The Wallace Line, Part 1

In this episode of Stuff to Blow Your Mind, Robert and Joe discuss the faunal boundary line between Asia and Australia known as the Wallace Line and the British naturalist it was named for, Alfred Russel Wallace.

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Episode Transcript

Speaker 1 (00:03):
Welcome to Stuff to Blow Your Mind production of iHeartRadio.

Speaker 2 (00:12):
Hey you welcome to Stuff to Blow your Mind. My
name is Robert Lamb and.

Speaker 1 (00:16):
I am Joe McCormick.

Speaker 2 (00:18):
And as I mentioned in at least a couple of
previous episodes of the show. Over the summer of this year,
in twenty twenty five, my family traveled to Indonesia for
some snorkeling, and in learning all about the local environment
of Raja Ampat, the guides kept mentioning an individual by
the name of Alfred Russell Wallace, as well as the

(00:38):
faunal boundary named in his honor, the Wallace Line. In fact,
I would say that Wallace was invoked, one way or
another nearly as much as Darwin was invoked on my
visit to the Galapagos Islands in a couple of years prior. So, yeah, Wallace,
the Wallas line I mentioned a lot in terms of
just describing what was happening in the natural world around

(00:58):
us and in Indonia at large.

Speaker 1 (01:01):
That's a funny comparison, because, of course, if you know
one thing about Alfred Russell Wallace, it is probably that
he was the other guy to come up with a
version of the theory of evolution by natural selection around
the same time that Darwin did. Though Darwin tends to
get most of the credit, and I think in many
ways people understand Darwin to have articulated a more rigorous

(01:24):
form of it. Wallace essentially had the same idea around
the same time.

Speaker 2 (01:29):
And to be clear that they knew each other, and
in fact, Alfred Russell Wallace greatly looked up to Charles
Darwin and they were on friendly terms their entire life,
even though they disagreed on some key issues here and there.

Speaker 1 (01:43):
Yeah. Well, actually the version of the book that I
was reading, so it's Wallace's book the Malay Archipelago, or
where he's writing about his travels and observations in that
region of the world. The edition of that book that
I was reading is actually dedicated to Charles Darwin. Charles Darwin,
author of the Origin of Species. I dedicate this book

(02:04):
not only as a token of personal esteem and friendship,
but also to express my deep admiration for his genius
and his works. So it's elaborate. It seems like no
heart feelings.

Speaker 2 (02:15):
There, right, right. It's also been pointed out that you know,
they knew what each other were up to around the
same time, and in Wallace's work and Wallace's ideas kind
of poked Darwin and got him to sort of realize, oh,
I really need to push forward with on the Origin
of Species and maybe not focus on other projects at

(02:35):
this very.

Speaker 1 (02:35):
Moment, stop collecting beatles, write the book.

Speaker 2 (02:39):
Yes, so we'll be talking more about Alfred Russell Wallace
here shortly. But as for the Wallace line, I'm gonna
go ahead and throw out the short answer of what
this is and we'll get into it more later in
this episode and in the next episode. But basically, it
represents the place between the Indonesian islands of Bali and

(03:00):
Lombac where the Australian and Asian faunas separate. So it
separates the Indonesian archipelago between the parts influenced by Asian
fauna and the parts influenced by Australian fauna. So you know, rhinos, elephants,
tigers on one side, kangaroos, monitor lizards, and koalas on
the other.

Speaker 1 (03:18):
Yes, exactly, with some caveats that we will discuss as
we move on throughout the series.

Speaker 2 (03:23):
So let's talk a bit about Alfred Russell Wallace here.
You can look up images of the man illustrations and photographs,
who is, of course a nineteenth century naturalist, explorer, traveler,
academic writer, and totally look the part, you know, you know,
English beardy guy who's out there in the wild exploring things,

(03:44):
or you know, back at home in his study writing
about them.

Speaker 1 (03:47):
I was almost going to say, if Darwin is Almond Joy,
Wallace looks like Mounds. He just looks like a kind
of like, I don't know, a less crunchy version of Darwin,
kind of a softer, smoother text here.

Speaker 2 (04:00):
You get. You could definitely say that, and it holds
up in many ways, but in other ways, as we'll discuss,
Alfred Russell Wallace was kind of the Almond Joy to
Darwin's Mounds. Okay, so yeah he let. Alfred Russell Wallace
lived eighteen twenty three through nineteen thirteen, so long lived
and fascinating individual. Multiple books have come out in recent

(04:22):
years about him, but the one that I was mainly
looking at is Radical by Nature, The Revolutionary Life of
Alfred Russell Wallace, and this is by James T. Costa,
came out in twenty twenty three, and as the author
points out, yeah he was like a lot of people,
he was a complicated individual, and there were certainly some
seeming contradictions in the way he made sense of the world,

(04:46):
the natural world, humanity's place in the cosmos, and so forth.
So I'm going to break into a little bit of
his biography here. I'm not going to go in to
super detail, but I'm going to try and hit some
of I think maybe the key points to getting like
an overall understanding of who this guy was and some
of the more interesting aspects of his life, and certainly
those contradictions. So he was born to a middle class

(05:08):
Scotch English family. A family on his father's side claimed
to have an an ancestral connection to thirteenth century noted
individual William Wallace, the Brave Heart guy for those of
you relying on cinema for your history.

Speaker 1 (05:24):
For fans of accurate history.

Speaker 2 (05:27):
But yes, it claimed to be descended from William Wallace.
Whether that's true or not, who knows. But he initially
worked as a surveyor, but remained vitally interested in many
aspects of the world. So he was luckily was interested
in botany. He had all these other natural history pursuits
that he was leaning into and at the same time

(05:47):
he was also attending talks about socialism, about spiritualism. He
was also interested by mesmerism.

Speaker 1 (05:54):
The practices of Franz Mesmer, also known as the theory
of animal magnetism, not given any credit today.

Speaker 2 (06:02):
Yeah, yeah, definitely, but also gets into the sort of
the whole hypnosis sphere of things for sure. On top
of this, he taught, he lectured, and of course he read.
He was familiar with the writings of the time of
Alexander von Humboldt, of Charles Darwin and many others, and

(06:22):
in part due to their inspiration, he decided that he
too would go out and see the world as a
naturalist explorer.

Speaker 1 (06:29):
That's right, because, of course Darwin became famous for his
writings about the Voyage of the be Goal, long before
he actually published on the origin of species, before he
had a theory of evolution, he just had his travelogue
of observations or going around the world on a ship
called the Beagle.

Speaker 2 (06:45):
Yeah, so that seems very much be the blueprint that
Wallace has selected for his own life as well. And
so he departs on a journey to South America, particularly
focused on the Amazon, and he and his team they're
studying the peoples of these areas the natural history of
this region, and then on the return trip, their boat

(07:07):
catches fire and they're stuck in a life raft for
I believe ten days, and then eventually rescued. So he
apparently lost all of his notes in a misadventure, this
part of the adventure anyway, but he was still able
to write multiple papers about about it when he got
back to England. Also, I believe that a number of
specimens that he'd collected had been shipped back ahead of time,
so not everything was lost, but a lot was lost.

Speaker 1 (07:30):
On that ship.

Speaker 2 (07:31):
But he wasn't quite done with traveling and exploring, which
may come as a shock because I don't know. I
think a lot of us might think that once your
ship has burned and you've wound up in the lifeboat
for ten days, you might have had enough. But not
so for Wallace.

Speaker 1 (07:44):
I'm going to read later in this episode from a
chapter in the Malay Archipelago where he's talking about his
experiences in Bali and Lombach. But he is not above
complaining about the hardships he faces on his journeys and
the difficulties he has in doing his work. But it
is still admirable about that he can just like face
that kind of thing and move right on.

Speaker 2 (08:06):
Yeah, and in a way admirable that you can still
be irritated by the little stuff later on, you know,
after having wound up in the lifeboat for ten days,
to still be able to say, ah, this desk is
the worst.

Speaker 1 (08:18):
We're gonna get some epic complaints about it's hard to
do science when everything is covered in ants.

Speaker 3 (08:24):
Oh, good goodness, I bet that is true.

Speaker 2 (08:36):
So anyway, he was not done traveling, and after he'd
gotten back, and you know, he published a bit about
his travels. He soon became fascinated with the Malay Archipelago
or the Indo Australian Archapelago, consisting of what is now
Indonesia and neighboring nations also known as the East Indies
at the time. His subsequent travels in this region lasted

(08:58):
from eighteen fifty four to eighteen sixty two, so eight years.
And during this time he and his hired team collected
thousands upon thousands of specimens to return home and go
to various museums and institutions. I read a BBC article
pointed out that the number here was something like one
hundred and twenty five six hundred and sixty natural history specimens,

(09:21):
including more than eighty three thousand beatles.

Speaker 1 (09:24):
So the majority of it was beatles. Yeah, it's just
a lot of beetles, well over half. I mean.

Speaker 2 (09:31):
Also, it seems like the beatles would be relatively easy
to send back. It's a lot easier to send back
a beatle as opposed to say, a Komodo drag.

Speaker 1 (09:39):
That's true, And once again we're going to revisit why
it was so hard sometimes to send things back.

Speaker 2 (09:44):
And of course he wrote about his travels as well,
and this is when he wrote the eighteen sixty nine
book The Malay Archipelago. This is the book you were
talking about earlier, a book that would go on to
become an international bestseller, describing all the islands he visited,
the sorts of natural and human elements on each, a
little bit of griping about the ants and the desks.

(10:07):
But this is a book that resonated with people, you know,
within his profession and within academia, but also outside of
those boundaries. It was just a book that a lot
of people read and it kind of made him a celebrity.
Like it cemented his status and also ensured that he
was able to keep going and keep writing later on,

(10:28):
certainly after a few economic setbacks that he encountered.

Speaker 1 (10:33):
I found it captivating. There was while we were preparing
to record this episode, I started reading a couple of
chapters from this book, mainly because I was looking for
Wallace to describe a scientific theory that we're going to
get into, and I ended up not finding really any
sycinct place where he does describe this theory. But I

(10:54):
was just sucked into the writing because it's so interesting
and so good and in many ways reminds me of
his contemporary Darwin in that regard, who also I think,
and this of course doesn't diminish from the validity of
his theory. But also just like Darwin's books are a
great read, they're like, they're very well written, and I
would say Wallace is are.

Speaker 2 (11:14):
Two yeah, yeah, yeah. The Malay Archipelago of Volumes one
and two, the subtitle here being The Land of the
Orangutan and the Bird of Paradise, a narrative of travel
with sketches of men and nature.

Speaker 1 (11:28):
Oh well, Rob, since he mentions the orangutan in the title,
you should scroll down in the outline, because I included
a screen capture of the page opposite the title page
in the eighteen ninety edition I was reading, which has
an illustration of a brutal orangutan attack where the orangutan

(11:49):
is jumping on a guy and biting a chunk out
of his arm. Skeptical this happens that much in nature?

Speaker 2 (11:56):
Yeah, that's generally not the reputation they have today. It's
so weird that this was the second time today I've
had to think about the possibility of a killer orangutan. Because,
as many of you are aware, the actor Terrence Stamp died,
I believe over the weekend recently passed, and so there
was some some chatter here and there about his past movies,
and I was looking around and I realized he was

(12:18):
in a nineteen eighty six film called Link that is
about a super intelligent, malicious chimpanzee, but the chimpanzee is
played by an orangutan.

Speaker 1 (12:29):
Oh okay, I thought you were going in a totally
different direction. I saw the headline that Terence Stamp had died,
which you know Neil before.

Speaker 2 (12:36):
So odd.

Speaker 1 (12:37):
And I don't mean any disrespect here, but I truly
thought you were going to say he died in an
orangutan attack.

Speaker 2 (12:43):
No, no, no, but yeah, this this illustration from the
book definitely made me think of that. But it also
has a rather sweet image of an orangutan here, So.

Speaker 1 (12:53):
Yeah, yeah, it's both. Yeah. But from what I understand
to Ragatan, it's not that they can't attack humans. I
think they're known generally to only do this when like
really threatened in some way. They're generally aggressive.

Speaker 2 (13:06):
One thing we know from the interaction between humans and
animals is that if the animals can be provoked into
attacking humans, we will have done it at some point
or another.

Speaker 1 (13:17):
Yeah. But though, of course, some animals are much easier
to provoke than others, and orangutans are not usually thought
to be on the super high end of provokability. However,
this illustration is sick.

Speaker 2 (13:26):
I mean, yeah, bite some right in the arm. But yeah.
In this book, though, this is where he does get
in a bit into the idea of the Wallace line.
Now he didn't call it the Wallas line. I believe
Darwin's bulldog Thomas Henry Huxley called it that in his honor,
but he does get into the concept a little bit.

Speaker 1 (13:46):
Huxley also proposed some modifications to Wallace's original placement of
the line.

Speaker 2 (13:53):
Now we get into the details in a bit, but
basically the way that Costa describes it in his book
is it was the realization that there was there was
a growing realization quote, a growing awareness among naturalists that
anomalist patterns of distribution might provide unique insights into the
history of the planet geologically and climatologically. So so again,

(14:19):
this was this was happening with Wallace, but this was
happening in other parts of the world, with naturalists looking
at at distribution data and saying, well, this is interesting,
we have we have X going on here? Why going
on here? What does this tell us about how the
world works, About how species have moved around or been
moved around, about some of the barriers and potential barriers

(14:41):
to their movement and so forth.

Speaker 1 (14:43):
Yeah, and about the abiotic history of the planet, like
the fact that the distribution of animals as you find
them today can tell you things about the history of
climate change on the planet, about ice ages and sea levels,
and even about underlying geologic activity such as plate tectonics,
which would not be you know, fully accepted as a

(15:04):
theory I think until nineteen sixties or so much much later.

Speaker 2 (15:08):
So we mentioned the fact that he independently came up
with the concept of evolution by natural selection around the
same time as Darwin, and then Darwin kind of pushes
ahead and gets on the origin of species out in
some ways. Wallace was also an early environmentalist and his
voice concern over humanity's impact on the planet, and he

(15:30):
also engaged in a number of social activism causes during
his life, including women's suffrage, land nationalization, and various sort
of pacifist and anti militarism causes. But in an area
that might seem rather contradictory to all of these scientific pursuits,
he was also a spiritualist, and not just one in

(15:52):
his non academic life, not just like okay, academic scientific academic,
a naturalist by day and a spiritualist by night. No,
he actively wrote on it and attempted to defend it
in academic writings.

Speaker 1 (16:04):
Now, to clarify, in the context of these nineteenth century movements,
when we say a spiritualist, that doesn't mean the same
thing as like somebody who would say, oh I'm spiritual today,
that would this means something more specific about like beliefs
that you could contact the dead, or that you could
that living persons could have communication with spirits or other

(16:25):
beings other than living humans.

Speaker 2 (16:27):
Yeah, we're talking about specifically here. We're talking about the
sort of spiritualists that you would go to and there'd
be a seance or there would you know, offer generally
for money to help you connect with the spirits of
the dead. The kind of people that Houdini did not like,
the kind of people. If you watch The Gilded Age
on television, the most recent season has included this element

(16:50):
in its plot.

Speaker 1 (16:51):
Yeah, it's come up on the show before that. Actually,
a surprising number of people from history in nineteenth century
you're in America, people who are in many ways kind
of admirable for their time, really got into spiritualism, really
thought you could talk to the dead.

Speaker 2 (17:08):
Or other Conan Doyle is a prime example of this.
I really got into it late in life. So you know,
it's it's one of those one of those things where
there are multiple pieces to it. As I think we've
probably discussed on the past. On one level, you do
have people actively selling you this stuff, and on the
other you have a genuine desire on the part of

(17:32):
the bereave to connect with the people they miss, and
you know, there's in a perfect world, there's probably a
balance there between the two where no one's exploited and
everyone's life is made a little easier. But we don't
live in such a world, and so things will often
lean in the wrong direction there. But again, not just
a naturalist by day and a spiritualist by night, Like

(17:53):
I say, he wrote papers where he defended spiritualism and
so forth.

Speaker 1 (17:57):
Yeah.

Speaker 2 (17:57):
Now, on the other hand, he opposed flat earth pseudoscience
of the day and wrote against that, and then going
back to the other side of things, he did involve
himself in anti vaccination efforts of the day. This would
have been, I believe measles the vaccine that he was
opposed to. But in his opposition seems to have been
a mix of like sort of personal choice, like I

(18:19):
don't want to take it that. You know, we see
similar attitudes today. But also it seemed to factor into
his view that like nature was perfectly balanced already and
therefore there was no reason to tip the scales as
far as diseases go. I don't know. I would say
that the counter argument to that is that as far
as diseases and humanity go, that everything is already out

(18:40):
of balance, and therefore you need the vaccines in place.

Speaker 1 (18:44):
Well yeah, I mean a lot of the times people
prefer one course of action over another because it's more natural.
It just kind of reflects a vague and not very
well thought out understanding of what the concept natural really means.
I mean, there are a lot of things that just
kind of seem natural to you, but then you investigate
them and realize they're actually very much the product of

(19:05):
human intervention in some way.

Speaker 2 (19:08):
Well, his distinction is natural. It doesn't mean I want
for myself.

Speaker 1 (19:11):
Yeah, it is natural to just like all get disease
and die. Sure, I mean is that good?

Speaker 2 (19:18):
So yeah, he was. He was an interesting guy in this.
His spiritualism especially did put him in odds with many
of his fellow scientists, and even when it came to
evolution binatural selection, he argued for a kind of evolution
driven by the divine, essentially that animals evolved via natural

(19:38):
selection and humans did to a point, and then some
other force takes over something, something divine. He didn't actually
call it a creator, because interestingly enough, he himself was
a religious skeptic, so he at different times self identified
as agnostic or just a non religious person, and so
he referred to this as an overruling intelligence.

Speaker 1 (20:01):
It's interesting how if you go back just to you know,
one hundred years or so, you get a lot of
fine distinctions in religious beliefs that where the distinctions don't
make a lot of sense to people today, but they
you know, they made sense to people at the time.

Speaker 2 (20:14):
Yeah. Yeah, he was a firm believer that he thought
without this overruling intelligence becoming involved, there's no way that
the human brain, or human speech organs, or even our
hands or our bipedal posture could have possibly evolved. Like
there had to be some other force, you know, like
a monolith getting involved in our advancement. Yeah, and you

(20:39):
know that's kind of a sticky idea. That's why we
see it all over our science fiction, right Yeah.

Speaker 1 (20:43):
Yeah, and you know it's still a common idea. I mean,
this is formally argued by creationists today, but I mean
it's still it's naturally appealing to look at something very
complex and think, well, that couldn't have just happened. Of course,
I think that the leap that you're not able to
make is that it happened gradually and by degrees.

Speaker 2 (21:03):
Yeah. Yeah, And you know, I often think about this.
I think that, okay, you know, a much softened version
of this is is maybe quite reasonable, in a quite
reasonable way to balance science and religious faith. You know, say, well, okay,
evolution by natural selection is the method by which the
divine creates life? And why not because it seems like
the very sort of elaborate, long term method that an

(21:26):
eternal and all powerful entity unconstrained by time might very
well employ.

Speaker 1 (21:30):
Sure, I mean, I think that's what millions of people
believe today. Yeah, nothing wrong with that.

Speaker 2 (21:35):
Yeah. On the other hand, it is worth stressing that
when you get into the particulars of this sort of stance,
saying well, okay, everything evolves, but then humans evolve differently,
human brains are different because of some divine force, you
can get into some really nasty and even racist views
on human evolution by deciding just where and how you

(21:55):
want to deploy this theory.

Speaker 1 (21:57):
Ah, yeah, okay, So appealing to supernatural force is to
inject a certain specialness into you know, certain you know,
animals on Earth, and certainly there's nothing that prevents somebody
from thinking that some humans are more special than others.

Speaker 2 (22:11):
Right, right, So I'm not saying that was Wallace's whole deal,
but those are kind of those are the waters you
can easily creep into by pursuing this line of thinking. Yeah. Now,
with Wallace, it certainly put him in odds with many
of his fellow scientists, including Charles Darwin himself, who who
worried that Wallace was hurting their cause by adding this

(22:32):
caveat to his own take on natural selection, and according
to Tacosta, even wrote to him and said, quote, I
hope you have not murdered too completely your own and
my child, referring to the theory of natural selection. Again, these
two were friends, and Wallace, you know, continued to respect
Darwin the rest of his life. But yeah, Darwin rather

(22:56):
bluntly saying I really wish you hadn't put it like that,
you know, trying to get this theory of natural selection
out the door and accepted at this point, and you're
perhaps muddying the waters by coming in with this, you know,
your unique spiritualist take on everything.

Speaker 1 (23:11):
Yeah, though, I guess one thing that's supposed to be
good about being friends is that you can be frank
with each other.

Speaker 2 (23:16):
Yeah, you know, but yeah, Wall this seems to have
been a guy who you know, had, as I think
Costa puts it, at one point, he had a lot
of adventures and a lot of opinions in his life.
He was real quick to weigh in on things, and
well into his eighties he was still doing this, you know, still,
I mean, I think until the end of his life
pretty much, you know, constantly writing letters, writing his own

(23:38):
take on different topics, and in fact, in nineteen oh
four he put out the book Man's Place in the Universe,
and in that he takes his own serious look at
the idea of life on other planets, especially Mars, because this,
of course is the time when we have the whole
Canals of Mars idea out there in everyone's minds, you know,

(24:02):
the idea that we've seen things on Mars and what
of their canals, and we get this built up idea
of their people of some sort on Mars and they're
a dying race and they're having to build these canals
and so forth. It really captivated everyone's imagination.

Speaker 1 (24:15):
We've talked about that at some length on episodes in
the past, and now I don't remember which ones did
that possibly come up in our discussion of the ashen
light of Venus. It might have, Yes, that's my best guess.
So this was a nineteen oh four book and I
have not read it, But Costa gives his own breakdown
of it and points out that, okay, he's basically opposing

(24:38):
the idea of life on Mars on two levels. On
one level, he is making a very logic based counter argument.
He himself was an astronomer and pointing out things about
what was known.

Speaker 2 (24:50):
About Mars versus Earth at the time. He just did
not think it was likely that this was true, and
of course, as we would find out very shortly thereafter,
it was and true. But as Costa points out, it
also ran opposite to his belief that humans had a
privileged place in the cosmos, that we were the end
result of not only earthly processes but also cosmic processes

(25:13):
as well. This getting into the whole idea of humans
were special because some sort of force beyond us had
pushed us into these like upper levels of evolution that
were denied to you know, or other organic life forms
on Earth.

Speaker 1 (25:29):
So the overruling intelligence of Wallace's view of the universe
would not have allowed life on Mars.

Speaker 2 (25:34):
Right, right, The whole idea is that we're alone and
we're special. If the if, if we've got life next
door as well, then that just destroys the whole argument.
So that seems like it might have also been there,
you know, pushing his his criticism of this idea. Though
to be clear, this book, he's also apparently very polite
in his takedown of the Martian canal hypotheses because he

(26:01):
you know, he's ultimately you know, friends or at least
correspondence with everyone that's talking about it at the time.

Speaker 1 (26:06):
Well, I'm sorry if I misunderstood. Did he also have
like observation based or empirical reasons for doubting canals on
Mars or.

Speaker 2 (26:15):
It wasn't just based in his worldview, But no doubt
that worldview was also pushing him to make all of
these arguments. You know.

Speaker 1 (26:22):
Okay, so he was right, but for some of the
right and some of the wrong reasons.

Speaker 2 (26:28):
Yeah, that seems to be the take on it. But again,
I haven't actually read the book in question, So again
that's just a brief overview of the of the the
man here. I think it highlights some of the inherent
contradictions that are present there, that ultimately are going to

(26:50):
be present in anybody. But maybe you're a little more
expressed in the biography of Alfred Russell Wallace.

Speaker 1 (26:57):
Yeah, very interesting character. And so I guess now should
we move on to talking a bit about the Wallace
line at least what the concept is, and then I
think maybe in part two we'll get into some more
depth about it, nuances that have been added to it
since the time of Wallace. Yeah, all right, So we
alluded to this earlier, but to recenter us here. In

(27:18):
addition to independently discovering a version of the theory of
evolution by natural selection again around the same time Darwin did,
Alfred Russell Wallace is also widely considered the founder of
a field now known as biogeography, the study of how
life is distributed over the surface of the Earth. Another
way to put it is what lives where and why.

(27:42):
By the way, you mentioned him earlier, but another important
contributor to the early study of biogeography was the pre
Darwinian German naturalist Alexander von Humboldt. Very interesting figure who
we've talked about a good bit on the show before.
I think one of the main contexts was a summer
reading episode we did years ago where I was talking

(28:02):
about a great biography of him by Andrea Wolfe called
The Invention of Nature. Von Humboldt was important in helping
to move the burgeoning natural sciences of the nineteenth century
away from this long held Western view of nature as
a fixed order of discrete entities with eternal roles defined

(28:22):
by providence, and to replace that with a view of
nature as a complex and changeable web of relationships, these
interdependencies that are constantly in flux. Though unlike Darwin and Wallace,
von Humboldt himself never fully embraced the idea that species
themselves could evolve. His idea of change was more based

(28:43):
on the environment and relationships between species. So Darwin and
Wallace ended up going beyond von Humboldt. But anyway, as
I said, biogeography is the study of what lives, where
and why, and one of Wallace's most famous observations in
biogeography is the Wallas line. The Wallas line is what's

(29:03):
known as a biogeographical boundary line, specifically a faunal boundary.
In this case, meaning a boundary with reference to animals,
so it's an invisible border where you have one ecosystem
of animal species on one side of the line and
a very different collection of animals on the other. Animal
populations are not usually divided by hard boundaries. Normally, as

(29:28):
you wander toward the edge of an animal's population range,
you will notice a gradual thinning out of the population,
with the number of individuals becoming less and less dense,
sometimes being replaced more and more gradually with examples of
a different species in the same trophic niche meaning they

(29:49):
compete for the same food resources, So you may be
moving out of the range of one animal species and
into the range of another, gradually gradually. In both cases.
For the most part, the gea graphic range of an
animal species does not end in a hard boundary, but
in a soft and gradual one. But there are exceptions.
Sometimes you kind of hit a wall where there is

(30:12):
one set of animals over here and a pretty different
set over there, and that is to a large extent
what we find with Wallace's line, though, as we'll discuss,
there are some exceptions to this rule and some major
nuances added since Wallace first proposed this border in the
eighteen sixties. In fact, basically all biogeographical boundaries are somewhat permeable.

(30:35):
You will find exceptions to them, but they tend to
denote starker divisions in biodiversity than you will find elsewhere
in nature. So what's the story of the Wallas Line
in particular. Well, the Wallas Line passes invisibly through the
islands of the Malay Archipelago in the Strait between Borneo

(30:56):
and Sulawesi, and then further southwest through the lesser Sunda Islands,
cutting between the islands of Bali on the west and
Lombach on the east.

Speaker 2 (31:07):
While we were in Indonesia, we were east of the
Wallas Line, though we had to fly over it to
get to Raja Ambat from Jakarta. I will stress though
the pilot did not announce the crossing of the Wallace Line,
not that they had to, but I just want to
make it. And of course you can't see it.

Speaker 1 (31:23):
That's a plane, yeah, exactly, and there's nothing there to see.
In fact, it's kind of it's remarkable how invisible it is.
In a way. So I was speaking of the division
between these multiple land masses Borneo and Sulawesi, and Lombock
and Bali. The latter division is probably the most striking,

(31:44):
because the Lombok Straight, which passes between Lombac and Bali,
is in some places only a few dozen kilometers wide.
Like if the air is clear, you can stand on
the shore of one island and look across and see
the other island. You see the higher elevations on the
other island. So they're very close, and in terms of
environmental conditions they're very similar. And yet when Alfred Russell

(32:07):
Wallace studied the land animals and the birds of these islands,
he noticed a pretty stark difference. Wallace writes about some
of these observations in the book The Malay Archipelago, again
first published in eighteen sixty nine. So the version of
this book I was looking at is a scan of
the eighteen ninety edition. That's the one with the sick

(32:29):
illustration of the orangutan biting the guy. And Wallace writes
that the islands of Bali and Lombach are most interesting
actually because of two things. One of them is that
he claims they're the only two islands of the whole
archipelago in which the Hindu religion still maintains itself. And
then he also says, quote they form the extreme points

(32:52):
of the two great zoological divisions of the Eastern Hemisphere.
For although so similar in external appearance and in all
physical features, they differ greatly in their natural productions. So
what's the difference in these natural productions between the two islands. Again,
while there are exceptions and some nuances, will discuss later,

(33:12):
the range of a ton of major animal groups essentially
terminates at this tiny ocean gap. On the eastern side,
in Lombach you will find native cockatoos and marsupials, the
animals associated with Australia and New Guinea. And on the
western side of the gap, in Bali and Borneo, you

(33:33):
will not find those animals, not natively unless you know,
you find some imported. Instead, you will find mostly the
same animal groups that you find in the rest of Asia,
including at least as of a few hundred years ago,
before many of these animals were driven extinct. You would
find tigers, rhinos, elephants, and bears. So you've got one

(33:56):
on one side, one on the other, and then you've got,
of course, some more trans yusitional areas we'll talk more
in Part two. I think about the idea of a
whole group of islands known as Wallace Sea that are
thought of now as a kind of transitional island group.
But on the island of Sulawesi you will also find
more of a mix with some native Australian or Australasian

(34:18):
fauna and some Asian fauna. Now, the question of why
is really interesting, and that's something we're going to have
to come back to. But first I just wanted to
get some more color on Wallace himself and his travels
in these islands, specifically his chapter in the Malay Archipelago
on his visits to Bali and Lombach. He makes an

(34:39):
interesting biographical note that his first visit to these islands
in eighteen fifty six was quote somewhat involuntary. He was
like trying to get a He's trying to get a
ship to take him to Macassar on Sulawesi from Singapore,
but he couldn't for some reason, and his journey got
diverted to these islands at the east end of Java.

(35:00):
And he writes that if he had been able to
get the passage he wanted from Singapore, he probably never
would have gone to them quote, and should have missed
some of the most important discoveries of my whole expedition
to the east.

Speaker 2 (35:13):
So just pure travel mishaps playing into again the most
important discoveries of his career.

Speaker 1 (35:19):
So, Robert, are you cool if I read some passages
from wallas here?

Speaker 2 (35:22):
Yeah, let's have it, Okay.

Speaker 1 (35:23):
This will give us a flavor of his writing and
some of his experiences in Bali and Lombach, both those
that inform the formulation of the idea of the Wallace line,
and also just some interesting stuff he comes across. So,
first of all, there's a passage where he's describing the
terraced agriculture of Bali, where he says he says, quote,

(35:45):
a slightly undulating plain extends from the seacoast about ten
or twelve miles inland, where it is bounded by a
fine range of wooded and cultivated hills. Houses and villages
marked out by dense clumps of coconut palms, tamarin and
other fruit trees are dotted about in every direction, while
between them extend luxuriant rice grounds watered by an elaborate

(36:07):
system of irrigation that would be the pride of the
best cultivated parts of Europe. The whole surface of the
country is divided into irregular patches, following the undulations of
the ground, from many acres to a few perches in extent,
each of which is itself perfectly level, but stands a
few inches or several feet above or below those adjacent

(36:28):
to it. Every one of those patches can be flooded
or drained at will by means of a system of
ditches and small channels into which are diverted the whole
of streams that descend from the mountains. Every patch now
bore crops in various stages of growth, some almost ready
for cutting, and all in the most flourishing condition, and
of the most exquisite green tints.

Speaker 2 (36:50):
Oh that's nice, I would say, oh succulent. Yeah.

Speaker 1 (36:53):
I found his writing style very vivid, like it really
calls pictures to the mine way that a lot of
older writing, especially you don't quite get that immediate connection
to the visual imagination. Something about Wallace's style does for me.

Speaker 2 (37:10):
Yeah, there's a sense of awe here as well.

Speaker 1 (37:12):
Yeah, But anyway, from here, Wallace goes on to describe
his attempts to collect a few specimens in Bali. So
he says, in so well cultivated a country, it was
not to be expected that I could do much in
natural history. That kind of makes sense, right, Like it's
harder to collect specimens from all of this well kept

(37:32):
farm the farm, ye, yeah. And my ignorance of how
important a locality this was for the elucidation of geographical
distribution of animals caused me to neglect obtaining some specimens
which I never met with again. One of these was
a weaver bird with a bright yellow head, which built

(37:52):
its bottle shaped nests by dozens on some trees near
the beach. It was the Ploceus hypoxanthus, a native of Java,
and here at the extreme limits of its range. Westerly
I shot in preserved specimens of a wagtail, thrush, an oriole,
and some starlings, all species found in Java, and some

(38:13):
of them peculiar to that island. I also obtained some
beautiful butterflies, richly marked with black and orange on a
white ground, and which were the most abundant insects in
the country Lanes. Among these was a new species which
I have named Pieris tamar okay. So that's his experience
in Bali. You know, he doesn't collect a lot of

(38:33):
specimens because he doesn't know how significant this place is
going to be. And he got here by accident anyway,
didn't even expect to go here. Notices a few things,
but it's all the western fauna. It's all the same
kind of stuff you would see in Java, the same
kind of stuff you would see grouped with other animal
species generally in Asia. But then he moves on in

(38:54):
his ship to Lombach, and he notes by the way
that traversing the strait sometimes the weather or the chop
in the strait can be pretty rough. And there's a
story of him like pulling all of his things ashore
and you know, being very grateful to get all of
his specimens and bags and stuff on shore. And the

(39:15):
locals tell him, oh, it's good that you did. The
sea is hungry and it takes everything it can eat.

Speaker 2 (39:20):
Oh the South Sea Queen grabs.

Speaker 1 (39:23):
Yeah. So I was thinking of his loss of all
his previous stuff from the other boat. But yeah. So
he moves on to Lombach, and here he notes finding
bird species that are not like the bird species on
the other island. They are more similar to those found
in Australia and New Guinea. He writes quote The country

(39:44):
around was pretty and novel to me, consisting of abrupt
volcanic hills enclosing flat valleys or open plains. The hills
were covered with a dense scrubby bush of bamboos and
prickly trees and shrubs. The plains were adorned with hundreds
of noble palm trees, and in many places with a
luxuriant shrubby vegetation. Birds were plentiful and very interesting, and

(40:06):
I now saw for the first time many Australian forms
that are quite absent from the islands westward. Small white
cockatoos were abundant, and their loud screams, conspicuous white color,
and pretty yellow crests rendered them a very important feature
in the landscape. This is the most westerly point on
the globe where any of the family are to be found.

(40:28):
Some small honeysuckers of the genus to Lotus, and the
strange mound maker Megapodius Gouldieye are also here, first met
on the traveler's journey eastward. The megapodious birds, by the way,
these are these You may have read about these before
these mound builder birds that are native to Australia and

(40:49):
New Guinea, where they will build mounds. All he describes
actually in a passage, the locals telling him about how
they build mounds out of anything they can get, garbage
or whatever. And you know, the locals know what to
look for in one of these mounds to know when
there will be eggs in it that are good for snatching.
In fact, I'll just read a passage from Wallace. He says,

(41:11):
the mounds are to be met with here and there
in dense thickets, and are great puzzles to strangers who
cannot understand who can possibly have heaped together cartloads of
rubbish in such out of the way places. And when
they inquire of the natives, they are but little wiser,
for it almost always appears to them the wildest romance
to be told that it is done all by birds.

(41:34):
Excuse me that it is all done by birds, But
that does sound like the wildest romance. Now Here, I
want to come to the part where Wallace describes the
difficulties of the physical part of his work collecting and
preserving specimens. I've alluded to this several times, but this
passage really gripped me, so Wallace says quote. My collecting

(41:55):
operations here were carried on under more than usual difficulties.
One small room had to serve for eating, sleeping, and working,
for storehouse and dissecting room. In it were no shelves, cupboards, chairs,
or tables. Ants swarmed in nearly every part of it,
and dogs, cats and fowls entered it at pleasure. Besides this,

(42:19):
it was the parlor and reception room of my host,
and I was obliged to consult his convenience and that
of the numerous guests who visited us. My principal piece
of furniture was a box, which served me as a
dining table, a seat when skinning birds, and as the
receptacle of the birds when skinned and dried. To keep
them free from ants, we borrowed with some difficulty an

(42:42):
old bench, the four legs of which, being placed in
coconut shells filled with water, kept us tolerably free from
these pests. The box and the bench were, however, literally
the only places where anything could be put away, and
they were generally well occupied by two insect boxes and
about one hundred bird skins. In the process of drying

(43:03):
it may therefore be easily conceived that when anything bulky
or out of the common way was collected, the question
where is it to be put? Was rather a difficult
one to answer. All animal substances, moreover, require some time
to dry thoroughly, emit a very disagreeable odor while doing so,
and are particularly attractive to ants, flies, dogs, rats, cats,

(43:27):
and other vermin, calling for especial cautions and constant supervision,
which under the circumstances above described were impossible. Oh man,
I was getting so stressed to just reading that, trying
to think where to put the bird skin, where to
put the dead whatever I just found? Where can it go?
That it's not just going to be swarmed with ants?

(43:48):
And the whole time you've got ants everywhere, and it's
all stinking because you're skinning it and then hiding it
in a box that's the only other thing in the
room with you.

Speaker 2 (43:56):
In all manner of scavengers are coming into peek in
and see what's going on with your dead animals. Yeah,
it seems like quite an experience, and also Wallace quite
a house guest to have a saying as well, Right.

Speaker 1 (44:14):
I mean, one thing he notes in at least the
parts I was reading is he makes a special note
of the hospitality he encounters everywhere he goes. Seems like
he just keeps running into very nice, very helpful, accommodating people,
and he's like, I was received very you know, with
all this graciousness and all that. So I just get

(44:34):
the feeling from reading that he's a nice guest to have.
He's very appreciative, you know, very very polite. I think
probably at.

Speaker 2 (44:41):
Least skins a lot of birds, collects a lot of beetles.

Speaker 1 (44:44):
But a nice guy does stink up your house really
bad and they're already ants, but he probably attracts way
way more. Yes, this is actually something I almost always
find interesting in reading books about science history is just
the practical physical annoyances and problems with trying to do

(45:05):
the core work, the core physical work of your discipline,
whether that's collecting specimens and preparing them to be preserved
or doing experiments or whatever. You know, there are always
little like problems like this where it's like I can't
do it because this thing doesn't fit right, or I
don't have the kind of table I need, or you know,
or there's ants on everything. By the way, if you

(45:27):
work in any area of research out there, and you
want to write into the show about your experiences of
this kind, please do contact at stuff to Blow your
Mind dot com. I always find these things interesting.

Speaker 2 (45:37):
Yeah, tell us about your field work.

Speaker 1 (45:39):
What is your Wallace's Room full of ants?

Speaker 2 (45:52):
All right?

Speaker 1 (45:53):
Can I flag one more thing from this chapter by
Wallace about a boundary of sorts, but not a funal one.

Speaker 2 (45:59):
Yeah, yeah, I know what you're going to cover here.
And this is an interesting woman I was reading about
in my book as well.

Speaker 1 (46:05):
Yeah, okay. So Wallace, by the way, he's about to
refer to somebody named Manuel. Manuel is one of his
local guides. So this is a guy he's been working
with and has good relations with. But he says aborneyan
Malay who had been for many years resident here, said
to Manuel, one thing is strange in this country the
scarcity of ghosts. Hmmm, how so asked Manuel. Why you know,

(46:32):
said the Malay that in our countries to the westward,
if a man dies or is killed, we dare not
pass near the place at night, for all sorts of
noises are heard which show that ghosts are about. But
here there are numbers of men killed and their bodies
lie unburied in the fields and by the roadside, and
yet you can walk by them at night and never

(46:53):
hear or see anything at all, which is not the
case in our country, as you know very well, certainly
I do, said Manuel. And so it was settled that
ghosts were very scarce, if not altogether unknown, in Lombach.
And then Wallace goes on to make a comment that
I didn't know how to take it first, but because

(47:14):
I initially read this as maybe some kind of dry humor.
But he follows this up by saying, I would observe, however,
that as the evidence is purely negative, we should be
wanting in scientific caution if we accepted this fact as
sufficiently well established. That sounded like a kind of humorous
understatement to me. But now, Rob, now that we've talked

(47:34):
about his interest in spiritualism, that assessment actually seems like
he is interested in he is maybe actually interested in
doing a scientific catalog of where ghosts exist, because he
views them as quite likely a real phenomenon and something
that can be scientifically documented. And he is being, you know,

(47:56):
somewhat skeptical in his methodology here. He's like, well, we
only have the negative evidence here, So we can't fully
say that this is this is a rule. But here's
somebody saying, you don't get ghosts in Lombac, you do
get them over here.

Speaker 2 (48:10):
Yeah. This is a great point because, yeah, I think definitely,
at this point in his life he was at the
very least quite open to the idea that ghosts were real,
that there were some sort of spiritual essence out there. Yeah.

Speaker 1 (48:22):
And the really interesting aspect of that belief, at least
to me, being the assumption that you could study this
phenomenon in a scientific way. I mean, I think a
lot of times you would have people who might be
scientists or naturalists or natural philosophers in this era who
have supernatural beliefs, but they don't approach the supernatural beliefs

(48:46):
as open to investigation the same way there are beliefs
about the you know, the forces governing the natural world are.
And Wallace seems to be saying like, no, yeah, we
could just we could study this.

Speaker 2 (48:58):
Yeah, And I think we definitely have to look at
it within the context of the time too, a time
during which there's so many advancements are taking place, and Wallace,
along with Darwin and others are like right there on
the front lines pushing this this theory of what is
going to become known as the theory of evolution, the
theory of natural selection. And therefore, like there's probably this

(49:22):
spirit of we can figure it all out, and we
see this elsewhere as well, where people are like, yes,
we can, we can actually measure these things. We can
look and try and figure out what happens to consciousness
when life ends. And in Wallace's case in particular, we
know that he comes to see some sort of continuation
of the soul as being some special vibe, some sort

(49:46):
of higher intelligence, as being key to how evolution is working.
And therefore, you know, he just sees it as part
of the works, and therefore it's something that you surely
can prove out because we're proving out the other aspects
of how the natural world is working, and if ghosts
are part of it, if the spirit is part of it,
then he should be able to prove that as well.

Speaker 1 (50:07):
Yeah. I mean, in a way, you could look at
an interest in spiritualism as a way of you know,
I think that none of the underlying phenomena were actually real,
but as an attempt to empirically interact with the spirit world, yeah,
as opposed to just like having beliefs about it, but

(50:27):
those beliefs being something that you know, you don't interface
with or interact with.

Speaker 2 (50:33):
Right right now. At the same time, of course, obviously,
like entering in any kind of scientific enterprise with these
concepts in mind, you can end up putting blinders up
for yourself, and you can end up maybe engaging in
some of these questions without complete neutrality, right.

Speaker 1 (50:50):
And I mean, of course, I think that is what
we actually see in a lot of attempts to you know,
get really into the subject. But I would say that
in principle, if there were spirits that made contact with
the living on a regular basis, that's something that you
could study. You know, it might be difficult to study
because it might be more like the study of psychology
or something than like the study of biology or nature,

(51:13):
but it could be something you could look into in
a systematic.

Speaker 2 (51:16):
Way, right, right. And even the division of ghosts as well,
I mean, especially in a place like Indonesia. You know,
it ultimately speaks to other questions about the flow of
ideas and the flow of religious faiths, you know, in
a widespread and again, as we've stressed, very large spread
out country that has various cultures wound up in it,

(51:37):
various religious faiths, So that ultimately becomes the more interesting
question I think outside of Wallace's viewpoint, is well, why
would there be a tradition of ghosts here and not here?
What does that say about the people? Well?

Speaker 1 (51:49):
Right, exactly. I mean, I think that's a fully legitimate
and fascinating question to look into, not the question of
are there literally ghosts here and not ghosts here? But like,
why do you get these different beliefs in tradition in
different cultures? You know? How does history feed into the
development that way?

Speaker 3 (52:04):
Yeah?

Speaker 1 (52:05):
Yeah, One thing I would note is that Wallace says that,
so he recounts this conversation where this guy who comes
from Borneo says, hey, yeah, we've got ghosts back home.
They don't have ghosts here. Wallace does know that the
people of Lombach did describe a belief to him that
some men had the power to transform into crocodiles in
order to eat their enemies. So that's pretty cool. Hmmm.

(52:28):
Seems different than a ghost though.

Speaker 2 (52:30):
Yeah, And I'm not sure how crocodile transformation would like
how that ends up being interpreted by like European spiritualism
of the time. But that's still fascinating.

Speaker 1 (52:40):
Oh, I can just imagine the kind of distinction made, like, oh,
you know, our spirits are very real and legitimate. Nobody
actually transforms into crocodiles. That's ridiculous.

Speaker 2 (52:50):
All right, Well, we're gonna go ahead and close out
this episode of Stuff to Blow Your Mind right here,
but we'll be back for a part too. On the
Wallace line. We'll discuss the concept in more detail and
probably get into some specific examples too.

Speaker 1 (53:03):
Right well, and in the next episode we'll go into
more detail about why it exists to the extent that
it does, as well as sort of updates to the concept,
like the idea of Wallacea.

Speaker 2 (53:14):
Yeah. In the meantime, certainly, right in and tell us
all about your adventures in this part of the world
other parts of the world, and of course your your
field work researchers. Right in about your field work, we
would love to hear from you, as well as recommendations
for future episodes of Stuff to Blow Your Mind. We're
always we always have an ear open for good ideas.

Speaker 1 (53:36):
That's right, What is your equivalent of Wallace's dissecting room
covered with every surface covered in ants, and what the
box full of bird skins and so forth emitting odors.

Speaker 2 (53:47):
Yeah, maybe it's not your work, your work life even
maybe it's your personal life. Yeah, right in, we'd love
to hear from you, and just to remind it. Stuff
to Blow Your Mind is primarily a science and culture podcast,
with core episodes on Tuesdays and Thursdays, but on Fridays
we set aside most serious consers just talk about a
weird film on Weird House Cinema.

Speaker 1 (54:02):
Huge things, as always to our excellent audio producer JJ Posway.
If you would like to get in touch with us
with feedback on this episode or any other, to suggest
topic for the future, or just to say hello, you
can email us at contact at stuff to Blow your
Mind dot com.

Speaker 2 (54:23):
Stuff to Blow Your Mind is production of iHeartRadio.

Speaker 1 (54:25):
For more podcasts my Heart Radio, visit the iHeartRadio app,
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