Let’s continue talking about the various myths of human evolution.
Let’s start by looking at what is perhaps “myth number one”
on the list of anti-evolutionist arguments:
“Nobody has ever seen an ape turning into a human.”
I have deliberately not dealt this myth yet
because it has already been addressed by many reputed scientists.
I will now say few words about, but will do so in my own way,
trying not to repeat what others had already said.
I've just attended a Science Festival in Moscow
where I've heard the question like "Why aren't apes evolving into humans?" posed –
– at least three times.
Surprisingly, it was posed by well-educated people.
I think, the reason is that the phrase “humans evolved from apes or monkeys”
has really become a catchphrase that represents
the entire theory of evolution in the mind of most lay people.
In other words, the whole theory of evolution has been compressed into this single phrase.
Accordingly, if we take this phrase literally,
then we should be able to go to the zoo
and look at monkeys jumping to their feet,
shedding their tails and hair, and turning into handsome lads or lasses –
depending on their bi ological sex.
However, nobody has ever seen that happen,
so scientists must be hoaxing people, right? Well, not quite.
The truth is: this phrase is a major simplification.
For instance, it doesn’t explain what particular kind of apes had “evolved into humans”.
So, if someone tells you that apes are not turning into humans,
you should ask: what apes do you mean?
There are more than 400 species of primates currently living on our planet,
none of which is our ancestral species.
By the way, it’s interesting how mass culture works here.
Take for instance the film “Night at the Museum”.
There is a scene where one protagonist, Terry,
asks another one, Larry: “Who’s evolved? Who’s evolved?”
while pointing his finger at a capuchin monkey.
But capuchins are New World monkeys which inhabit South America.
Of course, they are primates, but they are only very remotely related to us,
our lineages having separated more than 30 million years ago.
The movie, however, implies
that the capuchin is a human ancestor that just failed to evolved.
That is, of course, complete nonsense.
In other words, it must be understood that no modern primate is our ancestor
and the apes that had once embarked on the path of evolving into humans
now exist only in the form of fossilized bones: they are long extinct.
Of course, if we are going to speak of anyone at all int his context,
it should at most be the great apes, and primarily the chimpanzee,
our closest relative in terms of constitution, genetics, and biochemistry.
But chimps also are not our ancestors.
If we look at our distant quadrupedal ancestor who lived,
the proconsul –here he is on the picture –
who lived about 15 million years ago and compare him with a human,
we will see that our two species are quite different.
But the proconsul is also ancestral to other great apes,
namely chimpanzees, gorillas, and orangutans – but does not resemble any of them.
Furthermore, they do not resemble each other.
For instance, in the course of evolution our ancestors’ legs
had been lengthening in relation to their arms.
But for chimp ancestors of chimps it was the other way around:
their arms had been lengthening in relation to their legs.
Our cuspids had been shortening (and we are proud of that),
but chimp cuspids, and, generally, their teeth and jaws were growing bigger.
One of the features which is often considered quintessentially human
is concealed ovulation.
That is, our women do not show external signs of ovulation
and, looking at a woman, one cannot tell the phase of her menstrual cycle.
But looking at a female chimpanzee uninformed people sometimes ask:
“Does she have a disease? What is that swelling?”
She gets a swelling that looks something like a red football.
In fact, that is a swelling the chimp’s genital skin.
When she is ovulating and is ready for mating,
she uses it to signal to the male
that she is ready and available.
But if we look at female gorillas or orangutans,
we won’t see any such external signs of ovulation.
It must be a specific feature of chimpanzees
which has emerged in the course of their evolution.
So here is what I am trying to say: while our ancestors were evolving into humans,
the chimpanzee ancestors were also not sitting idle.
They were turning into chimpanzees.
And in order for chimps to suddenly turn into humans…
Well, “suddenly” does not work because this has taken millions of years.
But in any case, the chimp would first have to rewind its evolution
by about 10 million years
in order to return to its primitive ancestral form.
But this is impossible.
Besides, neither chimps, nor other apes actually need to do that.
There is truth to the joke that apes are not evolving into humans
because they are afraid that they will be forced to work.
In other, if chimp evolution continues, it will not move towards humanity,
but rather in the direction of an “ultra-chimpanzee.”
Although, unfortunately, the more likely forecast
for modern hominids is extinction, given how much we humans
are contributing to their disappearance.
There is one more interesting point to make. Comparing a human
with other primates we view ourselves as an ultimate example of progress.
But if we look closer at other simians, we will see that,
in many ways, we are the ones who are behind in our evolution.
Traditionally, the following features are described as quintessentially human: a huge brain –
for a human – bipedalism, and, for instance, the ability to chuck spears at elephants.
But there are also other features, no less important.
For example, in the course of evolution our stomatognathic system has been reducing
and this is considered to be a progressive feature.
This has led to the fact that our third molars
or wisdom teeth which can erupt late in life, or not at all.
But callitrichids – those are very cure monkeys from South America
– never have wisdom teeth. Their third molars disappeared completely.
We also consider our reduced cuspids to be an advanced feature.
But the aye-ayes – lemurs native to Madagascar –have no cuspids at all.
In that sense, they have left humans far behind.
By the way: our science editor Stanislav Drobyshevsky
has recently published a Russian-language book
titled “Non-Missing Link” which describes plenty of monkey peculiarity like this
and which I strongly recommend.
Another example: our ears are small and immobile.
This feature too is considered to be evolutionary advanced.
But, if we look at an adult gorilla or an adult orangutan, we won't find – what?
External ears. They are so small and rudimental that one usually
cannot see them in the animals’ thick fur.
Thus, in terms of reduction of ear dimensions
gorillas and orangutans are far ahead of us.
Such examples are very numerous.
In sum, who is the faster evolver – our simian relatives, or us – is an open question.
Because, as you can see, in many ways, human actually resemble living fossils.