Naturalis Historia: Volume VI

African Exodus

Scientists have long believed that humans originated in Africa. Ethiopia, to be exact, could be called our homeland. All the different types, shapes, and shades of people on Earth can trace their ancestry to African hunter-gathers 150,000 years ago. The evidence is in our DNA, right there in our bodies. Genetic mutations act as markers and can tell us our history. On the Y chromosome, all males share the same basic configuration, rooted in Africa. The marker M168 was carried out of Africa and is found on all non-African males. The diversity of genetic markers is greatest in Africa, which could only have arisen as DNA mutated over millenia. So you see, we are all African.

Part 1.
Time: 200,000 years ago
Where: Ethiopia
→ Most anthropologists and geneticists agree that modern humans arose about 200,000 years ago in Eastern Africa. The earliest modern human fossils were found in Omo Kibish, Ethiopia.

Part 2.
Time: 70,000-50,000 years ago
Where: Red Sea
→ A small group of modern humans left Africa for good (“Out of Africa II” model) between 70-50,000 years ago. All non-Africans are descendants of these travelers, who eventually replaced all earlier types of humans, including Neandertals. This exodus might have occurred around the top of the Red Sea or its narrow southern opening, bringing humans into the Middle East.

Part 3.
Time: 50,000 years ago
Where: Indonesia & Australia
→ Artifacts around 50,000 years old from two sites in Australia, Malakunanja and Lake Mungo, indicate that humans followed a coastal path along southern Asia and then island-hopped until reaching Australia. Their descendants, Australian Aborigines, remained genetically isolated on the island continent until the fairly recent colonization.

Part 4.
Time: 40,000-30,000 years ago
Where: Europe
→ It was assumed that humans migrated into Europe from North Africa. However, genetic data now shows that the DNA of today’s western Eurasians resembles that of people in India. In other words, Europe was populated by an inland migration from Asia only about 40,000 years ago.

Part 5.
Time: 40,000 years ago
Where: Asia
→ From the Middle East, humans pushed into Central Asia and arrived north of the Himalaya. Others traveled through Southeast Asia and China, eventually reaching Japan and Siberia.

Part 6.
Time: 20,000-15,000 years ago
Where: The Americas
→ Genetic evidence shows that humans in northern Asia eventually migrated into the Americas. 20,000 years ago, sea levels were low and land connected Siberia to mainland Alaska, allowing migration to occur. The travelers would have continued down the west coast into South America since ice sheets would have covered the interior of North America.

Source: Shreeve, James. “The Greatest Journey.” National Geographic Mar 2006: 61-69.
Related Article: Austro-Asiatic tribes of Northeast India provide hitherto missing genetic link between South and Southeast Asia.

Naturalis Historia: Volume IV

(originally written for my Evolutionary Theory class)

Evolution of Bipedalism in Hominids

“We must, however, acknowledge, as it seems to me, that man with all his noble qualities… still bears in his bodily frame the indelible stamp of his lowly origin.”
– Charles Darwin, The Descent of Man (1871)

Humans are unique in the animal kingdom as being the only habitual terrestrial biped built for upright walking. Homo sapiens were not alone, however; a diversity of bipedal hominids thrived before us. Being adapted to bipedal movement changed the morphological structure and even behavior of these early hominids, but why did certain species make the transition to bipedal movement? There are many theories as to the origins of bipedalism and the reasons that led these hominids to walk upright. From examining the fossil record and modern primate behavior and anatomy, insights on the evolution of bipedalism can be uncovered.

Naturalis Historia: Volume I

A Natural History

Humans have been intriqued and interested in natural history all throughout time. One of the first important and thorough writings about natural history came from Ancient Rome, Pliny the Elder wrote “Naturalis Historia”, or A Natural History, in 77 AD. It was the first encyclopedia and consisted of 37 volumes. He wanted to “set forth in detail all the contents of the entire world.” With much information on geology, geography, meteorology, botany, zoology, astronomy, human physiology, and medicine, he also wrote about such mythical beasts as the basilisk as being real. Nevertheless, his work was a milestone in teaching the public about the natural world. If interested, you can find more about Pliny’s work and the Naturalis Historia text here (in Latin and English!).

Ever since 5-10 million years ago, when the first hominids began to dominate, humans have lived among animals and nature. Plants, herbs, roots, nuts, and berries were collected for food, and trees were used as shelter, much like how our primate relatives live. Early humans relied on their larger brains to think up new ideas and strategies for obtaining food. Eventually, domestication arrived. Humans learned ways of living with wolves that benefited each other so much that a new species evolved, the domestic dog. Cattle and livestock benefited humans in that it gave them a source of food without the need to travel and hunt. The livestock, therefore, were content since they were being continuously fed and cared for. A balance between humans and nature was thus established. Neither had more control or less control over the other.

Once the middle ages arrived, we tried to disassociate ourselves from nature. We were humans, afterall, not animals. Innovations in science arose during the Renaissance, which gave us new insights on astronomy, mechanics, physiology, etc. But nothing like the early writings of Aristotle or Pliny about the natural world. The industrial revolution came with a bang. All of a sudden we humans controlled the world. Factories, machines, technology; all to do everything for us. Humans were separated from nature. We no longer felt like we were part of mother earth. We forgot.

A truly remarkable thing happened in the 19th century. A naturalist named Charles Darwin wrote a book called The Descent of Man in 1871. He proposed, well actually, had evidence for the fact that all living creatures were descedants of a common ancestor. Maybe we weren’t so far from nature as we thought. In the years that followed, new research and knowledge in zoology led scientists to discover that animals aren’t so different from us. They think, have emotions, raise families. Zoologists began classifying species based common characteristics and ancestry. Humans also are classified, as part of the hominid family along with chimpanzees (our closest relative), bonobos, gorillas, and orangutans. Genetics has played a large role in finding so many similarities between humans and chimps that our DNA is 98% the same. Perhaps we are still that wild primate that lives in the forest.

Evolutionary Studies

Some articles on evolutionary studies:

Early Man Couldn’t Stomach Milk.
Chimps Use Spears To Hunt Mammals.
Chimp “Stone Age” Finds Are Earliest Nonhuman Ape Tools.

Giant Asian ape & humans coexisted

I forgot to post this article about Gigantopithecus blacki, the ancient giant ape. It has been determined that “Giganto” and humans coexisted for a time in China 300,000 years ago. Giganto may be related to Sivapithecus, an extinct ancestor of orangutans.

Elephants & Hobbits

Here’s an article on Elephants that use mimicry. Zoologists have noticed some elephants making car and truck noises, along with various other machines. Interesting, eh? Also, read about the new hominin species Homo floresiensis. This is really a huge discovery! Not only is it a new species of human, but it is evidence that humans too are under the forces of island pressure and shows the power of an isolated environment on natural selection. Here are some links. “Hobbit” Brains; Photos of the fossils; News story about the discovery; Wikipedia entry w/ links.