Category Archives: Evolution

Sedentary Behavior Makes Sense

Sedentary lifestyle NOT an option here

I had lots of evolution indoctrination during study for my zoology degree. It helps me understand the following.

From BioEssays:

Most people are aware of the health benefits of being physically active. The question arises then why people so easily fall into sedentary habits. The idea developed here is that sedentary behavior is part of a suite of behaviors to reduce levels of physical activity that were strongly selected in the evolutionary past, likely because high levels of physical activity had direct negative consequences for survival. However, hunter-gatherer populations could not reduce activity indefinitely because of the need to be active to hunt for, and gather food. Hence they never experienced low levels of activity that are damaging to health, and no corresponding mechanism avoiding low activity evolved. Consequently, gene variants promoting efficiency of activity and increased sedentariness were never selected against. Modern society facilitates reduced activity by providing many options to become less active and divorcing food intake from the need to be active. Choosing the less active option is hard wired in the genes; this explains why being sedentary is so common, and why reversing it is so difficult.

Source: An Evolutionary Perspective on Sedentary Behavior. – PubMed – NCBI

Steve Parker, M.D.

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Butchered Bones Found in Canada Indicate Humans Came to North America 24,000 Years Ago

Fresh off the Bering Strait from Siberia?

Fresh off the Bering Strait from Siberia?

From Ancient Origins:

“Archaeologists have found a set of butchered bones dating back 24,000 years in Bluefish Caves, Yukon, Canada, which are the oldest signs of human habitation ever discovered in North America. Until recently, it was believed that the culture that represented the continent’s first inhabitants was the Clovis culture. However, the discovery of the butchered bones challenges that theory, providing evidence that human occupation preceded the arrival of the Clovis people by as much as 10,000 years.

For decades, it has been believed that the first Americans crossed the Bering Strait from Siberia about 14,000 years ago and quickly colonized North America.”

Source: 24,000-Year-Old Butchered Bones Found in Canada Change Known History of North America | Ancient Origins

The First Humans In the Americas Arrived By Boat, Not the Bering Land Bridge

An article at ArsTechnica makes the argument:

“The standard story of how humans arrived in the Americas is that they marched 1,500km across the Bering Land Bridge, a now-vanished landmass between Siberia and Northern Canada that emerged roughly 15,000 years ago in the wake of the last ice age. But for the past decade, evidence has been piling up that humans arrived in the Americas by traveling in boats along the Pacific coast. Some 14,000-year-old campsites like Oregon’s Paisley Caves have been found near rivers that meet the Pacific, suggesting that early humans came inland from the coast along these waterways. Now, a new study published in Nature provides more solid evidence the first humans to reach the Americas could not have come via the Bering Land Bridge.”

Source: Time to scrap the idea that humans arrived in the Americas by land bridge | Ars Technica

Fire and Human Evolution

Richard Wrangham figures our hominin ancestors tamed fire and started cooking with it 1.8 million years ago. Other authorities date our mastery of fire from 12,000 to 400,000 years ago.

From the New York Times:

“When early humans discovered how to build fires, life became much easier in many regards. They huddled around fire for warmth, light and protection. They used it to cook, which afforded them more calories than eating raw foods that were hard to chew and digest. They could socialize into the night, which possibly gave rise to storytelling and other cultural traditions.

But there were downsides, too. Occasionally, the smoke burned their eyes and seared their lungs. Their food was likely coated with char, which might have increased their risk for certain cancers. With everyone congregated in one place, diseases could have been transmitted more easily.”

Source: Smoke, Fire and Human Evolution – The New York Times

John Hawks Says Humans Haven’t Stopped Evolving 

Writing at TheScientist:

“Skin color is a classic example. One of the largest and most obvious physiological differences between populations, skin color is influenced by more than two dozen genes in a pathway that produces the pigment melanin and regulates the amount of this pigment in different tissues. Changes to these genes interrupt the generation of the dark pigment eumelanin, leaving skin with larger amounts of the reddish pigment pheomelanin, leading to various skin tones and patterns of coloration, such as freckles. Despite its complex genetics, skin color shows consistent patterns of evolution across the globe. People whose ancestors lived in the tropics tend to be dark-skinned, while those who lived further north and south tend to be lighter. One of the revelations of the last 15 years is just how recent this pattern really is. According to analyses of ancient DNA, people who lived in northern Europe only 10,000 years ago would not have had the extremely light skin of today’s people in that region.”

Source: Humans Never Stopped Evolving | The Scientist Magazine®

Hawks also discusses lactase persistence, eye color, blood types, and malaria resistance.

16,700-Year-Old Tools Found in Texas Change Known History of North America

“Archaeologists in Texas have found a set of 16,700-year-old tools which are among the oldest discovered in the West. Until now, it was believed that the culture that represented the continent’s first inhabitants was the Clovis culture. However, the discovery of the ancient tools now challenges that theory, providing evidence that human occupation precedes the arrival of the Clovis people by thousands of years.”

Source: 16,700-Year-Old Tools Found in Texas Change Known History of North America | Ancient Origins

When I first read this, I thought it outdated my Paleobetic Diet book. But no. On page 33 I wrote, “Northeast Asians moved into North America (Alaska) 12 to 30,000 years ago.”

Paleobetic Diet-FrontCover_300dpi_RGB_5.5x8.5

Óscar Picazo Compiled a List of Scientific Articles on the Paleolithic Diet

Not Oscar Picazo

Not Oscar Picazo

Click the link below to see the articles, which are in English. Óscar’s introduction:

“Hace ya más de un año, compartí aquí la lista actualizada de estudios hasta la fecha, en relación a la paleodieta, dieta evolutiva, o como se le quiera llamar.El último año ha sido bastante activo en este sentido, con varios trabajos publicados, varios ensayos clínicos, y un meta-análisis.A continuación la lista actualizada. Si falta alguno, por favor indícamelo y lo incluyo.Y solo por recordarlo… mi opinión sobre el tema.”

Source: Paleodieta: Bibliografía actualizada | Óscar Picazo

Thanks, Oscar!

Almost Half of California Adults Have Prediabetes

The actual figure is 46%, according to researchers at UCLA. The LA Times has the story.

“Our genes and our environment are kind of on a collision course,” said Dr. Francine Kaufman, the former head of the American Diabetes Assn., who was not involved with the research. “It’s not stopping.”

The problem with prediabetes is that it often evolves into full-blown diabetes. It’s also associated with increased risk for cardiovascular disease such as heart attack and stroke. The Times article says “up to 70% of those with prediabetes develop diabetes in their lifetime.” I’d never heard that vague number before; I say vague because “up to 70%” could be anything between zero and 70. It’s more accurate to note that one in four people with prediabetes develops type 2 diabetes over the course of three to five years.

She has the genes of a cave woman

She has the genes of a cave woman

Prediabetes is defined as:

  1. fasting blood sugar between 100 and 125 mg/dl (5.56–6.94 mmol/l), or
  2. blood sugar level 140–199 mg/dl (7.78–11.06 mmol/l) two hours after drinking 75 grams of glucose

How To Prevent Progression of Prediabetes Into Diabetes

  • If you’re overweight or obese, lose excess fat weight. How much should you lose? Aim for at least 5% of body weight and see if that cures your prediabetes. For instance, if you weigh 200 lb (91 kg), lose 10 lb (4.5 kg).
  • If you’re sedentary, start exercising regularly.
  • Cut back on your consumption of sugar-sweetened beverages, other sugar sources, and other refined carbohydrates like wheat flour.

Steve Parker, M.D.

Paleobetic Diet-FrontCover_300dpi_RGB_5.5x8.5


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).

How Fast Are Humans Evolving?

paleo diet, Steve Parker MD,calcium, osteoporosis

I’m guessing she’s northern European, perhaps Irish

Most paleo lifestyle proponents think that, genetically speaking, those of us living today are pretty much the same as our ancestors living 50,000 or even 200,000 thousand years ago. That may not be the case.

Conventional Wisdom

The traditional view of the rate of human evolution’s is articulated by Artemis P. Simopoulos, who was with The Center for Genetics, Nutrition and Health in 2009 when he wrote: “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.”

Evolving Thought


On the other hand, the experts are debating now whether the pace of human evolution has accelerated over the last 10,000 years. The iconoclasts say it has. For example, remember that most mammals lose the ability to digest milk after they’ve been weaned off the teat in early life: they lose the lactase enzyme that allowed them to digest milk sugar (lactose). That’s why lactose intolerance is so common among adult humans—only a third of us worldwide can digest milk. Five or 10,000 years ago, a genetic mutation occurred that allowed those possessing the gene to consume and digest milk. So a whole new source of food for adults opened up: dairy cattle. Would that have conferred a survival advantage? You bet. We have evidence that the milk-digesting mutation spread fairly quickly since its appearance. But it hasn’t spread across the globe uniformly. The ability to digest milk in adulthood—called lactase persistence—is less than 40% in Greece and Turkey, but higher than 90% in the UK and Scandinavia.

Another oft-cited example of rapid and recent human evolution is the appearance and spread of blue eyes starting six to 10,000 years ago. Everyone with blue eyes today apparently has a common ancestor that had a gene mutation back then, when everybody had brown eyes.

For more information on the “rapid evolution” idea, check out the writings of Gregory Cochran, Henry Harpending, and John Hawks. Also consider a new book by Nicholas Wade, “A Troublesome Inheritance: Genes, Race, and Human History.” Wade is a science writer for the New York Times.

Steve Parker, M.D.