Origin Stories: Carl Sagan

Carl Sagan explores the evolution of human intelligence from the big bang, fifteen billion years ago, through today in this never-before-released archival lecture.

Carl Sagan. Credit: NASA

The Leakey Foundation is 50 years old this year, and we’re celebrating this milestone by sharing rare, previously unreleased lectures from the Foundation’s archive. These talks are like a time capsule that lets you hear from scientists and thinkers in their own words and in their own voices as they were making the discoveries that made them famous.

The Leakey Foundation’s Speaker Series on Human Origins has been ongoing since the Foundation’s beginning in 1968, and speakers from many disciplines have been invited to share their research and reflection on the origins, evolution, behavior, and survival of our species. Many of the world’s most celebrated scientists have given Leakey Foundation lectures, including many from disciplines outside of anthropology.

The first lecture in this “From the Archive” series is by Carl Sagan, the renowned astrophysicist and science communicator. He gave this Leakey Foundation lecture in 1977, around the time of the launch of the Voyager 1 space probe and five months before the release of his Pulitzer Prize-winning book Dragons of Eden,  a book about human intelligence and the evolution of the brain.

In this talk, he explores the origins of life on earth and shares his thoughts on how we came to have brains that can attempt to comprehend the vastness of the universe.

Listen here and subscribe on Apple Podcasts, Radio Public, Stitcher, Spotify, or wherever you listen to podcasts.

Help support our podcast by contributing to our quadruple-match podcast fundraising challenge! All donations will be matched 4:1!

From the Field: Rachel Bynoe, Happisburgh

Rachel Bynoe of the University of Southampton was awarded a Leakey Foundation Research Grant during our spring 2018 cycle for her project entitled “Exploring a submerged Pleistocene site off Happisburgh, UK.” She is a paleolithic archaeologist researching the submerged archaeology of the southern North Sea. This is an update on her recent field research.


Recent archaeological discoveries at Happisburgh (Figure 1), on the east coast of Britain, have radically changed our understanding of the timing and nature of early hominin occupation in these northerly environments, pushing this back to nearly one million years in significantly cooler temperatures. At this point, Britain was permanently joined to Europe by large swathes of landscape, now submerged beneath the North Sea. This project aims to search for these submerged landscapes, evidence for the existence of which comes from large collections of archaeology washing up on the beaches.

Fig 1: Location map for the work at Happisburgh, showing current archaeological sites and location of offshore deposits found (Rachel Bynoe)

For many years locals have been collecting the remains of long-extinct Pleistocene animal bones along this coastline. These include early mammoths, various species of giant deer, rhinos and even bears, and derive from a geological formation that outcrops along the coast called the Cromer Forest-bed Formation. This Formation dates to over half a million years ago at its youngest, all the way back to over 1.5 million years, containing sites deposits that demonstrate changing environments through this time.

A handaxe found on the beach recently. The location of these finds is helping us to refine where we search underwater (Credit: Darren Nicholas)

More recently, discoveries of stone tools (Figure 2) have added to this faunal record, and their spatial distribution has been used to pinpoint areas of seabed that they are likely to be eroding from. If we can locate their parent deposits, we will not only be developing the ways in which we are able to understand and investigate submerged Pleistocene landscapes but will also be working with the oldest submerged site so-far known.

The Leakey Foundation funded two separate weeks of diving fieldwork over the summer of 2018, where we were aiming to groundtruth areas of seabed to locate the source of the archaeology. Previous fieldwork over the summer of 2015 had resulted in the finding of an Early Pleistocene rhino radius, but otherwise little other than large sand waves were found; the seabed in this area is incredibly mobile, and these act to obscure the deposits they overlie. We set-out this year with high hopes for more, with the potential for weeks of looking at sand wave after sand wave in the backs of our minds. What we found was an unprecedented array of submerged, in situ Pleistocene deposits, providing new insights into these landscapes and far more questions to answer.

Fig 3: Underwater deposits of the Cromer Forest-bed Formation, located by divers as part of this project (Credit: Dan Pascoe)

Day one was an exciting indication of what was to come, when we dropped-down on a large exposure of laminated Cromer Forest-bed deposits (Figure 3). Having never been able to locate these offshore before, this was a breakthrough. The amazing weather—very unusual for a British summer—allowed us the full two weeks of work, and we spent this time both searching for finds, as well as trying to maximize the information we could come away with from the deposits themselves.

Three areas of exposures were found, surveyed and sampled (Figure 1). At the main area, one of our team—Daniel Pascoe—carried out a photogrammetry survey, creating a 3D model of the exposure to millimetric accuracy.

Fig 4: Pollen sampling of the located deposits (Credit: Rachel Bynoe)

For sampling, we initially used short cores, which were then split lengthways, photographed and analyzed for pollen (Figure 4), before upgrading to larger cores during the second week to increase sample sizes. Whilst we initially tried using the usual archaeological monolith tins, we ended up having far more success with drain pipes, sourced from a very helpful local.

Fig 5: Core splitting at the BOSCORF lab (Credit: Fraser Sturt)

The results from the initial, mini-cores show that we have a varied range of deposits, which relate in different ways to those known onshore. The significance of these is not only that we are able to extend the known extents of this archaeologically significant Formation, but that we can begin, through further analysis, to use these insights to further target them for areas of high archaeological potential. This work is currently ongoing, with the core splitting taking place in the British Ocean Sediment Core Research Facility, at the National Oceanography Centre, Southampton (Figure 5).

Fig 6: Side scan sonar imagery of the seabed in the main area of located deposits (Rachel Bynoe)

In addition to these samples, we also collected geophysical side-scan sonar data of the seabed, so that we can begin to calibrate the images that we see through this remote sensing with what is actually on the seabed (Figure 6). We are now in a position to understand what certain seabed substrates look like on the side scan and how these relate to underlying deposits, allowing us to better target certain areas in the future. More geophysical data will be collected in the coming months, but this time we will be using seismics to see below the sand waves. This has the potential to be a real game changer, with not only the ability to see where deposits are extant below the sands, but how far below the sands these lie and, with the sediment cores collected, the actual nature of these deposits.

In terms of archaeological finds, the search is still ongoing. A single stone tool was found, as well as a few small pieces of mineralized animal bone, all of which were out of context on this occasion. However, what was really important about these two weeks was the demonstration of how much information can be gleaned with increased time underwater. The archaeology is clearly there, but locating it is like a needle in a haystack. With the huge increase in knowledge that the location and investigation of these deposits gives us, however, this is now far more refined.

San Francisco Lecture Explores New Discoveries about Chimpanzees

Dr. Craig Stanford’s lecture “The New Chimpanzee: A Twenty-First-Century Portrait of Our Closet Kin” is just around the corner on Tuesday, December 4, 2018, at the California Academy of Sciences in San Francisco. Stanford will discuss the past two decades of chimpanzee field research. From culture to warfare, from our diet to our politics, the study of wild chimpanzees continues to change the way we understand both human nature and the apes themselves. What makes Dr. Stanford such an authority on the topic of chimpanzees?

Dr. Craig Stanford

Craig Stanford is a primatologist and biological anthropologist. He received his Ph.D. from the University of California, Berkeley, and is currently professor of biological sciences and anthropology at the University of Southern California. He also serves as co-Director of the U.S.C. Jane Goodall Research Center. He has conducted field research on chimpanzees and many other animals for 30 years in Africa and Asia. He has worked in collaboration with Jane Goodall in Gombe National Park in Tanzania where his study of chimpanzee meat-eating was funded by The Leakey Foundation. Stanford is the author of 16 books and 150 articles on animal behavior and wildlife conservation. His research has been supported by numerous grants from The Leakey Foundation, the Fulbright Foundation, the National Geographic Society, and many others.

In addition to being a well-known authority on primate behavior and human origins, Stanford is also a wildlife photographer and deeply involved with wildlife conservation.

Join The Leakey Foundation, California Academy of Sciences, and Dr. Craig Stanford on December 4th for this exciting lecture. Dr. Stanford will be signing copies of his recently released book The New Chimpanzee: A Twenty-First-Century Portrait of Our Closet Kin after the talk. Get your tickets now!

For more about Craig Stanford’s work studying chimpanzees and involvement with wildlife conservation, check out these resources:

The New Chimpanzee by Craig Stanford video provides insight on the focus of both his lecture and book.

‘The New Chimpanzee’ Review: Mysteries of the Chimpanzees” by David Barash, Wall Street Journal

Craig Stanford’s website features information about his research, wildlife photography, and books

Follow Craig Stanford on Twitter @craigstanford7 for the latest science.

Buy Tickets Now!

Origin Stories: Carl Sagan

Carl Sagan explores the evolution of human intelligence from the big bang, fifteen billion years ago, through today in this never-before-released archival lecture.

Carl Sagan. Credit: NASA

The Leakey Foundation is 50 years old this year, and we’re celebrating this milestone by sharing rare, previously unreleased lectures from the Foundation’s archive. These talks are like a time capsule that lets you hear from scientists and thinkers in their own words and in their own voices as they were making the discoveries that made them famous.

The Leakey Foundation’s Speaker Series on Human Origins has been ongoing since the Foundation’s beginning in 1968, and speakers from many disciplines have been invited to share their research and reflection on the origins, evolution, behavior, and survival of our species. Many of the world’s most celebrated scientists have given Leakey Foundation lectures, including many from disciplines outside of anthropology.

The first lecture in this “From the Archive” series is by Carl Sagan, the renowned astrophysicist and science communicator. He gave this Leakey Foundation lecture in 1977, around the time of the launch of the Voyager 1 space probe and five months before the release of his Pulitzer Prize-winning book Dragons of Eden,  a book about human intelligence and the evolution of the brain.

In this talk, he explores the origins of life on earth and shares his thoughts on how we came to have brains that can attempt to comprehend the vastness of the universe.

Listen here and subscribe on Apple Podcasts, Radio Public, Stitcher, Spotify, or wherever you listen to podcasts.

Help support our podcast by contributing to our quadruple-match podcast fundraising challenge! All donations will be matched 4:1!

What Drove Africa’s Megaherbivores to Extinction?

New research finds grassland expansion drove the decline of giant mammals over the last 4.6 million years.

UNIVERSITY OF UTAH – New research disputes a long-held view that our earliest tool-bearing ancestors contributed to the demise of large mammals in Africa over the last several million years. Instead, the researchers argue that long-term environmental change drove the extinctions, mainly in the form of grassland expansion likely caused by falling atmospheric carbon dioxide (CO2) levels.

Leakey Foundation grantee Tyler Faith, curator of archaeology at the Natural History Museum of Utah and assistant professor in the Department of Anthropology at the University of Utah, led the study. The research team also includes John Rowan from the University of Massachusetts Amherst, Andrew Du from the University of Chicago, and Paul Koch from the University of California, Santa Cruz.

The study is published today in the journal Science.

“Despite decades of literature asserting that early hominins impacted ancient African faunas, there have been few attempts to actually test this scenario or to explore alternatives,” Faith says. “We think our study is a major step towards understanding the depth of anthropogenic impacts on large mammal communities, and provides a convincing counter-argument to these long-held views about our early ancestors.”

A fossil tooth of a hippo (Hippopotamus amphibius) (left) and a fossil tooth of a white rhinoceros (Ceratotherium simum) (right), two of the few surviving megaherbivores, from the Late Pleistocene of western Kenya (left). Photo credit: Tyler Faith

To test for ancient hominin impacts, the researchers compiled a seven-million-year record of herbivore extinctions in eastern Africa, focusing on the very largest species, the so-called ‘megaherbivores’ (species over 2,000 lbs.) Though only five megaherbivores exist in Africa today, there was a much greater diversity in the past. For example, three-million-year-old ‘Lucy’ (Australopithecus afarensis) shared her woodland landscape with three giraffes, two rhinos, a hippo, and four elephant-like species at Hadar, Ethiopia.

When and why these species disappeared has long been a mystery for archaeologists and paleontologists, despite the evolution of tool-using and meat-eating hominins getting most of the blame.

“Our analyses show that there is a steady, long-term decline of megaherbivore diversity beginning around 4.6 million years ago. This extinction process kicks in over a million years before the very earliest evidence for human ancestors making tools or butchering animal carcasses and well before the appearance of any hominin species realistically capable of hunting them, like Homo erectus,” says Faith.

Taking a Closer Look

Faith and his team quantified long-term changes in eastern African megaherbivores using a dataset of more than 100 fossil assemblages spanning the last seven million years. The team also examined independent records of climatic and environmental trends and their effects, specifically global atmospheric CO2, stable carbon isotope records of vegetation structure, and stable carbon isotopes of eastern African fossil herbivore teeth, among others.

The team analyzed more than 100 sites in East Africa with rich fossil records to track the longterm decline of megaherbivore diversity. Image credit: Tyler Faith

Their analysis reveals that over the last seven million years substantial megaherbivore extinctions occurred: 28 lineages became extinct, leading to the present-day communities lacking in large animals. These results highlight the great diversity of ancient megaherbivore communities, with many having far more megaherbivore species than exist today across Africa as a whole.

Further analysis showed that the onset of the megaherbivore decline began roughly 4.6 million years ago, and that the rate of diversity decline did not change following the appearance of Homo erectus, a human ancestor often blamed for the extinctions. Rather, Faith’s team argues that climate is the more likely culprit.

“The key factor in the Plio-Pleistocene megaherbivore decline seems to be the expansion of grasslands, which is likely related to a global drop in atmospheric CO2 over the last five million years,” says John Rowan, a postdoctoral scientist from University of Massachusetts Amherst. “Low CO2 levels favor tropical grasses over trees, and as a consequence savannas became less woody and more open through time. We know that many of the extinct megaherbivores fed on woody vegetation, so they seem to disappear alongside their food source.”

The loss of massive herbivores may also account for other extinctions that have also been attributed to ancient hominins. Some scientists suggest that competition with increasingly carnivorous species of Homo led to the demise of numerous carnivores over the last few million years. Faith and his team suggest an alternative.

“We know there are also major extinctions among African carnivores at this time and that some of them, like saber-tooth cats, may have specialized on very large prey, perhaps juvenile elephants,” says Paul Koch. “It could be that some of these carnivores disappeared with their megaherbivore prey.”

“Looking at all of the potential drivers of the megaherbivore decline, our analyses suggest that changing climate and environment played the key role in Africa’s past extinctions,” said Faith. “It follows that in the search for ancient hominin impacts on ancient African ecosystems, we must focus our attention on the one species known to be capable of causing them – us, Homo sapiens, over the last 300,000 years.”