
some of his writing shown below
in in these ste
secret notebooks
he was developing phiri species
formation
you'd be a long time
before anyone read these theories
why secret notebooks why was he
suppressing this
well told him
that emu to bill in the species was
the doctrine of the time
darling at that time was getting
tremendous praising attention from
the scientific community in england he'd
been shipping the specimens back and
the paleontologists were studying the
fossils in the ornithologist for
studying the birds
and the mileage is we're setting the
mammals are having a fantastic time
and our own was a hero when he was
getting all sorts of honors all sorts of
invitations
and he knew that he
what set forth his ideas
he'd lose
all these privileges that he was in
joint
he worried about dishonor to his family
the good darwinian
if he spoke this heresy
eventually he also had another another
reason which was he married
uh... emma his his first cousin
and he was very sensitive to her
religious devotion
so he knew he would need more evidence
much more evidence
and so
and as he settled down
he set up really won the most fantastic
whole natural history stores
you could ever imagine
all sorts of experiments going on
all based unsworth at home
he became a pigeon breeder
it was a rage at the time in england
and he
actually frequented various pubs were
pigeon breeders hung out and talk about
their secrets
darling with mixed very very well five
years onboard ship was sailors taught
him a good love social
lubrication
so he did very well
what darling understood from the pigeon
breeders
is a fantastic variety can be derived
just with the art of the breeder
deciding which animals to bring
anne correctly inferred that all these
wild varieties carrier pigeons in this
old dutch variety and many more that
were in england at the time
were all descended from a fairly clean
looking wild rock cajun shown here at
the time
and darwin started to think
well if
the pigeons can be so different
descended from an ancestral stock
one of the actual species
me things back to the glock abyss
finches
he learned it
the finches it he collected were
actually very different from each other
each unique species from different
islands
than a different beat shape
that dependent
affected how much of a diet they had
whether the eight knots or fruit
etcetera
i thought well if
and maybe finches are all descended from
some common ancestral stock
anneke idea enters his mind this is a
page out of one of the secret notebooks
he conceived the idea that life
species are connected as in a family
tree
the ancestors give rise to descendant
species little bit different from
mrs
this notion of of of
life is a tree know when it had before
and if that's the right description he's
the one understand why wind with life
branch out to the tree
and he was reading
a much colder essay from forty years
earlier this is uh... a quote from his
autobiography in eighteen thirty eight
fifteen months after he had
started this inquiry upon his return to
england he happened to read for
amusement
malta some populations
now martha said put forth this idea that
they would be tremendous competition for
resources now being ultimately lead to
human growth
will darwin said being well-prepared to
appreciate the struggle for existence
which everywhere goes on
from long continued observation of the
habits of animals and plants at what
struck me under these circumstances
favorable variations would tend to be
preserved
unfavorable wants to be destroyed
when there's competition
there will be winners than losers
and that process
would give him a mechanism that would
drive species to be different
so this is a high at last i have a
theory with each to work
but no one would hear about this theory
for twenty more years
well the states must take hold you must
be very high he had lots of reasons he
was still young man he was only roughly
thirty when you can see this
he saw that he has his scientific state
would be
so we kept working and he kept working
kept working but eventually
events in life intervened
prompted him to go public we tell you
about two of those events
darwin father ten children
he was very much a family man he based
all his work at home he was
because of his illnesses he had this
queasy stomach all the time
he really was a home body
working all day
and among this menagerie of animals
plants controlled
well his
firstborn daughter
he was very very very attached to
uh... any darwin
was very very attached to his father
they had a very sweet relationships is a
very loving child
uh... she developed
an illness
despite all the interventions that
her mother and father took
she gradually declined
and died before darwin's fairy eyes
shattered
absolutely shattered
now he was a more of a middle-aged man
in him
i think this experience
they don't think well what could be
worse than losing his daughter
and he was
flew fearing
the repre conscience of the scientific
work less
and then a few years later
again as he kept working on this massive
development of the species theory
a package arrived in the mail
and it was from a naturalist working
and the malay archipelago alfred russel
wallis
wassup walls have gone in
to the tropics
almost a dozen years earlier
he had developed a furious species
formation
and knowing darwin's eminence is a
naturalist who sent it to dark
this he for darwin's approval for
darwin's recommendation of how to
publish it
on goodness there's darwin looking at
in short form
his life's work
penned by another scientist
so he was afraid he was going to be
scooped
it was terrible timing he had a two year
old son charles junior who was dying of
scarlet fever at the time
but darwin's friends his allies which
included the great geologist charles
lyle and many others
made sure that both wallace's
and darwin's theories were presented
together tuzla named society in eighteen
fifty-eight and this was the first
public airing
on this idea
that species change
and that natural selection is a force
so that's why we talk about our own and
wallace dot wallace always deferred to
darling
as having done the greater larger
and more original earlier work on
species formation
wallace was always humble about that
so after the appearance of these papers
darwin pushed on
in in the next year working anna fiedler
spinach he finally completed
that everyone is most familiar with
the origin of species
it is the amazing book
still very readable today
a masterpiece of evidence an argument
he nellie puts forth all of the evidence
he sees financial history four evolution
in fort snack in his arms
buddy puts forth all the arguments
against
and by sex that instead all thinking
from arguing with his father
evidence an argument
his lectures are largely to focus on two
main ideas in the origin of species
and our understanding today and how
evolution works
but darwin understood to make
these new ideas
attractive
inspiring to a new generation
you do more than just put forth the raw
facts
the or just bcs contains all sorts of
poetic passages in the closes with these
words
from so simple beginning
endless forms most beautiful and most
wonderful
have been
and are being of all
and i'm a talk about that we take a long
time for questions
those two main ideas in this book
and eventually
how we've learned
how the process of endless forms of all
actually occurs
swiss take a little break
and open up the room too
some questions
device publish anything else for the
east d
prevalence wallace did not become
anywhere near as prominent as darman
wallace published lots and lots of
papers he wrote the great deal
but on his writings never captured the
popular audience that darlington
and darwin's books themselves inspired a
lot more writers so there were more
people in the decade following darlin
took up the pen andrew their accounts of
evolution of their accounts of geology
inspired by the theory set forth by
so we really don't have a literature
from wallace to read anywhere near as
extensive as from
and haven't family nine he said he
interest-sensitive has
when the and thank you
is that need to find out when he
nottingham
that's one question so what about our
one's family
darling was very
tender he was very careful because his
wife were so close
and they were so close the playback in
every night for their entire life in
darwin
being somewhat compulsive kept track of
the lifelong score i don't remember what
approx
they had ten children seven of who
survive to adulthood
they raise this menagerie together
he was always very careful of her
feelings
and she
e she would let her read these things
now in the early eighteen forty three
first put this
theory together in sort of outline form
he let her read it and then asked her to
put it in a drawer and publish it after
he died
he changed his mind when he lived lot
longer than expected
uh... she was well aware of his thoughts
in all she hope for was that it would
not
his theories would not
disqualify them
time and have been together
there's a lot of very tender
correspondence between the mets on the
record
little notes that she would scroll to
him little notes that he was crawl back
to her
so it was understood he did not pay the
price that he feared
with his family whatsoever
or have to wrap up will save some of
those questions where another question
answer session after ike
financial talk here about
what was in the origin of species so
thank you for those questions
and i owe you a teacher
so let's move on
to what's really
even the origin of species
new main ideas
tylenol six hundred pages
it's great reading i really incursion of
sometime take the time to read the real
thing
but i would adjust focus point two ideas
here's the first
dissent with modification
darwin said we'll just take it right out
of the origin of species several classes
of facts
seem to me to proclaim so plainly
at the end numer both species generated
families of organic beans with which
this world is peopled
have all descended
each within its own classroom group from
common parents
and all the modified in the course of
dissent
this
was a huge idea this idea that all life
is connected
through ancestors back further and
further and further and further into
time
it was a bold idea
very very bold
ever really built on at the time
a modicum of evidence
but nonetheless and youth agreement
theory
dot represents this idea really with his
tree of life this is the only figure
in the origin of species not a very
happily host rated book
one figure
and darwin points out that this great
real life
fills with its data broken branches
across to the earth
uncovered the surface whatever branching
and beautiful ramifications
now if powell wrote like this today all
of my peers would just
wipe me out
you're just not allow this kind of
poetry in scientific journals alright
but i was trying to get people to
understand the inspirational view the
grand jury of his view of life
and that's why he talked about filling
the cost of the earth and covering the
earth with it's broken
it's beautiful ramifications well what
do you mean by filling the data broken
branches of the course of the earth
he's talking about fossils
he had good first-hand experience
with fossils and of course fossil record
was one of the best sources of evidence
of the fact an evolution
darling as he
explored south america for example
he was exploring the mountain ranges in
the sea coast in
to show you hear a couple of uh...
paintings that depicts
explorers from the beagle going across
south american mountain ranges and the
bottom is a drawing by darwin mapping
out some of the mountain ranges
while he was up on a road in the
mountains at thirteen thousand feet anne
siese fossil waster pants
at thirteen thousand feet
above sea level
of course the land forms have changed of
course
the species have changed
he understood that life at the surface
of the earth was far more dynamic and he
was first pot and that most of the world
believed at the time
so the fossil record is a tremendous
source and insight
into the actual history the earth in
from about eighteen sixty two not
nineteen twenty
after the publication of the origin of
species was a golden era of in
paleontology christmas spectacular
deposits
were discovered
that gold key insights into life's
history
and the highlights for locations in
north america each of which can be
visited
that hold some of the oldest youngest
and most dramatic episodes
in the fossil record
so in a map of the show you some they're
all
west of here
uh... but as i said some of our
more easily accessible now this is your
seat
from on some of the pictures of these
locations
summer start with one of the almost five
full deposits
i don't talk about the burgess shale
now this is in british columbia it was
discovered by charles walk on the early
twentieth century
that's walcott on the right
at the quarry that he was working on
and what came out of the score east
where these little animals
some somewhat familiar to his trial
bites others it might look a little more
uh... foreign
aside as an example
these are some of the earliest complex
animals
in the fossil record
there over five hundred million years
old
jill specimens can be seen
right at the smithsonian institution in
washington two-step right inside the
hall of dinosaurs
and some glass cases right there you'll
see pieces of the burgess shale
with these very animals that you've seen
pictures of
inside
so over five hundred million years old
bounce golden younger
the dinosaur national monument on the
border of colorado and utah
fantastic place both in terms of scenery
as well as
fossils
jurassic age deposits
course drastic should probably ring a
bell
golden age of the dinosaurs and in
dinosaur national monument early
twentieth century
phone koris
were found
the main corey that you can see the
visitor's center at dinosaur national
monument contains attic somewhere over
two thousand
expose dinosaur bones
and you see these things exposed like
skulls in major pieces of backbones
accused dinosaur legs altogether
this is probably somewhere
formed by some river washing lots of
bones down all been covered up in
river sediment
and so you had just sort of this
hodgepodge of
uh... dinosaur pieces but many falling
tax skeletons
came out of this quarry
and they have been assembled in and
exhibited in all sorts of natural
history museums
uh... all over the world
fossil butte
this is a national monument this is a
uh... administered by the national park
service
foss abuse in southwestern wyoming
what you can see it
of your car these rock formations uh...
this is a very area to area
uh... endings
layers that you can see here is sort of
a horizontal layers of what they were
for to his horizons
some of these horizons are extremely
rich and fossil deposits amazingly rich
and when uh...
the transcontinental railroad was going
through this region
and they were dynamiting your way
through the rock the workers were just
going to find
rocks everywhere
full a fossil fish
and the reason why therefore fossil fish
is that fossil butte
is part of an ancient lake bed
uh... fifteen million years old and
enormously that covered that region at
that
of the united states
uh...
in these leaks there would be some
annual dialogues media's as water levels
became lower oxygen levels became known
to be massive die-offs
and as those fish became covered
insult
and then
protected from further erosion
uh... for from further decay they became
fossilized and what you can find in
layers of this rock almost like the
pages in the book that you crack them
open an open them up
you find
these mass fish kills mstislav alone
somewhere perhaps eighty fish
in a piece of rockets maybe
uh... maybe six people
there other fantastic fossils of fossil
butte to tell us something
about what the area was like
this is not the sort of fossil if you
look at the current landscape of wyoming
this is not the sort of thing you expect
to see perhaps but yes
fifteen million year old palm trees
beautiful fossils this one's probably
about eight feet tall
of palm trees
palm trees are telling us this was a
tropical area semi tropical area
probably had a climate a lot like south
florida
fifty million years ago
very different course today
environments have changed
the animal forms of change
platforms of change
now moving to even very recent deposits
here's a picture
from about nineteen ten
of an area known as the low brea tar pit
from a steaming becos oil derricks and
what does or not there to doing is
they're extracting the petroleum
products out of this dead this bed is
full of this
gooey
stinky
a petroleum necessary tari sort of
substance
but had to use as a
uh... petroleum derivatives
these carpets are now
in the dead center of los angeles
there you are surrounded by los angeles
skyscrapers but these targets have been
set aside
and preserved as a park and as a museum
because they contain
the most spectacular deposits icj
mammals
from twelve to fourteen thousand years
ago
in these bone beds which as you look
down at the news lots of open bone beds
that you can view as you walk through
the park
if you look in there you see just
powell's of boats and what happened was
as animals became tracked inist hari do
let's say something like a mammoth
scavengers would come along to feed on
it
and become trapped
in the target
and scavengers would come by to feed on
them
and become trapped in the terry do
so you just have this piece of the
equivalent of early l_a_ traffic jam
just a pilot
of dead animals
forming in these targets
or the other great benefit is this car
is an incredible preservative salah
takes a lot of work to clean it off
the bulls underneath are exquisitely
preserved
so there's hundreds
of beautiful skulls of saber tooth cats
in a dire wolves and full skeletons of
neomycin mastodon so
i like what happens when say a dinosaur
gets washed into rivers all broken to
pieces
these things were preserved as they fail
so spectacular intact fossil self
one xmas at the l_a_ i highly recommend
visit to a great art
so what are these
specimens from the fossil record telus
lee tells four main ideas
first of all undoubtedly that animal and
plant forms have changed over time
secondly the time span evolution
is immense
i've shown you just the animal record
spanning more than five hundred million
years
but also
most of the stuff that i'm showing is
not around it all not around anymore
so extinction is the fate of most p_c_'s
it ever existed
biologist at the press ninety-nine point
nine percent all species ever existed
environments of every locale has changed
often drastically cell
fair burgess shale creatures i showed
you those were marine animals now found
above the tree-lined in british columbia
those palm trees of course
look nothing like
the current landscape
so environments change and one other
main messages theories i want to tell
you so much about
darwin's geological observations and the
fossil record
revealed things
are occupying a planet who surface as
always changing
hurricanes
earthquakes volcanoes
tectonic movement
ice ages
climate changes with the local or global
all of these
keep changing the environments that
species are in
they are running
to keep up
and most of the time
about birth history to understand life's
history with understand what's going on
any particular place to appreciate
what's going on in particular species
or record tells us that evolution has
happened but the main questions are
wanted to address
was how
and this is the second big idea
the second big idea
is natural selection
philomena
tell you about the whole childhood quote
here from georgia species kit contains
every element every ingredient necessary
for
natural selection to work
as well as the clearest definition of
the process
darlin says kenneth then we thought
improbable
but other variations useful in some way
to each being in the great in complex
battle of life
should sometimes occur in the course of
thousands of generations
the such do accordingly doubt
remembering that many more individuals
are born they can possibly survive
individuals having any damage however
slight over others
we have the best chance of surviving
appropriating their current
on the other hand when they feel sure
that any variation in the least agree
injurious would be rigidly destroyed
this preservation of favorable
variations and the rejection of injuries
variations
i call natural selection
two sides to the cooling
rejection of things that are
preservation of those things and more
favorable
one of these ingredients what we look at
the back darwin's quote
he sang variation
there in red
thousands of generations
time an advantage he means selective
advantage
so these are the three ingredients this
is the fuel devolution
variation
selection
if you want to think of it they get any
process
the produces a product
usually have raw material some work
overtime
the raw material is very asian
selection does the work
anti-nuke it takes a very smacks of time
for the process to happen
so that illustrate this process of
natural selection i want to give you
just one example
sort of a modern example but it you know
streets all the features that i want to
tell you about of i've seen these
ingredients of evolution
and we think about
the adaptation of a really modest humble
species to a changing landscape
when showing here is allowable flow
across part of the desert
in american southwest
over the last couple of million years
there's been a rupture users leads a lot
of to uh... lava flows
when that lava cools it forms these
black rock formations
journal back premise or sandy
dry soil
in this habitat loose
the humble rock pocket mouse
and that rock pocket mouse occurs in two
varieties
sandy colored mouse
and a dark-colored men's
and showing you these
animals on different colored backgrounds
missed any mails that matches well to
the sandy color proc
the dark mouse that matches well to the
dark color rock
and you can see the mismatch when into
the darkness is unlike rock or the like
colored version is on dark rock
and it matters this color matching
really matters with respect
to predators religious explained a
little bit about
color matching in mice for the short
video
so when that darkness
finds itself
white-collar habitat
kicking me in big trouble
natural predators are all
but of course if we change the backdrop
dartmouth blends in well but the white
colored mouth
isn't running
so we now know a lot
about ecology
about
the genetics and about the evolution of
this pattern that's what i want to tell
you the rock pocket mouse inhabits these
please lava flows in the surrounding
rocks this color mansions importance to
a survival
there's to forms of the mouse that's all
the same species and that
those two forms are determined by
genetic variation
there's a single gene
it will be here called mc one r the
comes into alternate versions or reels
and sammy colored mice have two copies
of the light at the wheel
for this gene
the duck mice have either one copy or
two copies
of the darco
side of the university of arizona have
pinpointed the exact genetic basis for
the color of the for color difference
between
the two populations of months
let's consider how long would it take
all-black master rise in the senate
colored population
that lava flows happened
how long would it take
isn't isn't connection selection really
do the job to allow population mice to
adapt to a new land for in this case
lava rock
well the ingredients there
have to do the interplay between
variation in time
and what i'm going to do
so to walk you through the variables in
milwaukee through quenching little bit
of the numbers
and rather than take notes and
discouraging to just follow along
watch the wash the board whatever don't
worry about the numbers we could always
go over them again later
but just follow along the logic of of
crunching the numbers of how these
ingredients of evolution in iraq
so to know how often a black coat
mutation can arise that's gonna depend
upon three things
the mutation rate
the reproduction rate in these mice
and population size i mean my starter
how awfully reproducing
but we know a lot about the mutation
rate from
decades of study
and the mutation rate in mice
is about to mutations
billion sites in d_n_a_
innate copying is highly accurate but
not perfect
that was perfect there would be no
evolution
we need variation
for the fuel evolution at work
for about ten sites in the mc one r gina
can be mutated to cause this black type
of appearance
and there's two copies of the mc one r
gene in every mouse
we multiply all those together
when we come up with
is one in twenty five million mines
eighteen months
will have a black coat mutation
one in twenty five million
one teaspoon o does that mean
one twenty five million is that a long
shot does that mean that that i can see
how this evolution would work
not at all
because now we have to
introduced some other factors
and those other factors
on the reproductive rate
and the population size
so each femaleness population is having
at least five babies
at least five a_b_c_ here
average population is about five
thousand females
so about twenty five thousand pocket
mice being born here in this population
now from multiply twenty five thousand
babies times one in twenty five million
that means that we found in years
there will be spontaneously
mouse born to sandy color parents
one of thousand years
now let's put it into a logical factor
framework
those lava flows and showing you summer
one point seven million years old
so this mutation kind of a reason
seventeen hundred times
independently
plenty of time
for the raw material to relax
seventeen hundred times over
okay so how does this
black coloration actually spread through
the population
well that's elections job
how long does it take for every mouse to
become black
now we have figure some other variables
it depends on population size i mean my
southern the population
and it depends upon something called the
selection coefficient we denote that is
belittle s
and that is the advantage
that allows carrying the black gene
over my sweetheart
that's a relative measure of fitness
measures a product of reproduction
and survival
okay so if we put this in terms of if
black twice in general producing a
hundred and one survivors for every
hundred mice produced by sony colored
lines
that's a one percent advantage in we
would write estes point no one
you've got to see that one percent is
plenty of advance revolution to work for
natural selection it work
and it is a five percentage
okay we write dennis as point oh five
remember decide under one
two hundred
compound in overtime
you're gonna see how this works
so it's so this in animated in in this
animation
consider the southwestern united states
sandy colored
landscape until some water flows happen
that lava cools
and now that black rock
is gonna be invaded by the senate
colored lights
once every thousand years or so black
now sister pop up
the owls are going to be there circling
overhead for eons
and if we start with a population we're
just one else this black
and we know and has just a one percent
advantage
watch what happens
over the generations
than about a thousand generations
ninety five percent of the monks will be
black
that's just natural selection doing the
work one mutation one founding mutation
can spread in ninety five percent of the
population
in a thousand generations now what
happens if there's a ten percent
advantage being black
very quick
and a hundred generations ninety five
percent mostly black
it turns out from measurements in awhile
there's an even greater than ten percent
advantage
of mike's being black on the black
lava flows
natural selection
is very swift and
and the amount of time that we have more
speaking on the geologic time scale for
evolution at work is ample time
for mutations to rise
and for selection to spread favorable
mutations
throughout populations
so what's the bottom line the bottom
line is
that how long it takes for these first
street ste
traits to spread
it's a lot faster and most people
realize
on the order for these things of maybe a
century irma landed and you can hear a
lot more examples
about this
in doctor king's woodstock
suit understand more about the power
selection it's a pride so powerful
that our civilization depends upon it
you seemed more about that from dr
kingsley
so it's raw material
plus election
overtime
that's the formula
and we see vivid evidence of natural
selection working
and all sorts of cases
both natural and artificial
so let's stop there
i'll take some questions
in the back right
usually
so the question is how does indication
rice mutation isn't completely random
process so
is
sperm and egg are produced
for reproduction
there are air is made in the copying a
d_n_a_
that women
these areas change the d_n_a_ code
every and and and that creates random
variation
in jeans
some of those genes control for color
i've told you the example of one of
those
so at annual rate
one in twenty five million there are
mice born that look different than their
parents in terms of for coloration
but that isn't highly product it just
became a call me to meet a shame that
happens
as the billions of sites in d_n_a_ are
copied
in every generation of us there's about
a hundred new mutations in you that were
not in your parents for example
raises money to use the flames and
reduces tonight
was u
news
arcane great question
at overhead child care for him
the uh... the question is if they were
if the black by steven do you see any
habitat it's actually very easy to
inactivate this team
so it doesn't work
and that the mice are lightly pigmented
possession lots of what ways you can you
take a chance of the frequency of
actually going black to white is even
higher
than it is from going white to black
and there are examples in nature of
where this has happened
uh... for example there some bears on
the northwest coast of canada that are
all-white for and they have mutations in
this chain have been activated rather
make it
form the black for
so there are both directions are
happening in the wild i can tell you
that the same gene i'm telling you about
is responsible for the black color phase
of jaguars
for the black phase of snow geese
for the black phase a certain other
types of cats
uh... and for some black phases in
domestic dogs
so this is a gene that have been called
upon repeatedly to end our mammals with
dark for coverage
g home resentment usually fine with the
blacking out of the communities on
inordinately
commonly found when the mormon just
because the and reforms could be the the
bernadine
that's a great question so the question
is about whether it matters with the k
one or two copies of the of the gene is
released like the difference
it turns out there's a bit of an
additive effect of these
of the annuals
and so that the
the mice carrying two copies are bit
darker
they want those carrying one copy that
may be a selective advantage
so that you may be still favoring the
home as i get more than they had a
recital
but still
uh... in order to really know that we'd
have to prove pretty large population
studies
to end and gina tribal homeland amongst
understand
relative contribution of those two gena
types in a while
preparing for the camera
up north in the front first
bleacher seats for no incidents
users
his times
manageagents economies
just these two taxes just to please
instead
environment and planning
his black asian
i don't want to make it sound that
there's a coincidence that all the
change in the environment courses
outside of the enormous control
uh... but there are mutations that occur
in population than if you look through
this room at two hundred humans and you
consider our features
that are visible
hair color i colored skin coloration
uh... facial features it so you see
tremendous variation if you have that
sort of a cutie in a mouse population
you'd also if you if you were looking at
other night she'd say well there's a
little bit a small variation here you
know friends got a little bigger had
little longer whiskers and color is it
senator
so there's tremendous variation in
populations
now the inquiry here
the selected pressures on for coloration
because of the setup between predator
and background-color
but if you want to say well look what if
the rocks were a little different color
like say tanner settling back in the
senate with the sandy soil was pure
white
with their b advantage for being
ten coloration in code the mice involved
that color
and i'd say absolutely
different sets of mutations difference
elective process but eventually as this
competition runs if there is an
advantage to particular for color scheme
this will this process will repeat
itself again and again and again so the
coincidence really the mutations arise
at raymond but there's nothing random
about selection selection is the
conditions that the animals living in
and that even predators or for example
nate's impose upon it
some after wrap up but i'm happy to take
some questions uh... while we have a a
break you will have many more
opportunities to talk about
uh... evolution in the process of
national selection over the next three
lectures
thank you sean carroll forgetting our
lectures on evolution off to a really
great start
it's amazing to see how darwin's
insights continue to inform today's
research and thank you students for some
really great questions now we're going
to take of thirty minute break when we
resume david kay slay will focus in on
this idea of the role of selection and
how it plays into evolution
