1
00:00:01,649 --> 00:00:14,830
Like all other species on our planet, our species was produced by the process of biological

2
00:00:14,830 --> 00:00:15,830
evolution.

3
00:00:15,830 --> 00:00:17,829
But where and when did we evolve?

4
00:00:17,829 --> 00:00:22,390
And will we one day be able to direct our own evolution in the future?

5
00:00:22,390 --> 00:00:24,949
Scientists have contemplated these questions for centuries.

6
00:00:24,949 --> 00:00:29,589
Perhaps unsurprisingly, the co-discoverer of the theory of evolution, Charles Darwin,

7
00:00:29,589 --> 00:00:33,270
was first to formulate a testable hypothesis about where we evolved.

8
00:00:33,270 --> 00:00:35,609
All it took was a trip to the London Zoo.

9
00:00:35,609 --> 00:00:39,549
After spending some time observing chimpanzees and gorillas, he thought it likely that our

10
00:00:39,549 --> 00:00:42,490
species' common origin was African.

11
00:00:42,490 --> 00:00:47,109
Although this idea offended British royalty and proved academically controversial for

12
00:00:47,109 --> 00:00:50,509
well over a century, Darwin, of course, turned out to be right.

13
00:00:50,509 --> 00:00:54,710
You, me, and everyone else we know is technically African.

14
00:00:54,710 --> 00:00:58,990
Since Darwin's time, scientists have collected an overwhelming amount of evidence to support

15
00:00:58,990 --> 00:01:00,570
this claim.

16
00:01:00,570 --> 00:01:04,590
Some of the first convincing clues came from the discovery of ancient human-like fossils

17
00:01:04,590 --> 00:01:06,310
throughout East Africa.

18
00:01:06,310 --> 00:01:10,109
These fossils weren't quite African apes, and not quite what we would think of as modern

19
00:01:10,109 --> 00:01:11,250
human either.

20
00:01:11,250 --> 00:01:15,689
They were species with a mosaic of human and ape-like features.

21
00:01:15,689 --> 00:01:16,689
Who were they?

22
00:01:16,689 --> 00:01:21,480
Your great-great-great-great-great-grandparents.

23
00:01:21,480 --> 00:01:25,719
One of the most well-known of our ancestors is Australopithecus afarensis.

24
00:01:25,719 --> 00:01:29,739
We know so much about afarensis thanks to a well-preserved fossil of a partial skeleton

25
00:01:29,739 --> 00:01:31,280
named Lucy.

26
00:01:31,280 --> 00:01:35,939
They lived over 3 million years ago in what is today Ethiopia, and like all other hominids

27
00:01:35,939 --> 00:01:40,840
from this time period, their brain size was closer to that of modern day chimpanzees than

28
00:01:40,840 --> 00:01:42,599
it is to humans.

29
00:01:42,599 --> 00:01:47,200
But interestingly, we know from Lucy's lower body that she was habitually bipedal, meaning

30
00:01:47,200 --> 00:01:49,519
she walked on two legs.

31
00:01:49,519 --> 00:01:53,200
This was an important find for scientists because it suggested that our ancestors started

32
00:01:53,200 --> 00:01:58,299
to walk upright before we started to evolve larger brain size.

33
00:01:58,299 --> 00:02:01,540
Of course, this was not a straightforward transition.

34
00:02:01,540 --> 00:02:06,760
Recent finds of Australopithecus sedeba date to about 2 million years old and reveal a

35
00:02:06,760 --> 00:02:11,539
species that was exceptionally well adapted to walking bipedally, but also exceptionally

36
00:02:11,539 --> 00:02:15,340
well adapted to climbing trees and perhaps sleeping in them.

37
00:02:15,340 --> 00:02:20,199
Such discoveries reveal that our mode of locomotion today evolved gradually over a period of millions

38
00:02:20,199 --> 00:02:21,259
of years.

39
00:02:21,259 --> 00:02:25,659
As for our big brains, current evidence suggests that we started to see an explosion with the

40
00:02:25,659 --> 00:02:30,379
emergence of our genus Homo 2 million years ago. Perhaps as a result of this relatively

41
00:02:30,379 --> 00:02:34,800
rapid brain growth, our ancestor Homo erectus started spreading throughout Eurasia. They

42
00:02:34,800 --> 00:02:39,039
may have been the first human species to leave Africa and adapt to alien environments, but

43
00:02:39,039 --> 00:02:42,840
we have more than just the fossil evidence. You have the evidence of your African ancestry

44
00:02:42,840 --> 00:02:48,199
in your genes as well. When geneticists started comparing human DNA with ape DNA, the startling

45
00:02:48,199 --> 00:02:52,819
similarity between our strands was undeniable. Studies on the amino acid sequence of our

46
00:02:52,819 --> 00:02:57,520
DNA proved Darwin's initial hypothesis. Chimpanzees were our closest living relatives, followed

47
00:02:57,520 --> 00:03:00,740
closely by gorillas and then orangutans.

48
00:03:00,740 --> 00:03:05,639
But when did we start to leave Africa? Today humans are truly a global species, permanently

49
00:03:05,639 --> 00:03:10,099
inhabiting every continent on the planet. Here the fossil and genetic evidence prove

50
00:03:10,099 --> 00:03:14,520
slightly contradictory, but it is safe to say that there was some form of modern human

51
00:03:14,520 --> 00:03:19,479
migration onto the Arabian Peninsula around 100,000 years ago. It is likely that these

52
00:03:19,479 --> 00:03:24,300
migrations from Africa were only of small bands of modern humans. We also know that

53
00:03:24,300 --> 00:03:28,699
the first modern humans out of Africa travelled down the shorelines of Asia and may have island

54
00:03:28,699 --> 00:03:33,860
hopped to Australia by 45,000 years ago. Throughout this emergence we encountered, interbred

55
00:03:33,860 --> 00:03:38,900
with and outcompeted several other human species in Eurasia, which only exist today as a small

56
00:03:38,900 --> 00:03:42,860
percentage of the total modern human genome. What is even more interesting is that our

57
00:03:42,860 --> 00:03:47,139
evolution hasn't stopped. In fact, over the past 10,000 years humans have been changing

58
00:03:47,139 --> 00:03:50,120
in new ways due to the development of civilization.

59
00:03:50,120 --> 00:03:54,340
For most of our evolution we were hunters and gatherers, but over the past 10,000 years

60
00:03:54,340 --> 00:03:59,379
an increasing number of human groups domesticated animals and plants, then became sedentary,

61
00:03:59,379 --> 00:04:04,120
started building large scale structures, and congregating in ever denser urban centers.

62
00:04:04,120 --> 00:04:08,580
This led to certain biological changes, like varying levels of adaptation to the consumption

63
00:04:08,580 --> 00:04:11,900
of lactose, and resistance to communicable diseases.

64
00:04:11,900 --> 00:04:15,740
But the most significant change has come with cultural and technological evolution.

65
00:04:15,740 --> 00:04:19,620
With the development of civilization, a small fraction of humans could for the first time

66
00:04:19,620 --> 00:04:22,920
dedicate their time and energy to tasks unrelated to food production.

67
00:04:22,920 --> 00:04:27,240
As this trend continued, more and more people could dedicate themselves to science, art,

68
00:04:27,240 --> 00:04:31,860
engineering, music, sports, teaching, medicine, politics, and thousands of other possible

69
00:04:31,860 --> 00:04:32,860
vocations.

70
00:04:32,860 --> 00:04:37,060
In the modern world, accelerating cultural and technological evolution has led to the

71
00:04:37,060 --> 00:04:41,300
development of technology that could allow us to intelligently direct our own evolution.

72
00:04:41,300 --> 00:04:45,300
This could be done by directly engineering our own genomes, turning on and off different

73
00:04:45,300 --> 00:04:49,240
sections within it? We could also do this by gradually replacing our cellular structures

74
00:04:49,240 --> 00:04:53,199
with nano-engineered computers, designed to perform the same tasks our cells perform,

75
00:04:53,300 --> 00:04:57,819
only better? Either way, one thing is certain. The nature of our evolution will be considerably

76
00:04:57,819 --> 00:05:02,560
different from the natural selection process that created us. As futurist Peter Diamandis has said,

77
00:05:02,839 --> 00:05:07,120
it won't be natural selection, but intelligent direction that causes our future evolution.

78
00:05:07,259 --> 00:05:11,220
How does knowledge of human evolution influence your perceptions of life and our history?

79
00:05:11,220 --> 00:05:14,480
More importantly, what do you think is the future of human evolution?

80
00:05:14,980 --> 00:05:16,759
Let's talk about this together in the comments.

81
00:05:16,959 --> 00:05:19,720
As always, thanks for watching, and don't forget to subscribe.

82
00:05:19,879 --> 00:05:20,720
Advanced States.