The Human Gut as a Microbiome

As someone with an interest in humans and ecosystems, I was fascinated to read today’s New York Times Magazine article “Some of My Best Friends Are Germs,” in which author Michael Pollan describes how humans are ecosystems. When we account for the approximately 100 trillion diverse microbes (about one to two pounds worth!) that flourish in and on our bodies, he suggests that people might be better described as superorganisms, and our innards as “microbiomes.”

It’s a little strange to imagine that up to two pounds of my body weight is not “me” at all, but a collection of separate life forms. According to research cited by Pollan, most of these microbes are harmless, some are beneficial in a variety of ways, and very few are potentially harmful. He relates the presence or absence of specific microorganisms to a range of health issues, from allergies and obesity to inflammation and malnutrition. Most relevant to anthropology, Pollan compares Western behavior (our ongoing “war on bacteria”) and diet (heavily processed foods) to alternatives in other cultures:

“…scientists can’t even yet say with confidence exactly what a ‘healthy’ microbiome should look like. But some broad, intriguing patterns are emerging. More diversity is probably better than less, because a diverse ecosystem is generally more resilient — and diversity in the Western gut is significantly lower than in other, less-industrialized populations”

Again, we have much to learn from cross-cultural comparison, even at the microscopic level of our internal ecosystems.

Hey, look at this post!

Did the title draw your attention to the words I’m writing now? Maybe, maybe not. It would be much easier if we were talking in person because then I could use all sorts of facial expressions, gestures, and subtle changes in tone to convey my meaning (See how the smiley emoticon changes the “tone” of the words that precede it?)

Hand gestures and other types of nonverbal cues are a huge part of human communication. If I had to choose humanity’s most significant digit, I would choose our magnificent opposable thumbs. These, combined with our even more magnificent brains, have allowed us to manipulate our environment and transform the world around us. So I like to exclaim that “thumbs make us human!” or “brains make us human!” or “culture/language makes us human!” Undoubtedly, these things set us apart from other species, but recent research by scholars at the Max Planck Institute for Evolutionary Anthropology argue that pointing with the index finger also makes us human. Our opposable thumbs are only “opposable” when working in conjunction with the underrated index finger – so show this finger some respect!

Slate.com has a nice summary article about the significance of pointing among developing infants. One highlight:

“A group of psychologists there [Max Planck] have documented that infants, beginning at around 1 year of age, point and react to other people pointing in remarkably sophisticated ways. Babies point to refer to events in the past and the future. They point to refer to things that are no longer there [JF: referred to as displacement in linguistic studies]. They can figure out, when an adult points across the room toward a group of objects, what exactly the adult is gesturing toward (the toy they’ve previously played with, say). They can deduce that, by pointing, an adult is trying to communicate something specific (find that toy hidden in that bucket). And not least of all, babies point because they want to share their experience of the world—that puppy—with someone else. These may just be the talents out of which humans managed to assemble minor things like culture and language.”

Check out Nicholas Day’s “How Pointing Makes Babies Human” to learn more. Enjoy!

Is The Paleo Diet “Paleofantasy”?

You might have noticed that I really like to ask rhetorical questions…and then answer them! But the title of this post is a genuine question. I honestly don’t know enough about the so-called “Paleo Diet” to comment on it, though I do tend to be wary of all things “trendy” – especially when anthropological knowledge is used to support/justify them.

The facts are: for the vast majority of our history and prehistory (prior to about 10,ooo years ago), humans didn’t rely on domesticated plants and animals as staple foods because we hadn’t created them yet.

Some have argued that a Paleo Diet (presumably one that tries to approximate a pre-Agricultural Revolution diet?) would be healthier for us. Sorry to be so vague, but I have not yet read The Paleo Diet Revised: Lose Weight and Get Healthy by Eating the Foods You Were Designed to Eat, written by Dr. Loren Cordain (Ph.D. Exercise Physiology).

A counterpoint book Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live, by Dr. Marlene Zuk (Ph.D. Evolutionary Ecology) will be published next week. In the meantime, check out a summary of the debate here.

As someone with a background in evolutionary ecology, I’m initially biased toward Paleofantasy, but admittedly have much to learn, and plan to read both books as a starting point in my education on this subject. Regardless, I’m just happy to see prehistoric human subsistence getting media coverage.  Any readers familiar with the Paleo Diet and arguments for and against it? If so, please comment below!

 

“Group Selection” and the Human Conquest of Earth

Edward O. Wilson, professor emeritus at Harvard, is a highly respected pillar of modern evolutionary biology. Check out this link for a summary of his many contributions to our understanding of life and humankind.

I recently read Wilson’s latest book The Social Conquest of Earth and greatly enjoyed parts of it. Wilson’s writing is clear and compelling as he tackles THE BIG QUESTION: How did a single primate species (If you’re reading this, you’re a member of that species) so quickly conquer the world? But I was surprised to see that much of Wilson’s argument is built on the foundation of group selection, also called “multilevel selection.”

Group selection attempts to explain how traits (for example, altruistic behavior) that are costly to individuals, but beneficial to larger groups, can persist. Why doesn’t natural selection, which acts on individuals, eliminate such “maladaptive” traits? If it pays (evolutionarily) to be selfish, why do humans routinely perform selfless acts? As applied to humans, group selection is the idea that groups composed of cooperative altruists are able to outcompete groups of selfish people, increasing their populations, and fostering the spread of altruism.

Most scholars view group selection as highly unlikely or, at best, a very weak force in the evolution of human cooperation. It’s not a bad idea, just not as parsimonious an explanation as inclusive fitness or kin selection: “The concept that altruistic behavior can be selected for if it increases the probability of survival of close relatives” (Relethford 2013:148) – and for the vast majority of our evolutionary history, we lived in societies composed almost exclusively of close relatives.

This week, E. O. Wilson reiterated his support for multilevel selection in a New York Times piece called “The Riddle of the Human Species.” It’s a short summary of the argument detailed in his book. For a counterpoint from Jerry Coyne, professor of biology at the University of Chicago, please see this post at Coyne’s Why Evolution is True website (the linked post also includes links to previous posts on this topic of group selection).

I highly recommend these resources for anyone interested in anthropology and the evolution of human behavior. As stated, I think kin selection is a better explanation for the evolution and spread of altruism than group selection, but remain open to the possibility of new evidence. What do you think? Did multilevel selection, as argued by Wilson, play a role in the social conquest of Earth by Homo sapiens?

We’re Made of Star Stuff

At the risk of turning this blog into little more than a list of recommended readings, here’s another book worth checking out.

Neil Shubin, associate dean of biological sciences at the University of Chicago, and author of the wonderful Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body has written a new one. Titled The Universe Within: Discovering the Common History of Rocks, Planets, and People, it’s about as “big picture” as a book can be – relevant to anthropology because it explores humans and our connection to…(dramatic pause)…everything.

My hero Carl Sagan used to say that “We are made of star stuff.” It sounds kind of like mystical nonsense, redeemed only by the fact that it’s literally true! Hard not to feel some cosmic connection when we reflect on that fact.

The “star stuff” shared by rocks, planets, and people is the subject of The Universe Within. As someone who is endlessly fascinated by where humans fit in the whole scheme of things, I look forward to reading this book soon (I have a copy sitting here on my desk just begging to be read when time allows). Enjoy!

Happy 100th Birthday, Mary Leakey!

I was just lecturing about Mary Leakey’s many accomplishments in an introductory archaeology class yesterday. Little did I know that today would mark the 100th anniversary of her birth.

Google.com has honored her as their Google doodle for February 6th, 2013. Check it out and be sure to search “Mary Leakey” while you’re there. You’ll find plenty of tributes and great information on her contributions to the study of human origins. For starters, here is a brief biography from Leakey.com:

“Mary Douglas Leakey was recognized in her lifetime as one of the world’s most distinguished fossil hunters.  Because of her many important discoveries and her dedication to field research, she is considered a giant in the study of human origins.

She was born Mary Douglas Nicol in London on February 6, 1913. She was the daughter of a popular landscape painter, Erskine Nicol, and Cecilia Frere. Mary herself was interested in art and archaeology at an early age. As a child she frequently travelled to France with her parents.  There, she visited a museum of prehistory and was allowed to participate in archaeological digs where she found ancient stone tools. She also visited the French caves at Font de Guame and La Mouthe, which are famous for their prehistoric paintings.  As a result of her father’s death in 1926, Mary and her mother moved back to London.  She rebelled against the constraints of the Catholic schools to which her mother sent her. In 1930, she began auditing university courses in archaeology and geology. She soon established herself as an authority on flint points and was recognised for her mastery of scientific illustration. She was introduced to Louis Leakey in 1933. Louis invited her to join him in Africa to draw the stone tools he had found. Three years later (after Leakey’s divorce from his first wife Frida) they were married. They had three sons (Jonathan in 1940, Richard in 1944, and Philip in 1948).

Among her many scientific accomplishments, Mary is credited with the discovery of Proconsul africanus in 1948, Zinjanthropus boisei (now known as Australopithecus boisei) in 1959, Homo habilis in 1960, and an amazingly well-preserved 89-foot long trail of early human footprints found at Laetoli (1979). These footprints have been dated to about 3.6 million years old and their discovery proved conclusively that our ancestors were at that time practicing bipedal locomotion. Mary and her team continued to find important hominid and prehistoric animal fossils until her retirement from active fieldwork in 1983.

Upon retirement, she moved to Nairobi from Olduvai Gorge, where she had lived for nearly 20 years. In retirement, she continued to contribute to science, writing articles about her lifetime of incredible discoveries. She died in 1996 at the age of eighty-three” (Source: http://www.leakey.com/bios/mary-leakey).

Remains of King Richard III Confirmed!

The University of Leicester issued a press release today confirming that skeletal remains recently found under a parking lot in Leicester, England are those of King Richard III. It’s a wonderful and very well-documented piece of archaeological detective work – especially because it demonstrates how multiple lines of evidence can be used to strengthen our interpretations.

Check out this site for the University of Leicester’s full press release, background information on King Richard III, multimedia presentations, and more. Enjoy!