About 13 billion years ago, matter, energy, time and space came into being in what is known as the Big Bang. The story of these fundamental features of our universe is called physics. Physics examines how matter, energy... time and space interact with one another and behave. About 300,000 years after their appearance, matter and energy started to combine into complex structures, which we call atoms.
And these atoms then combined into even more complex structures, which are called molecules. The story of atoms, molecules, and their interactions is called chemistry. Chemistry examines what happens when an oxygen atom comes into contact with a hydrogen atom or when a salt molecule comes into contact with a water molecule. This is what chemistry does.
About 4 billion years ago, on a planet called Earth, certain molecules combined to form even larger and more complex structures which we call organisms or living creatures. The story of organisms is biology. Biology examines how, for example, a lion or a giraffe function, and what happens when a lion comes into contact with a giraffe.
This is biology. About 70,000 years ago, organisms belonging to a very particular species, our species, Homo sapiens, started to come together and combine and form even more elaborate structures which we call cultures. The development of these human cultures is history. This is what this course will be about.
The formation and development and interaction of human cultures from about 70,000 years ago until today. From this perspective, what is essential to realize is that there is no unbridgeable gap between history on the one side and physics, chemistry and biology on the other side. History is simply the next stage in the process of on-growing complexity in the universe. We have physical dynamics and then they become more and more complex. We have chemistry, chemical dynamics and then chemical dynamics become more and more complex.
We have biology, biological dynamics and when biology becomes very, very complex, then we get history. Now, three very important things happened in history. You can summarize the whole of history in just three main revolutions, or three main events. The first is the Cognitive Revolution.
The Cognitive Revolution began about 70,000 years ago. In this revolution, Homo sapiens... which previously was just an insignificant species of African ape, evolved unique cognitive abilities. Cognitive abilities means thinking, remembering, communicating, learning.
These are the cognitive abilities. So Homo sapiens developed unique cognitive abilities that gave it immense power and turned it into the most important animal in the world. So this is the first big revolution of history, the cognitive revolution.
The second big revolution of history is the agricultural revolution, and it began about 12,000 years ago. During the agricultural revolution, Homo sapiens domesticated certain kinds of animals and plants, established villages and cities and other permanent settlements, and began to create... ever more complex societies, cities and kingdoms and empires and churches and so forth. So this is the second big revolution of history, the agricultural revolution.
The third big revolution of history is the scientific revolution. It began about 500 years ago. And during the scientific revolution, Homo sapiens understood better and better the rules.
that governs the natural world around it and inside it, and thereby gained more and more power, and became the master of the entire planet, it has become the master of the entire planet. It has become so powerful that today it actually begins to change the most basic rules of life. For about 4 billion years, life on Earth evolved according to the laws of, to the rules of natural selection, evolution by natural selection. And today, Homo sapiens is gaining so much power thanks to technologies like genetic engineering.
and direct brain-computer interfaces and so forth, that it is expected that in the next century or two, it will really completely change the way that life evolves on planet Earth and in the universe in general. We will come to speak about this in greater depth at the end of the course, when we will discuss the revolutions, the technological and political changes of the 20th and 21st century. What we will do...
in this course is to survey these three fundamental revolutions of history, the cognitive revolution, the agricultural revolution, and the scientific revolution, and we'll examine what was their impact, both upon human beings and upon their fellow organisms and the environment around them. Now, it's very important to realize that humans existed long before history. History began with the Cognitive Revolution about 70,000 years ago, but animals, much like you and me, much like modern humans, first appeared about 2.5 billion years ago in East Africa.
However, for most of these 2.5 million years, our ancestors, our human ancestors, were just another kind of animal. There was nothing special about humans. There was no hint that their...
great-great-great-grandchildren would one day walk on the moon, or split the atom, or understand DNA, or write history books. The most important thing to know about prehistoric humans is that they were unimportant creatures. They did not have more impact upon the world than, say, gorillas, or fireflies, or penguins.
The history... of ancient humans was just another chapter in the big book of biology. Now, biologists classify animals into species.
Animals are said to belong to the same species if they tend to have sex with one another, to mate with one another, giving birth to fertile offspring. Horses and donkeys, for example, they look quite similar, and they are indeed. very similar in many of their qualities, but horses and donkeys usually have little sexual interest one in the other.
People sometimes force horses and donkeys to mate, and then they even can produce offspring, but their offspring, which are called mules, are always sterile. This shows that horses and donkeys, despite all the similarities between them, are in fact two completely different species. Since they cannot exchange genes between them, they are evolving over the generation in different directions. When there is some important genetic mutation in a horse, it can never pass to donkeys because they can't produce fertile offspring together. So this is why they are separate, different species.
In contrast, A bulldog and a Cocker Spaniel may look very different from one another, but they will happily mate, they have a lot of sexual interest one in the other, and when they mate, they can produce fertile puppies that will grow up to mate with other dogs and produce more puppies and so forth and so on. So this is why bulldogs and Spaniels are considered members of the same species. They are both dogs.
Now, species that evolved from a common ancestor, even when they are different from one another, like horses and donkeys, still, similar species that evolved from a common ancestor are bunched together by biologists under the heading, under the title, genus. This is how scientists called a group of species that evolved from a common ancestor. They call it genus.
The plural of genus is genera. For example, lions, tigers, leopards, and jaguars are different species within the genus Pantera. Also, it's important to know that scientists usually like to use the Latin language in order to name things, because everything sounds far more impressive and scientific when you say it in Latin. So, for example, all the medicines we use or all the names of the muscles in our bodies, they are all in Latin. Also, the names of animals, biologists, and plants, and all other organisms, biologists like to use Latin to give animals their scientific name.
And the rule is that the scientific name of each animal has two parts. First, the genus, and then the species. Lions, for example, the scientific name. of the lion is not lion.
When you write in scientific articles about lions, you don't speak about lions. You speak about Pantera Leo. This is the scientific name of the lion. Pantera is the name of the genus, it comes first, and then Leo, this is the name of the species, it comes second, so lion is Pantera Leo. You and me, and I guess everybody who watches this video, we are all Homo sapiens.
This is the scientific name of our species, Homo sapiens, which means the species sapiens, a Latin word meaning wise. Of the genus Homo, a Latin word meaning men. So the meaning of our scientific name, Homo sapiens, is wise men.
This is the name that we gave ourselves. We might be very wise, but we are not particularly modest. Genera, so this is genus and genera. Genera is the plural of the word genus.
It's quite complicated. Genera, in their turn, are also grouped by biologists. into larger collectives, which are known as families. So we have in nature, for example, the cat family, which includes many, many genera and species of cats.
Like all the lions and cheetahs and house cats, they all belong to the cat family. And we have the dog family, which includes not only dogs, but all kinds of wolves and foxes and jackals, they all belong to the big family, the dog family. And we have the elephant family, which includes Indian elephants and African elephants and extinct species of elephants like mammoths and mastodons.
What is important to know is that all members of a family trace their lineage back to some ancient ancestor who is the great-great-great-grandmother or grandfather of all of them. All the cats, for example, from... the most ferocious lion in the African savannah, to the smallest, cutest house kitten in your house, they all have the same great, great, great ancestor who lived about 25 million years ago. So these are families. Homo sapiens too, our species, belongs to a family, a biological family.
This banal fact used to be... one of the most closely guarded secrets of history. For thousands of years, Homo sapiens preferred to view itself as totally different from all the other animals, as set apart from all the other animals, as a kind of orphan which has no family, no cousins, no siblings, and most importantly, no parents.
As if Homo sapiens just popped up on Earth without having any evolutionary ancestors. But that is just not the case. Whether you like it or not, the truth is that we, the species Homo sapiens, are also members of a large and particularly noisy family called the family of great apes. Just as lions and cheetahs, they belong to the family of cats, so we Homo sapiens have a family called the great apes.
There are some other members of this family which are still living today in the world. Our closest cousins, our closest relatives which are still alive, include the chimpanzees, the gorillas, and the orangutans. Of these, the chimpanzees are the closest to us.
Just six million years ago, if you went back in time six million years, you would find somewhere in Africa a single female ape who had two daughters. One of her daughters became the ancestor of all the chimpanzees, and her sister, the other daughter, she's yours and mine, great-great-great-great-grandmother. So, Homo sapiens belongs to a family. Homo sapiens has kept hidden an even more disturbing secret. We have not only a big family with many cousins, Once upon a time, we also had quite a few brothers and sisters.
We, that is, Homo sapiens, we tend to call ourselves not Homo sapiens. Usually when we speak about ourselves, we use the title human, as if only us are human, we are the only humans. But the fact is that there used to be many other human species on planet Earth.
Humans simply means animals. that belong to the genus Homo, that is men in Latin. So these humans, they first appeared in East Africa about 2.5 million years ago. They did not appear out of nowhere, they evolved from an earlier genus of apes, which is called Australopithecus.
It has nothing to do with Australia, this complicated name, it simply means southern ape. So Australopithecus was the ancient ancestor of humans. The first human species evolved from Australopithecus somewhere in East Africa about 2.5 million years ago. At first, it was the only human species, but about 2 million years ago, some of these archaic men and women left their homeland in East Africa and spread around the world. settling various areas in North Africa, the Middle East, Europe and Asia.
And in each area, these men and women encountered different conditions, a different climate, different geography, animals and plants. And in order to adapt to these different conditions, the human populations in each of those areas began to evolve in different ways. this created, with time, completely different human species.
For example, humans who, after leaving Africa, reached northern Europe, they needed to adapt to the very cold climate of northern Europe, with lots of ice and snow, and all kinds of big animals like bears and mammoths and mastodons. Other humans, after leaving Africa, they eventually ended up in Indonesia. And they needed to adapt to the very hot tropical climate of the jungles and swamps of Indonesia.
Other humans meanwhile reached Central Asia, the deserts of Central Asia, and they needed to adapt to the very dry climates of Central Asia. The result was that over the years, many, many different species of humans evolved in different parts of the world. And to each of these different human species, scientists have assigned its own pompous Latin name.
Now, you don't need to remember the names of the different species and the details that I'm going to tell about the different species, but I would like to take a few minutes to tell you about some of these ancient brothers and sisters of ours, some of these ancient human species, so that you will know our family. a little better. In Europe and the Middle East evolved a species of humans which scientists called Homo neanderthaliensis. This means in Latin men from the Neander Valley. The name was given because the first remains of these ancient humans were discovered by archaeologists in the Neander Valley in Germany.
So they called this species men from the Neander Valley Homo neanderthaliensis. But they also gave these humans a nickname, which everybody uses, and I will also use, they are the Neanderthals. Neanderthals were well adapted to the cold climate of Ice Age Europe and the Middle East. Even the Middle East was, at that time, much colder than it is today.
Neanderthals were bigger, more muscular than us. They had insulating layers of fat covering their bodies to give them better protection. from the cold, and they even had bigger brains than we have.
So this was one human species that evolved in Europe and the Middle East. In another part of the world, on the island of Java in Indonesia, evolved Homo Soluensis. This means in Latin again, men from the Solo Valley, because the first remains of this human species were discovered by archaeologists in the Solo Valley. on Java Island. And Java had tropical climate, so Homo Soluensis was evolving over the years to become better and better adapted to living in the jungles and swamps of tropical Java.
On another Indonesian island, the very small island of Flores evolved a very unique and interesting human species, which is called by scientists Homo Floresiensis. This means, you probably can now guess it by yourself, men from Flores Island, because this is where this species lived, on Flores Island. Now, the unique thing about these humans, about Homo floresiensis, is that they were dwarfs. They were very, very small. What happened is that Flores used to be connected to the mainland by land, and at some time...
the sea levels rose, the ocean rose, and Flores was disconnected from the mainland. Some people who walked over the land to Flores, they got stuck on this island when the sea level rose. And Flores is a small island, and there is not much to eat on such a small island, so the big people died first. The big people need a lot of food in order to survive, so they died first.
And smaller people, who need less food in order to survive, they managed to survive better. And this happened generation after generation. The smallest people had the best chances of having enough food and keeping themselves alive.
So over the years, the people who got stuck on Flores Island became smaller and smaller and smaller until they became dwarfs. And it's estimated, according to the bones that scientists have found, that homophilocensis, reached a maximum height of no more than one meter and a maximum weight of 25 kilograms. Nevertheless, these tiny people, they still were humans. They were still able to manufacture and use all kinds of tools, like spears and so forth. They even managed, at least from time to time, to hunt elephants.
Now, it wasn't very big elephants. It was also dwarf elephants, because also... Elephants that got stuck on Flores Island, the same thing that happened to humans happened also to the elephants, and then it became smaller and smaller and smaller until Flores was populated by tiny people hunting tiny elephants.
So this is Flores. While this was happening in the tiny island of Flores, in the big open spaces of Asia evolved a different human species, which is called by scientists Homo erectus. Homo erectus means upright men because these men, these people, were very tall.
They were taller than us, reaching heights of 1.8 and even 1.9 meters tall. Another important fact about Homo erectus is that it was probably the most successful human species ever in terms of how many years it managed to survive. Homo erectus first appeared, first evolved, about 1.5 million years ago, and survived until about 50,000 years ago. So Homo erectus existed, this species existed, for close to 1.5 million years.
In contrast, our species, Homo sapiens, began to evolve maybe 300,000, 200,000 years ago. We exist only about 200,000, 300,000 years. And it is very unlikely that we will break the record of Homo erectus. It's very unlikely that our species will manage to live for more than one and a half million years.
In fact, as we will see in the last lesson of this course, which we'll discuss in the future, it is doubtful if we will manage to exist even for a thousand years. So what to speak about a million and a half years? So this is Homo erectus.
In 2010, scientists discovered the remains of another lost brother or lost sister when they excavated the Denisovka cave in Russia, in eastern Russia. So archaeologists excavating the cave, they made an amazing discovery. They found there a finger, or not a finger, they found the fossilized bone of a human finger.
And... And they managed to extract DNA from this fossilized bone and to map it, to see what kind of DNA was inside. And they compared the DNA from the finger of the Nisova cave to the DNA of all other known human species, and it didn't match.
So they came to the conclusion, based just on this single finger, that it was a human. Previously there existed, at least in Central Asia, another species of humans which they now called Homo Denisovans, men from the Denisovans cave, which was different from the Neanderthals and Homo erectus and all the rest. So this is Homo Denisovans. Who knows how many other ancient human species existed in the past and are waiting to be discovered in all kinds of caves and remote islands. We don't know for sure.
While all this was happening in Europe and Asia, evolution in East Africa, where humans first emerged, did not stop. Evolution continued, natural selection continued to put pressure on humans in East Africa, which resulted in the evolution of more and more human species also in Africa. We have, for example, Homo rudolfensis, men from Lake Rudolf, whose remains were found near Lake Rudolf.
We have Homo ergaster, which means working men, because archaeologists discovered alongside the bones of this species also many, many tools made by these ancient humans. So they called them working men, as if they just went around making tools, stone tools all the time. And eventually, our own species, Homo sapiens, also appeared in East Africa about 200,000 or 300,000 years ago. We don't need to remember the names and details, as I said, of all these different human species. What is important, however, is to realize how they are related to one another, or the general picture, this is more correct.
What is important is to understand the general picture of the human family. And the general picture of the human family is that there are many human species, and not just one. Some of these species were massive, very big, like Homo erectus and the Neanderthals.
Others were dwarfs. Like Homo floresiensis. Some human species were fearsome hunters, subsisting mainly by hunting animals.
Other human species lived mainly by gathering plants. They are vegetarians. Some human species lived on a single island, like Flores Island or Java Island.
Other human species roamed over entire continents, like Homo erectus or Homo denisova. But... All of these different human species belong to the genus Homo.
They are all human beings. They are all part of the human family. Now, many people have heard that once upon a time, there were all kinds of human species on planet Earth. However, we often tend mistakenly to arrange these different human species in a straight line of descent. As if we have Homo ergaster that slowly evolved into Homo erectus, and then Homo erectus slowly evolved into the Neanderthals, and the Neanderthals evolved into us.
According to this linear model of human evolution, at any particular moment in time, there was only one type of human species inhabiting planet Earth, and all previous species of humans were just older models of ourselves. They evolved eventually to become us. But the truth is different.
The truth is that from about 2 million years ago, until about 10,000 years ago, the world was home, at one and the same time, to several human species simultaneously. And why not? Today, there are many different species of pigs in the world. There are many different species of foxes.
There are many different species of bears. Like you have grizzly bears, and you have arctic bears, and you have brown bears, and you have black bears, all living together at the same time on planet Earth. So 100,000 years ago, there were at least six different species of humans living side by side on planet Earth. We know for sure about six. There might have been many more, and this should not surprise us, that in different parts of the world, there were different human species at the same time.
What is surprising, what is strange, is the current situation, that in all the world, there is just one human species, our species. You go to Europe, you go to India, you go to China, you go to Australia, you go to America, everywhere. you encounter just one species, our species, Homo sapiens.
This is very strange, and actually it's a bit suspicious. As we shall shortly see in the next segments of this lesson, Homo sapiens has pretty good reasons to hide the fact, to forget the fact that it once had brothers and sisters, because there is some evidence that we, Homo sapiens, had a hand. in the disappearance of all the other human species.
What exactly happened to the other human species, and what we, Homo sapiens, may have done to them, will be discussed in the next segment of this lesson.