In this episode of Big Biology, Kate Wong explains human evolution and the fuzzy line that separates us from our ancestors.
A combination of racism and Victorian-era resistance to the idea that humans first emerged in Africa impeded our understanding of early human evolution.
Human evolution is not linear. Ancient Homo contains several offshoots Co-evolving hominin groups split apart and merged many times on the African continent.
Language and tools were not exclusive to the genus Homo. There is evidence for language in Neanderthals with cave symbols, jewelry, and body paint. Researchers have also found tools associated with hominins over a million years before the genus Homo ever emerged.
It’s hard to tell why Homo sapiens became the last hominid standing. Maybe we developed some skills that made us more fit, or maybe we were just lucky. Cultural exchange with ancient human-like relatives may be part of the answer.
SUMMARY
In this episode we talk to Kate Wong, a senior editor atScientific American with a keen interest in biological anthropology and the origins of humankind. Through her writing she has explored the complex web of human evolution and how there is still so much left for us to understand. In our chat, we cover topics such as: How views on human evolution have changed since the time of Darwin? Where in the world does our genus Homo find its roots? And what makes humans...human? Are we truly special or just lucky?
In her recent article “The Origin of Us”, Wong discusses how in the early 20th Century, some European scientists were reluctant to recognize Africa as the birthplace of humanity. They sometimes cherry-picked evidence to fit their beliefs or even faked evidence altogether, as in the case of Charles Dawson and “Piltdown Man.” In that incident, an ameteur archeologist claimed to have found an ancient human ancestor in England, however it was really just orangutan bones paired with modern human bones. Despite the attempts at creating a more European origin of humankind, actual hominin fossils were turning up all over Africa and Asia.
Once these early fossils began appearing, scientists seemed to find all kinds of evidence pointing to our special status among hominids. Our ancestors fashioned stone tools, hunted in sophisticated groups, spoke languages, and painted stories on cave walls. More recently, though, scientists have discovered evidence that other hominid species, including Neanderhthals, also could do many of these things, pushing the origins of key human traits further back in time.
“We used to have these hard lines in the sand. These are things we know Homo sapiens does that nobody else does,” Kate said. “Oh wait, Neandratals did that and that and that. Even Homo erectus did this little shell engraving”
Kate explains how spectacular new fossil finds and rapid advances in DNA sequencing and analysis have dissolved many preconceived notions and forced us into our modern, more nuanced view. This includes acknowledging that the evolution of modern humans was not a straight line---and that interactions and cultural exchange with our close relatives were likely a key part of our success.
"Homo spaiens had the advantage both of everything they've kind of gleaned from their time in Africa and this new sorts of influx of genes and cultural practices from the Neanderthals and Denosovans when they got to the rest of the world,” Kate said. “Maybe that’s the magic combination that helps them succeed. Maybe we are where we are today, the last Hominid standing, because of those encounters with our archaic relatives."
Last, we discuss Kate’s journey into writing, what led her to Scientific American, and why she continues to write about and be fascinated by the stories of human evolution.
RESOURCES
Here are links to a few of the resources we talked about on the episode or used to prepare for the interview:
Articles
Ancient Stone Tools Force Rethinking of Human Origins - Scientific American
A traditional view of human evolution holds that stone-tool technology originated with members of our genus, Homo, as an adaptation to shifting climate. In this scenario, that adaptation quickly helped to establish a feedback loop that dramatically expanded brain size and technological prowess in our lineage. However, archaeologists at a site in northwestern Kenya called Lomekwi have unearthed the oldest stone tools in the world--predating the oldest known fossils of Homo sapiens by 3.3 million years. This discovery undoes the belief that H. sapiens were the first in the genus to utilize tools.
The Littlest Human - Scientific American
Remains discovered on the Indonesian island of Flores have proved that Homo sapiens were not the only species of human on earth for the past 25,000 years. The remains are believed to belong to a dwarf species of Homo that lived as recently as 13,000 years ago, but the discovery does not come without controversy. This small hominid is small in both body and brain, yet it appears to have made sophisticated stone tools, leading some experts to wonder if the associated tools have been mischaracterized and actually associated with modern humans.
Mysterious New Human Species Emerges from Heap of Fossils - Scientific American
In September 2015 researchers unveiled the discovery of a new hominin species, Homo naledi, that was discovered in an underground cave system called the Rising Star in Johannesburg two years prior. Over the course of two expeditions scientists recovered more than 1,550 specimens belonging to at least 15 H. naledi individuals.The discovery caused quite a stir among scientists, calling into question long-standing ideas about the rise of Homo.
Why Is Homo sapiens the Sole Surviving Member of the Human Family? - Scientific American
New findings from archaeology, paleontology and genetics suggest that Homo sapiens emerged from groups located across Africa and that interbred with other human species across the continent and possibly beyond, contributing to our success. This upends the previously held beliefs of H. sapien origin, where we arose from in a single region of Africa and replaced older human species throughout the Old World without interbreeding.
How Scientists Discovered the Staggering Complexity of Human Evolution
(The Origin of Us) - Scientific AmericanCharles Darwin began the conversation of human evolution, but treaded lightly, likely due to the culture of the era in which he lived. Despite this, his words set in motion a chain reaction of research and discovery, made ever more powerful by the discovery of ancient human remains. In the 160+ years after On the Origin of Species was published, we have made an enormous amount of progress unravelling the mysteries surrounding our ancestry and how we navigated the world to become the sole surviving member of the genus Homo today.
IMAGES
Original illustration of the March of Progress aka ‘The Road to Homo sapiens”: In 1965, in a book about the evolution of humans, the media company Time-Life published an image often called the March of Progress. It erroneously depicts a linear path from chimpanzees to humans. Kate Wong argues the path his much more complicated.
VIDEO
The ametuer archaeologist Charles Dawson forged the “Piltdown Man”: Chris Stringer from the Natural History Museum, London explain how we know in the video below. Read more about the hoax on the museum’s website.
MEET THE GUEST
Name: Kate Wong
Institution: Scientific American
Area of Expertise: Human Evolution
Follow Kate Wong on Twitter: @katewong
NOTABLE QUOTABLES
“What has become clear largely through genetic work, but also through fossil and archaeological evidence, is that you definitely get homo sapiens appearing first in Africa--that indisputable.”
“For a long time there was this idea that tools were a defining trait of our branch of the family tree, Homo, and that is how we achieved our success. But then there comes, out of the blue, this discovery from Kenya. Ultimately they discover tools that are about 3.3 million years old....[and] when you are at that depth of time, that's way older than any evidence for the genus Homo. So it just kinds of explodes everything that people thought they knew about the origin of tools and how it affected hominin evolution.”
“There are so many experiments happening over a really long period of time. And by the time you get to Homo sapiens you've also got the Neanderthals, you've got Denisovans, you've got other creatures running around in different parts of the world. And we aren't the only ones who are developing bigger brains and better technology, and symbolic expression. And what I've had several paleoanthropologists say to me is ' well, maybe Homo sapiens is just a little bit better''
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