in a cold sterile room a figure
looms the chill doesn't seem to affect
it the skin of this creature is a
seamless dark canvas a protective cloak
born in a world where the sun's rays are
strong enough to kill those who linger
Outdoors for too long as the creature
moves we get a full appreciation of its
imposing stature tall and wiry with
muscles not designed for bulk but pure
efficiency each movement the creature
makes is calculated and precise not a
drop of energy is wasted it's a body
sculpted by a society that has conquered
disease and Decay extending life and
eliminating what was once deemed natural
Frailty despite this the creature's face
is almost beautiful it's blessed with
near perfect symmetry the result of
countless ancestors choosing from a wide
array of mates rather than battling
against the harshness of natural
selection in the wild but it doesn't
react in response to an observer's
presence it just looks placidly on its
temperament a far cry from that of its
ancient ancestors that Ward with
neighboring tribes and everything the
creature feels from Pain to cold to
comfort is felt within a brain that is
smaller than yours or
[Music]
mine this vision of the future of
humanity is speculative but it is a
projection based on the direction our
bodies have taken in the last few
million years humans have become taller
with thinner bones and narrower Jaws as
we evolved our brains grew dramatically
but now they are actually getting
smaller and so it is tempting to think
about our future and see whatever we
might become as a more evolved species
with bodies perfectly adapted for a new
hyp sedentary existence but just as
today not every part of their body would
have been tailor made for that lifestyle
indeed its narrow jaw grows the same
number of teeth as us and our ape
ancestors leading to removals that leave
the nerves permanently tender its spine
excels at stabilizing its body to walk
upright but has sustained a vertebrae
injury that a more durable chimpanzees
back would not have and just like us it
has too many bones in its feet these
bones evolved for grasping branches but
were forced into a rigid standing foot
when its homine ancestors learned to
walk changing their angle and shape the
creature's body and ours are a patchwork
of physical parts some beneficial some
not and so why do we have these floors
and what would we be without them
[Music]
is sahal anthropus CH Denis discovered
in Chad in 2001 the missing link between
hominins and chimpanzees it's a huge
question and one explored by our
documentary recommendation on mellan TV
today this video is sponsored by mellan
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they've been excellent supporters of our
content for a while now they provide
highquality context for our videos and
this week's recommendation is no
exception T the oldest human ancestor is
a great Deep dive on that incredible
Discovery and its effects on our
understanding of Humanity's Journey a
mellan is always a great choice for more
information about our videos whether
it's history of the earth history of the
universe or history of humankind it's
basically a bingeable Netflix for
documentaries it has a huge range of
Natural Science content available among
lots of other genres many available in
high quality 4K so click on the link in
the description for an exclusive
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humankind
[Music]
viewers in the forests of Madagascar
there is an orchid with a nectar tube
over a foot long when a specimen of this
flower was sent to biologist Alfred
Russell Wallace in the 19th century he
theorized the existence of a pre
previously undiscovered Sphinx Moth with
an equally long proboscis or tongue that
could pollinate
it indeed in 1867 he wrote that such a
moth exists in Madagascar may be safely
predicted a naturalists who visit the
island should search for it with as much
confidence as astronomers searched for
Neptune true to the prediction the moth
was discovered in 1903 and in 2021 it
was given the name Wallace's Sphinx Moth
after a genetic study proved it to be
its own species The Moth is now known to
have the longest proboscis of any insect
and the longest tongue relative to body
size of any animal in an environment of
foot long nectar tubes the animal with
the foot long tongue wins the day but as
impressive as Wallace's Sphinx Moth is
it's hardly the strangest result of
evolution consider the deep sea angler
fish not only are they some of the most
recognizable of all fish with biolum
escent lures protruding from their heads
and Jaws that can open to a 90° angle
they also demonstrate almost
unparalleled sexual dimorphism for when
the first species of deep sea anglerfish
were discovered the researchers were
baffled because all of them were female
and several seemed to have tiny
parasites attached to their bodies it
was only later that they realized that
these parasites were in fact the male
anglerfish it turned out that in some
species that although the females grow
to be metal long Predators with teeth
like needles the males are much much
smaller and totally lack the predatory
characteristics of the females in order
to reproduce they permanently fuse
themselves to the bodies of the females
effectively becoming nothing but pairs
of gonads that periodically release
sperm to fertilize the female's
eggs and so in a way in comparison with
deep see anglerfish and moths with
tongues as long as your forearm humans
seem almost
normal
almost and yet have you ever noticed how
rare our large white areas around the
eye are in the animal
kingdom these white areas are called
Scara and in most species they're either
pigmented to blend in with the rest of
the eye or they're not visible at all so
why do they stand out in human eyes and
why we one of the few species with this
peculiar feature despite the Rarity of
this trait The evolutionary advantages
of having conspicuous white SCA are very
obvious they allow us to see where other
people are looking for highly social
animals like humans this helps us
communicate nonverbally with each other
and enhances our ability to share
information build trust and cooperate
within groups but there are also parts
of our bodies that have much less
obvious functions or even the not only
serve of little to no purpose but can be
harmful in certain cases the appendix
for example is a tube likee attachment
connected to our large intestine this is
a fidal organ that we inherited from our
herbivorous ancestors and that we
apparently have little use for today
it's been suggested that the appendix
functions as a reservoir for beneficial
gut bacteria but people who have had
them surgically removed suffer no
adverse
effects appendixes even have an
unfortunate habit of becoming inflamed
even bursting if they're not removed
soon after the onset of appendicitis
symptoms indeed appendectomies or the
surgical removal of the appendix are
some of the most common surgical
procedures in the world why then do we
still have appendixes when so many of us
seem to be better off without
them considering that there are
disadvantages to traits like these it
seems strange that they were selected
for in our evolutionary past so how and
why did this
happen back in the 1860s around the same
time that Alfred Russell Wallace
predicted the existence of the Sphinx
Moth the scientific Community was still
arguing over Darwin's On the Origin of
Species which was published in
1859 his argument was of course that
species evolve through the process of
natural selection to Darwin the world
was a vast everchanging place in which
count count organisms fought for
resources mates and shelter individuals
with traits that gave them a slight
Advantage compared with others in their
environment had a slightly better chance
of surviving and passing on these
advantageous traits to their offspring
in other words Nature has a way of
selecting the best suited traits for
survival and reproduction within a given
environment and eventually through
successive Generations these traits
become more common within a population
as more individuals pass them on through
reproduction
which can ultimately result in
population level changes but perhaps the
most controversial thing about Darwin's
theory of natural selection was one of
its main
principles the evolution was fueled by
small physical
changes contrary to popular belief by
the time Darwin published On the Origin
of Species most naturalists were quite
comfortable with the idea of evolution
but many believed that Evolution had
some kind of end goal usually
culminating in human mind or that it was
governed by an external power or form of
Consciousness Darwin was therefore
asking them to accept that their
existence and the existence of
everything around them was the product
not of a grand plan but of random
chance car Ernst Von Bayer a naturalist
who rejected Darwinism argued that
forces which are not directed so-called
blind forces can never produce order and
then there was Thomas Henry Huxley
another naturalist history remembers him
as Darwin's Bulldog a staunch champion
of natural selection but he didn't start
out that way tiny variations seemed too
inconsequential to result in the
extraordinary diversity he saw in nature
and in the fossil record initially
hugley and most other naturalists
favored a different approach to Natural
Selection known as saltation
saltationism posits not that species
evolved gradually over time but that
they undergo abrupt significant changes
one of saltationism key criticisms of
Darwin's theory of many small changes
was the apparent lack of transitional
fossils that evidenced these steps but
then during the time of Darwin and
Huxley one of the most famous
transitional fossils of all time was
Unearthed in the late 19th century a
groundbreaking discovery was made in
Germany that would forever alter our
understanding of the natural world the
arop
fossil here was a creature with the
unmistakable characteristics of a
dinosaur a reptile by conventional
wisdom of the time and yet it bore
feathers and the rudimentary structures
of wings traits undeniably Avan in
nature archaeopteris represented
tangible evidence of the gradual
transformation of species over eons a
concept at the heart of Darwin's theory
of evolution by natural selection the
Aven features of ancestral Birds
including archaeopteris such as feathers
likely served initial purposes unrelated
to powered flight possibly for
insulation or display over time these
features were adapted for new functions
including flight showcasing the
incremental adaptive changes that bridge
the ancient dinosaurs with today's Birds
this fossil discovery underscored the
reality of gradual evolutionary change
providing key evidence to support
natural selection archaeopteris also
clearly shows us that Evolution doesn't
have a predetermined goal or path indeed
it would appear that feathers did not
evolve for flight but were later
repurposed for it and so just as living
bodies are filled with features that
could prove to be useful later so too
are they filled with Once useful
features that are now either obsolete or
even
problematic and humans are a perfect
example
it's 1922 in Egypt's Valley of the
Kings a team led by egyptologist Howard
Carter has just Unearthed a tomb that
has not been Disturbed for more than
3,000 years it's the final resting place
of the Pharaoh Tuton
Caron to this day the tomb remains one
of the most lavish in graves in the
history of egyptology and yet beneath
the resplendant gold mask of the Pharaoh
we see irrefutable evidence of Frailty
and
disease for despite their near Divine
status in ancient Egyptian Society even
Pharaohs were not immune to the inherent
vulnerabilities of Being Human modern
analysis of King tuts mummified remains
have painted a vivid picture of his many
physical ailments including but not Ed
to a club foot scoliosis several
possible genetic abnormalities and an
inherited vulnerability to infectious
diseases like malaria indeed for all the
Grandeur of his burial tudan kmon was
only 19 when he died and it's now
thought that his untimely demise was the
result of a badly broken leg and
possibly even subsequent
necrosis King Tut might have had an
unusually high number of physical
problems but many of the ailments
themselves are not uncommon even in
modern society the National Scoliosis
foundation for example estimates that
close to 7 million people live with
scoliosis in the United States alone
indeed the story of human evolution is
Rife with examples of how our greatest
advances came with their own sets of
complications the balance of advantages
and disadvantages that have shaped The
Human Condition
there's a popular depiction of evolution
one that shows the progression of life
from the earliest microbes to fish and
the first tetrapods all the way up to
humans at the very far end of the scale
it is pervasive but also very misleading
aside from simplifying the complex
process it suggests a linear Journey
towards Perfection where humans
represent the peak of evolutionary
success but this is clearly not the
case as with all life humans are flawed
and many of our evolutionary traits are
tradeoffs where the benefits of certain
features must be balanced against their
costs a classic example of this from a
nonhuman animal is the male peacock's
bright plumage and tail which while
attracting mates with its vibrant colors
and patterns also increases the bird's
visibility to Predators similarly a now
extinct group of animals the
saber-toothed cats evolved exceptionally
elongated canine teeth an adaptation for
precis killing while hunting large prey
that went along with plenty of its own
disadvantages a well-known species
Smilodon populator had canines that grew
up to 28 cm in length which were thought
to have been used to deliver a killing
bite to the necks of unfortunate bison
and camels Smilodon was certainly a
large apex predator with intimidating
teeth and a powerful build but it also
had a relatively weak bite force when
compared to Modern big cats in order to
accommodate beat its massive can9 teeth
smod Don's lower jaw was actually rather
narrow and this came at the expense of
its biting power in fact it's estimated
that Smilodon had a bite force only a
third as powerful as that of a modern
Lion in addition to this weak bite smod
Don's canines grew so long that they
became vulnerable to Breaking especially
while trying to hold on to struggling
prey these animals were well adapted to
Precision hunting but only so long as
their teeth held out once they broke
Smilodon would have struggled to catch
prey and it's hard to imagine a saber
saber-tooth cat lasting
long for humans simply stepping outside
shows us a key example direct sunlight
risks Sunburn and carcinogenic damage to
our skin because we've evolved not to
have a protective coat of hair on our
bodies and in cold temperatures we're
susceptible to hypothermia without warm
clothing and access to adequate shelter
opting to stay indoors may seem safer
but then we run into other issues
prolonged sitting weakens our muscles
and invites our bodies to store excess
fat plus a lack of sunlight leads to
vitamin D deficiency which can have its
own health risks and yet hairlessness
has persisted as it allows us to sweat
using our own hugely effective cooling
system but what if some traits persist
by
accident this is a phenomenon known as
genetic drift and it can sometimes lead
to the accumulation of negative genetic
mutations imagine that you have a bag
full of marbles some are red and some
are blue if you were to reach into the
bag and take out a handful of marbles
without looking it's unlikely that you
would get an even 50/50 split of colors
let's say you happen to get 70% red and
30% blue now imagine if something
similar were to happen to a population
of living organisms perhaps the chance
event like us reaching into our
proverbial bag of marbles was a natural
disaster a devastating earthquake
perhaps This Disaster caused the death
of 70% of the population creating a
population bottleneck in which the
remaining third is characterized by
reduced genetic
diversity in cases such as these the
remaining population could be
disproportionately affected by a
particular trait if the trait is a
disadvantageous one it probably never
would have been selected for under
normal circumstances but the extinction
has shrunk the population and when the
surviving individuals reproduce they are
more likely to pass on that
trait an example of something similar
that offers a compelling explanation for
the prevalence of seemingly
disadvantageous traits is the founder
effect this occurs when a small group
splits off from a larger population to
found a new population of their own
taking with them only a small sample of
the larger group's genetic diversity
10,000 years ago for example there could
have been a human population where just
a a few individuals possessed a mutation
resulting in their irises having less
pigment leading to Blue Eyes a small
group could have split off from the main
population and migrated to a new area in
search of fresh possibilities and new
hunting grounds and by sheer coincidence
most of the blue-eyed individuals from
the original population decided to join
this
Exodus consequently the founder effect
increased the likelihood of blue-eyed
babies being born in this new population
eventually leading to what was once a
very rare genetic trait becoming much
more common in future
Generations indeed scientists still
aren't really sure if there are any
advantages to having blue eyes it's
possible that they are better adapted to
long periods of low light leading to a
lower prevalence of seasonal depression
but there are several proposed
disadvantages such as heightened light
sensitivity and a possible increased
risk of coral damage from exposure to
ultraviolet at Rays it is therefore
clear that just as the elongated canines
of saber-toothed cats came with serious
drawbacks humans have a suite of
features that necessitate physical
compromises Evolution doesn't follow a
clear Progressive path instead more
often than not it's a series of
tradeoffs and it's clear that among
these the compromises we have made to
enable us to walk on two legs are some
of the most significant
because we are habitual bipeds we have
highly dextrous hands and comparatively
immobile feet that's why we are able to
perform such intricate tasks with our
hands but also why it's so difficult for
us to climb trees like our primate
relatives indeed walking upright is not
a common trait in the animal kingdom in
fact aside from humans fulltime habitual
bipedalism is only seen in Birds
Kangaroos and a handful of hopping Road
despite this however a variety of
animals can adopt bipedal stances for
short periods of time for example some
lizards and even cockroaches have the
ability to momentarily switch to bipedal
running when making a quick getaway but
even compared to fellow bipeds human
anatomy is Extreme let's take a moment
to consider the most common form of
bipedal animal on the planet
birds birds are all descended from the
theropod dinosaurs and most use their
tail feathers for balance while moving
around just as dinosaurs use their thick
tails to do the same thing they also
generally employ a digitrade stance
meaning that they walk on their toes
with the rest of the foot held off the
ground this posture allows for quick
agile movements and AIDS in Flight
takeoffs therapod dinosaurs move like
this as well making them very fast
Runners whereas in contrast humans a
plantigrade we walk with with our entire
foot on the
ground this provides stability and
endurance for long-distance travel but
lacks the rapid acceleration of digital
gray Locomotion the shape of the spine
in Birds is very different to human
spines too unlike humans birds have
rigid spines that contribute to their
stability during flight The Limited
flexibility of a bird's spine means it's
far less likely to suffer from spinal
issues similar to those in humans also
most birds do not bear weight on their
spine the same way humans do as their
bodies are horizontally aligned whereas
ours are uniquely vertical indeed in
humans almost every part of our anatomy
is designed to fight against gravity our
spines have an s-curve shape which is
critical for keeping us upright when
we're walking and running and even when
we're standing still or sitting down
this curvature helps to distribute the
weight of the upper body over the hips
and legs and serves as a shock absorber
during movement however since we humans
are primates our spines were originally
designed to distribute weight
horizontally but now must do so
vertically this is not a task to which
the human spine is perfectly suited
which makes us particularly susceptible
to a range of problems including lower
back pain herniated Diss and
degenerative spinal conditions like
arthritis and
scoliosis another direct consequence of
bipedalism is that we humans have narrow
pelvises when compared with other Apes
although the shape of our pelvis evolved
for more efficient upright walking this
anatomical change limits the size of the
birth canal leading to issues like seop
pelvic disproportionation where the
baby's head is too large to pass through
the pelvis this explains why giving
birth is painful and potentially
traumatic for humans whilst most other
mammals seem to have very few problems
with it and it doesn't stop there
because we humans stand without feet
fully planted on the ground we suffer
from a host of problems with our souls
as well in fact humans are the only
plant grade bipeds known to science even
kangaroos which employ a planter grade
STS while standing have the good sense
to rise up onto their toes when they
start moving
around but how does this happen a recent
study published in the journal Nature
has offered a compelling explanation for
the presence of some of these
compromises it is thought that as Apes
began to adopt a bipedal posture more
often using only two limbs to support
their bodies while they foraged or
navigated tricky areas they also lost
the need for their tails which are
usually used for balance in fully
quadrupedal primates this evolutionary
shift took place around 25 million years
ago and may have provided an advantage
for our ancestors in terms of posture
and Mobility but it also introduced a
new set of problems the researchers who
worked on this study found that our
missing Tails might be linked to a
peculiar genetic Quirk known as a
jumping
Gene these are sequences of DNA that can
relocate within the genome the gene
involved in tail development is called
tbx but the jumping Gene interferes with
the way it's processed ultimately
resulting in tail lessness indeed when
this mutation was replicated in mice
those with a jumping Gene were much more
likely to be born without tail so this
might explain why humans and other Apes
lack Tails but the study also found that
the jumping gene mutation increases the
risk of spinal conditions such as
spinabifida this is a congenital defect
that causes problems with the
development of the spinal cord causing a
gap to form in the spine of babies born
with the condition there is therefore a
serious cost to The evolutionary
advantage of being tailess and again
this is just one example genetic
variants that help humans fight
pneumonia can also predispose us to
Crohn's disease and heightened
resistance to malaria can come with its
own compromise in the form of sickle
cell
[Music]
disease and finally sometimes our own
natural inventiveness can actually help
to resolve some of these
issues over 2,000 years ago Plato
defined humans as featherless bipeds
drawing attention not just to our
two-legged postures but also to the fact
that we appear to be almost completely
bald when compared to other animals we
seem to have very little to protect us
from environmental hazards unlike in
Apes the skin of our early human
ancestors had to take over as the
outermost protective layer on our bodies
and in so doing became highly
susceptible to Cuts insect bites and the
harsh ultraviolet rays of the sun
increasing the risk of skin Cancers and
infections
this might have led to our ancestors
inventing natural sunscreens perhaps
using mud or plant extracts to Shield
themselves from the harsh sun and then
as ancient humans migrated Out of Africa
they encountered a completely different
challenge the temperatures in these new
regions were much lower than anything
they' experienced before necessitating
innovative solutions to stay warm and so
to combat the cold our ancestors used
animal skins plant fibers and bird
feathers to create clothing that would
insulate them from The Frigid conditions
they found shelter in caves which they
had been doing for many years before
offering some rest bite from the
elements but eventually they began to
build their own artificial structures to
better protect themselves it can
sometimes seem strange that we humans
have to go to such lengths to protect
our bodies from things that barely seem
to affect other animals most species are
simply born with natural adaptations
that help them thrive in their
environments thick fur for warmth in the
cold tough hides for protection sharp
teeth and Claws for hunting whereas we
use our intelligence to shape our
environments and meet our
needs looking at the human body then we
can see that it is a rich Patchwork
built of a myriad of features some are V
digal hangovers that can be useless or
even harmful others are tradeoffs where
our bodies have adapted to give us a new
ability but sacrifice something else in
return and as we can see from our
ability to remedy some of these problems
human evolution has taken a particularly
unique path so just as some parts of our
bodies are vulnerable others are truly
[Music]
remarkable each day in the Sahara Desert
as the Sun reaches its Zenith the
landscape is bathed in sweltering Heat
Heat at midday temperatures can soore to
58° C transforming an already sparsely
populated place into a truly Barren
Wasteland even the hardiest desert
species seek Shelter From the Relentless
heat retreating to the safety of
underground
burrows but look closer and this Endless
Sea of sand isn't so Barren after all
for it is precisely during these extreme
conditions that one species emerges from
nests below the Earth braving the
scorching heat they venture out to
forage making the most of a time when
most predators and competitors remain
hidden away from the sun's Fierce Rays
the Saharan silver ants named for their
striking silver Hue have tiny reflective
hairs covering their bodies these hairs
reflect sunlight away from the ants
dramatically reducing the amount of heat
they
absorb this ingenious adaptation allows
them to endure even the harshest periods
of Desert Sun for a short time a feat
that would spell Doom for most other
creatures and it's not only their
reflective hairs that allow the Sahar
and silver ants to survive such deadly
temperatures as well as this relative to
their body size they can cover a
distance 108 times their own length in
just 1 second for the ants this speed
translates to a 180 cm human running 720
km an hour but while humans May lack
reflective silver hairs or the capacity
to run at Super speeds we do possess our
own set of remarkable
adaptations these traits have empowered
us to conquer every imaginable
environment on Earth from the Frozen
poles to the deepest jungles and even to
venture beyond our planet into the
vastness of
[Music]
space the human body though we may not
always realize it is just as much a
product of evolutionary finesse as that
of the Sahar and silver ant and perhaps
the greatest example of this is our
brains this isn't to say that all other
species are unintelligent when compared
to Homo sapiens indeed chimpanzees
regularly outperform us when given tasks
to test their short-term memory but we
cannot deny that there is something
unique about the way our brains are
built to start with the human brain is8
times larger than what would be expected
for an animal of our size making us the
most
inphiza brains are tied to everything we
do in our day-to-day lives even the most
basic of tasks like tying our shoelaces
writing down a shopping list or making a
cup of coffee are all multi-step actions
that result from millions of years of
brain Evolution and if our brains are
the centers that process all the
information we need to complete these
tasks our hands are the part of our
bodies that make them
possible so what is it that makes human
hands so special the most significant
difference between our hands and those
of other animals is the presence of
opposable thumbs this is a relatively
rare trait that is generally associated
with tree dwelling animals because it
can help them grasp branches most
primates have opposable thumbs and so
does some tree frogs and koalas but
what's interesting about human hands is
that although we are no longer arboreal
we retain our opposable thumbs and have
even modified the shape of our hands to
better suit the demands of our
lifestyles in other primates the fingers
and Palms are usually much longer than
in humans which allows them to hang from
tree branches with ease their thumbs
however are much shorter and are less
flexible than ours as such humans are
able to hold and manipulate objects with
greater Precision thanks to our ability
to touch each fingertip to our thumb we
are also capable of performing a pinch
grip which is something you'll be
familiar with if you've ever threaded a
needle Studies have shown that our
closest evolutionary relatives the
chimpanzees and bonobos are unable to
replicate such Precision a study
published in 1992 for example found that
Al Lough chimpanzees are more than
capable of making and using tools they
employ a power grip while doing so
suggesting that the anatomy of their
hands limits the Precision with which
they can manipulate objects indeed the
evil ution of our hands has deep links
to our species affinity for Tool use
trying to understand which came first
tools or human hands is a bit like the
chicken or the egg because the two seem
to have co-evolved each influencing the
development of the other current
evidence suggests that early hominins
made and used tools long before the
evolution of fully modern-shaped hands
archaeological discoveries even show
that some of the earliest known stone
tools date back to about 3 .3 million
years ago during the time of ostr leius
these tools are relatively simple often
made by striking Stones together to
create sharp edges but the presence of
these early tools indicates that some
hominins may have created objects to
manipulate their environment even before
the emergence of the homo genus however
tools certainly became more complex as
time went on homo habis one of the
earliest members of our genus exhibited
hand structures more similar to Modern
human than Australopithecus indicating a
progression towards hands designed for
greater precision and Tool manipulation
and by the time Homo sapiens and the
Andals appeared in the fossil record
tools had come on Leaps and Bounds with
evidence for projectile Weaponry sewing
needles and fishing
equipment and so while our big complex
brains generated the ideas that drove
our progress it was our unique hands
that turned those ideas into
reality and bipedalism has fed into this
as well with our upright posture our
hands are free to perform more complex
tasks including the creation of tools
and we are better able to carry objects
over long
distances because of our ability to
sustain bipedal walking our ancestors
were able to transport food tools and
other essential items while moving over
vast expanses ancient ient humans could
also carry young children while walking
or running bipedally which offered
greater mobility within early human
groups but bipedalism is not merely a
characteristic of human evolution in
terms of anatomy and Locomotion it also
represented a significant shift in how
we consumed and conserved energy
especially when compared to our closest
living relatives the
chimpanzees chimpanzees primarily move
through a combination of knuckle walking
which in itself is an uncommon method of
getting around and occasional bipedalism
when it comes to daily energy
expenditure a chimpanzees lifestyle
which includes climbing through trees
and traveling several kilometers every
day in search of food and water is quite
demanding of course the lifestyles of
human hunter gatherers are no less
physical walking or running in average
of 8 mil every day but the way humans
expend energy during Locomotion is
remarkably different re search involving
chimpanzees hooked up to treadmill
monitors has shown that they expend
around four times more energy than
humans when walking this disparity in
energy use highlights the efficiency of
our bipedal gate especially over long
distances which would have been critical
when we consider the context of human
evolution and the environments in which
our ancestors found themselves
as the forests of Africa receded and
grasslands expanded during the late
Meine and early Pine our ancestors were
faced with the challenge of traversing
open Landscapes to find food water and
avoid predators in such environments
being able to walk efficiently on two
legs over long distances would have been
a significant Advantage not only were
our bipedal ancestors able to carry
objects and conserve energy while moving
around they were also better able to
regul their temperatures by exposing
less body surface area to the Sun and
coinciding with this humans evolved to
have less body hair this trait likely
emerged gradually and was driven by the
same environmental pressures that
selected for
bipedalism as early humans spent more
time in direct sunlight while foraging
and hunting they needed less body hair
and better Thermo regulation and so by
around 1.2 million years ago humans were
likely as hairless as we are now
so why do we still have hair on our
heads current research suggests that
having a full head of hair has its own
role to play in thermo regulation you
might think that having thick hair on
our heads would be counterproductive
especially in a hot environment but
because we humans are bipedal our heads
are placed directly under the sun this
puts our heads and therefore our brains
at risk of overheating therefore our
ancestors needed a solution to this
problem that wouldn't compromise their
ability to regulate their body
temperatures to find out more Dr Tina
Lei of the University of Michigan
conducted a series of experiments
involving thermal mannequins fitted with
human hairwigs in different styles she
found that hair on the head reduces heat
gain from the Sun protecting the brain
from overheating with tightly curled
hair being the most effective at
reducing heat gain without compromising
heat loss this unique character istic
acts like a peculiar parasol offering
solar protection while allowing the body
to cool down through natural heat
dissipation our hair therefore provides
us with a significant advantage in terms
of thermo regulation especially allowing
those of us with tight curls to thrive
in sundrenched environments that other
animals would quickly overheat
in and so while it's true that our evil
evolutionary Journey has left us with
some vulnerabilities these do not
diminish The Wonder of what it means to
be Human Instead they serve as reminders
of our shared Heritage with the rest of
the natural world a Heritage that
includes both our incredible strengths
and our
limitations our human bodies are without
doubt extraordinary our remarkable
adaptability and our unique adaptations
have enabled us to conquer every corner
of the globe and reach for the stars the
human body with all its intricacies and
capabilities is a Marvel of
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nature but it is also not
done we have entered a new age of
technological and cultural advancement
in which our biological evolution seems
to have taken a backseat but that's not
to say that we are immune to physical
change as societies grow in complexity
and environments shift how will the
human body adapt how exactly will we be
shaped by the
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future the Blair of sirens carries
through a futuristic
city this is a domain of concrete and
glass where night is never truly dark
and and every day is a battle to adapt
in a world where change is the only
constant and yet life persists in this
man-made
labyrinth in darkened Canyons between
reflective towers and Cold Steel urban
birds flit amongst the
gray gone of the days of bright plumage
and elaborate courtship displays these
creatures like so many in the cities of
the future are like Shadows it's it's
only when they pass under one of the
metropolis' Abundant lights that we can
catch brief glimpses of them we can hear
them though these birds while evolving
darker feathers to help them blend in
among the smog and dust of the city are
much louder than their ancestors to be
heard above the everpresent urban noise
they have needed to raise their voices
they saw between glass Giants and
concrete monoliths Adept at navigating a
landscape that reflects the sky but
offers no Passage through only those
skilled enough at avoiding these almost
invisible barriers continue to thrive
their success a grim reminder of
Nature's unyielding force of
selection this is just one version of
what the future might look like indeed
studies suggest that urban birds already
beginning to sing at a different pitch
than they used to and some are
developing the skills needed to help
them navigate around skyscrapers but
things could go very differently
depending on the course humankind
takes and so as we gaze into this
hypothetical future you might find
yourself wondering what the future might
hold for
Humanity how will our world change and
how will those changes shape our
bodies once more let's imagine ourselves
find 5,000 years in the
future here we find not a cold
impersonal City inhabited by genetically
engineered Shadows but a world shaped by
balance humans have moved on from the
domineering days of their ancestors and
have evolved in perfect harmony with
nature this has obviously had profound
benefits for the environment but it has
also been advantageous for human bodies
too in this new world humans stand
taller than ever before
and they are free from the diseases that
once plagued our
species indeed this might sound like a
utopian idea but such speculations are
not without Foundation historical and
contemporary data for instance reveal a
clear link between advancements in
nutrition and healthare with increases
in human stature in 2016 the NCD risk
factor collaboration published their
meticulous research on this phenomenon
analyzing data from 200 countries from
between 1996 and
1996 they found that human height has on
average shot up by as much as 20 cm in
certain regions and that's just in one
century indeed Healthcare has already
advanced beyond what past Physicians
would have thought possible the
introduction of antibiotics for example
began with Alexander Fleming's discovery
of penicillin in the late 1920s and has
since reduced human mortality from
bacterial infections dramatically in
addition vaccination programs have
eliminated diseases that once claimed
thousands of human lives every year in
1980 for example the World Health
Organization declared the eradication of
small poox and polio was eliminated in
Europe by
2003 globalization will also play a
critical role in shaping the bodies of
future humans we are already seeing
increasing rates of InterContinental
travel and Intercultural relationships
and we can assume that this trend will
continue as a direct result of this more
mixed skin tones will become common
across human populations this may also
mean that certain traits which are
usually associated with people who have
light skin like blue or green eyes and
blonde or red hair may become
increasingly rare in the future these
traits are genetically recessive meaning
that they will not usually be selected
for if one biological parent has the
genes for a more dominant eye or hair
color similarly wisdom teeth or third
molers may also disappear or become a
rarity originally necessary for grinding
plant tissue these teeth have become
less essential as human diets and
cooking methods have evolved modern
human Jaws are smaller often leaving
insufficient space for wisdom teeth
leading to dental issues such as
impaction and
infections this genetic shift could lead
to Future Generations born without these
teeth potentially resulting in fewer
dental health issues and a decreased
need for related medical
interventions another noticeable shift
in the evolution of future humans while
not influenced by gene flow but rather
by subtle genetic mutations over
Generations concerns the average size of
the human brain contrary to what you
might expect human brains will likely be
smaller in the future
the concept of brain size reduction in
future humans might seem
counterintuitive but it's not without
precedent the trend of decreasing brain
size in human populations has been
observed over the past 10,000 or so
years and is thought to be related to
changes in Social organization diet and
reductions in physical aggression back
in the Neolithic the shift from nomadic
to agrarian Lifestyles coupled with the
rise of the first civilizations reduced
survival pressures on individual humans
and so as responsibilities became
distributed within communities and
farming brought increased food security
The evolutionary imperative for large
brains
diminished and that is why we have
brains that average around 150 cubic cm
smaller than the brains of our ancestors
who lived during the last ice
age and considering the high energetic
demands of large brains which currently
demand about 20% of our total energy for
only 2% of our body weight smaller
brains might actually be much more
beneficial than larger ones and as for
the future it's plausible that continued
advancements in technology and changes
in social structures could favor
cognitive specialization and efficiency
over sheer brain
volume of course these future scenarios
also invite us to reflect on the
limitations and Imperfections of the
human body
these trade-offs remind us that
evolution is not a process aimed at
Perfection but at
adaptation we might imagine that we are
the most intelligent most evolved
creatures on the planet but evolution
doesn't work like that it's not like
climbing a ladder to reach the highest
rung it's more like a sprawling bush
with branches spreading out in all
directions this evolutionary Bush never
stops growing with new branches or
species con L emerging While others
shrivel and die as species go
extinct and so our bodies with all their
quirks and vulnerabilities carry the
legacy of our ancestors adaptations to
their environments adaptations that were
never about achieving an ideal state but
about surviving and reproducing in a
world of constant change
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and we'll see you next time
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