I recall reading that in one of Jared Diamond’s books as well, that as a whole, we’re allowing maladaptive features to exist because of civilization and our ability to take care of all. I also recall him saying that amongst the tribes he’d met, they were, contrary to popular belief, far from unintelligent. In fact, he argued that on the average, they were more intelligent, though in Western society, their inability to use a computer or do other tasks of “education” would label them as stupid. Just as I and most others here probably have the intelligence to learn to fly a plane, we lack the knowledge. In a hunter-gatherer society, they have to remember the locations of feeding and watering grounds and which of thousands of plants are edible or poisonous; we just have to remember how to get to Kroger. Diamond argued that the less intelligent get weeded out in a hunter-gatherer society because they do something unintelligent. In our society, the less intelligent go on Jerry Springer.

Anyway, I agree with you that “evolved” is a tough word. The gene to keep lactase turned on is a genetic modification, but on the whole, humans are largely the same as we were 15,000 years ago.

Cheers
Scott Kustes
Modern Forager

I think I may have to do a piece on this. Part of what we are dealing with here is a semantic issue: how is the term “evolved” to be used in the context of the Primal Blueprint? On the one hand, evolution does mean “the changes seen in the inherited traits from one generation to the next”…on the other hand, I have always put evolution in the context of “favorable heritable traits that become more common in successive generations of a population while unfavorable traits are selected out”. And I think here we see the distinction being argued.

Scientists are showing that there is more genetic diversity now than ever before. Agreed. But in my mind, that is NOT indictative of evolution as it relates to natural selection. What they are measuring is/are simple SNPs and gene variants and then calling that “sped up evolution”. In many cases, they are suggesting that there are more harmful SNPs than beneficial. These can add up to thousands of points of difference between races or geographically isolated populations. I see it as a natural effect of having millions of people on earth (and now billions) who have allowed short-term non-lethal mutations to be passed on to their progeny. The fact that there are effectively none of the selection pressures that our ancestors dealt with for the first 2 1/2 million years of human evolution means that any and almost all products of random mutation or genetic drift are incorporated into the genome without penalty. And passed on to the next generation similarly. As a result we have a litany of documented SNPs that predict greater risk for certain diseases…but they certainly do not guarantee that the possessor will get the disease. I really do think it is a form of devolution. I argue that adhering to the same type of diet and lifestyle (environment) that surrounded the original “design” process of the prototypical pre-agricultural human will almost always significantly reduce the disease risk of the offending SNP. But that’s just my theory.

Furthermore, the concept of epigenetics has not been discussed here, but we may find that, in terms of gene expression, our maladaptive agriculture-based diet not only promotes higher birthrate AND allows an individual to attain reproductive status regardless of “fitness”, but also actually influences outcomes of future generations. You could argue that we are in a mid-adaptation phase in our evolution vis a vis grain for instance, but since we haven’t fully adapted, we still suffer from the ill effects (some are affected far more than others, but all are in some way affected negatively). I say, When in doubt, consult the orginal blueprint.

Surely we are also seeing diseases that would be maladaptive in younger people, but are not selected against because they occur either after our reproductive years or so late in reproductive years that we have already passed the genes on to at least one offspring. I’m thinking of things like diabetes and most cancers, of course. I don’t think that particularly supports either Mark or Tim’s point, but it’s fascinating to contemplate whether natural selection cares about the survival of postmenopausal women. I think it was Diamond who suggested that having a grandmother around to care for children was, in fact, adaptive, because offspring in our species are more vulnerable, for longer, than virtually any other species.

Another thing we have to consider when we try to talk about what would happen to humans in nature is that pretty much anything humans do IS nature. So the fact that we have learned to process grain, allowing more of us to survive (though not necessarily to thrive) to reproductive age means that we are evolutionarily adapted to eat grain, because we evolved big brains and opposable thumbs that helped us grow, store, sprout, grind, and/or cook it. (Sorry, Mark, I think that’s a point for Tim.)

However (and this is a point for Mark, I think), the problem with natural selection is that it doesn’t “care” whether we thrive, it just cares about whether we survive long enough to reproduce and to rear our notoriously helpless offspring. So evolution may favor the eating of grain simply because it provides enough energy for us to squirt out a few seedlings. That does not imply that we will thrive on grain in the long term, though. That does not mean that we are biologically equipped to eat grains for 80 years.

One final point - maybe you can argue that 10,000 years is long enough for us to have evolved some adaptations to the agricultural diet. But surely you can’t argue that 150 years (about 5 generations) is enough. And certainly the worst stuff in our diets - highly processed breakfast cereals, artificial flavorings and colorings, trans fats, HFCS - have all appeared in that time frame or even less. So whatever we think about the pace of evolution, surely we can all agree that any processing that our great-grandmothers couldn’t have undertaken in their own kitchens - chopping, grinding, fermenting, cooking - is sketchy at best.

This is turning into a nice little discussion. I like your idea of accumulating mutations due to a lack of selective pressure. I’ve often thought about that myself. I call it “devolution”. I’m not sure that was happening when we first adopted agriculture and it was making us really sick, but I bet it’s happening today to some extent.

We live in a climate-controlled world where we can drive and take elevators almost everywhere. If we can’t see, we get glasses and cataract surgery. 20,000 years ago, if you couldn’t get around and couldn’t see, you were dead. With technology and medicine coddling our lives, even the very sick survive, and we don’t “weed out” mutations that would have conferred a disadvantage in the past.

And about the duplication of salivary amylase and lactose tolerance, I agree that those are crude adaptations. Not the kind of thing you see with true long-term adaptation.