From Where We Came: A Physicist's Perspective on Human Origin, Adaptation, Proliferation, and Development

By Chris Young Kelly

Did you know that a significant percentage of us are part Neanderthal in our genetic makeup?

So, were they as smart as we are? Why and how are we different? Could we talk to them? Or more interestingly, did we? What do these questions have to do with "from where we came?”

A comprehensive overview of how we came to be.

If you're searching for answers and tired of information overload from the media, you are not alone. Fortunately, despite all the noise, evolution boils down to a few physics and math principles. A significant part of the basic process by which we evolved from molecules can be summed up with math similar to the process of boarding a city bus.
Through pop culture references, personal experiences, humor, graphics, and common sense, let's explore this topic through one physicist's eyes, wrapped in plain English. We will dive through evolution at the molecular and human levels connected by cause and effect.
Follow along as we explore how humans have survived and even prospered, against all odds, through millions of years. It should become apparent that we are all alike in every way, except for minute differences in our genes. We cannot help but be motivated to find ways to better ourselves as a species. We are all blood brothers and sisters, all 7.8 billion of us, after all.

• Language: English
• Publisher: Publishdrive
• Release date: Apr 18, 2021
• ISBN: 9798737195656

Book preview

AUTHOR

1

SOLVING HUMANS’ OLDEST MYSTERY

Where did we come from? This simple question has confounded human beings for ages. It is reasonable to assume that someone might have raised this question as soon as we started to have communicable language and cognitive ability eons ago. The recent discovery of a fossil piece showing similar voicing capability as ours may date verbal communication to 500,000 years ago. Likely, it was not language as we know it today. Modern chimpanzees show a hint of the thinking process (i.e., cognition, implying that humans could think very early on). Without any hard evidence as to the origins of our language and intelligence, we might never know when or how this question was first asked.

It is commonly believed that we ask this question out of natural curiosity, which has been around since early in our existence. Humans have always been curious by nature indeed since the early days. Early humans were curious about practical matters, mostly things about which they had immediate concerns. For example, they might have been curious why some nuts (bitter almonds, for example) might cause breathing difficulties upon ingestion, why some plants had the ability to stop the bleeding from open wounds (e.g., yarrow), or why fire could not arise from damp wood. Such a non-tangible question of our origins could only be entertained when they did not have to worry about their livelihood and had tons of time on their hands.

Why might that question even be contemplated and in need of answers? Some believe there was a need to know all along.

WHO NEEDS TO KNOW?

Early humans' basic social units might have consisted of immediate families, close relatives, and friends during hunter-and-gatherer times. We do not have written records as to how these human clans were organized, but it would be reasonable to assume that our social structures were similar to those of our closest relatives: advanced primates. Evolution psychologists suggest that typical social group sizes were a few dozen—around 30 individuals—in those days, similar to modern-day chimps in their natural habitat. It could be as many as 150 in some rarer cases, but larger groups tend to disintegrate into smaller cliques unless rules and regulations are established and observed throughout.

Just try to imagine that we are members of such a social group during our early tribal days for the time being. To keep the units cohesive and survive, we encourage and foster innate empathy, compassion, and altruism. Similar to what we observe in modern-day primates, these emotions are reflected in how we take care of each other. Not all is well all the time, though. There are always occasional scuffles, vying for resources. The conflicts are usually reconciled between engaging parties by some material offering, a friendly jab on the chin, some backslapping, or guffawing at each other. Lives are, in general, peaceful, because we know each other intimately in these small groups, and the subsistence is quite serene and satisfying on most days.

But our lives are more complicated since there are unavoidable yet necessary interactions with other groups that stir commotions in the middle of the doldrums. According to a recent study, this type of social networking among early human groups is the main driving force of our complex civilization. What was the interaction between groups? In our xenophobic nature, the first instinct is to put up a defense to try to find out from where the other group had come through some forms of communication. During this probing dance, one of the first questions asked would most likely have been Where are you from? much like any partygoers striking up a conversation in modern days. Only when the interacting groups are deemed nonthreatening to each other would we start sharing food and stories, trading surpluses for shortages, and establishing alliances for common causes like hunting or fighting disasters.

Reaching out to other groups is, at times, intentional. In some cases, this is a means to look for mating opportunities outside of one's own unit. Whatever the motivation might be, the urge to know about us is part survival and part reproductive. A desire from this instinctual perspective should be enough motivation to care about from where we—or others—have come.

ANSWERS THROUGH THE AGES

These practical inquiries would have been reciprocated by the groups involved to keep the interaction going. Having done so numerous times, the groups must have had a few canned answers. These group-specific answers would have been left up to the smartest—the shamans or the sorcerers—to formulate. Shamans can cure simple problems like wounds or sicknesses and are the most-trusted person in the group. They can also imagine and abstract mundane daily activities into stories well-received by the members. Shamans are practically in every aspect of our lives—why not create a narrative to answer the question of from where we have come?

One of the most critical tasks for the shaman is to keep the social group or tribe together through myths. These stories are woven together to be mysterious and fantastic.

MYTHICAL ANSWERS

Most myths try to convince us that we are the creation of some mighty divine deity. We believe that we are unique, strong, powerful, fertile, smart, and excellent at getting resources for living. In other words, our origin makes us worthy as a group, belonging to each other as friends or formidable enemies to foreign groups. There are real benefits bestowed upon those who believe in the myths. Communicated properly, these beliefs would have undoubtedly improved the chances of being granted a bride/groom's hand, bartering for resources, or establishing alliances.

The shamans, as smart as they were, no doubt knew that the question of from where we have come had no real credible answers because they did not know themselves. It was best if members of the group just believed the myths to be the truth. Until the modern era, that is.

From the beginning of time as recent as mid-nineteenth century, mythical answers have dominated humans' imaginations. The myths do not have to be real or right—they just have to be convincing, so people are not bothered with lives’ uncertainty hanging over their heads. A belief in something larger than life seems to be a human necessity.

Myths of from where we have come abound and vary, attesting to the imagination of sorcerers and the wise ones. There is a legend from the Boshongo people of Central Africa that claims they all came from Bumba, the great creator, who vomited out the universe and everything in it, including humans, as its last act of creation. Pachamama is a goddess revered by the Indigenous people of the Andes, according to Wikipedia. A Quechuan native in Peru told me the native’s version during my trip there two years ago. Pachamama is the great-grandmother of everyone, as she was created from Mother Earth (i.e., the mud). In a 4,600-year-old myth of Fuxi and Nüwa, they are humans' first ancestors—the Adam and Eve of China. An alternative version about Nüwa says that she was all alone and created humans as her companions by molding them from the mud. Discovering that humans die eventually, she made humans with sexes—women and men—and dictated that they mate with each other so their offspring would be her companions forever. Of course, there is Adam and Eve in Genesis in the Christian Bible.

THE FOSSIL STORIES

Most of these myths fell apart when the concept of evolution permeated through our civilization, removing the mystical aspect of our stories around the mid-1800s. The early evolutionists recognized the evolutionary nature of all biological organisms except human for fear of religious repercussion. When an abundance of proto-human fossils was continuously discovered in the early 20th century, we finally accepted that human beings were a part of evolution. It became clear that we were from something between apes and ourselves, or even apes. However, there have been continuing religious myths about our origins, which might be around for a long time to come.

Many fossil-based evolutionary theories have persisted for at least 100 years, since the mid-1800s. These years have seen various versions constantly revised and overturned. The turmoil was mainly due to the ambiguous interpretation of fossils because comparative anatomy cannot be precise and uncertain based on the fragmented and rare fossils. In some cases, the theories were as vague as a fossil's interpretation itself. In other instances, they were promoted with ulterior motives, profiting one party or the other through creative interpretation. There were also hoaxes, mistakes, and prejudices, all of which contributed to various roadblocks of learning about ourselves.

By around the 1940s to 1960s, significant advances had been made by the Leakey family along with many contemporary anthropologists. They were the main contributors to our generally accepted family trees and evolutionary theories leading up to the 1980s. There was not a single theory that could reconcile the inconsistencies among contemporary theories. At the same time, theories were frequently updated or even subverted whenever there were important fossils discovered during those times. There has been no compelling argument to unify all of the evidence and theories under one roof, and advances, where knowledge about ourselves is concerned, has simply stagnated.

THE DNA ANSWERS

The advent of genetic biology around the mid-1960s changed all that. The progression toward a gene-based understanding happened gradually but assuredly, mostly because of the advances of DNA. The professionals and scientists making that possible came from various scientific disciplines and injected fresh ideas into our evolutionary story. This merge of the general genetic science culminated in the late 1980s, when one of the groups declared a provocative modern-human story. They summarized it as the following: All the living human beings today are descendants of a few ancestors who lived 200,000 years ago in sub-Saharan Africa. As significant as this one-line summary settling a vital part of our origin, it only deals with the common ancestors of today's living human beings. It still left the origin of our common ancestors' predecessors shrouded in genetic mystery.

In addition to the landmark conclusion about modern humans, this work's approach to human evolution laid the foundation for modern-day molecular anthropology. Its power helps fill-in many details about us, leveraging the advances of science and technology infrastructures. It even allowed us to peek into the genetic constructs of Neanderthals, an extinct close relative of ours, who disappeared from existence about 40,000 years ago. It is also possible to go further back in time to check on older ancestors. Given time, we may improve, support, or disprove these purely fossil-based evolution theories.

As of the beginning of 2020, molecular and fossil anthropology together has helped us understand ourselves quite well. We are reasonably confident that we have, by and large, answered the Where do we come from? question. To me, what is missing is more fundamental than what happened. It is the question of what the driving force behind evolution that eventually gives rise to the evolutionary actives and outcomes.

MOTIVATION OF THE PURSUIT?

As a physicist, I believe there are two indispensable qualities for anything fundamental—it should be simple and all-inclusive or universal. Isaac Newton's theory of gravity is simple: everything is attracted to everything else through a single gravitational force governed by one formulation. This theory cannot be more straightforward, and its validity has tested true for centuries. The gravity formulation controls every motion, from celestial bodies to the drop of a pencil on earth. In addition, the theory of gravity is also logical in that the theory is the cause of the observed motion, the effect. I believe that there is a similar cause and effect (i.e., causality) principle behind biological evolution with simplicity and universality.

That concise summary line of All the living human beings today are descendants of a few ancestors who lived 200,000 years ago in sub-Saharan Africa is the culmination of more than 100 years of academic pursuit. As far as I can tell, it has both the simplicity and the universality quality. After studying human evolution for a few years, the principles of evolution are becoming clear to me. Yes, there is a driving force behind evolution, and it is both simple and universal with a causal logic. The cause is the principles governing the interplay among the naturally occurred materials and forces. The effects are the resulting evolutionary activities, organisms, and phenomena. This realization will be explored in detail for the first time from a physicist's point of view and will be an ongoing theme throughout this book.

GENESIS OF THE BOOK

Other than high school biology, I did not know much about evolution, not to mention that of humans’ evolution. Before 2014, I was a complete evolution novice except for knowing superficial tidbits. It took me about four years to finally become conversant on the subject; yet I know I am still an amateur at best. Writing this book is the closure I need to retain my knowledge and learning so I may retrieve them in the future.

LIFELONG CURIOSITY

The journey from my curiosity to writing this book takes up more than half of my life. I have always been curious about mysterious things. Once in the fifth grade, I dismantled my dad's watch into many tiny pieces just to see how it worked, and I needed to put it back together in a rush before Dad came home. As hard as I tried, there were always one or two pieces left on the table. Of course, that watch never ran again. I was so perplexed by the shadows of rings when we had an annular solar eclipse in the early 1960s (I can find out the exact year if I try harder) that I pestered my dad (he was a smart guy) for answers to no end. We raised chickens on our small farm, and I would spend hours watching intently in amazement as eggs hatched and turned into chicks. Like a lot of the kids in those days, I was also obsessed with everything dinosaur.

My interest in many subjects without focus did not last. I could not entertain every curiosity coming my way when each of the extracurricular excursions would have taken up a lot of time. Besides, there were other distractions, like movies, sports, camping, parties, trips, and yes, girls. I had to decide that on which to focus, and physics was it.

While becoming a physicist, engineer, husband, and father, the puzzlement about from where humans have come never faded. I would pay attention to anything about humans whenever public interest spiked with sporadic discoveries. The most exciting article, one that impressed me with a simple statement about modern humans, was in Newsweek in 1988. By then, I was raising a family, working a job, and paying hefty monthly mortgage payments—I had to see that American Dream through first, and the interest in evolution was put on the back burner.

GETTING TO THE BOTTOM

I finally started to dig into human evolution when I wrapped up my career, became free of my mortgage obligation, and was moored in an empty nest. I had been an engineering manager for most of my career, and by definition, a taskmaster. A taskmaster is a person who is not known for his congeniality but who is goal-oriented and gets things done. Reaching the intended goals as directly and quickly as possible has driven all of my undertakings. I believe that getting to the bottom of this human evolution story should be no different.

Putting the human story's final target into laser focus, I set a rough time for completion: three years. I also had a somewhat lofty goal of putting my arms around the whole human evolution story from a fundamental perspective. I had no illusion that I would master all the needed background, including subjects that are career-makers: anthropology, human anatomy, geology, anatomy, fossil dating techniques, biology, molecular genetics, statistics, and evolutionary psychology, to name a few. Instead, I planned to zoom in on the core principles of evolution and how they relate to their outcome, believing there is a hidden order of cause and effect with simplicity and universality.

To achieve this modest goal, I planned to search, identify, and construct a framework that (1) identified a most fundamental driving force, and (2) manifested itself in the resulting evolutionary activities and outcomes. The intent was to find the equivalent fundamentals, like a theory of gravity as the evolution guidelines, while at the same time, putting all the evolutionary activities in their proper positions in the framework. I believe that I succeeded in constructing the framework, as well as the knowledge base therein, in about four years.

MEMORIALIZING THE PURSUIT

Once I started to dive into the subject, it was like a flood gate had suddenly opened and overwhelmed by the information influx. I had decided, early on, to take copious notes and organize them in a logical manner whenever possible. After a couple of years, I was surprised at the massive amount of notes and scratch papers I had collected. They included course notes in biological anthropology, archaeology, prehistory, and even philosophy. The records also included doodles of my thoughts on journal articles, popular science magazines, and news clips. It never occurred to me what I would do with the notes I gathered and created.

Looking back over the past few years, it was mostly fun, even exhilarating at times, but also frustrating when things just did not fit together. It was, above all, most satisfying and definitely worth the intellectual exercise and effort. At the end of the four years, I was confident that the framework was in good shape, though I continued to add more details whenever I found anything worthwhile. It seemed that 2019 would be a logical breakpoint at which to reflect on my experiences. I thought that the best closure would be to organize everything—the notes, my thoughts, and my take on the principle of evolution—into a self-contained book.

The book started to take shape in early 2020. I had no particular audience in mind except to make it intelligible and well-organized. I realized that I had slowly and firmly developed a physicist's view of evolution that is unlike any other. To me, this perspective had subconsciously acted as a color filter, casting a unique hue on almost every thorny subject. In particular, I had crystalized a basic evolutionary framework casting the principle as the cause and treating all evolutionary outcomes as the effects. Encouraged by this realization, I decided to re-edit what I had written into a book with this fresh perspective as the book’s central theme.

When I decided to share my take on human evolution, I also considered another option. I thought of getting involved with a reputable research institute, focusing on one or two specific molecular anthropology topics. What could be more satisfying than being a participant of and contributor to human story, rather than being a bystander? I even had the topic picked out if I had the chance to propose it to them. One thing at a time, though. I will entertain myself with putting the book together for now.

As I edited the book, I noticed that I simply could not be anything but a physicist. My physics instinct tends to seep into everything that has a connection to physics or math, as you will see through the book. I believe that will be another difference between my book and other anthropology books.

BOOK OBJECTIVES

The original manuscript was simply a lengthy memorandum for myself to record the knowledge and the vision of human evolution without specific objectives. When I decided I would turn that into something more, I could not help but think about its objectives, and I homed in on two very pedestrian ones.

The first is to memorialize what I had learned with a physicist’s perspective. In the end, I would like the readers to come away with needing the least possible effort to be able to answer, Where did we come from?. At the same time, I believe my constant search look for the simplest explanation in the complex evolutionary processes should help us better understand our origin.

The second objective did not materialize until I was about halfway through the book. I noticed that I kept referring to the genetic closeness among every living soul irrespective of our apparent differences. I started to emphasize that view and made sure that I touch on the kinship and closeness amongst us whenever appropriate. I would feel the objective accomplished if we become more appreciative of that brotherhood feeling and keep that in mind whenever we make decisions affecting our fellow human beings. Eventually, the hope is to awaken our innate empathetic selves to steer us toward a better human species.

OVERVIEW

There are many books on human origin written by renown anthropologists, archaeologists, scientists, and popular science writers. I have always been anxious in reading about what is behind the big question of where did we come from?. I use that question as the title. The subtitle of a physicist perspective on what is behind the human origin, adaptation, proliferation, and development highlights that the human evolution is treated through the eyes of one trained experimental physicist.

My journey from a complete novice to being some-what familiar with the subject has been circuitous and exciting. I would like to share that experience with those interested in the topic but are too busy to chase after every nitty-gritty of human evolution.

The majority of my effort has focused on sorting out a fundamental evolutionary principle or the inner workings of evolution. The third chapter will cast the evolution in the framework of physics, engineering, and mathematics, although not in an overly sophisticated way. This framework will give you a perspective that will be the underlying theme for every key subject in this book.

It is essential to clarify who we are in the grand scheme of things first. Once that is out of the way, it makes the family tree a lot easier to construct, knowing how we are related to other humans. The next part, then, outlines the human family tree in a straightforward and modern-human-centric way, so we have a useful reference for subsequent reading.

I had planned to edit this book to be as non-technical as possible, but as the saying goes, you can't make an omelet without breaking a few eggs. We have to introduce a few fundamental scientific principles and impressive sounding but essential technical terms to fully appreciate our exciting story. This will happen in only two of the fifteen chapters. There may also be a few necessary technical terms sprinkled in spots where needed. This deep dive will make the rest of the reading a lot more enjoyable.

We are over the hump after breaking a few eggs and toughing it out. We can now dive into our molecular constituents and what they mean with considerable ease. Next, we will genetically relate ourselves with some of our extinct ancestors using the languages that we are familiar with. We will also review the hot subject that modern man and Neanderthals, or other ancient humans, have overlapped in space and time, resulting in very close contact. This rendezvous has left forensic clues in our DNA and the undeniable liaison between us.

One of the most intriguing puzzles gnawing at me is how we first became the species that eventually led to modern humans. We approach this from the contemporary version of principles introduced in the technical ordeal in chapter 9. It is amazing how complicated the process is and how long it took for us to completely split from the chimpanzees about 7,000,000 years ago. It is equally amazing that modern molecular anthropology is able to unravel, at least on the conceptual level, what happened millions of years ago.

Next, we will discuss what makes us humans demonstrably different from other species and what makes every one of us different from each other. The commonality we share is the differentiating factor between us and the chimps. The varieties among human beings are what give us the diversity that vastly enriches all aspects of our lives. However, we also have a tendency to homogenize this into a more unique and uniform species quite quickly.

We follow up with stories of how well-traveled we had been over the last two million years, and we talk about the two sides of the travel: where we have been and how and when we got there. We use both genetic and fossil clues to trace out migration maps for when, and where we travel and settle eventually.

The book closes with my optimistic observations that we humans are capable of treating each other well through our intrinsic empathetic nature. I hope to remind us of our natural benevolence and, in a small way, propose means to make us a better species. Finally, we should wholeheartedly celebrate that we have been a successful species and our ability to steer toward a better one.

BIBLIOGRAPHY

For typical primate social group sizes, see, for example, Dunbar, R. I. M. (1992). Neocortex size as a constraint on group size in primates. Journal of Human Evolution,22 (6): 469–493. doi:10.1016/0047-2484(92)90081-J.

Emile Zuckerkandl (July 4, 1922 – November 9, 2013) was an Austrian-born French biologist considered one of the founders of the field of molecular evolution. He is best known for introducing, with Linus Pauling, the concept of the molecular clock, which enabled the neutral theory of molecular evolution. This theory is somewhat controversial and has not gained wide recognition.

The Search for Adam and Eve, Newsweek, 111, 46-52 (1988).

Front cover background uses the following cave paintings: SantaCruz-CuevaManos-P2210651b, Color Change by ChrisKelly, https://creativecommons.org/licenses/by-sa/3.0/legalcode, Lions painting, Chauvet Cave (museum replica), Color Tweaking by John Young Kelly, https://creativecommons.org/publicdomain/zero/1.0/legalcode, Prehistoric Rock Paintings at Manda Guéli Cave in the Ennedi Mountains - northeastern Chad 2015, Color background by Chris Young Kelly, https://creativecommons.org/licenses/by/2.0/legalcode, Bradshaw rock paintings, Color change by Chris Young Kelly, https://creativecommons.org/licenses/by-sa/2.0/legalcode

2

WHERE DID WE COME FROM? ANSWERED

The last 150 years have seen Where did we come from? mostly answered through the efforts of archaeologists, anatomists, anthropologists, biologists, geneticists, mathematicians, statisticians, scientists, and even artists. We have a good answer for living human beings: we are all descendants of a few ancestors who lived 200,000 years ago in sub-Saharan Africa. This statement tells us three facts about modern humans, all 7.8 billion of us. We are a very closely-knit family that shares a few, most recent common ancestors (MRCA). We have identified our original homeland in Africa. Finally, we have determined our family's age, which is the age of the MRCA, or the time to the most recent common ancestors (TMRCA).

Of course, there are more details if we zoom in closer. We are closely-knit through genetic similarities, but we may appear very different. Out of the 25,000 genes in human DNA, only less than 150 are different between us. The permutations of these 150 genes number in the trillions, guaranteeing that every one of us is distinctively, albeit minute, different from one another. If we had a family photo of all 7.8 billion of us together, we would not find two identical people; even identical twins are not truly identical.

We might have a problem if the question concerns our home addresses 200,000 years ago. We cannot answer this for the same reason that we cannot pin down where our grandfathers lived unless we know that they did not move at all. Unless we have a detailed genealogy, we would also not know our grandfathers' ages. For now, this short summary of modern humans will have to do.

We also have some reasonable answers if we zoom out a little to include more than modern humans in our family. We can tell, with less certainty though, who our MRCAs were and the age of their expanded family. It may include modern humans and our nearest but extinct relatives, like the Neanderthals, for example. This line of continuous questioning is what this book is about until we run out of questions. We can continue to zoom out to include humans a lot older than Neanderthals. If we start from when we split from chimps, our family has had at least 30 ancient relatives. In that case, our MRCAs are the common ancestors of early humans and early chimps, around 7,000,000 years ago.

As far as the most expanded human family goes, we are still very close to one another that we differ by less than three percent genetically. This is the upper bound of genetic difference because we know that we differ from our closest non-human relatives—chimpanzees—by this much.

You could say that we know quite a bit about ourselves. Starting from the beginning, we split our way from the chimps about 7,000,000 years ago. We have constructed a family tree from then to modern times, including all extinct family members.

HOW DID WE KNOW THE ANSWERS?

Our more concerted quest for the answers started around the 1850s. We have experienced two periods characteristic of academic approaches since then. For the first 100 years, traditional paleoanthropologists weaved together our family trees based on human fossils. This was the fossil study age when before we knew anything about DNA. The 60 years after the 1960s can be considered the molecular anthropology age, when the molecular genetics combined with traditional anthropology. We have since drastically enriched our evolutionary stories and continue to resolve more subtle and complex human histories.

These two periods focus on two different aspects of evolution. The fossil-study age gave us a macroscopic broad-stroke of our ancestral lineage, starting from 7,000,000 years ago, while the molecular anthropology age expands beyond the physical evolution and provide microscopic genetics on the DNA level. The latter also has been successful in unraveling the stories of our extended family story as far back as a few million years.

THE FOSSIL STUDY: CONFIRMING HUMAN EVOLUTION

Human curiosity in this period has been primarily stoked by the discovery and interpretation of human fossils. Since we first discovered Neanderthal fossils in the mid-1800s, we have accumulated thousands of fossil pieces, representing the remains of 6,000 early human individuals. Through the fossils, we now understand things like how and when early humans adapted to walk upright, live in hot and cold habitats, and the speed at which the children of early humans grew. Most importantly, we found out we are a branch of a large and diverse family tree. Fossil discoveries show that the human family tree has many branches and deeper roots than we knew about even a couple of decades ago. The number of branches on our evolutionary tree has nearly doubled since the discovery of the famed Lucy fossil skeleton in 1974.

While the existence of a more massive human evolutionary family tree is not in doubt, researchers continued to debate its size and shape because fossil records only offer a fragmented look at our ancient past and the number of branches. The debates concern the precise evolutionary relationships, essentially who is related to whom, when, and how. What we know about our ancestral line is dependent on what fossils reveal to us. There has even been some debate concerning evolutionary theories based on different interpretations of the same fossils. We keep repeating the claims that we have settled the arguments to the most plausible theory by its proponents until the next significant fossil discovery subverting the status quo.

TRANSITIONING TO MOLECULAR ANTHROPOLOGY STUDY

The discovery of DNA and its implications for biological traits in the 1960s led to significant advances in molecular biology and genetics and changed our reliance on fossils. Around the 1970s, a few visionaries saw that molecular genetics and anthropology were closely related. The groundswell of DNA knowledge and genetic studies culminated in a pioneering work, concluding in our origins with that single line summary: All the living human beings today are descendants of a few ancestors who lived 200,000 years ago in sub-Saharan Africa.

The group of scientists responsible for this revelation was working at UC Berkeley, consisting of Rebecca L. Cann, Mark Stoneking, and Allan Wilson, in the mid-1980s (referred to as Cann et al. from this point on). Their breakthrough was not just in their conclusions, their adoption of rigorous scientific methodology to anthropology practically ushered in the molecular anthropology age. Their publication, entitled Mitochondrial DNA and Human Evolution, helped coin the moniker Mitochondria Eve, commonly referred to as the ancestral mother by the general public these days.

The full transition from the time of fossil-study to molecular anthropology was not by any means smooth. Triggered by Cann et al.'s claim, the immediate reactions were reflective of the state of affairs around the mid-1980s. Quite a few debates continued for a while, highlighting how hard it was to alter deeply entrenched misconceptions, such as the earth being flat.

There were four significant debates in the aftermath of the publication that have expended our intellectual effort. The first is a clash between old and new academic groups. The other three argued about the age of modern humans, the lineage of modern humans, and finally, the location where modern humans' MRCA lived.

The Old Guards Versus The New

The first debate—or more appropriately, feud—was a clash between the new camps and the old: the traditional paleontologists and anthropologists and a new breed of molecular biologists and geneticists. The debate started in the mid-60s and was both academic and personal through at least the mid-90s.

As for the personal feud, the older camp held an incredulous attitude toward the new one. The traditional paleontologist and anthropologist camp worked tirelessly to establish the ages and locations of our ancestors and gave us a great start on our family tree. Then came the new breed of scientists who never had to spend a single day in hot, arid, ancient lands to sift through tons