Tag Archives: human evolution

If You’re Interested In Human Evolution, You Need to Know About the Denisovans

So here’s a 10-minute video from Pique. Denisovans are a hominin group, some remains of whom were discovered in the 1970s in or near Russia. Modern native Tibetans share at least one gene with the Denisovans, a gene that helps them tolerate hypoxia (low tissue levels of oxygen).

White Skin in Europeans Only Took Off 6,000 Years Ago

…according to an article at Science magazine. Europeans 10,000 years ago didn’t look much like those of today.

When it comes to skin color, the team found a patchwork of evolution in different places, and three separate genes that produce light skin, telling a complex story for how European’s skin evolved to be much lighter during the past 8000 years. The modern humans who came out of Africa to originally settle Europe about 40,000 years are presumed to have had dark skin, which is advantageous in sunny latitudes. And the new data confirm that about 8500 years ago, early hunter-gatherers in Spain, Luxembourg, and Hungary also had darker skin: They lacked versions of two genes—SLC24A5 and SLC45A2—that lead to depigmentation and, therefore, pale skin in Europeans today.

But in the far north—where low light levels would favor pale skin—the team found a different picture in hunter-gatherers: Seven people from the 7700-year-old Motala archaeological site in southern Sweden had both light skin gene variants, SLC24A5 and SLC45A2. They also had a third gene, HERC2/OCA2, which causes blue eyes and may also contribute to light skin and blond hair. Thus ancient hunter-gatherers of the far north were already pale and blue-eyed, but those of central and southern Europe had darker skin.

Pale skin may be advantageous in northern latitudes because it allows production of more vitamin D.

The article also discusses European evolution of lactose tolerance and height. The ability to digest milk in adulthood apparently didn’t spread through Europe until about 4,ooo years ago.


A Brief History of Human Evolution and Migration

paleo diet, Paleolithic diet, hunter-gatherer diet

Huaorani hunter in Ecuador

Evolutionary theory holds that we humans—Homo sapiens—evolved from non-human primates (hominins) in a process that started 2.5 million years ago in Africa. Prominent ancestors include Homo habilis (2.3 million years ago) and Homo erectus (1.8 million years ago).

Homo sapiens eventually hit the scene 200,000 years ago, probably in east Africa, which is considered the cradle of humanity. (All Americans can honestly fill out forms that ask for our race as “African-American.”) The paleoanthropologists tell us we share many genetic traits with long-extinct hominins from two million years ago.

African Diaspora


The “Out of Africa” hypothesis to explain the worldwide spread of humans says that Homo sapiens arose in Africa, then began migrating out 50 or 100,000 years ago. A competing “multiregional” hypothesis involves Homo erectus dispersing to many regions throughout Africa, Europe, and Asia, then somehow interbreeding and culminating in Homo sapiens in several regions. Homo erectus may have begun to spread out of Africa as long as 1.4 million years ago. Among the experts, the Out of Africa theory is currently favored over the multiregional hypothesis.

Anyway, starting roughly 100,000 years ago, anatomically modern humans began migrating out of Africa, into the Near East. By 50,000 years ago we were into South Asia, then Australia 40 or 50,000 years ago. We spread to Europe 40,000 years ago. Northeast Asians moved into North America (Alaska) 12 to 30,000 years ago; South America followed. We have evidence of behaviorally modern humans from about 50,000 years ago, if not longer. In other words, in addition to looking like us, they acted like us. At this point, we’ve made it to every spot on Earth that can support life. Not to mention the moon.

As points of reference, the Bronze Age started 5,500 years ago in the Near East and the earliest known writing was 5,000 years ago.

I wonder if God made Adam and Eve 200,000 years ago, and Homo habilis, Homo erectus, and our other hominin “ancestors” are just extinct animals like the dodo bird and dinosaurs. Probably not.

Steve Parker, M.D.

John Hawks’ Perspective on the New Dmanisi Skull

…at his blog. A snippet:

What population structure characterized the African ancestors of the Dmanisi hominins? If we look to the MSA African model, the structure would be one of multiple populations, strongly differentiated, that had existed for hundreds of thousands of years. They may have had adaptations to local ecological conditions, but they were not isolated — they shared genes and one might occasionally replace another, only to re-differentiate as climate fluctuated. The African populations that existed at 1.8 million years ago were probably a modified subset of those that existed 2 million or 2.2 million years ago. Some of these populations would have been morphologically distinctive enough that paleontologists might call them different species. Some of the remixture between them would have been slight, on the scale of Neandertal mixture into today’s human populations. But those cases were at one end of a continuum that included larger amounts of genetic exchange and more rapid turnover. It was a braided stream, in which some of the rivulets were long, but others were short.

Read the rest and you’ll find a brief review of early human evolution.

How To Start A Fire With Two Stones

Richard Wrangham figures our hominin ancestors tamed fire and started cooking with it 1.8 million years ago.  A recent article at Slate reviews the debate among anthropologists.  Some respected authorities date our mastery of fire from 12,000 to 400,000 years ago.

Any caveman worth his salt can start a fire, right?

Visit Wildwood Survival for the two-stone technique.

Let me know if you find a video demonstrating this.

Notable Quotes From Kuipers’ “Multidisciplinary Reconstruction of Palaeolithic Nutrition”

Australian Aborigine in Swamp Darwin

I scored of copy of “A multidisciplinary reconstruction of Palaeolithic nutrition that holds promise for the prevention and treatment of diseases of civilisation” by RS Kuipers, JCA Joordens, and FAJ Muskiet. I’m not going to review it here. I’m just assembling some interesting “facts” for my files, so this could be boring. You won’t offend me much if you stop reading now.

This paper is from the University Medical Center Groningen and Human Origins Group (Faculty of Archaeology, Leiden University), both in The Netherlands. It’s 23 pages long, not counting the 450 references.

I’ll following the spelling conventions of the paper’s publisher.


“…our genome has remained basically unchanged since the beginning of the Palaeolithic era.”

“Since the onset of the Agricultural Revolution, some 10 thousand years ago, and notably in the last 200 years following the start of the Industrial Revolution, humans have markedly changed their dietary habits. Consequently, it has been advocated that the current pandemic of diseases of civilization results in part from the mismatch between the current diet and our Palaeolithic genome.”

These are some of the diseases that may result from the mismatch of our Palaeolithic genome and modern lifestyle (including diet): type 2 diabetes, high blood pressure, osteoporosis, fertility problems (polycystic ovary syndrome), pregnancy complications (pre-eclampsia, gestational diabetes), some cancers (colon, breast, prostate), heart disease (such as coronary artery disease), major and postpartum depression, autism, schizophrenia, some neurodegenerative diseases (Parkinsons disease, Alzheimer’s disease). [Sorry, Dr. Cordain – no mention of acne. And I wonder about dental and eye problems.]

Evolutionary Medicine

“Many, if not all, diseases can become explained [sic] by both proximate and ultimate explanations. The science searching for the late explanations has become known as ‘evolutionary medicine.’ Unfortunately, modern medicine deals mostly with proximate explanations, while ultimate explanations seem more prudent targets for long-time disease prevention.”

The term “evolutionary medicine” was coined by Randolph M. Nesse and George C. Williams in the early 1990s. It’s also called Darwinian medicine.

“…about 20% of modern hunter-gatherers reach at least the age of 60 years.”

After the transition to the Agricultural Revolution about 10,000 years ago, life expectancy fell from about 40 years to about 20 years. This is astounding news to me, assuming it’s accurate.  (Remember that for most of human existence, infant and child mortality has been very high. If an infant dies at 6 months old and an adult dies at 40 years, average life expectancy for the two would be about 20 years.)

Average life expectancy among modern hunter-gatherers is about 40 years—same as it was for students of the Harvard College class born in 1880.

Life expectancy in the Neolithic era was stable until the late 18th century, rarely exceeding 25 years in civilized nations.  At that point, life expectancy started to improve dramatically thanks to sanitation, water and food hygiene, immunizations, and quarantine practices. (Thomas Jefferson was the third president of the U.S.  His wife Martha had six children but only two survived to adulthood.)

The earliest species in the genus Homo appeared about  two million years ago.   Homo sapiens appeared about 200,000 years ago in south or east Africa. Several different hominin lines co-existed with modern humans.

The current world population of humans may be derived for only 1000 or so individuals that survived a decimating event.

The ability to store fat is one of the things that differentiate us from other primates.

Hunting and Our Ancient Diet

The composition of the early human diet is still hotly debated.

Lotta work to snag one of these

In modern hunter-gatherers, only about 30% of diet energy is derived from hunting, with the rest coming from gathering plant food and aquatic animals.

In contrast to the arid, hot, iconic savanna, “…the combined evidence strongly suggests that early hominins frequented the land-water ecosystem and thus lived there.” If rainfall and other conditions allowed, there would be wooded grasslands.

“…the proportion of the human gut dominated by the small intestine (>56%) suggests adaptation to a diet that is highly digestible, indicating a closer structural analogy with carnivores than to [animals that eat leaves and fruit].”

“The data of combined studies of early hominins and the more recent hominins suggest a gradual increase in dietary animal protein, a part of which may derive from aquatic resources. In the more recent human ancestors, a substantial part of the dietary protein was irrefutably derived from marine resources, and this habit was only abandoned in some cases after the introduction of agriculture at the onset of the Neolithic.”

Sea levels have risen over the past 17,000 years, up to 150 meters.

“In conclusion, there is ample archeological evidence for a shift from the consumption of plant towards animal foods.”

“For a long time period in hominin evolution, hominins derived large amounts of energy from (terrestrial and aquatic) animal fat and protein. This habit became reversed only by the onset of the Neolithic Revolution in the Middle East starting about 10,000 years ago.”

“The Homo genus has been on earth for at least 2.4 million years and for over 99% of this period has lived as hunter-gatherers.”

“We conclude that gathering plays, and most likely always played, the major role in food procurement of humans. Although hunting doubtlessly leaves the most prominent signature in the archaeological record, gathering of vegetables and the collection of animal, notably aquatic, resources (regardless of whether their collection is considered as either hunting or gathering), seems much easier compared with hunting on the hot and arid savanna. We suggest that it seems fair to consider these types of foods as an important part of the human diet, unless proven otherwise. Conversely, while hunting might have played a much more important role at higher latitudes, dietary resources in these ecosystems are rich in n-3-fatty acids (for example, fatty fish and large aquatic mammals), while the hominin invasion of these biomes occurred only after the development of more developed hunting skills.”

Even though traditional Maasai showed extensive atherosclerosis with fibrous changes and lipid infiltration, they had very few complicated arterial lesions and rarely had clinical cardiovascular disease events.

The Agricultural and Industrial Revolutions

“Contrary to earlier belief, the advent of agriculture coincided with an overall decline in nutrition and general health, but at the same time provided an evolutionary advantage since it increased birth rates and thereby promoted net population growth.”  [Both supporting references are from CS Larsen.]

Good news for birth rates

With the advent of the Industrial Revolution, nutritional quality and general health declined even more rapidly.

“Among the many dietary and lifestyle changes are: a grossly decreased n-3:n-6 fatty acid ratio, the combined high intakes of saturated fatty acids and carbohydrates, the introduction of industrially produced trans-fatty acids, reduced intakes of n-3 and n-6 long-chain polyunsaturated fatty acids, reduced exposure to sunlight, low intakes of vitamins D and K, disbalanced anti-oxidant status and high intakes of carbohydrates with high glycaemic indices and loads, such as sucrose and industrially produced high-fructose maize syrup.”  [Aren’t we eating more n-6 fatty acids, not less?]

Potential Benefits of a Palaeolithic Diet

The authors conclude with a review of the few medical scientific studies of Palaeolithic diets in modern humans. These are the ones by Frassetto, Osterdahl, Jönsson, and Lindeberg. I’ve already reviewed those here.  They missed O’Dea and Kerin’s study.

My Overall Impressions

This article seems very well researched.  It lays out a logical framework for the discipline of evolutionary medicine and should spur further clinical research.  It’s well worth a read if you have more than a passing interest in paleo lifestyle theory.

Bear in mind I’m not a paleontologist, anthropologist, paleo-anthropologist, or archeologist.  So caveat lector.

Steve Parker, M.D.  (B.S. degree in zoology)

Reference: Kuipers,RS; Joordens, JCA; and Muskiet, FAJ. A multidisciplinary reconstitution of Palaeolithic nutrition that holds promise for the prevention and treatment of diseases of civilization. Nutrition Research Reviews, 25 (2012): 96-129.  doi: 10.1017/S0954422412000017

PS: The Paleolithic diet is also called paleo, ancestral, hunter-gatherer, Stone Age,  Old Stone Age, and caveman diet.

Can A Christian Be A Paleo Advocate?

If you’re squeamish about discussions of religion and God, read no further! What follows is controversial and much of it not subject to scientific investigation.

In case you’re wondering, I’m a Christian.  This simply means I believe I was given life by God, that His son Jesus became a man and died for my sins, and that I will have everlasting life in heaven for believing on this.  I strive to live the way God would want me to live, as written in the Holy Bible.  I was brought up in the Catholic faith, even attending parochial school in grades 1-8, but I’m Protestant now.  I went through an agnostic period between the ages of 19 to about 38—I’m glad I made it through that alive!

I’ve been learning more about paleo eating over the last year since it overlaps a fair amount with low-carb eating. (Paleo-style eating is also referred to as ancestral, Old Stone Age, hunter-gatherer, or the caveman diet.) The Paleolithic Era covers about 1.5 to 2 million years of human evolution, admitting that there probably hasn’t been much genetic change over the last 50,000 years (debatable). The cornerstone of paleo eating is that we should eat the things we are evolutionarily adapted to eat. We’ll be healthier that way. We didn’t have corn chips, soda pop, and candy bars 20,000 years ago, so we shouldn’t be eating them now.

Sounds reasonable, doesn’t it? Various species of animals thrive on certain foods and not others. My horses eat three meals a day – all hay; you and I couldn’t survive on that.

I have a college degree in Zoology, so I was thoroughly indoctrinated in Charles Darwin‘s evolutionary theory, at least the version current in the mid-1970s. Darwin’s theory requires no God, or didn’t include a role for God or gods. How Darwinians answer the question of Creation, I don’t know.

Many proponents of evolutionary theory seem to be atheist or agnostic. Natural selection determines who lives or dies, not the hand of God. Some brands of Christianity, but not all, reject the idea of human evolution in its entirety. They believe God created us just as we are about 6,000 years ago. So can a Christian be a paleo diet advocate?

(I don’t know where Judaism, Islam, and other major religions stand on evolution.)

Human evolution is central to paleo diet theory. A religious person may reject the idea of human evolution; can he nevertheless participate in the modern “paleo community”?

I believe God made us and the universe. There’s no proof – it’s a matter of faith. I don’t know if He made us 6,000 years ago or two million.  The bulk of the science speaks clearly against 6,000 years ago.

Our bodies are made to thrive on certain foods and not others.  That’s true for all animals.  If you find an injured bird in your yard and hope to nurse it back to health,  you better find out what it eats naturally and provide it, or you’ll fail.  The range of foods humans can thrive on is pretty broad. Whether the optimal way of eating is determined by godless evolutionary processes or by the intelligent design of a Creator doesn’t matter so much if you’re looking at it from a purely nutritional viewpoint.

From an “everlasting life” viewpoint, it matters.  Big time.

The paleo guys might be right about the best way to eat. Science continues to accumulate evidence one way or the other.

Christianity and paleo diet theory are not mutually exclusive. A Christian can ignore the possiblity of a million years of evolution, believing instead that God made our bodies in such a way that we’d be healthier eating certain foods and not others. Those foods may be the components of the paleo diet, whatever that is.

Steve Parker, M.D.

Further reading:

Carl Drews has written extensively on Christianity and Evolution, including his essay on Theistic Evolution.

Phil Porvaznik’s article on theistic evolution and the Roman Catholic Church.

Wikipedia: Catholic Church and Evolution.

Can a Christian follow a paleo low-carb diet? at Jimmy Moore’s Livin’ La Vida Low-Carb blog.

A few questions for the atheists.  Where did the universe come from?  Was it created? By whom or what?  What if God exists, and he made us for a reason and wants us to live a certain way?

Consider this excerpt from Walter Isaacson’s book, “Einstein: His Life and Universe”:

One evening in Berlin, [Albert] Einstein and his wife were at a dinner party when a guest expressed a belief in astrology. Einstein ridiculed the notion as pure superstition. Another guest stepped in and similarly disparaged religion. Belief in God, he insisted, was likewise a superstition.

At this point the host tried to silence him by invoking the fact that even Einstein harbored religious beliefs.

“It isn’t possible!” the skeptical guest said, turning to ask Einstein if he was, in fact, religious.

“Yes, you can call it that,” Einstein replied calmly. “Try and penetrate with our limited means the secrets of nature and you will find that, behind all the discernible laws and connections, there remains something subtle, intangible and inexplicable. Veneration for this force beyond anything we can comprehend is my religion. To that extent, I am, in fact, religious.”

Natural Selection

Paleo diets (aka Stone Age, Paleolithic, or caveman diets) have been increasingly popular over the last few years.  The idea is that, for optimal health, we should be eating the things that we are evolutionarily adapted to eat.  Those foods pre-date the onset of large-scale agriculture 10-12,000 years ago.  So grains, dairy products, and industial seed oils play little or no role in someone who has “gone paleo.”

My recollection from college courses years ago is that average lifespan in paleolithic times was perhaps 25-30 years, or less.  If you’re going to die at 25, it may not matter if you eat a lot of  wooly mammath, berries, insects, cholesterol, saturated fats, Doritos, Ding Dongs, or Cheetos.  The diseases of civilization we worry about today—coronary heart disease, high blood pressure, cancer, dementia, type 2 diabetes, etc.—don’t usually appear until after age 30.  Paleolithic Man worried more about starvation, infection, and predation.

More recently, I’ve read that average lifespans of Paleolithic man were so low due to high infant and childhood mortality.  If you survived early childhood, you had a much better chance to hit 50 or better.

But now we live to be 80, long enough for diet-related diseases to appear. We have cancer, heart attacks, and strokes that paleo man rarely saw because he died of trauma or infection or starvation. We even see the expression of genes that were not subjected to survival or selection pressure: Alzheimers disease, Huntingtons chorea, and some breast cancers, for example.  People with genes for these diseases reproduce before the genes do their damage.

In other words, we carry genes that don’t matter if you die at age 30. If you live longer, they express themselves, and I believe we can modify their expression through diet and lifestyle. 

Jenny Ruhl, at her Diabetes Update blog, takes a critical look at the paleo diet concept.  I’m not saying I agree or disagree with her.  Newbies should look at all sides.  

Steve Parker, M.D. 

Extra credit

For purposes of discussion, let’s assume that human evolution actually occurred over millions, or at least hundreds of thousands, of years.  In other words, assume that God didn’t make Adam and Eve in human form in one day.

The theory of evolution proposes that genes that allow an animal to live and reproduce more vigorously in a particular environment will be passed on to the animal’s offspringNature will select those genes to spread through the animal population over time, assuming the environment doesn’t change.  The offspring with those genes will be able to compete with other animals more successfully for food, shelter, and mates.  Factors that promote the persistence and inheritance of specific genes are called “selection pressure.”

Here’s an example of selection pressure.  Remember when you were in grade school on the playground, some people could naturally run faster than others?  Were you one of the fast ones?  If you’ve never seen it for yourself, take my word for it: Some people are naturally gifted with athletic genes.

Let’s say you and I are outside collecting berries and nuts in paleolithic times.  A saber-toothed tiger spots us and charges, hungry for a meal.  You don’t have to outrun the tiger: you just have to outrun me.  I’m slower than you, and get eaten.  I can no longer pass on my slow-running genes to the next generation.  You live another day and pass on your fast-running genes to your children. 

Viola!  Natural selection, via selection pressure, has promoted your genes over mine.

The tiger also passes on her genes since she was fast and smart enough to catch me, preventing starvation of her and her offspring.

[I’m 99% sure I wrote the preceeding few paragraphs originally a couple years ago.  My notes, however, hint that they may have been written by Dr. J., a regular contributor at CalorieLab.  Dr. J., let me know if I’ve plagiarized you and I’ll give you full credit and delete my writing.]

Free Online Paleoanthropology “Textbook”: John Hawks Blog

I’ve never seriously studied anthropology, paleontology, or paleoanthropology.  When I read someone who seems or claims to be an expert on paleoanthropology or certain aspects of evolution, it requires a degree of trust on my part. 

(I have a stronger background in evolution, thanks to a B.S. degree in Zoology.  I was thoroughly indoctrinated in the mid-1970s.)

It was a slow day at work, so I just spent a couple hours perusing the blog of an actual paleoanthropologist named John Hawks.  It’s a massive database that may be the equivalent of a paleoanthropology textbook.  Naturally, it will reflect the biases of the author, if any (and we all have some, don’t we?) . 

Some interesting things you’ll find there:

Regarding the pace of human evolution in the Neolithic period, Artemis P. Simopoulos (with The Center for Genetics, Nutrition and Health in 2009) has a different view:

The spontaneous mutation rate for nuclear DNA is estimated at 0.5% per million years.  Therefore, over the past 10,000 years there has been time for very little change in our genes, perhaps 0.005%.  In fact, our genes today are very similar to the genes of our ancestors during the Paleolithic period 40,000 years ago, at which time our genetic profile was established.

I dunno; you decide.

Steve Parker, M.D.

Reference:  Simopoulos, Artemis P.  Evolutionary aspects of the dietary omega-6:omega-3 fatty acid ratio: medical implications.  World Review of Nutrition and Dietetics, 100 (2009): 1-21. Epub August 17, 2009.

Old Stone Age Diet Depended On Latitude

There isn’t any single Stone Age diet, according to J.A.J. Gowlett, who (whom?) I assume is an archeologist with the University of Liverpool.

(I was tempted to write “there isn’t a monolithic Stone Age diet.”  Get it?  “Lith” is Greek or Latin for “stone.”)

This is probably old new for you guys who have been interested in the paleo diet for much longer than I.

Here are a few more of Gowlett’s ideas:

  • The Stone Age is is more accurately referred to as the Old Stone Age.
  • Hominids (the family of human ancestors) branched off from ape ancestors around eight to 10 million years ago.
  • Roots and tubers have been a part of our ancestral diet for perhaps as long as three million years,  which “places starchy carbohydrate consumption as part of the deep ancestry of human beings.”
  • Meat eating assumed greater importance about two million years ago.
  • Migration to colder environments necessitated more meat consumption because plant foods were more limited.
  • Our ancestors migrated from tropical to temperate latitudes about by 1.7 million years ago.
  • Early humans began using fire for cooking between 500,000 to 1.5 million years ago.
  • Neanderthals were heavily carnivorous.
  • “Ancestors of modern humans are now believed to have evolved in the tropics, probably in Africa, from about 200,000 years ago.”  Their diet was perhaps 70% plant-based.
  • “In contrast, modern humans entering Europe 40,000 years ago would have adopted a meat-based diet by necessity, and maintained this over hundreds of generations.”
  • “Modern hunters and gatherers echo the variety of past diets, ranging from largely plant based in the tropics, to being also heavily meat based in the arctic.”
  • No ancient human population depended heavily on cereals or non-human milk.  “Fruit certainly came first of all….”

Potential Implications For a Paleo Diabetic Diet (highly speculative)

Diabetics with tropical lineage may do better with a plant-based diet.  Those with northern European ancestry may do better with meat-based.

Paleo diets likely had very high fiber contents, reflecting the degree to which they were plant-based.  We’re looking at 70+ grams of fiber daily.  That much fiber would tend to reduce the effect of carbohydrate on blood sugar levels.

Fruits and roots have a high concentration of carbohydrate, with potential adverse effects on blood sugar (raising it, of course).  Diabetics eating paleo-style may need to avoid or limit certain fruits and roots: the ones with lower fiber content and higher glycemic index.  Blood sugar responses will vary from one diabetic to another.  Monitor blood sugar levels one or two hours after carb consumption to learn your idiosyncratic response.

Steve Parker, M.D.

Reference: Gowlett, J.A.J.  What actually was the Stone Age diet?  Journal of Nutritional and Environmental Medicine, 13 (2003): 143-147.