Update-Prof. William (Bill) Kimbel- RIP

Update: His funeral is being broadcasted to registered individuals via Zoom Saturday the 28th, you can register here.

It is with the utmost sadness that I inform you, for those who do not already know, that the famed paleoanthropologist, who served as the director of the IHO at ASU for 13 years, Dr. Bill Kimbel, passed on this morning.

Photo courtesy of Arizona State University

This is the third obituary for a famed, well loved, and amazing scientist that I have had to write, not since I started my career as a science communicator and journalist, but the third just this year.

We have lost many a great minds this year, it has been a crushing blow to paleoanthropology. From Richard Leakey, to Isaiah Nengo, and now Bill Kimbel, all of these professors have left a massive, permanent mark on the field. Whether you agree with their hypotheses, methods, or ways of doing things, there is no way to deny the contribution that these three men have made for the world of anthropology.

Dr. Kimbel received his Ph.D from Kent State University, and went on to lead an impressive career, from ASU’s website, “For more than 30 years, Kimbel has conducted research on Australopithecus and early Homo in Africa, Neanderthals in the Middle East, the evolution of hominin skull form and function, and concepts of biological systematics as applied to paleoanthropological problems. Since 1990, he has codirected or directed research at the Hadar hominin site in the Afar region of Ethiopia. Kimbel is also a Virginia M. Ullman Professor of Natural History and the Environment in the School of Human Evolution and Social Change. He is a founding member of the Afar Rift Valley Research Consortium, a group working on a region-wide understanding of human evolution and its contexts. Kimbel was elected Fellow of the American Association for the Advancement of Science in 2005.”

Dr. Kimbel will be deeply missed, not only by the friends and family that he leaves behind, but the many students and minds that he has touched.

After a long, and arduous battle with cancer, Dr. Kimbel passed away this morning, Sunday the 17th of 2022.

He has earned his rest, and may he take it in peace.

Seth Chagi

“Discovering Us” by Evan Hadingham Review

World of Paleoanthropology

When you ask many anthropologists today, what got them into anthropology in the first place, many of them will tell you this or that, but often enough it is that they came across the now famous book, fondly known as “The Lucy Book” by Dr. Don Johnson, published in the 80’s. This book details the astounding discovery of the A. afarensis partial skeleton, the most complete of its time, detailing the anatomy, the adventure, and the science. So many people fell inn love with this book, that it drove them into the field themselves! People like Dr. Lee Berger, and many others owe their careers to the collective work of the past, and in thanks to mentors and people like Don Johnson.

Today, while “the Lucy book”, for those who are interested is still a great place to start, it is a little out dated. There is, however in my…

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What is Paleoanthropology? An introduction!

Today, in one hour I am excited to premiere a new video! (You can watch it on this page once it has premiered, otherwise this is the link: (https://youtu.be/pqpsqWktqMM). We are going to learn all about Paleoanthropology, what it is, and how it relates to our modern world. There is a great deal to learn about anthropology, humans, and our origins. 

But where does one begin? Well, a great place to start is with this video, as I introduce to you just what paleoanthropology is, and how it relates to our modern world, I hope you will all learn something new, and exciting. 

The goal of this video is to provide a basic introduction on what Paleoanthropology is, and why it is important. 

If you like this video, please like and subscribe, as I will be making more of them if the reception is positive enough. 

I had a blast making this video, and I hope you all enjoy it as much as I did making it! 

Enjoy! 

A small tooth, a big surprise, and Denisovans in Laos!

View on Academia.edu if you please 😉 I’d appreciate it!

If you have been on the up and upon the most recent goings-on in paleoanthropology and human evolution, by the way, evidence points these days, is that up until as recently as 70 kya; we were living amongst as many as six species of  humans. From the well-known Neanderthals, found in western Europe into the deserts of the Middle East, to the Hobbits on

 the island of Flores. Being the only bipedal ape on this planet is something relatively new. As we explored in my recent paper titled “Planet of the Apes”, you can read here which goes into much more detail on this subject. For today’s topic, however, we are going to be talking about one specific group, or population of ancient peoples, commonly known as the Denisovans. 

The Denisovans are an enigmatic people, while not designated as an official species just yet, due to a lack of physical evidence, we have a wealth of knowledge about them from their DNA. For you see, back in 2008, in the Altai Mountains of Siberia, in a well-known archaeological site known as Denisova Cave, a tiny portion of a pinky bone was found. It would turn out that this pinky bone belongs to an ancient little girl, dating to around 75 kya. But there would be something extra special about this little girl, she was from a species previously unknown to science. 

Amazingly, from this small piece of bone, scientists at the Max Planck Institute for Evolutionary Sciences were able to gain a piece  of DNA that contained around 70% of the entire Denisovan genome. This was more than the entire yield of Neanderthal DNA yield that researchers at the Max Planck had at the time. We would learn a great deal about these people from their DNA, but we would go a long time without finding any more fossils that we could contribute to them. While there is some speculation, that certain skulls such as the Harbin, or “Dragon Man” skull may actually belong to Denisovans, without DNA, we cannot know for sure. 

Discovered some forty years ago, but only recently handed over to scientists, was a mandible found from a high Tibetan plateau, which had giant, almost nonhuman molars. DNA would show that this would be the first Denisovan fossil outside of Denisova Cave. It also showed how wide the range of these people could have been. But now, a new find is showing just how far that range could have been, with physical evidence. We know from the DNA that many people of Asian, and South Asian descent, as well as aboriginal Australians, have up to 7% of Denisovan DNA. This has to be explained by some introgression into the modern populations of Homo sapiens. 

Now, however, a new find from Laos, in the Tam Gnu Hao 2, or Cobra Cave, a singular, small tooth was found and reported this last week. Dating to the middle Pleistocene, or 164-131 kya with the use of luminescence dating on the sedimentary matrix. These places the tooth well within the region of Densivoans who could have lived here at the time. According to the researchers, “Analyses of the internal structure of the molar in tandem with palaeoproteomic analyses of the enamel indicate that the tooth derives from a young, likely female, Homo individual. The close morphological affinities with the Xiahe specimen from China indicate that they belong to the same taxon and that Tam Ngu Hao 2 most likely represents a Denisovan.” 


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So what does this mean? Well, it means that Denisovans were covering a great deal of ground, and were doing it up until somewhat recently. While there are three groups or populations of Denisovans that are known to science at this time, and we do not know which this belongs to, we know that this tooth, which again belonged to a small girl, is going to shed a great deal of light on the presence of Denisovans, and other early humans in Southeastern Asia. 

As always, with more answers, and more information that we get, we are just led to more questions, but that is what makes science great! There is always more to learn, and if you keep at it, you will always be finding answers! 

Did you learn something about the Denisovans today? Are you surprised that they have been found so far south when compared to their close Neanderthal kin? 

Original Paper:

It’s here! Welcome to the Origins of Bipedal Walking!

Well, the day has come! Earlier today, Dr. Throckmorton, Dr. McNutt, Dr. Hammond and Dr. DeSilva and I got together and held a symposium about discussing the Origins of Bipedal Walking. 

This is a special recording of “The Story of Us” that we have been preparing for months. It has taken a great deal of effort and work to put this together, but we are all very happy and proud to present to you the following recording. 

Please enjoy, stir conversation, debate in the comments, ask questions! There is always more to learn! 

While I do not know what, or when the next Symposium will be, be sure there will be one, so stay tuned! 

The Origins of Bipedal Walking

We have an upcoming event that might peek the interests of any #paleoanthropologist! I have brought together some experts in the field, especially concerning the subject of the #origins of #bipedal #walking.

So join us! The event is not live, but recorded, and will be posted the same day. I encourage anyone who is interested to send their questions to worldofpaleoanthropology@gmail.com to have them asked during the Q/A that will follow the presentations.

If you want to learn about #TheOriginsOfBipedalism there is no better place to check it out! See you on the 9th!

Verisimilitude in Moche Iconography; A different aspect of Anthropology

Please view on Academia.edu if you can:

The Moche people are one of the greatest, and most organized pre-Incan cultures in the Northern Andes, existing during the Early Intermediate Period, the successor of the lands once ruled by the Chavín culture, until their fall around 700 AD, to the Wari culture. The Moche are well known for many things, from the large territories, and trade routes that they established and upheld, to the drastic and intricate rituals that they held. Most of all, they are probably known for the legacy of art that they left behind. Textiles, pottery, and finer arts are well known to have been produced by the Moche on an almost industrial scale, where there were workshops to produce these artifacts (Quilter, 2013). 

Their fine-line art is some of their most well-known contributions to Andean culture. Their art has mystified and made people wonder since modern eyes were first laid upon them, and many researchers have spent their lifetimes trying to determine just what this art means. Some of it seems easy to understand, acts of daily life, while others are of a more esoteric appearance. In the following papers that were examined, I have come to the following conclusion. The verisimilitude shown in Moche art is very apparent. It is how the iconography is interpreted, that changes the meaning. While it is clear that not everything that occurred during the Moche’s rule is depicted, those of highly ritualistic significance was. We can see from the archaeology, that these depictions are supported by finds such as those at Sipan (Bourget, 2001). But where is the line? We will go over evidence supporting various aspects of Moche iconography to support the hypothesis that Moche iconography has a strong verisimilitude within the ritualistic world that the people of the Moche found themselves in. We have a great amount of archaeological evidence to support the idea that what was being depicted in the fine Moche art, actually has a strong basis in reality, as we will see. 

While many Andean archaeologists like to focus on the warfare aspects of Moche culture, which of course are very important, other aspects can reveal light on the situation. One great example of the use of textiles that are represented in the art, and are found in the archaeology, is what archaeologists found in the multiple tombs at Sïpan, especially the one deemed “The Lord of Sïpan”(Bourget, 2001). With the archaeological aspects of the ceramic pottery were not fully looked into until the archaeological digs began to take place, around one hundred years ago, it becomes clear that “Moche images are not intended to describe, explain, or explore, but to convey lore meaning” (Benson, 2008). 

The textiles that the Moche took part in were of a wide variety, from tunics, stirrup-type pottery and ceramics, icons, and many more types of art. Much of the art depicts various scenes, many of which are grand burial, or sacrificial themes. So detailed are these scenes, that it has made researchers ponder just how real to life they were. Until the finds at Sípan, it was doubted just how accurate these textiles were when it came to what individuals were wearing and doing during these events. But after the tombs were discovered and opened, it is uncanny how accurate the iconographical decisions are when it comes to real-life (Bourget, 2001). The individuals in the tombs were dressed and were in possession of many of the items depicted in the art, whether it be ceramics, textiles, or other forms of art. 

Another aspect of Moche life that has been highly contested, is the place of warfare among them. Some researchers believe that the Moche had one polity and that any warfare occurred in a foreign place, and not within the “empire”. Others, however, are conceived that there was a great amount of inter Moche conflict (Butters, 2014). While the art shows that a great deal of conflict did occur, the evidence for this is not highly available in the archaeological record. We do not have large battlefields, or for that matter, even small ones where there are injured, and slain individuals. It is also important to note, that these warriors, who are so often depicted in the iconography, brave, and scary as some of them seem, do not carry the typical weapons of warfare( Butters, 2014). What we see instead, are weapons that are easy to break, such as ritualistically made clubs, that would not be of any use in an actual battle (Bourget, 2001). 

So what does this mean for the iconography? With so much battle and warfare depicted, sacrifices, death, and gore, why is there no physical evidence for it? Well, the story may not be as simple as that. While the Moche may have grown their empire through various ways, not military-related, such as through trade and relationships with their neighbors. Food and trade played a very important role for the Moche (Jackson, 2021). What is left of all the warfare that we see depicted almost more than anything else? Well, there is a strong possibility, with the discoveries at Huaca de la Luna, that there may have been another purpose for all of these depictions, one that is much more true to reality, and that of Moche life, was it more of a spiritual endeavor than a physical war? There may be evidence to support this idea above any other. 

The site of Huaca de la Luna is impressive, one of the greatest along the northern coast of the Andes. It is also one of the greatest examples of verisimilitude in Moche iconography ( Bourget, 2001). For the most part, until recently all that we have known about Moche iconography is from the iconography itself, and we have been left to interpret it the best we can, with very little archaeological evidence. One of the most complex, and often depicted scenes in fine-line Moche ceramics, is known as the “Sacrifice Ceremony”. In this scene, naked men are being sacrificed, by having their necks slit, and allowing their blood to flow out into Moche-styled bowls that we are very familiar with archaeologically. Sometimes the hearts are also removed and shown in the imagery (Bourget, 2001). Once the bowls are filled with blood, it seems that they are offered either to other humans of more elite status or to supernatural beings themselves. In 1995, the largest single sample of human remains around this time are found at Huaca de la Luna. 

More than seventy individuals were found and sacrificed during at least five different episodes, two of which were closely related to El Niño. ( Bourget, 2001). Some of these individuals had wounds that were healed, but then fatal wounds. This suggests, that it is possible that these men were captured during the battle, and were taken back to the temple and sacrificed. That there is the key point. There is much more evidence in Moche iconography, and within the archaeological record to support the fact that the Moche were not having warfare in the sense that we think of it today. No armies were meeting across battlefields, but rather, as the iconography depicts, there are small scale, even one on one individual, ritualistic battles between individuals. The losers were then sacrificed to the powers at be. With so little evidence of actual/ secular warfare among the Moche, this seems to be a much more appropriate explanation (Bourget, 2001). 

While there is a great deal that we can learn from Moche iconography about the lives they lived, how they dressed how they were buried, and what their lives were like, there is still a great deal of mystery surrounding their lifeways. Especially those aspects that surround death, battle, and sacrifice. But with the archaeological evidence that we do have, as limited as it is, if the iconography is interpreted as a more spiritual and ritualistic scene than that of what happened, then we have a good match of the two. Instead of war, which is not depicted in the art, (we know this once again because they lacked the proper weapons for war) but rather had what was required to pursue ritualized versions of battle, and death. As far as how close Moche art is in general to reality, it is strikingly close. From the clothing and arts that we see in ancient tombs of the elite, and even burials of those of lower classes, to the sacrificial pits of Huaca de la Luna, we can see that the Moche life was diverse in behavior, but generally followed a similar outline of spiritual belief, mixed with reality to form their worldviews. I think we can conclude that Moche art is very high in its rate of verisimilitude.

Recoures Cited 

Benson, Elizabeth

2008 Iconography Meets Archaeology.  In Art and Archaeology of the Moche, edited by Steve Bourget and Kimberly L. Jones, pp. 1-22. University of Texas Press, Austin.

Bourget, Steve

2001 Rituals of Sacrifice: Its Practice at Huaca de la Luna and Its Representation in Moche Iconography. In Moche Art and Archaeology in Ancient Peru, edited by Joanne Pillsbury, pp. 89-110. Studies in the History of Art 61, Center for Advanced Study in the Visual Arts Symposium Papers XL, National Gallery of Art, Yale University Press, New Haven.

Castillo Butters, Luis Jaime 

2014 Taming the Moche. In Embattled Bodies, Embattled Places: War in Pre-Columbian Mesoamerica and the Andes, edited by Andrew K. Scherer and John W. Verano, pp. 257-282. Dumbarton Oaks, Washington, D.C.

Jackson, Margaret.A. 

2021 The Symbolic Value of Food in Moche Iconography. In Andean Foodways, edited by J.E. Staller, pp 257-279. The Latin American Studies Book Series. Springer,

Quilter, Jefferey. 

2013. “The Early Intermediate” in The Ancient Central Andes. London: Taylor and Francis. Apple Books 

“Discovering Us” by Evan Hadingham Review

When you ask many anthropologists today, what got them into anthropology in the first place, many of them will tell you this or that, but often enough it is that they came across the now famous book, fondly known as “The Lucy Book” by Dr. Don Johnson, published in the 80’s. This book details the astounding discovery of the A. afarensis partial skeleton, the most complete of its time, detailing the anatomy, the adventure, and the science. So many people fell inn love with this book, that it drove them into the field themselves! People like Dr. Lee Berger, and many others owe their careers to the collective work of the past, and in thanks to mentors and people like Don Johnson. 

Today, while “the Lucy book”, for those who are interested is still a great place to start, it is a little out dated. There is, however in my opinion, a book that has just come out that may take the crown for the most influential anthropology book for the next few decades. A book that covers not just one find, but all of anthropology, from the far reaches, to the dear and near. A book that takes a close look at individuals doing the work themselves, and making the world a better place. We get to see, as if we were there through the astonishing writing ability of author Evan Hadingham. 

In “Discovering Us” by Evan Hardingham, in conjunction with The Leakey Foundation, we are taken on a journey of the last fifty years, through fifty miraculous discoveries from people all over the world. We hear astonishing stories, and see the finds themselves through the elaborately formatted and incredibly well photograph filled book. 

We follow along with fifty of some of the greatest stories in paleoanthropology on the path to discovering just who we are, and how we came to be here. Not only does the reader get a grand understanding of what it means to be human, but also the journey it took us to get here. Through expeditions and extravagant fossil finds, including Lucy, we are able to see the whole picture of what the science is today. I truly cannot say enough good things about this book, and little to nothing bad at all. 

If you want to support, and be involved with the current scientific work that is going on, this is a great way to find out about who is doing what, where they are in their careers as of the writing of this book (which was published in late 2021) and support them how you can, and see fit. While this book was not written to drive attention to The Leakey Foundation, it is abundantly true that this book would not have happened without them. As Mr. Hardingham tells us in our interview at the book, which you can find at the bottom of this page, The Leakey Foundation’s team is very small, and it was a great collaborative effort to get all of this done. 

While this book is on the more pricey end of books, it is more than worth the read, especially if you can find it in a local library or other such place. This book, is going to inspire the next few generations of anthropologists, I have no doubt about it. As someone who is so utterly 100% dedicated to the field, and have been told by many they have not seen others with such passion for this field, I can tell you, the people in this book share that passion; and it screams off the page at you. 

Pick up this book!

The Story of Us- Ep 34 with Evan Hardingham

Welcome to the next episode of The Story of Us! 

On this episode we are joined by non other than the Senior Editor of NOVA, brought to us by PBS. Evan has been working at Nova for over 30 years, an illustrious career. Although he started by exploring ice age caves in France and Spain, and working as an archaeologist. 

Today, he is a successful author, editor, and archaeologist known world round. 

We are honored to have him, as most of you know those of my generation, and others grew up on NOVA, so this, for me at least was a BIG DEAL! 

On this episode, we are discussing his newly published book, created in tandem and with close partnership with The Leakey Foundation, titled “Discovering Us,” one of the best books on the field as a whole I have read, ever. Period. And that is an unpaid opinion, as all of my opinions are! You get them whether you want them or not! 

So please join us on this episode, you can view it on 

And Listen with a subscription on Apple Podcasts (3-Day Free trial, $2.99 a month after that, each episode becomes free the following month)

“Discovering Us”- Buy your copy here: https://www.signaturebooks.com/books/p/discovering-us

I hope you enjoy, and above all I hope you have learned something, and if I dare to hope, you have even been inspired by our discussion! 

Thanks, and see you next time! 

Seth 

Project Director 

World of Paleoanthropology 

A Planet of Apes 

View on Academia:

Today, we literally, walk alone (at least on two feet) and are the last of a long-lasting line of creatures known as hominins. Our lineage dates back 6-7 million years ago. Over that time we have gone through many changes as animals, and it is only in the last 100 years that we have really begun to study and learn about our evolutionary history. As we learn more about our past, our future becomes more clear, and we can learn ways to apply the lessons of the past to the problems of the present. 

While today, there are only four species of Great Apes left walking the planet today, only of them are bipedal in their form of locomotion, or that they walk on two legs. That would be us, Homo sapiens. This, as well as many other aspects of our lives, bodies, and cultures, make us a special species, possibly the most unique to have ever walked the earth (at least the most successful). But we were not always alone. In fact, being the only bipedal hominin is a relatively new development in the course of Earth’s history since hominins split from our last common ancestors with Chimpanzees some 7 million years ago. 

Today, we dominate the world, with over 7 billion of us, no other species of our scope or size have reached these proportions, to the point where we strain the ecological resources of the Earth almost to the tipping point. Something about the way we go about doing things has allowed us to survive past many challenges. Disaster after disaster that wiped out other species of hominoids, our close relatives and ancestors. 

There have been many branches of the hominin family tree, or braided stream as we will discuss, and all of them ended in dead ends except for our line. Why is this? Why are we the only living hominins, and for long how has it been like this? Today we will be exploring some of the ideas behind this, in an attempt to understand the complex landscape of the last 7 million years of hominin evolution.

Not so long ago, we were not the only species on Earth, in fact, many other hominin species were competing and coexisting in Africa for millions of years. Some are more successful than others, but all-important to the human story. It was long thought that human evolution was a linear path, that we had one species, which evolved into another, and so on until you reach the pinnacle, which would be modern-day humans. This is expressed explicitly in the “Progression of Man” illustration. However, as we are discovering over the last few decades, this is not how it was. In fact, it was quite the opposite. As we are learning, it is more likely that there were multiple species of hominins walking on two legs throughout Africa. From Australopiths to Homo, many species coexisted and could have, and in fact, did have contact with each other over the millions of years. With each new discovery, our place as unique creatures in the animal kingdom decreases. 

For one example, we have the footprints at the site of Laetoli, Tanzania, which was discovered by Mary Leakey and her team, which has some great evidence to support this view. There are millions of tracks at this site or footprints, and some of them are even hominin, without a doubt. But to whom do they belong? That is the question, one of the sets of tracks we are pretty sure belonged to A. afarensis the species that Lucy belongs to. However, another track is right near it, and laid down around the same time, are the prints of a completely different biped. These two bipedal animals could have looked at each other across these plains. It is an amazing thing to think about as described by Dr. Ellison McNutt in my interview with her, as well as her recently published a paper about the Site A prints. 

The evidence is mounting that hominins created and lived in multiple niches at once, coming in and out of the braided stream that we are learning is a better definition than even the family tree analogy. 

It is through these discoveries that the picture of our origins becomes more clear. As we see how we became bipedal to being with, we can see how other adaptations followed, which help make us who we are today. At some point along the line of our cousin, and ancestral evolution towards becoming human, our genus had to eventually set itself apart. Our genus, Homo is one that we believe directly follows the Australopiths, and it is with Homo Habilis which lived about 2.5 million years ago, that we see the first species in our genus. With a brain size larger than those of the australopiths, and more habituated bipedal anatomy, Louis Leakey and his colleagues argued that this hominin ought to be the first in our family line, and after a great deal of discussion and debate, it was finally accepted taxonomically. 

While Homo Habilis has had its place challenged many times, it remains to be the first recognized member of our genus. But it would not be the last. Not only did H.habilis possibly lived with other ancient humans, such as H. erectus towards the end of their longevity, but they also coexisted with various species of Australopiths, such as sediba, and others. From the very start of our genus, we were not alone on the plains but accompanied by many various creatures that would have looked similar to our contemporaries at the time. It truly was a Planet of the Apes, and it was only going to get more complicated, as more gaps in the fossil record are filled, we seem to find even more spots that are missing. 

One of the biggest misconceptions over the last hundred years or so about human evolution is that it was one definitive step at a time. You had this species, it led to this one and then died out. They did not coexist and were not contemporaries. It was more of a ladder up to the top, where European Victorians believed were stood. Since then, and with new technologies, the blurry image of human origins is becoming slightly more clear. We now know, beyond a doubt that multiple species of humans coexisted for almost all of hominin history, except the last 40ky or so. From fossil and dating evidence, we can trace much older fossils of our earliest progenitors to living around the same place, around the same time. Then of course there are examples of snapshots in time, which are so rare, at Laetoli where there is near indisputable evidence that there were two types of hominins walking in the same field, within hours, if not minutes of each other shortly after a volcanic eruption. 

It was only when the Neanderthals went extinct, sometime around 40,000 years ago, that we were truly the only humans left on earth. (Save a few populations that could have been modern hybrids we are still learning about, such as the Red Dear Cave People) Even just 100,000 years ago; we had H. sapiens, H. florensiensis, aka the Hobbit, H. luzonensis, Neanderthals, and Denisovans. Possibly even a third branch of the related Neanderthal clade in Asia, represented by the Harbin crania. Some populations of H. erectus may even have survived in some parts of southeast Asia. Slowly these species would die out, leaving us as the only survivors, and while there are many reasons why we can not be sure as to what led to their extinction. All of these hominins have a great deal in common, in anatomy, capabilities, and the reasons for why they went extinct. Each of them, including ourselves, is a mosaic of evolution, meaning certain parts are “more evolved” or better adapted than other parts we may have inherited from our ancestors. Derived vs. Acquired traits. So, instead of one hominin leading to another, and then going extinct, and event instead of a family tree to represent all of our cousins and ancestors, a better analogy that has been used for the last few decades, is that of a Braided Stream. 

The idea of a Braided Stream, which is growing ever more popular, shows that traits and aspects of human evolution came in and out of the fossil record and our timeline, for various reasons. As they were needed, as they were not, they were discarded. An example of mosaic evolution, we can look at H. naledi with very modern human-like aspects, this creature was still suited for climbing in the trees, thanks to their long curved fingers, but their upright posture and long arched feet show that they were great at terrestrial bipedalism as well (walking on the ground like us), these features combined are called mosaic evolution (along with many other possible combinations). 

The braided stream of human evolution has given us a much better way of explaining where, and when other hominins come into our story, how they evolved, and what traits they had. But why then, if these other hominins were so similar to us, are we the last ones left? While there is no absolute answer, to researchers it seems to be pretty clear cut. We did not drive other hominins to extinction, such as the Neanderthals, as some would like to believe, but rather we just out-competed them. We are very good at finding, and creating ecological niches, anywhere in the world to a level never seen before, which allows us to not only survive but thrive almost anywhere in the world. Other humans could not do this, and as the climate changed, and as they had to move around to maintain their lifestyles, as a species or as a small group, misfortune would soon befall them, the natural misfortune of natural selection. 

These groups simply could not compete with Modern Humans on a social, cultural, or skill level, and this led to either their extinction, leaving us, or their assimilation into our own people, such as with the Denisovans and Neanderthals. We may never know what put the final nail in the coffin for these seemingly very successful species, who had been on the Earth much longer than we have so far, to go extinct. As we get more clues, one day perhaps it will be clear. 

Well, I hope that answers some questions about whether or not a straight progression for humans, or really any species works, as we can see it does not. A much more appropriate example of how hominin evolution occurred is the Braided Stream hypothesis. Regardless, a few things have become clear in the last few years that were once doubted highly, and that is that multiple human-like creatures lived on the Earth at one time, interacted, bred with each other, and created new types of humans. All through the world, but especially within Africa, before migrating out. With evidence like that from Laetoli, Tanzania, we can actually see a moment in time, as if transported there ourselves, and can see that these footprints were laid down around the same time and that they do not belong to the same species. To me, this is fascinating, and I hope leads to many more years of research on the topic to come! 

Sources: 

1.Homo habilis | Description, Traits, Tools, & Facts

2. Just How Many Extinct Types of Human Did Our Ancestors Meet?

3.How many early human species existed on Earth?

4. A Braided Stream?

5.What is the ‘braided stream’ analogy for human evolution?

6. New Analysis of Foot Prints Found at Laetoli!