Fire's Role in Human Evolution

In the previous segment, we saw that humankind, for most of its existence, had large brains, had the ability to produce and use tools, had complex social structures, but remained weak and marginal in the ecosystem. Eventually, however, human beings, at least in the last 100,000 years, ascended to the top of the food chain and became the most powerful animals around. How did they make this jump? Perhaps the first significant step on the way to the top was the domestication of fire. We don't know exactly when, where and how humans did this to domesticate fire. But we do know from archaeological evidence that By about 300,000 years ago, some humans, like Neanderthals and later Homo sapiens, were using fire on a daily basis. Fire had important advantages to offer humans. It gave humans a source of light in darkness and a source of warmth in winter when it's cold. Fire also gave our ancestors the first really effective weapon. against dangerous animals like lions and bears. Fire could also be used to start changing the environment to fit our, not our, but our ancestors' needs, the needs of humans hundreds of thousands of years ago. People, for example, could use fire to burn down forests. And once the forest and once the flames die down, then humans could walk in and collect. All kinds of dead animals that were caught in the fire and eat them. So it was an easy meal. You just burn down a forest and you come and collect a lot of food, which you can now eat. So this was another important advantage of fire. But the most important thing that fire did, the best thing about fire was that it enabled humans to cook. We don't often think about cooking as one of the big steps forward in the history of humankind, but cooking was of immense importance. First of all, cooking opened entire new sections in the supermarket of nature before humankind. I mean that all kinds of foods that exist in nature, but that humans cannot digest, cannot eat without cooking them. such as wheat and rice and potatoes, once humans had control of fire, they could start eating these foods. You cannot go around and just pick, say, wheat and eat it, because you can't digest wheat in its natural form. And similarly, you cannot dig potatoes in the ground and just eat them. A cow can do it. A pig can do it, because they have a digestive system that can digest wheat and potatoes and rice. But humans can't. until they had fire to do much of the job for them. Once you cook potatoes, or once you bake wheat, you can eat it and enjoy the calories and the vitamins that it can give you. So this was a big advantage of fire. People could start eating many new things. Another advantage was that cooking kills germs and parasites that infest food. especially in meat, but also in other kinds of food. So once humans began to cook their food, it protected them against all kinds of health dangers and against all kinds of parasites that otherwise may enter their body and live there and kill them. Another big advantage of fire, sorry, of cooking, is that it reduced the time that humans have to invest in chewing their food. and the time and energy needed to digest food. Food, when it comes raw, uncooked, you have to chew it for a long time, and then it takes the stomach and the guts a long time and a lot of energy to digest them properly. Our cousins, the chimpanzees, they spend an average of five hours each day just chewing and chewing food in order to make it easier for the stomach. For people who use fire in order to cook their food, one hour a day is sufficient, and they need to expend much less energy. to digest the food. So basically what fire, what cooking enables people to do is to outsource much of the digestion to fire. We don't have to do it ourselves. Much of our digestion is actually done by fire. This means that humans, in contrast, for example, to chimpanzees, they can survive with smaller teeth, with less powerful jaws, and with shorter intestines. When you eat cooked food, you don't need very big teeth, and very powerful jaws, and very long intestines, because you don't need to invest so much effort in chewing and digesting. Actually, there are scholars who believe that there is a direct link between the beginning of cooking, the shortening of the human intestines, and the growth of the human brain. And, And why do they claim this? Well, one of the interesting things about the energy economy of the body, of the human body, is that the two greatest consumers of energy in the body are the brain and the digestive system, the stomach and the intestines. This is why it's quite difficult to have both very long intestines. and a large brain at the same time, because they compete for the limited energy of the body. Once you shorten the intestines, you don't need so much intestines to digest your food, you can now open the way for a really big brain. And there is evidence that the big jump, we discussed earlier the growth of the human brain, and we said that it began already 2.5 million years ago. But, The really big jump in the size of human brains came only in the last 300 or 400,000 years with the appearance of species like the Neanderthals and Homo sapiens with giant brains. And this is exactly the time that people began to cook. So some scholars say that there is a direct link that once you cooked your food, your intestines became shorter and then your brain really got big. So this is a very big advantage that fire and cooking gave to humans. And this is why, again, many scholars, many scientists say that the first really significant gulf between men and all the other animals was the domestication of fire. The power of almost all the other animals in nature depends... upon their body. There is a direct link between what kind of the force, the power of your body, and the power of the animal. The power of the animal depends on the strength of the muscles, on the size of the teeth, on the breadth of the wings in case of birds. So there is a link here between the body and the power of the animal. Now it is true that some animals can use natural forces to increase their power. For instance, animals can harness the power of water currents or the power of winds. But even when animals do that, there is still a very close connection to the abilities, to the physical abilities of their bodies. Eagles, for example, they can use their power relies not only directly on their bodies, but also on identifying winds and thermal columns, columns of hot air that eagles use in order to fly. Eagles are able to identify a place where there are currents of hot air coming up, and then they spread their wings, and they allow the hot air to carry them upwards. But eagles cannot decide, they cannot control the location. of these hot air columns. And even when they use the winds and the hot air, their maximum carrying capacity, their maximum power, is still proportional to their wingspan. Even if an eagle locates a very, very powerful column of hot air, it's not enough to be able to lift an elephant, because the eagle's wingspan is simply not big enough. So this is what I meant when I said that the power of animals is always directly dependent on the power of their bodies, on the sound. size and shape of their bodies. When humans domesticated fire, it broke the link between the power of the animal and the size and power of the body of the animal. Because when humans domesticated fire, they gained control of an obedient force and also of a potentially limitless force, a force without limits. Unlike eagles, Humans can choose when and where to ignite a fire. It's up to them to decide that. More importantly, the power of fire is not limited by the power of the body of the human who ignited it, or by the form, or by the strength of the muscles, or anything like that. A single woman, which carries a torch or a flint, can burn down an entire forest in a matter of hours. An entire forest. with thousands of trees and thousands of animals and birds and so forth, she can burn it down by herself. It's not like the eagle, that even when it can use the wind, it is still limited by the size of the wings. In the case of a woman burning down an entire forest, there is absolutely no proportion between the power of her body and her power as a master of fire that can burn down the whole forest. So the domestication of fire in this respect was a sign of things to come. The domestication of fire was, in a way, the first important step on the way to the atomic bomb. And fire made humans more different from all the other animals and more powerful. However, it should be emphasized that even after the domestication of fire, Humans were still not the most important animal in the world. They were still not the most powerful animal in the world. The real jump to the top of the food chain had to wait a few hundred thousand years more to the appearance and the spread and the triumphs of our species, Homo sapiens. And this... This, the appearance and spread of our species of Homo sapiens, will be the subject of the next segment.

But we do know from archaeological evidence that By about 300,000 years ago, some humans, like Neanderthals and later Homo sapiens, were using fire on a daily basis. Fire had important advantages to offer humans. It gave humans a source of light in darkness and a source of warmth in winter when it's cold. Fire also gave our ancestors the first really effective weapon. against dangerous animals like lions and bears.

Fire could also be used to start changing the environment to fit our, not our, but our ancestors' needs, the needs of humans hundreds of thousands of years ago. People, for example, could use fire to burn down forests. And once the forest and once the flames die down, then humans could walk in and collect. All kinds of dead animals that were caught in the fire and eat them.

So it was an easy meal. You just burn down a forest and you come and collect a lot of food, which you can now eat. So this was another important advantage of fire. But the most important thing that fire did, the best thing about fire was that it enabled humans to cook.

We don't often think about cooking as one of the big steps forward in the history of humankind, but cooking was of immense importance. First of all, cooking opened entire new sections in the supermarket of nature before humankind. I mean that all kinds of foods that exist in nature, but that humans cannot digest, cannot eat without cooking them. such as wheat and rice and potatoes, once humans had control of fire, they could start eating these foods.

You cannot go around and just pick, say, wheat and eat it, because you can't digest wheat in its natural form. And similarly, you cannot dig potatoes in the ground and just eat them. A cow can do it.

A pig can do it, because they have a digestive system that can digest wheat and potatoes and rice. But humans can't. until they had fire to do much of the job for them. Once you cook potatoes, or once you bake wheat, you can eat it and enjoy the calories and the vitamins that it can give you. So this was a big advantage of fire.

People could start eating many new things. Another advantage was that cooking kills germs and parasites that infest food. especially in meat, but also in other kinds of food.

So once humans began to cook their food, it protected them against all kinds of health dangers and against all kinds of parasites that otherwise may enter their body and live there and kill them. Another big advantage of fire, sorry, of cooking, is that it reduced the time that humans have to invest in chewing their food. and the time and energy needed to digest food. Food, when it comes raw, uncooked, you have to chew it for a long time, and then it takes the stomach and the guts a long time and a lot of energy to digest them properly.

Our cousins, the chimpanzees, they spend an average of five hours each day just chewing and chewing food in order to make it easier for the stomach. For people who use fire in order to cook their food, one hour a day is sufficient, and they need to expend much less energy. to digest the food.

So basically what fire, what cooking enables people to do is to outsource much of the digestion to fire. We don't have to do it ourselves. Much of our digestion is actually done by fire. This means that humans, in contrast, for example, to chimpanzees, they can survive with smaller teeth, with less powerful jaws, and with shorter intestines. When you eat cooked food, you don't need very big teeth, and very powerful jaws, and very long intestines, because you don't need to invest so much effort in chewing and digesting.

Actually, there are scholars who believe that there is a direct link between the beginning of cooking, the shortening of the human intestines, and the growth of the human brain. And, And why do they claim this? Well, one of the interesting things about the energy economy of the body, of the human body, is that the two greatest consumers of energy in the body are the brain and the digestive system, the stomach and the intestines. This is why it's quite difficult to have both very long intestines.

and a large brain at the same time, because they compete for the limited energy of the body. Once you shorten the intestines, you don't need so much intestines to digest your food, you can now open the way for a really big brain. And there is evidence that the big jump, we discussed earlier the growth of the human brain, and we said that it began already 2.5 million years ago. But, The really big jump in the size of human brains came only in the last 300 or 400,000 years with the appearance of species like the Neanderthals and Homo sapiens with giant brains. And this is exactly the time that people began to cook.

So some scholars say that there is a direct link that once you cooked your food, your intestines became shorter and then your brain really got big. So this is a very big advantage that fire and cooking gave to humans. And this is why, again, many scholars, many scientists say that the first really significant gulf between men and all the other animals was the domestication of fire. The power of almost all the other animals in nature depends...

upon their body. There is a direct link between what kind of the force, the power of your body, and the power of the animal. The power of the animal depends on the strength of the muscles, on the size of the teeth, on the breadth of the wings in case of birds. So there is a link here between the body and the power of the animal. Now it is true that some animals can use natural forces to increase their power.

For instance, animals can harness the power of water currents or the power of winds. But even when animals do that, there is still a very close connection to the abilities, to the physical abilities of their bodies. Eagles, for example, they can use their power relies not only directly on their bodies, but also on identifying winds and thermal columns, columns of hot air that eagles use in order to fly. Eagles are able to identify a place where there are currents of hot air coming up, and then they spread their wings, and they allow the hot air to carry them upwards. But eagles cannot decide, they cannot control the location.

of these hot air columns. And even when they use the winds and the hot air, their maximum carrying capacity, their maximum power, is still proportional to their wingspan. Even if an eagle locates a very, very powerful column of hot air, it's not enough to be able to lift an elephant, because the eagle's wingspan is simply not big enough. So this is what I meant when I said that the power of animals is always directly dependent on the power of their bodies, on the sound.

size and shape of their bodies. When humans domesticated fire, it broke the link between the power of the animal and the size and power of the body of the animal. Because when humans domesticated fire, they gained control of an obedient force and also of a potentially limitless force, a force without limits. Unlike eagles, Humans can choose when and where to ignite a fire. It's up to them to decide that.

More importantly, the power of fire is not limited by the power of the body of the human who ignited it, or by the form, or by the strength of the muscles, or anything like that. A single woman, which carries a torch or a flint, can burn down an entire forest in a matter of hours. An entire forest.

with thousands of trees and thousands of animals and birds and so forth, she can burn it down by herself. It's not like the eagle, that even when it can use the wind, it is still limited by the size of the wings. In the case of a woman burning down an entire forest, there is absolutely no proportion between the power of her body and her power as a master of fire that can burn down the whole forest.

So the domestication of fire in this respect was a sign of things to come. The domestication of fire was, in a way, the first important step on the way to the atomic bomb. And fire made humans more different from all the other animals and more powerful. However, it should be emphasized that even after the domestication of fire, Humans were still not the most important animal in the world.

They were still not the most powerful animal in the world. The real jump to the top of the food chain had to wait a few hundred thousand years more to the appearance and the spread and the triumphs of our species, Homo sapiens. And this...

This, the appearance and spread of our species of Homo sapiens, will be the subject of the next segment.

Transcript for:Fire's Role in Human Evolution

Transcript for:
Fire's Role in Human Evolution