The central theme is to clarify the phylogenetic classification of humans within the primate lineage, specifically addressing the controversial question of whether humans are monkeys, by explaining the principles of cladistics and monophyletic groups.
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well hi there this is a primate and so
is this and so is this and so is this
and this primate is a monkey and so is
this and so is this and so is this
hey that's
me what's what's going on here from a
pho genetic standpoint humans can be
considered a type of monkey within the
larger primate clade okay well thank you
AI so humans are monkeys in modern
taxonomic and common usage humans are
not referred to as monkeys the
distinction reflects significant
evolutionary morphological and cognitive
differences that have emerged since the
human lineage diverged from other
primates oh okay so organisms can evolve
out of a clay no an organism cannot
evolve out of a clay in
phenetics uh a clade represents a group
of organisms that includes a single
common ancestor and all its descendants
once an organism is part of a particular
Cay all of its descendants will also
belong to that clay regardless of how
much they change or diversify over time
okay well um Chad GPT was a bit
conflicted about whether or not humans
are monkeys but this is a question that
hits me real close to the heart it cost
me a year of my life I've just sapped
one year of your life away because I got
into a debate about this very point with
a member of my PhD committee right in
the middle of my dissertation defense
who else is part of the smallest
monoptic group that includes both the
Old World and New World
monkeys okay I think you're ready to
chat chat with each other now all right
so who who else would be part of this
have so anybody else by the way
gor or and all of their ancestors and
all of their ancestors does that make
sense okay so now here's the question
just discuss this immediately with the
person next to you do we come from
monkeys in fact if there's a monoptic
group a bad question who's in it you
should be more specific what you mean by
monke well if there's such a thing as a
mon grp for monkeys that includes all
the monkeys so what do you guys think I
say no you said no all right let's have
it why not because you're not sure that
that ancestor is a monkey okay is it
part of the group
monkeys that's why I said you more
specific about what you mean by monkeys
well I'm in this case I would just be
talking about the monoptic group that
includes all monkeys that would be the
smallest group I can make called monkeys
are they in it is your common ancestor
that you share in it or not I guess what
at the point I'm making is you don't
know what those ancestors are are those
ancestors all monkeys
too that was a bit hard to watch
so that is the question are those
ancestors all monkeys too and since this
question has cost me so much and because
the answer is so
interesting let's talk about all of the
primates how they're related and whether
or not you might be a monkey's uncle and
since we're going to be digging into the
philogenetic relationships of primates
and trying to answer some very
controversial questions what's better a
monoptic group or a paraphilic group
monoptic groups or clades are favored in
phog gentics because they include a
common ancestor and all its descendants
providing a complete picture of
evolutionary relationships paraphyletic
groups include a common ancestor but not
all its descendants and polyphilic
groups don't include the most recent
common ancestor of its members both
paraphilic and polyic groups give an
incomplete or misleading view of
evolutionary history making monoptic
groups more valuable for understanding
and representing evolutionary
relationships accurately okay so what we
want are monoptic groups clades a common
ancestor and all of its descendants well
good news primates are a cla a monoptic
group a common ancestor and all of its
descendants and as we learned earlier no
matter how different The Descendants
become from their shared ancestors it is
impossible to evolve out of a clade that
would be paraphile we don't want that
primates themselves are part of a larger
CA called primat amorpha which includes
all of the primates a group called
dermoptera often called Flying lemurs
the last common ancestors of primates
and dermapteran and everything in
between and guess what those common
ancestors and all of their descendants
are all primmorphs that's the way
monopile works one of the major
advantages of monopile is that it
teaches me things about the members of
the groups that I didn't know before I
put them into the groups it has massive
predictive power I didn't need to know
all of their names to know that they
were all primat amorphs including all of
the primates and that is the way that a
nested hierarchy works the primates are
a large CLA that is nested within larger
clades such as primat amorpha all
primates are primat amorphs but not all
primat amorphs are primates primates are
also nested within many other other
larger groups such as the eutheria the
mamalia the tetrapoda the vertebrata the
Cordata and the Animalia and most people
don't seem to have a problem with the
fact that humans are nested Within These
groups it is entirely controversial that
humans are mammals vertebrates or
eutherians for example but if you bring
up that humans are bony fishes or
animals some people and even artificial
intelligences push back and saying that
we are monkeys is a bridge too far even
for some evolutionary biologists
apparently but are we monkeys well let's
start with primates primates can be
identified by their relatively large
brains large forward-facing eyes
opposable digits on their hands and or
feet and Nails as opposed to claws the
primates form two clades the haini and
the strep serini and right here I want
to address a major misconception that
many people have the h arini and the
strip serini are both equally evolved
because Evolution only has one goal the
survival of genes and since all
individuals die this means that the goal
of organisms is to pass their genes on
to Future Generations many individuals
may not know that this is the goal and
they may not succeed at doing so and the
result of this is that the genes of
individuals that stink at achieving this
goal are not well represented in future
Generations the genes that make it to
Future Generations are
disproportionately and non-randomly the
genes that assist with that one goal
though random forces can have an impact
too especially in small populations or
with respect to what mutations occur and
when but by and large Gene variants that
increase the likelihood of an individual
possessing them achieving the goal of
passing on its genes become more
prevalent over Generations importantly
being a human is not the only way to
achieve this goal and the more similar
you are to humans the more directly you
compete with them what I'm saying is
that other organisms are not failed
attempts at becoming humans nor is there
a particular evolutionary pressure to
become more like humans if anything the
opposite is true humans are great at
being humans but they make lousy strip
serines strip serines are identifiable
by their wet not noes like those of a
dog or a cat though strip serini means
something like turned around nose or
turned around nostrils in reference to
their comma-shaped nostrils they also
make their own vitamin C remember that
it's important and not just because you
need Vitamin C though you do you scurvy
dog which is an odd thing to call
somebody because dogs make their own
vitamin C in fact almost all mammals
make their own vitamin C very few do not
but we'll talk more about them in a
moment so like dogs strip serines make
their own vitamin C and have wet noses
which greatly increases olfactory
ability and the strip serine CLA itself
is divided into two large groups the
Lemur oidia lemur endemic to Madagascar
and the Loris oidia the lorises and bush
babies of Africa and Asia lemur are such
a rad group that they could definitely
get their own video at some point now
lemur means ghost there are around a
hundred species in Madagascar eight
distinct families ranging in size from
about 30 G about a 15th of a pound to
around 9 kilos 20 lb that's now when
humans arrived on the island around
2,000 years ago there were lemurs the
size of gorillas they are basically the
monkeys of Madagascar though they aren't
monkeys but they're rather convergently
similar in many ways since there were no
monkeys in Madagascar until we showed up
so all of the monkey Niche space was
wide open and the Lemurs filled it now
you're unlikely to confuse most lemurs
with monkeys and not just because of
their location wet comma noses and
vitamin C synthesis but because their
faces tend to look more like those of
carnivorans than those of monkeys with
long pointed snouts and ears that look
more like a dogs than they do like well
yours generally though that breaks down
a bit with some groups like The sportive
lemurs and my favorite lemur the I ey
which looks more like a ground Gremlin
and not one of those happy Gremlins it's
a monster I love it now most lemurs have
front teeth called tooth Combs not just
them but also the lorid that we will
discuss soon and the flying lemurs so it
may be the ancestral condition of the
primat amorpha anyway the I I it doesn't
have one instead they have some crazy
paired continuously growing in sizers
the skull looks like what you would get
if you crossed a rodent with a parrot
Len czers be crazy but why be they crazy
Clint oh I'm so glad you asked because I
eyes are woodpeckers but instead of
pecking holes and trees they chew holes
and trees and why make holes and trees
because there are tasty insect morsels
in there but how do they know where they
are you ask the best questions they
listen for them with their hideous
grumpy grumling ears and their long
freaky knocking finger look at that
finger it isn't really so much long as
it is is skinny and terrifying and it is
terrifying that knock is one of the
scariest sounds a grub could ever hear
that in Hakuna Matata once it is located
to Grub it chews a small hole in the
tree and then inserts the spider leg
death finger into the hole hooks the
disappointed larvae within and then
hauls it out so that it can be
masticated and ingested what a wonderful
Beast now I mentioned that the largest
of all lemurs was about the size of a
gorilla that's true they were called
sloth lemurs but the largest extant
lemur is the indry a close relative of
the extinct giant sloth lemur and in
addition to being large and colored like
a panda they also have a very short tail
like a bear but interestingly not much
like a panda pandas have huge tales for
Bears but I want to ask you a question
if the descendants of injuries
eventually lost all external vestages of their
their
tails would they cease to be lemur no an
organism cannot evolve out of a clay oh
yeah thank you okay so we have a pretty
good idea how to distinguish lemur from
monkeys but what about from their
closest relatives the members of the
clay laures soia well a good place to
start is by asking yourself the age-old
question am I in Madagascar that should
handle the question but to be perfectly
honest unless you have the ability to
examine its DNA or look at its internal
anatomy it's otherwise pretty difficult
to answer this question this is a bush
baby also called a galago it's adorable
it obviously has big front-facing eyes
somewhat opposable thumbs and
fingernails it's a primate it has a pair
of wet commas so you can probably guess
about whether or not it can synthesize
vitamin C it can and you could double
check yourself by looking for a tooth
comb it has one this is a slow lorus
same deal but in addition to that it
also has a toxic bite used primarily in
slow motion battles with other slow
lorises but you know what it doesn't
have a visible tail and you know what
that means it's no longer a member of
the luris oidia it evolved right out of
that CLA
right of course not it just doesn't have
a tail they could evolve to not have a
head and that wouldn't change the fact
that the descendants of the first lores
oids will always be lores oids if you're
in Asia or Africa and you find a soggy
commoner with or without a tail you'll
know that you have a member of the Loris
oidia but the strip seren is really not
the primate lineage that we're most
interested in exploring because the
monkeys are part of the other big
primate lineage the haini the simple
noosed primates with dry non-common
noses and no ability to synthesize
vitamin C these are the scurvy primates
and scurvy probably doesn't increase
your likelihood of passing on your jeans
so why hasn't this been a problem well
largely because most primates have diets
rich in vitamin C Haines might not make
it but that wasn't really an issue they
didn't need to make their own not an
issue at least until primat started to
live in places where foods rich in
vitamin C were uncommon especially say
at sea for months at a time but there is
a reason that I bring it up what is the
simplest explanation for why this entire
CLA would lack the ability to synthesize
vitamin C all of them now it could have
happened multiple times and been
successful or at least not devastating
repeatedly but the simplest explanation
is that the mutation occurred in the
Haine lineage somewhere after the split
from the strip Serene and reached
fixation in the population before the
first split within that lineage of
course just because it's the simplest
that doesn't make it true so how would
you know well the enzyme needed to
synthesize vitam vamin C is coded for by
a gene called G and the guo gene is roughly
roughly
202,000 base pairs long if it is
broken it won't make vitamin C and the
likelihood of the same exact break
happening independently in two different
lineages is astronomically small guinea
pigs are one of a small number of other
mammals that have a mutation to their G
Gene resulting in a lack of vitamin C
production unsurprisingly it is a
different break from that found in
Haines which makes sense same thing goes
for the bats that don't produce vitamin
C it's a different break from the one
that you find in guinea pigs or in
Haines but what about among the hings
well it's the exact same break straight
across the board and again it happened
before the first Haine lineage
Diversified from the rest that first
lineage to diversify away after this
break would be the taries today
represented exclusively by the family
Tara day of Maritime southeast Asia the
Tarsiers now the first thing that you
might notice about Tarsiers is that
their Rostrum is much more flat than
that of the strep serini reflecting the
fact that these are less reliant on Old
faction but that's not the first thing
that you noticed was it it was those
colossal freaking eyeballs that they've
got if not you're probably just
listening to this video because how
could you miss them they are enormous in
fact in many cases each individual eye
is larger than their entire brain and
these guys are Haines they aren't small
brained they're just giante eyed I mean
look at the skull of this thing where
would you even put a brain but somehow
that wasn't the feature that caught the
proportionately tiny eyes of the
researchers who named them tarsier is
due to their long foot bones called
tarsel which give them very long legs or
more accurately very long feet but I'm
not done with those eyes yet because if
you look at them they are always looking
directly forward with the most intense
stare you have ever seen in your entire
life though owls may give them a run for
their money because owls like Tarsiers
are always looking straight ahead you
have never never seen such determination
in the eyes of anything else and there
is a good reason that they never side
eye anything they can't their eyes are
too big the muscles required to move
those eyes would be huge and heavy not
good for a bird or a primate so they
can't they can see really well but only
what is straight in front of their faces
which means that if they're going to see
say uh behind them well they will need
to turn their whole head backwards like
some sort of possessed white-eyed Cowboy
everything now they can't do the full
Cowboy but they can spin it all the way
to the rear 180° giving them the ability
to see in any direction without moving
their bodies and somehow Vision might
not be their primary tool when hunting
like owls Tarsiers are nocturnal and
rely heavily on their hearing they have
big thin ears like a bat and their
brains are particularly Adept at
processing auditory information it
really is like a wizard tried to make an
insect eating owl out of a leaping
monkey mission accomplished but it is a
monkey and that gets us to our mission
monkeys and uh are you a monkeyy uncle
oh and just by the way all of our
patrons get access to a video that
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video please consider checking us out on
patreon everything we have discussed so
far can easily be excluded from the
smallest Cade that includes all of the
monkeys but now we are moving into the
Cade sories and the group of sories
least related to all of the others is a
clade of monkeys and I think it is fair
to say that a clade of monkeys cannot be
removed from the smallest CA that
includes all of the monkeys do we need
to verify that with AI or are we all on
the same page so monkeys are monkeys
okay I'm going to work under the
assumption that we can agree that
monkeys are monkeys and this CA the
plini the flat or broad-nosed monkeys
are monkeys because flatos monkeys live
exclusively in the Americas and because
they are the only simeons native to the
Americas they are often referred to as
new world monkeys the other clay in the
sories the katerini being entirely from
the old world are often called the
katarine monkeys or the oldw world
monkeys though the latter is often
applied exclusively to one single clay
of katarine monkeys and uh we'll get to
them soon enough but what we can see is
that the two remaining clades in this
lineage they're both Monkeys new world
and Old World monkeys for the moment
let's talk about New World monkeys the
platan today there are five living
families of New World monkeys like all
simeons new world monkeys have large but
not insanely large and therefore movable
eyes with great daytime color vision
accompanied by large brains that
specialize in visual perception more
than old faction interestingly while
both the new world and Old World monkeys
have large brains even for primates they
seem to have evolved those larger brains
independently from one another which
isn't the case for their lack of ability
to synthesize vitamin C they both seem
to have inherited that from the same
Haine ancestor and I know that because
once again all of the Haines look to
have inherited it from the same common
ancestor and the last common ancestor of
all hains as well as all of their
descendants so everything from that
point until now have all been Haines and
I know this because that's how monoptic
groups work you probably get this but I
have encountered evolutionary biologists
that seem to still struggle with this
concept so I'm just being really
explicit so what makes new world monkeys
unique from Old World monkeys other than
geography well let's start with their
noses their names both refer to their
noses New World monkeys are the plini
the flat-nosed monkeys and the oldw
world monkeys are the katerini the down
noosed monkeys it really just has to do
with the position of the nostrils New
World monkeys have side pipes like a
Dodge Viper a Shelby Cobra or a 427
Corvette American cars American monkeys
not every American car has side pipes
but face it you'd be shocked to see side
pipes on a Ferrari a BMW or a Toyota now
why because the old world doesn't do
side pipes oldw World monkeys Point down
well unless they're snub-nosed monkeys
that have the same plastic surgeon as
Michael Jackson and Skeletor and He Who
Shall Not Be Named and Red Skull those
last two are from the old world really
not sure if the first two are even from
this world great dancing [Music]
[Music]
but the point is that new world monkey
nostrils point out the side not down and
so there is a much greater space between
the nostrils they are also the only
monkeys that have prehensile tails not
all of them have prehensile taals but
you'll never see a prehensile tail with
down pipes prehensile Tales have
actually evolved two different times in
New World monkeys but never in the old
world they also have 12 premolar instead
of eight but that can be difficult to
count at the zoo it would be fun to do a
whole video just about this group but
right now we're on a mission and that
mission will require us to dig into the
down noosed old world monkeys of the
katerini now you probably already know
how to distinguish these guys they have
all of the attributes of other simeons
and can be distinguished from the new
world monkeys by their nostrils that
don't point out the sides as well as the
fact that they have eight premolar and
they never have prehensile tails some
don't have tails at all which as you
know means that they've evolved right
out of the cay no an organism cannot
evolve out of a clay oh yeah silly me
anyway they also tend to have flatter
finger and toenails and much more
opposable thumbs unless they've lost
their thumbs which means that they have
lost their thumbs that's it cbus monkeys
are still monkeys because you can't
evolve out of a Cay no matter what you
lose unless it's all of your ancestors
it's a heck of a thing to lose so you
can identify a katarine monkey with or
without a tail or thumbs thumbs up got
them so what's in this group well these
and these monkeys see the narrow septum
between the nostrils now did you notice
that one of them didn't have a tail and
remember what that means yeah it means
that it doesn't have a tail now there
are two different lineages of katerine
monkeys the copath aidia and and the
homonoia this guy is a copid and this
guy is a hominoid the easiest way to
distinguish between the two is to look
for the tail hominoids don't have them
copds do there are other differences if
you get a good look at the cusps of
their molers but the presence or absence
of a tail is the best giveaway though
it's not exactly foolproof barbery maacs
and crested black maacs for example are
C opoids and their tals are tiny to
non-existent which means that they they
have no tals anyway the copics are often
referred to as the oldw world monkeys
but as you may recall that name was
already taken by the caterini and given
that copds are part of this group and
that all of the katerini is an entirely
oldw World group The question as to
which group most deserves the title is
simply whether or not all members of the
katerini are monkeys or if only the
cercopithecoids are monkeys and so we're
going to need to back up and take a look
at the philogyny for just a
second what is a monkey I think before
we agreed that monkeys are monkeys and
therefore New World monkeys the plini
are monkeys and I've never seen anybody
contend that the
cercopithecoids are not monkeys can we
agree that both of these groups are
monkeys now we could very easily say
that all primates are monkeys or all
mammals but that seems a bit over broad
let's instead make the smallest possible
monoptic group that we can from monkeys
the smallest group that can be created
that includes all of the animals that we
all agree are monkeys they're most
recent common ancestors and everything
that came from those ancestors and
absolutely nothing else we will exclude
every animal that we possibly can
without creating a parap phytic or
polyphilic group the smallest monkey CLA
possible so what's the last common
ancestor shared by both the plini and
the copath aidia well that would be uh
these guys right here the first true
monkeys I'm sure that whatever came
before them was very Monkey likee but I
can exclude everything before this point
from the monkey group at least if I want
to but not these These are monkeys and so
so is
is
everything that came from them because
that's the way that monopile works and
if we look at who came from them you
will notice that the plini came from
them the copi
aidia they came from them and so did the
homonoia I can't exclude the homonoia
from the monkey CLA because they share
ancestors more recently with the copath
aidia than the copath aidia do with the
plini this means that while I could
potentially justify excluding the plini
from the monkey CLA I cannot exclude the
homonoia from any clade that includes
both plini and copi aidia it is
impossible in a nutshell the
copds are not the only old world monkeys
they are just the only old world monkeys
with tails even though not all of them
have one so that brings us to the
tailess old world monkeys the homonoia
the manlike oldw world monkeys and what
is so manlike about them well like men
they have all of the basic attributes of
primates not to mention the attributes
of eutherians mammals synapsid
vertebrates chordates duter batarians
Etc so they have relatively large brains
large forward-facing eyes opposable
digits on their hands and or feet and
Nails as opposed to claws like men and
every other primate that we've discussed
so far but that is not where their
similarities to men and they also have
all of the attributes of Haine primates
so they have dry noses and can't make
vitamin C and they can't make vitamin C
due to the same change in the goo Gene
as the one that we see in uh men and
women just in case you were wondering
but that isn't where the similarities
end either like men they also have all
of the attributes of simeons which is
the smallest clay that can be created
that includes all of the monkeys
attributes such as even larger brains
that prioritize Vision over all faction
and movable eyes with great color vision
and that's not where it ends the
hominoids also share all of the
attributes of catarine monkeys with men
so their nostrils Point down and have a
small septum between them they also
don't have prehensile tails and their
thumbs are fully opposable uh and eight
prolar but that's not where the
similarities end either because they
also share all of the attributes of
hominoids for example they don't have a
tail but more than that they don't have
a a tail for the exact same reason they
all share the same insertion mutation to
the tbx T Gene that plays a big role in
tail vertebrae formation do you think
that's the same mutation that you see in
tailess Maca I don't think that analysis
has been done just yet but I'd be very
surprised if it is and that's not the
full extent of the similarities between
hominoids and men just some of the most
conspicuous ones but plenty enough to
help you identify a homonid when you see
one and plenty enough to justify calling
them man like so let's dig into these
manlike monkeys and let's start with the
least manlike of the manlike monkeys the
Hyo badade the forest Walkers as opposed
to the forest
runners run forest run run forest hob
baded is composed of the roughly 20
species of Gibbons and just at a glance
you can probably distinguish a hyob
baded from the other hominoids in the
family hominid hyob beds look much more
like the monkeys that we've discussed so
far just typical tailess katarine
monkeys that aren't maacs maacs have a
very distinctive face in case you're
struggling they're smaller than the
other hominoids and they tend to be
built more for swinging around in the
trees than are the hominids their long
arms and ball and socket wrists make
them the fastest of all brachiators tree
swingers and one of the silliest of forest
forest
Walkers they also have some key
behavioral differences compared to H IDs
they tend to parir bond more than
hominids probably leading to reduced
levels of sexual difference sexual
dimorphism compared to hominids they
also do not tend to build nests like the
hominids do and on that note let's talk
about the nest building tailess old
world monkeys in the family hmin the
manlike manlike monkeys manlike monkeys
are often referred to as apes and the
manlike manlike monkeys are often
referred to as great apes possibly
because they are bigger possibly because
they're a little more Hanky Panky and
possibly because the more manlike a
manlike monkey becomes the greater we
think it is though I think it has more
to do with the size because in my
opinion gorillas are greater than
bonobos even though they're not quite as
manlike and nothing is more Hanky Panky
than a bonobo except for ducks they're
screwed up anyway today there are only
eight or nine species of manlike manlike
monkeys those are in order of
relatedness to the Pinnacle of creation
orangutans three species honin three
species and the Pinnacle of creation
gorillas two or three species we should
do a whole video just diving into these
nine species but right now we need to
dig a bit deeper into the closest
relative to the Pinnacle of creation the
hini the manlike manlike manlike monkeys
not the greatest of the Apes but the
most most manlike there are three extent
species of manlike manlike manlike
monkeys in two lineages Pan the
chimpanzees and bonobos and Homo the
well us while chimpanzees and bonobos
are more closely related to one another
than they are to us and they aren't the
closest relatives to us known to have
ever existed they are our closest living
relatives and are more closely related
to us than they are to gorillas
orangutans iibb any other monkeys any
other primates or anything else alive
today other than the women they are the
most manlike of all prime Apes that
aren't men and the men while tailess are
nonetheless still great apes which are
still Apes which are still catarine
monkeys which are still monkeys which
are still primates because that's the
way that monil works and now you know as
always like And subscribe and we hope to
see you real soon
do we mention the name of no that
Professor he took a real bad position
and wrecked a year of my life over it I
didn't I deliberately didn't say his
name in this good
video um or say where he is what his
institution is or anything like that I
don't I don't want anybody to know that
his name is he no no no
stop we're not adding that to patreon
extras his address
is Doc [Laughter]
[Music] sucker
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