When and where did humans evolve
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Like all other species on our planet our species was produced by the process of biological evolution:
But where and when did we evolve and will we one day be able to direct our own evolution in the future?
Scientists have contemplated these questions for centuries.
Perhaps unsurprisingly the co discoverer of the theory of evolution, Charles Darwin,
was first to formulate a testable hypothesis about where
we evolved. All it took was a trip to the London Zoo.
After spending some time observing chimpanzees and gorillas he thought
it likely that our species common origin was African,
although this idea offended British royalty
and proved academically controversial for well over a century,
Darwin, of course, turned out to be right. You, me
and everyone else we know is technically African.
Since Darwin's time, scientists have collected an
overwhelming amount of evidence to support this claim
Some of the first convincing clues came from the discovery of
ancient human-like fossils throughout East Africa.
These fossils weren’t quite African apes, and not quite
what we’d think of as modern human either.
They were species with the mosaic of human and ape-like features.
Who were they? Your great, great, great, great,
great grandparents.
One of the most well-known of our ancestors is Australopithecus Afarensis
We know so much about Afarensis
thanks to a well-preserved fossil of a partial skeleton named Lucy.
They lived over three million years ago
in what is today Ethiopia and like all other
hominids from this time period their brain size was closer
to that of modern-day chimpanzees than it is to humans,
but interestingly we know from Lucy’s lower
body that she was oficially bipedal meaning she walked
on two legs. This was an important find for scientists
because it suggested that our ancestors started to walk upright before
we started to evolve larger brain sizes.
Of course, this was not a
straightforward transition. Recent finds of the Australopithecus
Sediba dated about two million years old
and reveal a species that was exceptionally well adapted to
walking by pedley but also exceptionally
well adapted to climbing trees and perhaps sleeping in them.
Such discoveries reveal that our motives locomotion today evolved gradually
over a period of millions of years.
As for our big brains, current evidence suggests
that we started to see an explosion with the emergence of our genes Homo
two million years ago perhaps as a result
of this relatively rapid brain growth, our ancestor Homo Erectus
started spreading throughout Eurasia. They may have been the
first human species to leave Africa and adapt to alien environment but
we have more than just the fossil evidence. You have the evidence of
your African ancestry in your genes as well. When geneticists
started comparing human DNA with ape DNA,
the startling similarity between our strands was undeniable.
Studies on the amino acid sequence of our DNA proved right our initial hypothesis
Chimpanzees were our closest living relatives
followed closely by gorillas and then orangutans.
But when did we start to leave Africa?
Today humans are truly a global species permanently inhabiting
every continent on the planet.
Here the fossil of genetic evidence proves slightly contradictory.
When it is safe to say that there was some form of modern human migration
onto the Arabian Peninsula around a hundred thousand years ago,
it is likely that these migrations from Africa
were only of small bands of modern humans.
We also know that the first modern humans out of Africa travelled down the
shore lines of Asia and may have hopped off to Australia by
45,000 years ago. Throughout this emergence
we encountered interbred with, and out competed several other
human species in Eurasia, which only exist today
as a small percentage of the total modern human genome.
What is even more interesting is that our evolution hasn’t stopped. In fact,
over the past ten thousand years, humans have been changing in new ways
due to the development of civilization. For most of our
evolution we were hunters and gatherers but over the past ten thousand years
an increasing number of human groups domesticated
animals and plants, then became sedentary, started
building large-scale structures and congregating in ever denser urban center.
This led to certain biological changes like
varying levels of adaptation to the consumption of lactose
and resistance to communicable diseases
But the most significant changes come with cultural
and technological evolution. With the development of civilization
a small fraction of humans could for the first time dedicate their time and energy
to task unrelated to food production. As this trend continued,
more and more people could dedicate themselves to science, art,
engineering, music, sports, teaching, medicine,
politics and thousands of other possible vocations.
In the modern world, accelerating
cultural and technological evolution has led to the development of technology that could allow
us to intelligently direct on our evolution. This could be done
by directly engineering our own genomes turning on and off
different sections within it. We can also do this by gradually
replacing our cellular structures with nano engineer computers,
designed to perform the same tasks our cells perform, only better.
Either way, one thing is certain: the nature of our evolution
will be considerably different from the natural selection process
that created us. As futurist Peter de Menendes said,
it won't be natural selection but intelligent direction that
causes our future evolution. How does knowledge of human evolution
influence your perceptions of life? And our history?
More importantly, what you think is the future of human evolution?
Let's talk about this together in the comment.
As always thanks for watching and don't forget to subscribe to The Advanced Apes.
Transcription and subtitles by Alicia Santos Mendoza