by H. Gregory

This is the first in a series of articles written for those of you who might appreciate a little extra background information on the science behind some of the projects we share with you. Enjoy!

In this year's Spring/Summer AnthroQuest we describe how Getty Grant recipient Thure Cerling is using stable isotope analysis of tooth enamel from fossil primates in order to determine the percentages of C 3 and C 4 plants that contributed to the their diets, and in December Oliver Paine updated us on his team’s progress in analysing the mechanical and nutritional properties of C4 plants in savannah habitats . Though these projects approach the questions from somewhat different angles, they will undoubtedly help us gain a greater understanding of early hominin diets, behavior and environment. Perhaps we should take this opportunity to review some of the basic science behind the study of C 3 and C 4 plants as they relate to human evolution.

Carbon: The Building Block of Life

Yes it is! With its four valence electrons, Carbon (C) is quite suited to act as the backbone in the molecules that are the foundation of life as we know it (proteins, the nucleic acids of DNA, lipids, etc.). Carbon exists naturally in three forms (or isotopes). Remember, in non-ionized atoms the number of negatively charged electrons spinning around the nucleus is equal to the number of positively charged protons in the nucleus. Typically the number of neutral neutrons in the nucleus is equal to the number of protons. In the case of isotopes, the number of neutrons is variable.

If an isotope is stable, then unless some outside force acts upon it, this isotope will sit around and do its thing, stably, forever. Unstable isotopes (or radioisotopes) will not. They will emit energy in the form of ionizing radiation until this instability is sufficiently resolved. The end result may be a more stable isotope of the same element or even another element altogether. This is the process behind what we call radioactive decay.

Of the naturally occurring carbon isotopes, one of them is a radioisotope called 14C. (The 14 tells us that the atom contains the usual 6 electrons, 6 protons and 6 plus an additional 2 neutrons.) This radioisotope exists in trace amounts and is mainly created when carbon atoms in the upper atmosphere encounter cosmic radiation. It takes in the thousands of years for this isotope to decay into a stable nitrogen atom (14N).

It is interesting to note that the decay of 14C provides scientists with a useful tool in dating biological material, otherwise known as radiocarbon dating. By measuring the percentage of 14C remaining in non-living biological material and comparing these numbers to known values of the environment, one can estimate the age of this material. (Remember, once an animal or plant is dead, it would not be incorporating new 14C into its body.)

12C and 13C are the stable isotopes of carbon. 12C exists much more abudnantly on earth at 99%. Except for the trace amounts of 14C, 13C makes up the rest. Also, it turns out that these isotopes are utilized in different amounts by C3 and C4 plants.

Carbon Fixation

We should probably go back to our high school science classes, all the way back to the chapter on photosynthesis. This is the biochemical process by which plants use the sun’s energy, water (H2 O) and carbon dioxide (CO2) to create sugar, otherwise known to us animals as food. The process by which the inorganic CO2 is integrated into an organic sugar is called carbon fixation, and C3 and C4 plants “fix” the carbon in different manners.

C3 Pathway (or Calvin Cycle)

C3 plants are by far the most common type of plant on earth (~95%). They mostly live in environments with a moderate amount of sunlight, moderate temperatures and plenty of water, and they use the C 3 carbon fixation pathway (or Calvin cycle) to integrate the CO2 into a three carbon sugar, hence C3.

Except for humans, modern primates have a mostly C3 derived diet. They eat a range of foods (fruits, insects, leaves), all similar to those foods that would be sourced from a tropical canopy.

C4 Pathway (or Hatch-Slack Pathway)

C4 plants (tropical grasses and sedges) use the C4 carbon fixation pathway (often referred to as the Hatch-Slack pathway) to incorporate CO2 and H2O into a four carbon molecule. This process takes more energy than C3 fixation; however, C4 fixation is more efficient when it comes to its utilization of H2O and CO2. Therefore C4 plants typically live in environments with more sun (open environments), longer growing seasons and less water. The C4 pathway is a relatively recent adaptation, probably arising due to changing environment.

What do humans eat? Our diets consist of about 50% C4 derived foods. Corn, millet and rice are examples. We also eat the meat of animals that graze upon C4 plants.

So yes, it makes sense that plants have adapted to different environments. In turn, animals have adapted as well, but what about these carbon isotopes?

As I mentioned, C3 and C4 plants utilize different amounts of the 12C and 13C isotopes. This means that their bodies contain different ratios of these isotopes. For example, C3 plants have less 13C in their tissue than compared to what naturally occurs in the atmosphere. C4 also have less 13C, but this “fractionation” is less severe. This is all due to the manner in which these plants fix carbon. The biochemical pathways have differing affinities for the lighter and heavier isotopes. Without getting too deep into the chemistry, this is due to the fact that 12C can “slide” through the C3 pathway more easily than 13C can. Same is true with the C4 pathway, just not as much. The result is that the isotopic signatures of these plants are different, and the 13C/12C ratios can be measured using isotope-ratio mass spectronomy, which can measure the known behaviors of these isotopes.

Please note, I have left out CAM plants, which utilize both carbon fixation pathways. These types of plants are usually restricted to desert environments.

Cerling and Paine

Let us return to the two projects that began this conversation. Dr. Cerling is examining the 13C/12C ratios in the tooth enamel of fossil primates from Kenya. Though the ratio in tooth enamel is not exactly the same as that of the diet of the animal, this “enrichment” percentage is known, and Dr. Cerling will be able to determine the relative amounts of C3 and C4 derived food in the diet of these primates.

I keep saying derived because there are limitations to this analysis. You cannot determine whether the animal got this 13C/12C ratio from eating C3 and C4 plants or if it ate meat of an animal that ate such plants or if it was a combination of the two. However, this ratio does give us information on where these animals derived their food. As we have now learned, these C3 and C4 plants grow in dissimilar environments.

As research on early hominin diets progresses, using stable isotope analysis as well as dental microwear analysis, we are finding that perhaps our early ancestors consumed more C4 plants than earlier thought.

So, this begs the question, what exactly did they eat? If our ancestors were roaming savanna habitats through different seasons, what types of plants might they have eaten at different times? What parts of the plants might they have focused their attention, and how would they have satisfied their energetic requirements on such a diet? Oliver Paine’s project will help us begin to answer these and many more questions.

As you can see, a great amount can be learned by utilizing the properties of C3 and C4 plants as a tool to investigate the diets and environment of our early ancestors and relatives. We look forward to sharing the the results of these and other scientists in the time to come!





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AuthorH Gregory

Rob Blumenschine's Leakey Speaker Series talk, "Olduvai Gorge and the Origin of Human Ecological Dominance," is coming up on April 22, 2015 at the California Academy of Sciences. Rob will discuss how humans have become one of the most adaptable and ecologically dominant species through intelligence and technology. What makes Rob so qualified to discuss this topic?

Rob has worked with the Comprehensive Olduvai Database Initiative (CODI) to expand upon the groundbreaking work of Louis and Mary Leakey at Olduvai Gorge for over two decades. Rob and his colleague Dr. Fidelis Masao have co-directed CODI's Olduvai Landscape Paleoanthropology Project (OLAPP) since 1989, which is the longest-running of current projects at CODI. OLAPP focuses on reconstructing Olduvai's ancient landscapes and identifying signs of Homo and hominid land use, such as tool making. This project has uncovered over 20,000 stone artifacts and 25,000 vertebrate specimens. It has also uncovered nine new Homo and hominid individuals including OH 65, a Homo habilis maxilla excavated in 1995 by Rob and his team. OH 65 shed new light on variation within Homo habilis. Read further about OH 65 in the Scientific American article "Tanzanian Fossil May Trim Human Family Tree."

Rob is not only passionate about the science, but scientific outreach as well. 

“The study of our past and our origins is not just of interest to scientists and maybe to a lay public when a big fossil discovery is made; but that the field has broad relevance to each of our lives, and the society in which we live.” - Rob Blumenschine

 Rob currently is the Chief Scientific, Education, and Fundraising Strategist at the Paleontological Scientific Trust (PAST) of Johannesburg, South Africa. PAST is a non-profit dedicated to Africa’s ancient natural and cultural heritage providing public outreach, student support, technical training, youth development, research support and publication and conference support.

Join The Leakey Foundation and Rob Blumenschine on Earth Day, April 22, 2015 at 7:00 PM at the California Academy of Sciences for "Olduvai Gorge and the Origin of Human Ecological Dominance."

Tickets are available for purchase online at Calacademy.org. General Admission is $15, Leakey Foundation Members, California Academy of Sciences Members, and Seniors are $12. 

For more about Rob Blumenschine watch this interview.


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AuthorArielle Johnson
CategoriesSpeaker Series
2015originstorieslogo-e-01.jpg

Origin Stories is our new podcast about what it means to be human and the science behind what we know about ourselves. We'll have interviews and stories from scientists about their research on a vast and fascinating range of topics. We'll learn about the biology and the millions of years of evolution that shape the way we look and act today.

Our first full episode comes out in late April, and we'll have monthly episodes after that. 

When it's released, you'll be able to find it on iTunes, Soundcloud, Stitcher, or your favorite podcast app. We'll also post episodes here on our website. We hope you'll listen, subscribe, and tell your friends! 

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AuthorMeredith Johnson
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Lauren Gonzales is a PhD candidate from Duke University.  She was awarded a Leakey Foundation research grant in the fall of 2013 for her project entitled "Intraspecific variation in semicircular canal morphology in platyrrhine monkeys."

Lauren Gonzales

Understanding the functional relationship between locomotion and the morphology of the semicircular canals is an important adjunct for the reconstruction of locomotor adaptations of extinct primates. It may also be the only source of data when limb bones are unknown or fragmentary. Unfortunately, data from large populations is not available for most primate groups, and functional interpretations for extinct species may be confounded by factors such as brain-size/canal shape interactions and intraspecific variation resulting from differences in ontogenetic trajectories. The goal of my dissertation is to document intra vs interspecific variation in semicircular canal dimensions associated functionally with locomotion and to elucidate the roles of selection and constraints influencing inner ear structure.

Transparent Alouatta side view

My work concentrates on focal species matched for relatedness, body size, locomotion (defined as habitually fast or habitually slow), and components of relative brain size. To this end, I have proposed several research foci: 1. Provide data on the levels of variation found in canal radius of curvature and canal orthogonality in a large population of strepsirrhines and platyrrhines. 2. Evaluate the relative contributions of locomotor agility, brain size and body size to semicircular canal shape and size. This research will amplify and extend our knowledge of vestibular shape variation and provide the foundation from which more effective predictive models can be built and interpreted. Ultimately, a clearer understanding of intraspecific variation in canal morphology allows for a more accurate interpretation of fossil species.

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AuthorH Gregory

Alfred L. Rosenberger

In August 2009 divers of the AD Exploration Foundation discovered a well preserved skull, limb bones, ribs and vertebrae of a small extinct monkey (Antillothrix bernensis) submerged in an underwater freshwater cave in the Dominican Republic. A multi-agency team solicited the collaboration of Dr. A.L. Rosenberger of Brooklyn College to recover these remains in October 2009.

In the spring of 2010 Rosenberger and his team sought emergency funds from The Leakey Foundation to return to the cave for further fossil recovery. This was due to the fact that this cave, La Jeringa Cave, is situated near popular tourist and diving enthusiast destinations, and there presented the risk that the site would be disturbed.

In the report below, Rosenberger summarizes his team's findings and the progress they have made in demonstrating the scientific potential of flooded caves for primate paleontology.

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AuthorH Gregory
CategoriesResearch Report

In this charming animated interview from the PBS Series Blank on Blank, Jane Goodall discusses her early dreams of studying animals in the wild, and how meeting Louis Leakey in Kenya made it possible for her to start her pioneering chimpanzee research.

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AuthorMeredith Johnson

We are pleased to introduce Elizabeth Moffett, PhD candidate from University of Missouri, who was awarded a Leakey Foundation research grant in December 2014 for her project entitled "Birth and its effects on anthropoid pelvic shape and integration."

Elizabeth Moffett

Birth selection is thought to be one of the most important pressures shaping the primate pelvis. Yet, it remains unclear if and how obstetric (birth-related) selection produces consistent changes in pelvic form among primates with rigorous birth demands compared to species with relatively easy labors. Thus, there is a discrepancy between the hypothesized importance of birth in shaping the pelvis and what we actually know about the effects of obstetric demand on pelvic form. This discrepancy significantly hinders the interpretations we can make about functional pelvic morphology or how pelvic form is related to its function in extant and extinct primates, including hominins.

My research aims to explore the effects of birth-related selection on the bony pelvis using three-dimensional landmark coordinate data; this data will be collected on skeletal specimens from extant (i.e., non-extinct) primate species. Specifically, my research aims to answer the following questions: How does obstetric selection influence dimorphism, or differences between males and females within species, in the bony birth canal among primates? How do patterns of dimorphism in the birth canal correspond to patterns of dimorphism in the non-obstetric pelvis? How does obstetric demand shape integration patterns, or patterns of trait covariation, in the primate pelvis? Enhanced understanding of how obstetric demand influences pelvic form among living primates will provide insight into the form-function relationship in the primate pelvis. Moreover, this research will enable future researchers to make inferences about birth difficulty in extinct primates, including our closest fossil relatives.

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AuthorH Gregory

By Jeremy DeSilva of Boston University.

Jeremy will discuss the question "Why walk on two legs?" along with Brian Richmond during a SciCafe at the American Museum of Natural History on April 1, 2015. This article is an excellent introduction to the pros and cons of bipedalism.

Humans are weird. We are mammals, yet we have very little body hair. We are primates, yet unlike most primates, we are generally uncomfortable in the trees. Like other animals, our brain is energetically expensive to grow and maintain, yet unlike other animals, we have somehow been able to evolve a brain six times larger than expected for our size. And, perhaps oddest of all, humans navigate their world perched up on extended hindlimbs. 

Look around you today. You might see cats, dogs, squirrels, or cows. They, and most other mammals, move around on all-fours. Humans? Nope—we have released our front limbs from the duties of locomotion and left that responsibility entirely to the hindlimbs. Certainly if this behavior, and the accompanying anatomical adaptations, have evolved in the human lineage, it must have been beneficial for our ancestors. But, evolutionarily speaking, “good ideas” tend to evolve multiple times in different lineages—something called convergent evolution. For instance, the streamlined body form of sharks, marlin, ichthyosaurs and dolphins independently evolved because it is the biomechanically most efficient shape for navigating quickly through the water. The wings of bats, birds, and butterflies allow different lineages to have independently taken to the skies. 

ostrichfoot.jpg

But, what about bipedalism? While many mammals can certainly rise up on two legs and even take a few steps (think about a threatening bear, or a vigilant meerkat), there is no other mammal that habitually strides around on its back legs like humans do. Now, that is not to say we are the only animals who do this. Ostriches and other large terrestrial birds are also striding bipeds and so were their theropod dinosaur ancestors. While over 300 million years of evolution separate the ancestors of birds and mammals, the comparison between humans and terrestrial birds is not entirely useless. It allows us to see what evolution can do in a few hundred million years (the time it has taken for birds to refine bipedalism) versus a mere 5 million (the length of time our own lineage has been bipedal). And it is therefore instructive to compare the foot of an ostrich to your own. 

footanatomy.jpg

The human foot is composed of 26 bones. With your two feet, you have 52 bones in your feet—this means that roughly a quarter of all of the bones in your skeleton are in your feet. When two bones come together, they form a joint. And, motion is possible at joints—in fact, the 26 bones in your foot result in 33 joints in the foot and lots of potential for motion.  This seems a tad odd given that you need your feet to be a stable platform that converts into a rigid lever when you push-off the ground. What about ostriches? Well, all of the bones of the ankle and the sole of the foot have fused together into a single rigid structure called the tarsometatarus. The toes are reduced in number, and in total, there are only 8 bones in an ostrich foot. In fact, the foot of an ostrich looks a lot like the new design for human foot prosthetics—a single, flexible, but rigid “blade” that stores and releases elastic energy during gait and a stable, rigid base for propulsion. If ostriches and engineers have figured out this “design”, why does the human foot look the way it does? 

The answer is that evolution does not create the best “design” out of scratch. Evolution does not create perfection. It molds previous structures to produce anatomies just good enough to survive. Humans do not have feet like ostriches because our lineage has not been feathered and bipedal for 250 million years. Instead, we evolved from apes. These apes benefitted from having mobile feet, with lots of moving joints, to assist with navigation through the trees. That is the raw material from which the human foot evolved and evolution can only jerry-rig these pre-existing structures. How? Ligaments and subtle shape differences of certain foot bones have resulted in a slightly stiffer and less mobile foot in humans compared to modern apes, or our ape ancestors. This is the evolutionary equivalent of using duct-tape and paper clips to stiffen up an otherwise quite mobile structure. But, it works- kind of. 

Podiatry (foot medicine) is a billion dollar industry. Humans twist and sprain their ankles; we suffer from collapsed arches, plantar fasciitis, shin splints, bunions, and hammer-toes. Let’s face it, everyone has foot problems, and if you don’t yet, just wait. Undoubtedly, some of these ailments are a result of our wearing restrictive shoes. But, there are fossils of early human ancestors (who undoubtedly did not wear shoes) with healed ankle fractures, sprained ankles, flat feet, compression fractures, and other foot problems humans suffer from today. These afflictions have been with us from the very beginnings our unusual form of locomotion and they will continue to be with us for millennia. Why? Because we walk on modified ape feet. It is not an anatomy one would design from scratch, because we were not designed from scratch. We evolved and we retain our ape legacy all through our bodies, including in our feet. 

When your feet ache after a long day, or your shin splints flare after a short jog, you may want to curse your ancestors. But, I think you should instead thank them. Without their survival, there is no “you”, or even “us”. And, they had it much, much worse. When you break your foot, or have a severe case of plantar fasciitis, you can go to a hospital or visit your podiatrist. But, there was no such thing as a podiatrist on the predator-laden African savannah 3 million years-ago. So, how did our ancestors survive in such conditions? How did a broken ankle not guarantee death for these individuals? Certainly some of these individuals became leopard food, but we have fossil evidence that these injuries often healed. How? I propose that these fossils are evidence that as far back as 3 million years-ago, our ancestors were taking care of one another in a rather human-like way. It is just possible that the development of care and compassion in our human ancestors—qualities we hold so dear and regard as so human-like—may have developed in the context of our imperfect “design”. Bipedalism may have only worked as an evolutionary innovation in a lineage that already caring to some degree for the sick and injured. Compassion would have thus evolved as a by-product of, among other things, moving around bipedally on faulty equipment. It is a tough hypothesis to scientifically test, but worth consideration. And while you do just that, please sit—those feet could use a rest.  

Jeremy DeSilva is a functional morphologist and Professor of Anthropology at Boston University. He'll be giving a talk with Brian Richmond at the American Museum of Natural History on April 1, 2015. For more details on that see our Calendar. Admission is free.

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AuthorMeredith Johnson
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Mackenzie Bergstrom

For her PhD dissertation, Mackenzie Bergstrom of the University of Calgary studied 25 adult female capuchins living in three habituated social groups in a tropical dry forest in Sector Santa Rosa (SSR) of the Área de Conservaciόn Guanacaste (ACG) in northwest Costa Rica. To better understand how ecological and social variables affect the physical condition of these New World monkeys, the goals of this project were to document the dietary profile of these females, measure the extent of the seasonal variation in diet and nutritional intake, determine if seasonal variation in the availability of foods affects the physical condition of females and determine ecological and social correlates of energy balance and stress using urinary C-peptide and fecal cortisol.

Female white-faced capuchins (Cebus capucinus

Bergstrom conducted 12 months of behavioral observations, phenological surveys and nutritional analyses of food items consumed, radio-immunoassays of urinary c-peptide of insulin as a measure of energetic condition, and enzyme-immunoassays of fecal cortisol as a measure of stress. In the report below she describes the results of her project, providing insight into behavioral strategies employed by females at varying reproductive states and social ranks in response to proximate ecological and social pressures.  


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AuthorH Gregory

Samantha Porter in the lithics lab at the University of Minnesota

The next grantee from our Fall 2014 granting cycle is Samantha Porter. She is a PhD candidate from the University of Minnesota, Twin Cities, and her project is entitled "Investigating cultural transmission across the Middle to Upper Paleolithic transition in Western Europe."

Around 40,000 years ago, anatomically modern humans began migrating out of Africa into Western Europe.  Europe was not empty prior to this migration, but was already inhabited by our close evolutionary cousins, the Neanderthals.

Samantha Porter demonstrating how to make 3D models using photogrammetry

My research tests for evidence of cultural exchange between Neanderthals and anatomically modern humans during this tumultuous time in prehistory. It is based on the principle that social proximity between groups has an effect on the way groups apply knowledge they've learned from one another. My research hypothesizes that if groups are interacting closely, individuals will be able to learn all stages of a technological production process from start to finish. For stone tools, this encompasses both the creation of flake ‘blanks’ and the reshaping of these blanks to produce formal tools. Alternatively, if two groups are interacting with each other in a more socially distant fashion, perhaps only finding material traces of each other left behind on the pathways of the landscape, a group acquiring a new technology from another is more likely to use their own blank production methods and then attempt to replicate only the form of the final product or tool of the other group.

Samantha Porter measuring lithic artifacts in the Musée national de préhistoire in Les-Eyzies-de-Tayac, France

In short, by looking at similarities and differences between assemblages of artifacts associated with Neanderthal and anatomically modern human groups at different steps of the stone tool making process, I not only seek to find evidence of the presence or absence of cultural exchanges between modern human and Neanderthal groups but also gain a better understanding of how closely these groups may have interacted with one another.

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AuthorH Gregory
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Our understanding of human evolution has grown exponentially since Darwin's time. This week marks the 206th anniversary of the birth of Charles Darwin, so we're sharing a Darwin-related Leakey Foundation lecture from our archives. In this lecture, recorded in 2009 at the Field Museum in Chicago, Daniel Lieberman of Harvard University discusses the evolution and dysevolution of humans 150 years after On the Origin of Species.

The Leakey Foundation and the Field Museum present Dr. Dan Lieberman at The Field Museum. April 4, 2009. Full Title: Survival of the Swiftest, Smartest or Fastest: Human Evolution 150 Years After Darwin


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AuthorMeredith Johnson

The next fall 2014 grantee we would like to introduce to you is Maura Tyrrell. She is a PhD candidate from the University at Buffalo, State University of New York, and her dissertation project is entitled "Effect of competition on male coalition patterns in crested macaques."

Maura Tyrrell and a crested macaque

My dissertation focuses on the social relationships between wild adult male crested macaques (Macaca nigra) at Tangkoko Nature Reserve, Indonesia. I am specifically examining coalition behavior between males in different competitive contexts.

Competition between groups of related and unrelated males plays a large role in the political structure of early humans. However, current theoretical explanations of male coalitions in nonhuman primates focus primarily on mate competition within the group and seldom consider the influence of competition between groups. With my study I hope to create a clearer picture of social relationships in crested macaques by incorporating between-group and within-group competitive contexts into my examination of coalition and relationship qualities. I want to know if competitive context of coalitions (i.e. whether coalitions are directed towards a resident or male or an immigrating male/outside male in a neighboring group) varies with behaviors proposed to manage conflicts between individuals (i.e. "reconciling" after a fight, signaling friendly intentions, ritualized "greetings"). Additionally, does coalition partner choice in each context reflect differentiated patterns of affiliation, or is it primarily opportunistic?

The answers to these questions should help broaden our perspective of the evolution of human male coalitions by identifying components of early human alliances that may have evolved before the common ancestor of humans and chimpanzees. Findings of parallels between coalition patterns in crested macaques, chimpanzees, and humans will suggest that these parallels not only pre-date the common ancestor of humans and chimpanzees, but that they do not require male philopatry and clusters of related males. 

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AuthorH Gregory

Leakey Foundation grantees Israel Hershkovitz and Ofer Marder led an international team of archaeologists who discovered a 55,000 year old cranium in Manot Cave in Israel. Their discovery was described last week in the journal Nature

Photo courtesy of : Clara Amit, Israel Antiquities Authority

Photo courtesy of : Clara Amit, Israel Antiquities Authority

A key event in human evolution was the expansion of modern humans of African origin across Eurasia, replacing all other forms of hominin (humans and their predecessors) around 40,000-60,000 years ago. However, due to the scarcity of human fossils from this period, the path these ancestors took as they expanded out of Africa has largely remained a mystery.

Interior of Manot Cave. Photo courtesy of Amos Frumkin / Hebrew University Cave Research Center

Interior of Manot Cave. Photo courtesy of Amos Frumkin / Hebrew University Cave Research Center

The Manot Cave finding provides the first fossil evidence from the critical period when genetic and archaeological models predict that African modern humans successfully migrated out of Africa and populated Eurasia. It is also the first fossil evidence that there were populations of modern humans living near populations of Neanderthals in the Levant during the late Middle Paleolithic. This leads some to speculate that the Manot Cave people could be the population that initially bred with Neanderthals, giving all modern non-African people a little bit of Neanderthal DNA.

The Leakey Foundation recently awarded Ofer Marder of Ben-Gurion University a research grant to fund further excavation of Manot Cave. We are thrilled to be funding the exploration of this important site. We look forward to sharing news of more discoveries. 

The research appears in the journal Nature under the title "Levantine cranium from Manot Cave (Israel) foreshadows the first European modern humans" (DOI 10.1038/nature14134).

Inside the Manot Cave in Israel's Galilee, where a 55,000-year-old skull sheds new light on human migration patterns. Photo courtesy of: Amos Frumkin / Hebrew University Cave Research Center

Inside the Manot Cave in Israel's Galilee, where a 55,000-year-old skull sheds new light on human migration patterns. Photo courtesy of: Amos Frumkin / Hebrew University Cave Research Center

You can learn more about the discoveries at Manot Cave in the following articles:

"Skull Fossil Offers New Clues on Human Journey From Africa", New York Times.

"Neanderthals gain human neighbor", Nature.







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AuthorMeredith Johnson
CategoriesIn the News

Naomi Cleghorn, University of Texas at Arlington, was awarded a Leakey Foundation research grant in the fall of 2014 for her project entitled "Investigating a rare Early Later Stone Age site at Knysna, South Africa."

Naomi Cleghorn at Pinnacle Point site 5/6, Mossel Bay, South Africa

Despite widespread interest in the potential origins of modern human cognitive, social, and technological innovations in the Middle Stone Age (MSA) of Southern Africa, very little is known about how these developed into the suite of strategies exhibited by Holocene and recent foragers of southern Africa. Technologically, much changed between the earlier MSA and the Later Stone Age (LSA) of the Last Glacial Maximum, but the intervening industries are enigmatic and poorly represented. This is in part the result of a substantial drop in the number of documented archaeological sequences dating to the period between 45 kya and 25 kya. In contrast, the archaeological records of Europe and Western Asia document a proliferation of sites after 40 kya. The dearth of sites in South Africa is particularly difficult to reconcile with paleoclimate reconstructions indicating this region enjoyed a relatively mild, wet stadial, and with recent genetic research (Kim et al., 2014) suggesting that the southern African population was the largest on the planet during the Late Pleistocene. Where did these populations go for 20 k years and why did their technology change?

Graduate student Christopher Shelton (L) and Naomi Cleghorn working at Pinnacle Point site 5/6. They found KEH-1 in 2012 during a survey. Shelton is a research assistant on the current Leakey-funded project.

My team and I have recently discovered a site on the southern coast that will help answer these questions. Knysna Eastern Heads Cave 1 (KEH-1) is currently a coastal site, but in the late Pleistocene, it would have had looked south out over a coastal plain up to 75 km wide. KEH-1 is unique in preserving the only archaeological sequence dating between 44 and 18 kya on the southern coast. My international team of scientists and student researchers will expand on the previous test excavation in July and August of 2015 and then use the analyses of stone tools, fauna, plant remains, stable isotopes, and the micromorphology of site stratigraphy to investigate human responses to the changing landscape.

Naomi Cleghorn and Leesha Richardson during the test excavation of Knysa Eastern Heads Cave 1 (KEH-1)

600ft trail, Harkerville Forest, taken during 2012 survey in the Knysna area

Naomi Cleghorn (upper right) and excavation crew at Pinnacle Point

Naomi Cleghorn (upper right) and excavation crew at Pinnacle Point

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AuthorH Gregory

We are happy to introduce another one of our fall 2014 grantees, Shelby S. Putt, PhD candidate from the University of Iowa. Her dissertation project is entitled "Investigating the co-evolution of language and toolmaking:  An fNIRS study."

Shelby S. Putt

Our language and cognition are arguably the features that most distinguish us from other species, and yet, we still know so little about the evolution of these features. As products of evolution, our brains may hold clues to the ancient cognitive and linguistic capabilities of our distant human ancestors. For example, how our brains process the same stone toolmaking behaviors that early hominins practiced may be the closest we ever come to observing extinct hominin cognition in action.

There is evidence to suggest that language instruction reorganizes the cognitive networks involved in learning to make stone tools (Putt et al. 2014). For this reason my team and I are exploring how the act of making stone tools (i.e., flintknapping) is processed differently in the brain depending on whether it was learned verbally or nonverbally. This is an important question, as early Homo probably did not possess fully modern language and also may not have actively taught their young how to flintknap.

Research assistants Chloe Daniel and Danielle Jones demonstrate the setup for collecting data with fNIRS.

My research employs a cutting-edge brain imaging technique known as functional near-infrared spectroscopy (fNIRS) to measure brain activity while human subjects learn to make Early Stone Age tools. This is the first study to use fNIRS to address paleoanthropological questions, and in many ways it is an ideal neuroimaging technique for observing brain activity during stone tool manufacture.

The results of this study will address the motor theory of language origin, which argues that language developed out of a pre-existing motor system, such as that used by early hominins to make relatively complex stone tools. It is my hope that this research and future experiments will help pave the way to a clearer picture of how and when humans began to communicate and think with language.

Further reading:

"The role of verbal interaction during experimental bifacial stone tool manufacture" - Lithic Technology

"Validating a new methodology for optical probe design and image registration in fNIRS studies"NeuroImage

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AuthorH Gregory

We are pleased to introduce you to another one of our newest grantees, Amanda Lea, PhD candidate from Duke University.  She was awarded a Leakey Foundation research grant in the Fall of 2014 for her project entitled "Effects of social conditions on DNA methylation and immune function."

Amanda Lea

Many primates, including humans, live in complex social environments in which both competitive and affiliative interactions are common. The capacity to deal with this environment can vary substantially across individuals. While some individuals form stable, positive social bonds, others do not; similarly, only some individuals are able to achieve high social status. Research in both humans and nonhuman primates suggests that variation in these social experiences can have profound effects on physiology, health, and survival. However, we do not understand the molecular mechanisms that mediate these effects.

Baboon (Papio cynocephalus) in Amboseli, Kenya

To address this gap, my project tests the hypothesis that social adversity influences health-related traits by altering the way genes are expressed. Specifically, it asks whether low social status and/or social isolation lead to changes in DNA methylation (an environmentally sensitive modifier of gene expression) and whether these changes predict how individuals respond to an immune challenge. To do so, my project combines behavioral data from wild baboons in Amboseli, Kenya, with measurements of genome-wide DNA methylation levels and immune-related gene expression patterns.

Together, the resulting data will shed new light on whether, and to what degree, social experiences influence immunological traits that likely contribute to health and survival in wild primates. Identifying these connections is crucial for understanding the evolution of primate sociality, and for addressing the well-documented health consequences of social adversity in human populations. Finally, by using a genomic approach, I will be able to identify specific genes involved in the response to the social environment, which are likely to have been important in the evolution of group living in primates. 

More information:

Amboseli Baboon Research Project
The Alberts Lab - Duke University
The Tung Lab - Duke University
"The Role of Methylation in Gene Expression" - Nature Education
"Baboon Watch" - Science Magazine

Posted
AuthorH Gregory

Michael Granatosky, PhD candidate from Duke University, was awarded a Leakey Foundation research grant in our most recent granting cycle for his project entitled "Gait mechanics of inverted walking: Implications for evolution of suspensory behavior."

Michael Granatosky at the Duke Lemur Center

Specialized arm-swinging locomotion has arisen independently numerous times during the evolution of primates and yet has never appeared in any other mammalian lineage.  Currently, few theories explaining the transition to specialized arm-swinging locomotion in primates have been proposed, and none of these provide an experimental framework by which to approach this question.  My dissertation focuses on the mechanics of below-branch quadrupedalism, which is a form of suspensory locomotion commonly seen in primates and other mammals that requires few anatomical modifications.  The goal of my project is to understand the proximate strategies mammals use to adjust mechanically to below-branch quadrupedal locomotion and then determine whether below-branch quadrupedal locomotion relates to the ultimate evolution of specialized arm-swinging locomotion in primates. 

To answer these questions, I will collect locomotor data from primates, sloths, and bats during a number of experimental comparisons.  First, I will collect locomotor data from primates walking above and below a runway.  This comparison will determine what aspects of locomotor behavior changes between above and below-branch quadrupedal locomotion.  Next, I will compare the mechanics of below-branch quadrupedal locomotion between primate and non-primate mammals.  This will determine whether there are multiple strategies for adopting below-branch quadrupedal locomotion, or whether all animals are moving in a similar fashion.  Finally, I will compare the mechanics of below-branch quadrupedal locomotion with specialized arm-swinging locomotion in primates to determine if below-branch quadrupedal locomotion may have served as a locomotor precursor to specialized arm-swinging locomotion.   

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AuthorH Gregory

Anne E. Russon
York Univesity

Anne E. Russon

In spring 2012 The Leakey Foundation awarded Anne E. Russon a grant for her long-term study of behavior in east Bornean orangutans (Pongo pygmaeus morio) at the Bendili study area (Kutai National Park). This project focused specifically on orangutan ranging, feeding ecology and spatial cognition. 

Researchers have studied orangutans in the Bendili and nearby Mentoko study areas several times over the last 44 years.  During this time their habitat has undergone drastic changes, including commercial logging incursions, severe droughts and massive forest fires. In the report below Russon describes some of her team’s findings, including how intra-site comparisons of activity budgets and travel distances provide insight into how these orangutans coped with this series of habitat changes. 


Posted
AuthorH Gregory
CategoriesResearch Report

It is with profound sadness that we share with you the passing of Brad Goodhart, the devoted husband of the Foundation's Grants Officer Paddy Moore-Goodhart. 

Brad Goodhart and Paddy Moore-Goodhart on one of their many adventures.

Brad Goodhart and Paddy Moore-Goodhart on one of their many adventures.

Brad had an enduring love for Africa's people and nature, having led over 100 tours of East Africa over the past 35 years. He was a Board Member of the African Orphans Foundation where he helped coordinate fundraising for orphaned girls in Kenya, Tanzania, Uganda and Ethiopia. He taught science, math and English at Bishop O’Dowd High School from 1968-1997, and was most recently teaching at Geyserville High School.

His generous smile, insatiable curiosity, and helpful hand made him a special addition to the Foundation family.

He succeeded in living a full life while inspiring so many others to do the same. Please join us in sending our most sincere condolences to Paddy and her family.

A celebration of Brad's life will be held at 2:00pm on Monday, January 19 at Villa Chanticleer in Healdsburg, California. 

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AuthorMeredith Johnson
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