My God It’s Full Of Stars

13 Sep

One of the reasons I jumped on board the paleo wagon (or, more likely, paleo travois) so easily was because its basic philosophy made such immediate sense. In my own words, this core hypothesis can be outlined as follows:

“Living organisms evolve and adapt to have maximum reproductive fitness in their natural environments. On the scale of human history, grains and processed foods are relatively new things in our environment, so it might follow that they are presenting us with health and fitness challenges that we have not yet adapted to.”

A simple enough idea. As a scientist, though, I of course had to test it. My immediate data results were that I lost 40 pounds and cured my clinical depression, which was more than enough evidence for me to accept the hypothesis as true.

But in the last few years, I have noticed an interesting pattern when discussing the paleo diet with other people. Many common misconceptions in scientific understanding prevent people from grasping that same core hypothesis I understood right away. Because of this, many times these people focus on debating extraneous details of the paleo diet (missing the forest for the trees, so to speak) or simply write the whole thing off altogether. It is especially frustrating to me because these are the same misconceptions that that I see on a daily basis as a science educator.

One of these misconceptions is trying to grasp the vast periods of time involved in human evolution and how relatively short our recorded history actually is.  For many people, the founding of the United States (in the mid 1700s) is ancient history. Everything before that is a vaguely defined grey area, at some point during which some pyramids and castles appeared on the map. Ask them where we came from and their mind likely conjures some mammoth-pelted humans emerging blinking from a cave then setting off down the hill to immediately plant some grain and start working on building aforementioned pyramids and castles.

Thankfully, most of us are a little more clued-in than that, but we all have a difficult time trying to understand very large numbers or very large periods of time. When I used to teach intro biology in grad school, there was a timeline of Earth’s history painted on the wall of the hallway in the science building. It was to relative scale, with markers along its length showing the formation of the Earth, the development of simple single-celled life, the evolution of complex multi-celled life, the first point at which living organisms moved onto land, etc. I would walk my students along this timeline, narrating the story of the Earth along the way. I got really excited when I talked about things like the collection of liquid water into seas and the theory of endosymbiosis but—like on many long-winded tours—their eyes would glaze over. Eventually we’d hit things they cared about, like dinosaurs and mammoths and ice ages. Inevitably, at the end of the tour, my students were always shocked when we came to the segment showing human history, a tiny band painted at the end of the hallway, maybe an inch wide at most. They would look at that band and then turn and look down the length of the 100-yard hallway and go, “Whoah.”

Yep, just like that.

Yep, just like that.

Luckily, now you don’t have to travel to that science building and listen to me drone on to get that experience. I stumbled across this fascinating blog post that does a similar thing, visually breaking down time spans in history into relative bands. What’s really interesting is that they do it in a step-wise fashion, giving you a breakdown of a normal day, to a normal 30-year-old’s life (represent!!!), to a normal 90-year-old’s life (grandma, represent!!!), and so forth.

It does a very good job showing the difference between recorded human history and the spans of time in which we have been behaviorally or biologically human (spoiler alert: the latter ones are longer). The money shot, though, comes with an addendum added to the timeline of human history as defined by human behavior:

timeline

If you can’t read it there at the bottom, the author states:

“It’s also clear to see why so many modern people’s bodies have trouble with wheat or gluten products — the human digestive system evolved almost entirely before wheat products entered the situation.”

Look at how much of that timeline exists to the left of—aka, before—cultivated wheat (and most other cultivated grains, since they all came about around the same time). For scale reference, remember that blue box on the right represents only the last 2,000 years of recorded history.

The comparison gets even more drastic when we look at the next timeline in the series, which shows biological human history. This timeline dates anatomically modern humans to about 200,000 years ago (although I have heard some estimates floating around that are closer to 2 million). In any event, the point is still the same: agriculture is a relatively new thing in human history. This timeline didn’t reference wheat so I took the liberty of adding it in:

Wheat-emphasis my own.

Wheat-emphasis my own.

With this, we can see that human beings were around and surviving for inches and inches before wheat and grains came around.

The other major science misconception many people have is how long evolution takes to happen. “Sure,” they might say, “we’ve only had wheat and crap for a few thousand years, but shouldn’t we have evolved to deal with it during that time?” Well luckily the rest of the post helps address that point as well. Look at how long it took humans to show up in the first place:

timeline3

You see humans on that timeline? No? Well what about that leeeeeeeettle purple band at the far right? That’s human evolutionary history. And it’s not even humans as we know us. It is the very beginnings of bipedal, upright apes that evolved from ancient primate ancestors and first figured out how to throw rocks.  The point becomes clear: on average, evolution takes very long periods of time to occur, and most of these periods are way beyond our general scope of time.

(Note that the author of the blog post does make an error in saying that humans evolved from apes. Depending on their definition of “ape,” this is technically incorrect, or at the most misleading. We didn’t evolve from chimpanzees, bonobos, or gorillas. Rather, humans and other modern great apes share a common ancestor in our evolutionary past. The way I summarized it to my students is that the monkey is not our uncle, but it is our cousin.)

Even outside of the paleo-lens, it is an excellent blog post from a science-education standpoint. One of those things that simultaneously enthralls you about the vast wonder of the planet and the universe while simultaneously reminding you of your vastly insignificant place in it.

Or, as the author of the post themselves put it, “Hopefully this little exercise has put things into perspective a bit—at least for the next three minutes, until the next website you click on tears you back into thinking that things matter.”

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5 Responses to “My God It’s Full Of Stars”

  1. wilberfan September 14, 2013 at 4:07 pm #

    Nicely done, Madame. My vegan-hood of 18 years came to a screeching halt in Oct 2010 when I, too, immediately grasped the Core Hypothisis of Paleocity. (“Oh, fuck…” probably sums up my reaction.)

    And love the “2001” reference (my fav film ever?)!

    • Colleen September 16, 2013 at 11:48 am #

      Ha! Yes, sadly, it seems it can take a while for Logic to penetrate the thick clouds of Rhetoric and Dogma that we tend to be surrounded with on a daily basis ;p

      • Scott M September 16, 2013 at 3:23 pm #

        Yes, also known as, “everybody knows”. As in, “Everybody knows vegan is the healthiest way to eat…” :-\

  2. Se-e-eth September 16, 2013 at 8:25 pm #

    So, n = 1 gave you enough data to test that hypothesis?

    😉

    • Colleen September 16, 2013 at 8:27 pm #

      I didn’t say it was necessarily a *good* experiment! ;p ;D

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