Early Humans: Ice, Stone, and Survival

You are a member of the only species that has survived in the genus Homo since its 2.5-million-year evolutionary journey began. Homo habilis, H. erectus, H. neanderthalensis—plus many other species we know of and perhaps dozens yet to be discovered—have all come and gone. Homo sapiens alone has endured.

Who were these long-ago ancestors of ours? Where and how did they live and die? And how are we even able to learn about these humans, some of whom became extinct millions of years ago? These are only a few of the myriad fascinating questions explored in Early Humans: Ice, Stone, and Survival. In 20 captivating lectures, Professor Suzanne Pilaar Birch shares her expertise and passion for discovery as she peels back the millennia to expose the emergence and lives of early humans. You will learn about their environmental challenges, the methods they used to meet their basic needs, their cultural development, and the fascinating advances in our own technologies that have allowed us to take their few physical remains and develop a much fuller picture of who they were—and, thus, who we are, today.

Although we might imagine a timeline of the past 2.5 million years as a straight path from the emergence of the genus Homo to modern H. sapiens in the 21st century, the truth of our family tree is much more convoluted and fascinating than that. As Dr. Birch explains, there have been times when specific aspects of human culture developed simultaneously in disparate regions on the planet, and times when several Homo species existed on the planet at the same time. This makes the journey more complex, but also infinitely more interesting.

Tools of the Trade

Who were our direct ancestors? How far back can we trace our lineage? Moreover, how can we answer such important and complex questions at such a distant vantage point? We attempt to answer them with both the most basic and the most modern of techniques: trowels and brushes in the field and cutting-edge technologies in the lab.

One of the first advanced technologies that allowed archaeologists to get a scientific view into the past was radiocarbon dating. Developed in the mid-20th century, this technique estimates the age of organic material by using the known radioactive decay rate of carbon-14. Radiocarbon dating ushered in a new age for archaeological research, allowing scientists to approximate ages back as far as 50,000 years.

But as powerful as radiocarbon dating is, we now have many more tools to see more accurately and ever farther back in our own history. These include:

• Optically Stimulated Luminescence. This method of dating operates on the principle that granules of quartz—commonly found in rock and sand—absorb electrons when exposed to sunlight. In the lab, the sample’s trapped electrons are released and measured, and a date for archaeological site formation can be calculated as far back as 100,000 years ago.
• Thermoluminescence. This is another trapped-electron method, revealing when a sample was last heated above a certain temperature. It is extremely helpful in dating ceramic artifacts.
• DNA analysis. Perhaps the most powerful tool is the ability to analyze ancient DNA. Using genomics, scientists have discovered how ancient humans moved around the globe and if they interbred with other groups. They have also been able to estimate the astonishingly small number of ancient humans who survived the “mega-colossal” Toba volcanic super-eruption—only about 10,000 people.

These, and other technologies, have allowed us unprecedented access to the secrets of our past. As new techniques are introduced, the potential to solve even more of the mysteries of humanity’s earliest days increases.

Sharing Our Genus

We used to think we were the first animals to use tools, to organize ourselves into social groups, and to use language for communication. We now know that many other animals can claim those characteristics. What separates us from other hominids is our brain, which has grown relatively larger over time.

The current wisdom is that Homo habilis—known as the “handy man”—is the earliest member of our genus. This species’ brain size, measured as a percent of its body weight, represented an increase of about 50% over the genus Australopithecines. In Early Humans: Ice, Stone, and Survival, Dr. Birch will introduce you to many more extinct species of our genus, including:

• H. erectus stood notably taller than H. habilis and walked upright. H. erectus is one of the longest-lasting hominin species, persisting for more than 1.5 million years, overlapping with what we now know are multiple human species that developed during this same period, and potentially giving rise to several of them.
• H. floresiensis is one of the most recently discovered species in our genus. So far, it has only been found on the island of Flores, Indonesia. Despite their small body and brain size, H. floresiensis made and used stone tools.
• H. naledi was discovered recently in South Africa. Scientists believe H. naledi lived between 236,000 and 335,000 years ago and seemed to have the cultural practice of burying their dead.

The Family Album

If you were creating a family photo album of our shared Homo “cousins,” you certainly wouldn’t have many concrete visual materials in your book. While scientists have gleaned as much information as possible from every artifact and bone that has been found, relatively few remains have been uncovered, compared to the number of humans who lived. But some discoveries have been so exciting, that these individuals have been named, not just numbered.

One of the first famous specimens was Lucy, discovered in 1974. A human ancestor, Australopithecus afarensis, Lucy was able to climb trees and stand upright. You’ll meet many other famous specimens in this course, including:

• Turkana Boy who was discovered in Kenya. This H. erectus specimen is a male who lived about 1.6 million years ago and would have been between seven to 11 years of age at the time of death. More than 100 bones of his skeleton were found. Turkana Boy had modern limb proportions and would not have been able to live in trees.
• Omo I and Omo II who were discovered in Ethiopia. Estimated to have lived about 195,000 years ago, these two fossils are the oldest commonly accepted examples of Homo sapiens.
• Mungo Lady who was discovered in New South Wales, Australia. An H. sapiens, Mungo Lady’s burial, approximately 42,000 years ago, represents the oldest known cremation in the world. It’s thought that the body was burned, the skeletal remains crushed and then burned again, and then covered with ochre, transported from several hundred kilometers away.
• The Iceman who was discovered at the end of the 20th century in the Italian Alps near the border between Italy and Austria. An H. sapiens, The Iceman died about 5,300 years ago and his naturally mummified remains are the earliest known, direct example of a tattooed individual.

Today, we now can apply sophisticated science and powerful analytical methods to these specimens, and many others, in order to answer our questions about the trajectory of human history. But, as you will discover, we shouldn’t lose sight of what it means to be able to ask those questions in the first place. After all, isn’t it our awareness of the existence of those who came before us one of the things that truly makes us human?