Becoming Human: Last Human Standing

by PBS NOVA
Becoming Human

Why are we the only humans on Earth? If, 50,000 years ago there were four different species of early human living at the same time, why do we stand alone today? Since 6 million years ago, there have been around 20 different species of human. These include Homo floresiensis, Homo habilis, Homo erectus and many more. So why have all of these species died out, except for us, Homo sapiens? The question remains unanswered. Historians do not know the answer either, but they have come up with some possibilities.

 Around 140,000 years ago, Africa went through a drought, making most of it uninhabitable. Homo erectus, our ancestor, was forced to move out of the dry plains, and live on the coasts and high lands of Africa. They were pushed to the brink of extinction, meat was so scarce. So Homo erectus started to change their diet. Instead of meat, they gathered berries on the plains behind the cliffs. They also began a seafood diet, eating mussels and shellfish. There was just one problem: timing. Go out too early or too late, and the tide will wash you off the rocks and drown you. You have to go just when the tide is at its lowest, and this also reveals previously hidden shellfish.

Our ancestors did not know when to go out, so they started to watch the moon cycle to check when the tide was about to fall back. To predict in this way, you have to be very clever, so the less clever ones did not survive, and the clever ones did. This could be one of the reasons Homo sapiens was so ahead of other early humans: intelligence.

Another important factor is that with a different diet, you need different tools; so Homo sapiens began to make more sophisticated ones. Neanderthal man used brutish tools: the hand-axe and the heavy spear. Homo sapiens made very light, bone-tipped spears and other tools, and this meant that they could hunt from a further distance, making hunting less tiring and much safer. This made life span longer.

When climate improved, 60,000 years ago, Homo sapiens moved out of Africa. Wherever they went, species became extinct: mammoths, sabre-toothed cats, cave lions... when they moved into the Middle East, Homo erectus went extinct. When they moved into Europe, Neanderthal man went extinct. But why did we survive and not them?

Neanderthal man lived in Europe for almost 400,000 years, eating meat. What else? Meat. Only meat. Meat was hard to get, hard to find, hard to catch, especially during the huge climate change in Europe. Wherever Neanderthal man went, he never changed; Homo sapiens was, and still is, the most adaptable species on Earth. When Europe’s climate changed, they had already moved in and simply adapted to the climate, changing diets, clothes and personal habits. Neanderthal man, however, couldn’t find much meat, and was struggling to survive. They had big brains and big bodies, meaning that they required a huge amount of nutrients to live. We, Homo sapiens, required a very small amount.

Gradually, Neanderthal man and the last of its kind were pushed to the Rock of Gibraltar, on the tip of Spain. Then, the last of them vanished. Other humans also died out, leaving only us, Homo sapiens.

"Last Human Standing." Becoming Human. PBS NOVA. 31 Aug. 2011. Television.

From Grunts to Grammar: the Evolution of Language

by Jeanne Milller

Odyssey: Adventures in Science

English speakers get sentence sense from word order, while other languages use word endings or beginnings. Grammar is very important: it allows humans to express complicated thoughts, and therefore communicate more easily. To find out when language first started, fossils of early humans are indispensable because molds of brains and skulls show how brain size and complexity changed over the course of time. With this type of evidence, it is possible that, 2 1/2 million years ago, Homo habilis probably had at least the beginnings of speech and language capabilities.

What changes language capabilities is the larynx, the voice box. "The larynx contains the vocal cords that allow us to produce sounds from out throat." Most mammals' larynges sit high in the throat, connecting with nasal passages, and although the animals can breathe and swallow at the same time, they cannot make very many different sounds.

Evolution made human larynges sink lower down in the throat. This happened around 1 1/2 million years ago, and allowed humans to breathe through their noses and mouth, instead of only their noses. This meant that humans could run longer, and most importantly, lower larynges meant that as noises traveled up the throat, its muscles could modify the sound, making a wide range of possible sounds for humans.

Many years ago, when life was simple enough, with simple hunting and simple tools, language was not required. But as life began to get more complicated, man needed to communicate. This is probably the cause of the invention of language.

Miller, Jeanne. "From Grunts to Grammar: The Evolution of Language." Odyssey: Adventures in Science Oct. 2009: 34-36. Print.

Taming Fire: The First Scientist?

By Mary Beth Cox

Odyssey: Adventures in Science

One day, long, long ago, a person decided to try taming fire. Everyone was scared of fire because of their past experiences: wildfires. Wildfires were caused by lightning striking a tree, or by volcanic material. They destroyed everything in their path, burning entire forests to the ground, along with all the animals in it. No doubt this was very scary for the prehistoric people, seeing everything they knew swallowed up by the flames. But one person was curious about fire, and decided to try to tame it. That person changed humanity.
It is accepted that human have used fire for at least 250,000 years. At that time, hearths began to appear at prehistoric campsites in Europe. Hearths are basic fireplaces, usually surrounded by a ring of rocks. They sometimes contain burnt bone fragments and singed tools, and sometimes unburnt versions of these are sometimes scattered nearby, proof that those early humans used fire.
“Another very important distinction between hearth fires and wildfires is temperature. Hearth fires heat objects to much higher temperatures than wildfires do.”

Artifacts can be analyzed for chemical changes to find out if they were burnt during a wildfire or a hearth fire. With this type of scientific dating, it has been hinted that the first human intentional usage of fire might have occurred over 1,000,000 years ago!

One sample of this is the people of Swartkrans a million years ago. They could have known how to use fire, though not how start one. They could have dragged smouldering logs from wildfires back to their camps and lit them there.

The benefits of fire are many, though it might not sound like a good idea:
v  Cooked food was tasty and easier to digest than raw food.
v  It disabled some bacteria and worms in the raw meat.
v  It also destroyed toxins so that some usually poisonous food became edible.
v  Fire kept people warm in the winter.
v  It provided light for late-night dances and socializing.
v  It also warded off predators.

Experimentation with fire shows that prehistoric humans could experiment with a natural phenomenon that was normally a source of disaster, and put it to good use. “That’s what scientists do to this day!”


Cox, Mary Beth."Taming Fire: the First Scientist?" Odyssey: Adventures in Science Oct. 2009: 23-24. Print.

On Our Own Two Feet

by Stephen Whitt

Odyssey

Humans have developed a very strange skill: bipedality. Bipedality is walking on two feet, and is unique to primates and rare among all animals. It is very old, and came long ago, before humans developed big brains.

Chimpanzees are NOT our ancestors; they simply share a common ancestor. But take a look at their skulls, anyway. Compare it to a human skull, and there are differences everywhere. For example, the human face is quite flat, while a chimp’s face sticks out. Also, the human’s skull case is HUGE compared to the chimpanzee’s one, as well as all other animal skulls. But a very big difference is the foramen magnum. This hole allows our spinal cord to connect with the brain, through the skull. The chimp walks in all fours its foramen magnum is angled backward and downward. However, the human’s foramen magnum is right at the bottom.

If you compare those two skulls to a third, the skull of Australopithecus Afaresis, you will see that although our ancestor’s body is very similar to ours, its skull and a chimp’s skull are extremely like each other, with the face sticking out and a smaller brain case. But the foramen magnum, like ours, is at the bottom, proving that Australopithecus Afarensis walked on two legs.

There are many debates about why we started walking bipedally. It was thought to be for freeing our hands for tools, but our ancestors were walking on two legs long before stone tools were invented. Other people think that we did it to walk across Africa’s hot and growing savannah in search of forests, but it was proved that our ancestors were already walking in forests, before the African forests started shrinking. So some think that we walked because we had to wade across rivers or streams, or even swim across ancient seas. One man, C. Owen Lovejoy, thinks that they were useful for freeing our arms to carry food for our mates. Whatever it is, nobody has shared a proven theory for why we started walking on two legs...

"Humans are very strange."

Whitt, Stephen. "On Our Own Two Feet." Odyssey 1 Oct. 2009: 26-28. Print.

Why We Study Human Origins

by Randall Susman

Calliope: Exploring World History

Everyone always asks questions about our past. When did humanity start? Who are our direct ancestors? Why did they evolve, how did they live? Who were their prey, who were their predators? Our only source of this information is fossils. Fossils are ancient bones or evidence about past life (or death!). With fossils, we can compare our ancestors to ourselves, compare them to each other (counting how many there were in the last blog post!), or just find out about them, asking all the questions mentioned above. Yes, fossils provide what we need to know, they are our unique source of evidence to the lives of past humanity.

From all of these fossil finds, Susman explains that some believed "our ancestors were tree-dwelling apes, or four-legged knuckle-walkers, or even bipeds that lived in water."

Also, fossils prove wrong all the myths about how we started out and give people the real truth. Truth is important, and as wonderful as those stories are, they are just not true. (Though people can believe in them if they want to, no offence meant to religious humans!)

So, in the mis-1800s, Charles Darwin brought out the idea of evolution. He was not accepted at first, but after many years people began to believe that he just might be right... and another scientist, Thomas Henry Huxley, compared humans and apes, saying that we are more similar to them than monkeys are.

Many years later, in 1925, Raymond Dart discovered the first hominid fossil in South Africa. People now really began to believe in what so many scientists were trying to prove. It turned out that Huxley was right, too - the skeleton was both similar to us and to apes.

Since then, many hominid fossils and stone tools have been discovered, and there are yet more to come.

Susman, Randall. "Why We Study Human Origins." Calliope: Exploring World History Sept. 1999: 4-5. Print.