[MUSIC PLAYING]
SPEAKER 1: Jim Costa travelled
to us from Western North
Carolina.
And despite the impacts of
Hurricane Irma and many delays,
he made it in late last night.
So we're glad to have him here.
James T. Costa is a professor
of biology at Western Carolina
University, and Executive
Director of the Highlands
Biological Station and a trustee
of the Charles Darwin Trust.
He lives in the Blue Ridge
Mountains of North Carolina.
In his book, "Darwin's
Backyard, How Small Experiments
Led to a Big Theory," he
goes beyond the portrait
of Charles Darwin as
a brilliant thinker
to concentrate on him as a
nimble experimenter delving
into some of evolution's
greatest mysteries.
Please join me in
welcoming Professor Costa.
JAMES T. COSTA: Thank
you all for being here.
It's really a special pleasure.
I have a deep connection
with Cambridge.
But I've never had the pleasure
of visiting your offices here.
So this has been great
seeing the place with you.
So thanks so much.
And I do appreciate
your being here
and allowing me to share
one of my passions.
My background is entomology,
but some years ago
became pretty interested
in the history
of evolutionary thinking.
And a lot of my
work in recent years
has been on Darwin,
Alfred Russel
Wallace, his fellow naturalists
of the 19th century.
And I became intrigued by what
lessons Darwin might still
hold for us today,
kind of understanding
how he came to his ideas.
And some years ago, I worked
on an annotated version
of "On the Origin of Species."
And in working on
that project, I
came to realize that a
whole lot of the arguments
in "The Origin" are
based on these often
really quirky experiments, like,
literally backyard experiments.
And I became fascinated
by that side of Darwin,
especially because the
Darwin that I saw--
as you get to know this
individual, the flesh and blood
person--
really seemed at odds
with Darwin the icon.
This is the kind of Darwin
that most people think of.
And you think of
these portraits.
And this is the
melancholy Darwin.
This is the sad Darwin,
maybe the tormented Darwin.
I believe that what
we're seeing here,
this kind of cardboard
cut-out icon that
seems rather melancholy, is
really insightful, maybe,
of Victorian portraiture
conventions or limitations
of the photographic technology
of the day, where you're not
going to hold a smile
for many long minutes.
Really, I came to appreciate
this impish side of Darwin.
I saw this Darwin as a dad,
as a husband, as a friend,
as a jokester, a
practical joker,
sort of twinkle in his eye.
And I want to share
with you this idea
of what Darwin did
literally in his backyard
and how those activities
kind of give us
what I think is a much more
accurate portrait of the human
being, Darwin the person.
And as you'll see, my secondary
interest in this project
wasn't just to humanize Darwin.
But also, as an
educator, as a scientist
myself, I became
interested in the ways
in which Darwin and
his method could
be harnessed pedagogically.
We could use that
at really any level,
from kindergartners up
to college students,
to really use the way he
approached understanding
the natural world as an
interesting, novel way
to approach science education
teaching about ecology,
evolution, scientific inquiry,
those sorts of things.
So this is a portrait, really,
of a rather different kind
of Darwin than I
think most of you
would be familiar with
in all likelihood.
This is a quote from Darwin.
In his self-deprecating
way, he would talk
about his fools' experiments.
He loves fools' experiments.
He's always making them.
And that kind of gives some
insight into what he's up to.
The back story to Darwin's
books is, experiment
after experiment, some of
them very quirky, on-the-fly,
literally done at
home, because famously,
he became something
of a homebody
and did not travel much after
his around-the-world voyage
on HMS Beagle.
And I want to give you
sort of some insight
into Darwin, again, as
a family man and the way
that his family, his kids
played a role in many
of these quirky experiments.
Darwin had 10 children, seven
of whom survived to adulthood.
And throughout their
upbringing, they're
constantly involved in
dad's activities, as well as
his wife Emma, as well
as nieces, and nephews,
the extended family.
And so there are some
interesting little snippets
of getting some sense
of how the kids were
involved at different times.
So one anecdote,
for example, that's
pretty well-substantiated
comes from one of the kids
who, for about an
eight year period,
Darwin famously immersed himself
in the study of barnacles
of all things.
And so for at least one of the
kids, their whole life as they
were growing up,
they knew nothing
but dad working on barnacles.
And the story goes that
visiting some friends they
kind of looked around and
were wondering, well, where
does your dad do his barnacles?
Every kid's dad must work
on barnacles was the idea.
And some of their studies,
some of their investigations
were just fun but always an
interesting scientific point
behind them.
So One. episode involved chasing
around bumblebees, which we now
understand male bees
traplining, pheromonally leaving
trails kind of through an area.
They had no idea.
Pheromones h have not been
discovered yet at this time.
And they're running around
and marking bees with flour
to make them more visible.
And it was just really
quite a family adventure
to try to understand.
What are these bees
doing was the mystery
of the buzzing places.
One of the kids later
reminisced that, at that time,
his father was like a
boy amongst other boys.
And I think that
that says a lot.
And I think all of you can,
perhaps, appreciate this.
There's a certain
childish enthusiasm,
a sense of wonder and
enthusiasm about something
interesting in the natural
world and then trying
to understand it.
Here's just one other little
example of involving the kids.
This is from, you
can imagine, maybe
a little red periodical called
"The Entomologists Weekly
Intelligencer."
You can imagine
that every household
must be reading this magazine.
So here you've got a little
note about the capture
of some rare beetles.
And this is obviously
dad writing the note,
but signing it three of
the kids, Francis, Leonard
and Horace Darwin,
ages 11, 9 and 8.
And so that you can sort of
envision, that's the proud dad.
He loved beetles himself.
He's quite a beetle
collector and is
very proud to think that
his kids were really
into beetles too
and collecting them.
And so he fires off
this little note
to "The Entomologists
Weekly Intelligencer"--
pretty interesting.
So those are little snippets.
Darwin, at his home
in Kent, Down House,
had a thinking path.
This is his thinking path.
And he would famously
put a few stones
at one end of the thinking
path and kick them away
as he made his rounds.
And the kids would
go and replace them--
really wanted to keep
them going longer,
because there was
always something
interesting to be found
So I think that the thinking
path is a good place
to start in talking about
Darwin's experiments.
They are fun.
A lot of his experiments are
really just genuinely fun,
rather quirky, rather odd.
Always, there's an interesting
scientific question behind them
as well what we'll discuss.
They are accessible.
And this is interesting too.
I mean, Darwin working in the
Victorian period literally
at his home, he's
not working with
sophisticated scientific
instrumentation
maybe beyond a microscope.
Really, his experiments
are done on the fly.
He's just pulling together
whatever materials
are at hand at the
house and then devising
a way to test some
scientific question.
That actually makes
his experiments
eminently accessible today.
We don't need sophisticated
scientific instruments,
for example,
precision instruments,
in order to actually engage in
meaningful scientific inquiry
necessarily.
And there's interesting
implications for teaching
scientific inquiry, I think.
And of course, adaptable--
I think that any of
these experiments
and the questions
behind them are adapted
to virtually any age group.
Some of them are adaptable
to kindergarten age.
Some of them, there are
layers of sophistication
where you can get into more
sophisticated considerations,
like replication, or concepts
like statistical significance
of the college level,
perhaps, or high school level.
So it's scalable
and adaptable, which
I think also makes
them eminently
interesting from an educational
point of view today.
So what was the experimentizing
really all about?
Well, first and foremost,
about curiosity--
it all starts with curiosity
about the natural world,
natural phenomena,
pattern, process.
But ultimately,
as I'll show you,
Darwin became very keen on
really not just demonstrating
the veracity of his ideas
about evolutionary change
and the mechanism of
natural selection,
but ultimately,
extending that paradigm.
And so many of his
research programs
are really intended to flesh
out, reconfirm and extend
his evolutionary
insights, as we'll see.
So evidence is what
he's looking for.
If any of you have read
"On the Origin of Species,"
you may recall that,
near the end of the book,
Darwin refers to the book
as one long argument.
And it hangs together
in an interesting way
many different subjects.
And I became
fascinated by the fact
that there's another book
behind the book behind the one
long argument.
And that book is this
one, his experiment book,
his experiment notebook.
This was the book
that he committed
many, many observations,
experimental results,
musings and so on.
There's so much that
could be discussed.
I'm just going to give you
one example of a research area
that really shows off the
different facets of Darwin's
method and his interests.
So that example
will be dispersal.
Take dispersal.
That is the question of
geographical distribution.
How do species become
distributed on the Earth
as we see them?
And he undertook
just a diversity
of weird and
wonderful experiments
to gather data to
answer questions
that often we would just
say, well, of course,
or that must be obvious.
But if there were no
data, nobody really knew.
So he had to start somewhere.
So for example,
this is just a list
of some of the quirky
experiments that he undertook,
seeds in salt
water, sea buoyancy,
hitchhiker experiments
with duck's feet,
dunking ducks in aquaria
with duckweed and so on.
So So for example,
Galapagos Islands,
remote oceanic islands loom
large in talking about Darwin
in the history of evolution.
But it begs the question,
any remote island system
begs the question, well, how
do species get there exactly?
It's easy enough
to see that birds
might be blown far of course
or other winged animals.
But really, there's a
lot of other organisms
besides things that can fly.
How did they get there?
Well, maybe they
raft, or they float,
or they could be
carried in some way.
But how exactly?
Darwin was convinced that a
whole lot of these organisms,
seeds and such, actually
floated, some of them
just in salt water,
some of them rafting.
But his colleagues, his
friends and colleagues,
who were generally
supportive of him,
really were dubious of this.
They didn't think that seeds
could possibly survive exposure
to salt water.
So what to do but tests
to demonstrate this.
And Darwin never did
anything by halves.
So he embarked upon a
two-year investigation,
floating seeds in salt water.
And not just an n of 2 or
3, but really just taking
over the house, jar
after jar of salt water
with seeds of myriad species.
He fills up the cellar.
He fills up his study.
The object was to see, well, how
long can seeds survive exposure
to salt water?
So he would take
samples periodically.
Can they survive a week?
Can they survive two weeks, a
month, two months, five months?
And the kids were very excited.
Because his good friend
Joseph Hooker, the botanist,
was very dubious of this.
He didn't think that
anything would come of it.
So the kids got in on--
they saw it as a contest.
And in one letter to
Hooker, he reported
that the children
were very eager
and asked him often whether
he would beat Dr. Hooker
and show him that, yes, they
can survive in salt water.
Yes, it can happen.
Then there's the
inconvenience of Hooker kind
of pointing out that,
well, they might be
able to survive in salt water.
But oftentimes, they sink.
And so it's a moot point whether
they can survive in salt water.
They're never going to
make it to an island
if they're sinking.
And in another letter,
he writes to Hooker--
you see his exacerbation--
if the confounded
seeds will sink,
I've been taking
all this trouble
and salting the ungrateful
rascals for nothing.
The letters, his diary,
the letters, his notebooks,
they really are this phenomenal
window into Darwin the person
and the working method.
So here you see triumphs
and then setbacks.
What does he do in the
face of sinking seeds?
Well, let's try dried seeds.
Let's try drying vegetation.
Let's try fruits.
And so these are just pages
from the experiment book
where species, after
species, after species, he's
testing them and trying to
see, how long will they float?
How long will seeds survive?
Ultimately, this all makes
it into "On the Origin
of Species."
He's able to show that they can
survive, many of these species,
months at a time.
Ocean currents can carry
them thousands of miles.
He's triumphantly
saying, this is
a viable means for
getting species
to remote, oceanic islands.
As unlikely as it may be,
it clearly must happen.
In the book, each
chapter ends with a kind
of do-it-yourself section
where you can sort of
experimentize a la Darwin.
You can, for example,
replicate some of his seed
salting experiments.
And it's great fun.
I've done this with
science educators.
I've done it with my
kids and other kids.
I've done it with my students.
And again, it's not just fun.
But actually, there is
this interesting point
about better
understanding geographical
distribution, dispersal
of species on the planet.
If you think about
it, lakes and ponds
are like islands on the land.
How do aquatic
organisms get around
from lake to lake, pond to pond?
Well, logically you might think,
well, maybe they're carried.
Because clearly,
little aquatic snails
are not leaving a pond
to go miles and miles
to another pond.
Probably, they're carried.
Well, once again,
Darwin thought of that.
But there were no data.
There was just no information
one way or another.
So what does he do?
Well, he devises a test that
uses actual duck's feet.
Presumably, they're
eating these ducks.
He's saving the legs
and then dangling
the legs in aquaria
full of snails
to see if the snails
will hop aboard the feet.
He's imagining that
sleeping ducks in lakes,
as the feeder dangling down,
snails will become hitchhikers.
In the morning,
the duck wakes up.
Off it flies may
hundreds of miles
carrying the snail with it.
So I devised-- of
course, in my version,
we're not going to
use real duck feet.
But we there's a way to
make a model duck foot out
of a dowel, and a bobber,
or some kind of a float,
and a fabric duck foot.
And actually, this is
one of my kids here.
We're actually sort of casting
for hitchhikers in ponds.
And it's amazing,
actually, what you
will catch kind of casting
duck's feet in ponds
a la Darwin.
So it's really a
great way to get
young people engaged with
these scientific questions.
This is a general subject
that also says something
about Darwin the crowdsourcer.
I think he's maybe the
original crowdsourcer.
These are just four letters
to the editor, open letters
that he published in 1855 as
one example, where, again,
he's wondering about seeds
surviving in salt water.
He's wondering, has anyone
ever looked at this?
Are there any data?
Is there any information?
So publishing open letters--
will any of your readers
be so kind as to inform me
whether such experiments
have already been tried?
He's exhorting readers
of this magazine,
"The Gardeners' Chronicle."
Try this experiment.
Send me your results.
Ultimately, several people
took him up on this.
And they're cited in "The
Origin of Species," actually.
So it's pretty interesting.
So he's crowdsourcing here.
And he does this to good effect
with quite a few other subjects
as well.
He's also open to rather
unorthodox approaches
to the question.
Now here's yet another facet.
Here is one of the kids,
little Francis or Frankie
as he was called, when
he was eight years old,
came up with an experiment.
And it seems a little crazy.
But here is Darwin
reporting this
to his buddy, Joseph Hooker.
He says, look, I
must tell you another
of my profound experiments.
You know, he's sort of
very tongue in cheek
about how profound it is.
He says, Frankie says to
me, why shouldn't a bird--
imagine a bird with seeds
in its crop killed by hail,
or lightning or something
over the open ocean.
And then the carcass is
floating, and eventually,
is kind of washed up
on a distant shore,
and has fertilizer built in
with the rotting carcass.
And wouldn't that be
a dispersal mechanism?
So what does Darwin say?
No sooner said than done.
He takes a poor pigeon.
He's got seeds in the crop.
And this poor pigeon is killed
and is floating in a salt water
tank for 30 days.
And then Darwin is able to
report, once he plants it,
ah, the seeds, they
germinated splendidly.
Data, right?
Very interesting.
Well, a whole different
area of interest to him
had to do with field botany.
And this is from another letter.
If you ever catch
quite a beginner
and want to give him
a taste for botany,
have him make a perfect list
of some little field or wood.
And he speaks from
experience here.
He really was
passionate about botany.
And he enlisted the help
of Catherine Thorley,
who was a governess of the
kids, had a talent for botany
and very keen on helping
with experiments.
So they would botanize
and try to characterize
diversity and set areas,
really a forerunner
of the modern quadrat approach
to doing botanical surveys.
Here you see glimpses in the
letter of his sense of humor,
like, for example,
when he identified
his first grass, which
botanically, they can
be very difficult to identify.
And he says, hurrah, hurrah.
I never expected to make
out a grass in my life.
Well, what's interesting
about these experiments
with Ms. Thorely
is that they are
the forerunners of
experiments that are now
considered to be foundational
in modern ecology in evolution.
So modern ecological
concepts that you'll
find in any introductory
bio textbook,
any introductory college
course, the students
learn about niche partitioning,
competitive exclusion.
They learn about on demographic
analysis and population
pressure.
Those insights came from
these simple experiments.
And as you can see in
the upper right here,
literally in Darwin's
backyard-- this is Down House.
And he's has a 3 by 4 plot where
he is conducting experiments,
the so-called lawn plot where
he mows all around but he leaves
the unknown plot just
to watch the dynamics
of the different species
that come and go.
He's sort of chronicling that.
And he has a hypothesis
about the relationship
of the different species
that ended up coexisting,
the phyletic diversity
packed into a very
small geographical area--
or the weed garden, where he
clears the plot completely
and marks every
seedling as it comes up.
Essentially, it is a
modern demographic study.
He's looking at the mortality
rate of these plants.
And he documents the extreme,
what he calls, of course,
the struggle for existence, the
mortality rate, that ends up
reinforcing his arguments about
how natural selection works.
So I find it fascinating
that those cornerstone
ecological principles
today had their origin
in these simple
backyard experiments.
And again, anybody can
duplicate these experiments.
And I think it's
actually great fun
to take Darwin's
original data and then
compare that with one's own
data doing these different lawn
plots or weed gardens.
Well, if "The Origin"
is one long argument,
consider that "The Origin" was
far from Darwin's last book.
There's another dozen or so
books after "On the Origin
of Species," about half a
dozen of them on botanical .
subjects.
Every one of these books
has interesting experiments,
some of them
pioneering, where Darwin
made fundamental discoveries in
different aspects of ecology,
evolution, botany, behavior.
This is just a sampler of
topics, orchids, barnacles,
inheritance, the
construction of B-cells,
expression of emotions,
pollination mechanisms.
He's often juggling
multiple experimental areas
at the same time, which is
interesting in its own right--
planting experimental
gardens in his yard,
eventually building
a greenhouse.
This is Darwin's
greenhouse where
he would keep climbing
plants, orchids,
carnivorous plants and so on.
His first book
after "The Origin"
was on orchids, in fact.
And he's fascinated by the
different contrivances,
the highly derived
adaptations of orchids
and their pollination
relationship with insects,
often one-to-one
relationship, and fascinated
by the different ways that
orchids package their pollen
and then deliver the pollen
through adhering them
into insects.
And he discovered that some,
like the one in color here,
catasetum, some of them don't
simply stick their pollen
to an insect.
They can forcibly fire
their pollen at insects.
One of his neighbor and
protege, John Lubbock,
a memoir that he
published in 1874,
commented on how
Mr. Darwin's been
so good as to irritate one of
these flowers in my presence.
The pollinium was thrown nearly
three feet when it struck
and adhered to the
pane of a window.
Darwin, in his impish
way, would sometimes
take friends and family sort of
who were unaware showing them
around his greenhouse.
And then he was surreptitiously
trigger a catasetum
and get it to fire
pollen at his visitors.
There are several
accounts of that.
He would also go out to
a favorite family picnic
spot near the house.
The family called it Orchis Bank
for its nice native orchids.
And at sites like
this, he would study
how insects transfer pollen.
Like this beautiful
burnet moth, you'll
notice that this moth
on its coiled proboscis
has those yellow structures.
Those are the pollenia.
Those are the pollen
packets of the orchid.
And the drawing here is
from Darwin's orchid book.
He's looking at these
moths unfurling that
proboscis and really interested
in demonstrating exactly
how insects lock and key
sort of relationships
are fitting with their orchids.
And that's just one little
bit of his adventures
in pollination.
Darwin spent inordinate
amounts of time
studying the ways insects
interacted with flowers.
There are accounts of the family
visiting the zoological gardens
in London.
While the kids and everyone
else are looking at the animals,
Darwin is crawling
in the flower beds.
And he's making
observations like you
see up here, upper right.
This is taken from
the experiment book.
He's drawing the
ways in which bees
will approach certain flowers.
He is interested in also
trip action mechanisms,
like you find in
barberries or mahonia,
where they're very
touch-sensitive.
An insect approaches and
touches the flower slightly
and, bing, the stamens
will suddenly be triggered.
And they will shower
the insect with pollen.
Or the common bean, which
has its stamen and pistols
wrapped up, he calls
it like a French horn.
When bees land on those
down-hanging petals,
out it comes.
And it dabs pollen on
the back of the bee.
So he documented meticulously
innumerable cases
of pollination.
And he made an
interesting discovery.
It wasn't completely new.
Botanists knew about this,
but didn't know what it meant.
And this is the phenomenon
known as heterostyly.
And it's a case of two
or more flower morphs.
He first discovered
it in primroses,
a so-called female
morph and a male morph.
So the one on the left
here, the female morph,
has a very long pistol
and very short stamens.
The male morph has the reverse.
It has very long
stamens, as you see here,
and a very, very short pistol.
Well he was fascinated by this.
And Darwin in his
characteristic way thinks big.
And he's interested
in the evolution
of sexes, big picture.
And he thinks, maybe this is an
example of evolution in action,
that maybe the female
morph is eventually
becoming a female-only
flower evolutionarily
and the male morph is becoming
a male-only flower, which
you do find in some groups.
So maybe this is an example
of evolution in action.
So he has this hypothesis.
And so what do you do?
The first thing to do is
document the frequency.
He marshals the troops.
The troops are the kids.
So he gets the kids.
Horace, who's nine, Lenny,
Frankie, Bessy, out they
go this.
This is a page from
the experiment book,
collecting primroses.
And he says, on May 13th,
my children gathered
a great bunch of cowslips.
79 stalks were male flowers.
52 were female flowers.
And then he would do cross,
after cross, after cross,
after cross.
These are all from
the experiment book
documenting how he would
hand transfer pollen,
and ultimately, when the seeds
form, then count up the seeds.
And his hypothesis is that
the female morph, that
would, perhaps, have
significantly more seeds
produced than the male morph.
Well, interesting
hypothesis, but he
butted right up
against his friend
Huxley's great
tragedy of science,
the slaying of a beautiful
hypothesis by an ugly fact.
And the ugly fact,
in this case, was
that he found exactly
the opposite of what
his working
hypothesis suggested.
Indeed, it was
the man morph that
ended up producing more
seeds than the female morph.
So nonetheless,
informative in its own way,
ultimately, he got it right.
He published a
whole separate book
on this subject
in which he argued
that these different morphs,
their function evolutionarily
is to enforce out-crossing,
cross-fertilization.
And it's now been documented
in a great multitude
of plant groups.
In my book, in that spirit
of Darwin's experimentizing,
of course, I have
examples of some
of the plants that he
explored and instructions
on how their different
pollination mechanisms can
be explored by experimental
enthusiasts, school kids, et
cetera.
A couple more examples for you,
carnivorous plants-- so again,
thinking big picture,
Darwin is interested
in plant-like animals
and animal-like plants.
And of course, there
were two groups
of plants that are just
eminently animal-like.
And one is the
carnivorous plants.
And he's smitten
first by sundews.
And his wife, Emma, comments
in a letter to a friend,
he hopes in the end to
prove it to be an animal.
And she's only half kidding.
He really does think
that, in such groups,
you can see that
plant/animal intersection,
that they have common
ancestry, that there
are physiological and
other mechanisms that they
have in common.
So what does he do?
The very first thing
he does is begin
to explore their
dietary preferences.
So he's on holiday
in Bournemouth.
And first he tries his hair.
That he tries his
toenails, and of course,
not very profound results.
Clearly, though, they
sort of spit out the hair.
And they spit out the toenails.
But he embarks upon
years-long investigation
of the dietary preferences
of sundews and flytraps.
And eventually, he
really does get it right.
He understands he can see the
forerunner of digestive enzymes
that were later to be discovered
in animals, pepsins and such.
And so I give some examples
of how you can replicate some
of Darwin's experiments trying
different delights that they
really enjoy and
some that they don't
like very much and exactly
the way Darwin found it.
Flytraps as well-- Darwin found
that these little trichomes,
there's a certain
frequency and sequence
for touching these
little trichome
on the inner surface of a
flytrap necessary to trip
the trap.
And that's all easily replicated
using a probe or a hair.
Climbing plants,
that's the other group
of plants that seems
eminently animal-like.
And Darwin made an
independent discovery
of the principle
of circumnutation,
the constant circular probing
movement of climbing plants.
It turns out that almost all
plants, their growing shoots
move in that way.
But it's highly elaborated and
adaptive in climbing plants,
in tendrils and growing shoots.
So what did he do?
Well, he commandeered
the family terrarium.
So every fine home had a Miss
Maling's Patent Indoor Plant
Case, of course.
And in their parlor,
they had one of these.
But Darwin removed all
the ornamental plants,
took it over, put
climbing plants in there.
And you see in the
lower left here
how he used the top of the
glass with tracing paper
with a climbing plant inside
and little markers and reference
points, so he can follow
the movement of the very end
of the growing tip, and
in that way, documented
that circular movement.
And he coined the
term circumnutation,
which is still used today--
very, very interesting.
And of course, hops
is a great example
of a plant that circumnutates
in a wonderful way, fairly
frequent movement
or fast movement.
And so I give
instructions on how
one can create a
circumnutometer,
either using a clock-like disk
or compass coordinates and sort
of document the way
the chute is moving.
And finally, Darwin really,
way back in the 1830s,
was fascinated by earthworms.
And this is also the subject
of his very last book.
So this kind of bookends
Darwin's experimental life.
He's fascinated by earthworms
as a geological force.
And then also, later on,
he became really interested
in earthworms' intelligence,
and their personality traits,
and their preferences,
which seems a little funny.
But he's very
serious about that.
In one letter to a
niece, he sort of
confides how he has become
deeply attached to worms.
He is fascinated by them.
All through the 1870s,
he's working on them.
As a geological
force, he believes
that earthworms slowly,
surely, inexorably rework
the landscape.
They're undermining.
Their taking soil up in
the form of their castings.
They're turning over soil.
In that way,
objects slowly sink.
And he even collected data
from sites like Stonehenge.
He went out to Stonehenge,
great fallen blocks of stone,
and was measuring how
deeply it had sunk.
He was looking at Roman ruins,
how deeply different artifacts
have sunk, and then
experimentally trying this
by putting blocks of
stone out in fields
and then monitoring, over
years, how they slowly subside.
In fact, his son, Horace, who
later founded the Cambridge
Scientific Instrument
Company, really
showed his experimental
bent pretty early.
So this is his youngest son.
And Horace designed what
is known as the wormstone.
And this is still an
evidence at Down House today.
The wormstone is a millstone.
And Horace designed a
precision micrometer.
And you see it here.
He actually published the plans
for this in "Nature" in 1901.
And the idea was that, with
the precision micrometer,
the subsidence of
the millstone could
be very carefully measured,
so the action of the worms
could be quantified in that way.
So in that way, he quantified
the rate of subsidence.
But the other half
of that equation
is the soil brought
to the surface.
So with his niece,
Lucy Wedgwood,
he devised quandrats where they
would collect warm castings
and then ultimately
quantify, how much soil,
in the form of worm castings,
is deposited per unit area
and then extrapolate over time.
And this makes it, of course,
into that very last book
on earthworms.
They were able to show that
up to 16 tons of soil per acre
were moved annually by
the earthworms, which
is truly, truly remarkable.
One other interest, though--
so worms is a geological
force, but also, , again,
their intelligence,
their predilections.
If you visit Down House
today, this is the parlor
as you can visit it.
And you might notice something.
Over here on the
back on the piano,
you'll notice a flower pot.
And one might assume that,
in fact, there should
be flowers in the flower pot.
But, no, the flower pots
were Darwin's wormeries.
This is where he would
keep his earthworms.
And this recreates one
episode in the late 1870s
where Darwin, his son,
Francis, and his grandson,
Bernard, and his wife, Emma,
played musical instruments
to the earthworms.
So we Emma on piano-- she is
quite an accomplished pianist--
Frances on bassoon and the
little grandson on penny
whistle.
And the idea is to
sort of see, do they
have any musical appreciation?
Can they hear even?
Well, Emma, again in her
tongue-in-cheek style,
she writes a letter to
Leonard, who is away.
She says, Father has taken
to training earthworms.
Doesn't make much progress.
They can neither seen or hear.
But nonetheless,
he was convinced
that they do have the ability
to sense the vibration.
And by moving the flower pot
off versus on the piano--
and ultimately, too,
he devised experiments,
giving them paper cut-outs
of different shape and size,
and would document how
they feel the shapes,
and how they make selections.
They like to line their
burrows with these things.
And so you can see, for
example, in this reconstruction
that quite a few of-- these
are bits of cabbage and paper
cut-outs have disappeared.
You can kind of test
their preferences
for different shapes and
sizes of these paper cut-outs
exactly the way Darwin did.
Well, that is really just
them the merest introduction
to the weird and wonderful world
of Darwin's experimentizing.
Again, I really do
appreciate this opportunity
to share this with you.
Thanks so much for
your attention today.
And of course, thank you,
and of course, very happy
to answer any questions
that you might have.
Yes?
AUDIENCE: Thank you
so much for the talk.
It was quite interesting.
I didn't know
anything about Darwin
the man versus his science.
One thing I'm wondering
is, obviously, Darwin
was special in his time, because
he made a lot of discoveries
and had theories that
turn out to be true
that others did not make.
So why was he special?
I mean, what was it in his
upbringing, or in his person,
or something that made
him do those things?
JAMES T. COSTA: That's
a good question.
I mean, of course, he
blundered a lot too.
There were a lot of false
starts and dead ends as well.
Darwin, himself, reflected on
his insights, on his successes.
And he really thought
that a certain persistence
was a lot of it.
So if he's special, it
may be that he really
had to stick-to-itivness.
He would have an idea and
really pursue that idea.
I mean, just to the n-th degree,
he would he would pursue ideas.
And sometimes, they
just did not pan out.
He just blew it completely.
But other times, they ended up
yielding incredible insights.
And from a modern perspective,
it's really interesting,
especially for
historians of science,
how many fundamental scientific
principles in ecology
and evolution have their basis
in these very simple backyard
experiments.
But I think that a lot of it
is really the persistence.
Of course, he had
the advantage too--
this is with hindsight, right?
But he's one of the very
few, maybe apart only
from the great Alfred
Russell Wallace,
his colleague who independently
discovered the principle
of natural selection.
He had this evolutionary
view of things,
relationships of organisms,
the evolutionary history
of organisms, the mechanism
behind it, natural selection.
With the benefit
of that knowledge,
that guided many questions.
Now the fact that he got
so much right when he--
almost alone, except for
Wallace-- had this vision.
And so he's really the only
one asking such questions.
So that also accounts
for a lot of his success.
If you're about the only
one investigating an area,
you're bound to be making a
lot of the first discoveries
in that area.
AUDIENCE: You mentioned
a couple of his partners
that he worked closely
with and corresponded with.
And of course, he
partnered with his kids,
it sounds like, on some
of these experiments.
But was there a larger
network of scientists
that he was a part of,
sort of beyond the call
for crowdsourcing, on
a regular basis who
were sort of interested and
engaged in the same pursuits?
JAMES T. COSTA: Yeah,
that's a good question.
And so yeah, despite
the fact that Darwin
became quite a homebody--
he rarely traveled, except maybe
to some holiday destinations.
Maybe he went as far as Scotland
after his famous Beagle voyage,
but really, very
much stayed at home.
And yet, quite a few scientific
visitors came to him.
And his correspondence
is voluminous,
I mean, tens of
thousands of letters.
So he is very much a part
of a scientific network
that is global.
And of course, once he achieves
a certain level of fame,
people are very happy to send
in data, share information,
send specimens.
In addition, right there in
London, London's Scientific
Society, he benefits
from his buddies.
Joseph Hooker, one of
the leading botanists
of his day in the UK, certainly,
is the director of Kew Gardens.
And Kew is, perhaps,
at that time,
the greatest global
center of living plants
sent from around the world.
So Darwin is able to do
a lot of experimenting
on plants that Hooker would
very kindly just lend him.
So here you have the
greatest national collection
at your fingertips, fabulous.
And London was very
much the center
of British scientific society.
And he was never very far away.
He would sometimes go into
the scientific societies
to meetings reading papers.
But just as often,
they would come to him.
And so I think it's fair to
say that he was very much
certainly nationally and
also globally connected,
even though he rarely left home.
This is all a part, of course,
from a crowdsourcing, yeah.
AUDIENCE: I was
thinking of a question
before you sort of got into
that about that idea of--
geographically,
what do you think
were the advantages, besides
his proximity to London,
of Darwin doing his
studies where he did them?
Do you think that
there is something
about the ecology of the
sort of British Isles
that gave him an advantage?
Or do you think it
really was more just
being able to tap into
that global network
that the British
Empire had at the time?
JAMES T. COSTA: That's
a good question too.
I would say, no.
I don't think that
there's anything
really special about the place.
In fact, in some
ways, it's actually
not a very good place to conduct
certain types of experiments.
There are certain
groups of organisms
that are very low and
diversity, for example.
I think it more has to
do with, first of all,
these types of
experiments, they really
can be conducted
almost anywhere.
So there is that, but
beyond that, nothing,
in my opinion, very special
about that geography
immediately there--
so therefore, benefiting more
from his place in society,
proximity to London, his
good friends who were really
the leaders of British
science at that time, and then
his ability, through his own
fame and accomplishments,
to attract the support of
people around the world.
He had good friends
here in the US.
He had a global network.
I think that was more important
than the particular geography.
That geography turned
out to be tremendously
interesting and important.
But I don't think
that it, itself,
set the stage for these
interesting experiments
necessarily, maybe
with one exception.
And that would be earthworms.
In any glacial landscape--
so here, North America,
glaciated landscape, earthworms
were extirpated.
So you don't have
nearly the same--
there were exotic
worms introduced here.
But the native
fauna was extirpated
in the last glacial maximum.
So that did not happen
where Darwin lived.
And so maybe at
least the earthworms
depended on that geography.
AUDIENCE: Thanks for speaking.
My question for you is, why is
Darwin such a popular figure
in even modern era?
There's a lot of scientists
that did a lot of amazing work,
such as Mendel, Hooker.
And we don't really know their
name off the top of our heads.
Whereas Darwin,
even though he seems
like he's very
much of a homebody
and he's not like a fun,
quirky, kind of guy, everybody
knows who he is, even today.
So what is it about either the
volume of the work he created
or the type of work created
that made him so well-known far
and wide?
JAMES T. COSTA: Yeah, yeah.
Now that's a very
good question as well.
I mean, I think that
it has much to do
with the very subject
itself, Darwin
becoming associated
just inevitably
with this idea of evolution
by natural selection.
And now, as I showed here, after
"The Origin," book after book,
he really is reinforcing
and extending.
So he truly saw the
implications for this idea.
And he sought it out
in all of these areas.
So he's to be maybe commended
for really solidifying
and extending a
body of knowledge,
a certain way of
understanding the world.
But at the same
time, I think you all
recognize that, in some
parts of the world including
in our country, the
idea is polarizing.
And Darwin also became the kind
of therefore poster child for--
and it's a caricature,
really-- but this idea
that these scientific ideas
must therefore be opposed
to religion and society.
Some elements of that were
seen in British society
in the late 19th century.
And it really became
rekindled and intensified
in the 20th century,
especially in the US.
I think that he represents
that idea that some people find
deeply distressing,
disturbing, blasphemous,
however you want to put it.
As the sort of poster
child almost for this idea,
he then becomes iconic.
And I think that that's
all a lot of it as well.
And as it's true in the
history of science generally,
it's unfortunate but
true that there are just
a select few individuals that,
for whatever quirky reason, end
up becoming household
names and representing
whole, vast disciplines
that actually
have armies of very talented
investigators behind them.
And those investigators
are unsung, typically,
outside the field,
perhaps and unknown.
And certainly with Darwin, it's
on a whole different scale,
because of the societal
implications of these ideas,
I believe.
Thank you, everybody.
