Greasy Fingers and Evolution

I just posted a YouTube video on this topic. [https://youtu.be/lItwjRfxP7A ].

Much has been speculated and written about the evolution of human intelligence in all of its manifestations, including speech and tools. There is no reason that many of these ideas could not simultaneously be true.

One idea is that tool-making and intelligence evolved together. At first, a rudimentary form of human intelligence—the ability to envision how a rock could be made into a tool—was necessary to get the process started. Then, as stone tools, then spears and arrows and atlatls, became more sophisticated, a much higher level of intelligence was required. Even sexual selection was involved, with the idea that men invented better and better tools to impress their prospective mates.

It is impossible to think about human evolution without considering the origin of speech. Even the ability to make the sounds of which words are composed had to evolve. An evolutionary change in the larynx allowed a greater range of vowel sounds. And the evolution of dexterity of lips and tongue was necessary for consonants. Some have speculated that the ability to use the lips in speech (and for kissing) evolved from the ability of infant mammals to purse their lips around the mother’s teat.

All of this required an exponential increase in human intelligence, which was possible when more calories and nutrients were available for the growth and maintenance of the human brain. Human intelligence exploded when our ancestors began to cook their food, allowing a greater amount of nutrition to be available from the same amount of foraged or hunted food.

All true, but as I was eating greasy pieces of poulet rôti the other day, I realized yet another possible reason that human lips and tongues evolved dexterity. It is not enough to just capture and cut animals as food, or to cook them for nutrition. There is also an advantage to being able to get every last little morsel of meat from the bones of the cooked prey. An early human could get a great deal of meat from big pieces of cooked meat. But there was also an advantage to eating the little bits of meat hiding among the joints.

Those little bits of meat could provide just enough extra calories and nutrients to make a difference—slight, but significant—in production of offspring. Over time, the bits of meat and fat wasted by hominids with slightly less dexterity of lips, tongues, and teeth might give an advantage to the hominids who could glean the meat and fat more carefully. Of two tribes, both of which cooked their meat, the one with greater motor skills in their fingers and nibbling ability will get more benefit from their food than a tribe that threw a lot of perfectly good morsels of meat and fat on the bone heap.

It could also give an advantage within a group of hominids. A hominid that could say, “You done with that bone? There’s a lot of good meat and fat still on it,” might prevail over the hominid that handed the bone to him.

At least, this is what I was thinking as I ate every little bit I could get from the roast chicken. Think of that the next time you throw away a chicken leg with lots of good calories still on it.

A Thanksgiving Message: Adventures with Persimmons

Here is something to be thankful for this Thanksgiving Day: agriculture. Maybe we shouldn’t be thankful for every aspect of agriculture; industrial agriculture is ruining the Earth. But I, at least, am thankful for thousands of years of ancestors who domesticated the crops and livestock that we enjoy today.

The origin of agriculture was a gradual process. Take, for example, wild grains. Wild grains have small seeds, which fall off of the stem, and which will not grow when you plant them (physiological dormancy). Had any gatherers tried to “invent” agriculture using wild grasses, the experiment would have failed. But after thousands of years of gathering, our ancestors unconsciously selected the grains that were biggest, that held onto the stems (since they were not interested in scrounging on the ground for grains), and which grew most readily. Then, when someone tried the agricultural experiment, it worked. Since that time, artificial selection for useful crop plants has continued unabated. A similar process happened with wild animals becoming livestock. Horses, it turns out, were first domesticated for their milk somewhere in what is now Kazakhstan. And the North American natives domesticated turkeys.

The difference between wild and domesticated foods became clear to me when I decided to eat some wild persimmons. I found a female tree (Diospyros virginiana has separate male and female trees) near Lake Texoma and gathered about 50 fruits last weekend. (Message to Karl: Don’t worry, I left some for you.) The fruits were so smooshy that I often left the calyx cap behind on the stem. Most of the fruits had ripened simultaneously. But a couple were still just a little hard. Including not-quite-ripe fruits in your foraging pile is a bad idea: even slightly unripe persimmons are legendary for their astringency. Wild fruits often do not ripen simultaneously, while domesticated fruits have been bred to do so. That’s the first thing to be thankful about.

Then I had to remove the seeds from the pulp. Were I just eating the fruits, I might have skipped this step. It is possible to pop a persimmon in your mouth, mash it around gently, and suck away the pulp from the seeds, then spit out the seeds. The wild animals that eat persimmons usually just swallow the whole fruit. This is because they are at the edge of starvation and don’t have time to pick out the fruits, especially if (like coyotes) they could not, or even if (like raccoon) they could. By swallowing the seeds, the animals disperse them to new and perhaps distant locations, and drop them out with little starter cultures of fertilizer.

But I decided to isolate the pulp from the seeds. This was a long process. Each fruit has about ten seeds, constituting about half of the fruit volume. A tenacious layer of pulp clings to these seeds, even when you squeeze as much pulp as possible from them. This usually meant squeezing each seed individually (do the math: 500 seeds). The pulp, meanwhile, clings to your hands like paste. It is orange-brown and scratchy (from sclerids). So you end up with the fruits separated into two fractions: the pulpy seeds, and the pulp on your hands. You have to scrape the pulp off of your hands into a container on a regular basis. For about fifty fruits, this took me about the length of one performance of Mahler’s Fifth Symphony plus a couple of baroque shorts. But I got a little over two cups of pulp. I then sucked the remaining pulp from the seeds before depositing them in my back yard where they might, someday, grow, after several years when the seed coat softens to the same extent that it would from spending just a few hours in a raccoon gut. With domesticated fruits, you can more easily separate pulp from seeds (including domesticated Japanese persimmons, Diospyros kaki). The pulp can be squeezed through a colander, for example. This will not work for many wild fruits, especially persimmons. Was it worth an hour and a half of dedicated work to get a couple of cups of wild persimmon pulp? Yes, if that was all that was available. But I found myself questioning the wisdom of my use of this time. That’s a lot of work and a lot of Mahler. Be thankful for domesticated fruits in which you can easily remove the seeds. That’s the second thing to be thankful about.

The next day, I felt a little nauseated. It was probably just end-of-semester stress. But perhaps, I thought, after all that work, the raw persimmon pulp was contaminated? Just a little. So here’s the third thing to be thankful about: we modern humans can cook our food. This is just one of the many benefits of cooking cited by Richard Wrangham in Catching Fire: How Cooking Made Us Human. I hope 350 degrees will inactivate any bacteria that may be present. I decided to bake the persimmon pulp into bars. They are in the oven right now as I write. Get ready to copy and paste for a Thanksgiving dessert recipe:

Take about a half cup of smooshed persimmon pulp and mix it with 5 tablespoons of soft or melted butter, an egg, and a third of a cup of plain yogurt. Then blend in about a cup of flour, a half cup of sugar, and some baking powder, a little salt, and your choice of spices (something like cinnamon or nutmeg). Some pecans would have been nice, only I forgot them. Grease a small baking tin, put in the mixture, and bake it at 350 F until you think it’s done (the usual test is to insert a toothpick and see if it comes out clean). Notice, for the benefit of my lactose-intolerant wife and daughter: this recipe contains no untreated milk.

It’s almost done. Boy, this had better be good, after all that messy squishing.

The moment of truth! I will tell you how it tastes. If it makes me sick, watch for a dispatch tomorrow from St. Francis Hospital.

Verdict: Not bad. It does not have a strong persimmon flavor, which can at any rate be a little annoying. It is a little mooshy inside, but once again, not bad. It is definitely gritty with sclerids as only a wild fruit (or a pear) can be. I kept eating it.

I think I will use the rest of the batch of pulp in this manner for the Saturday family meal for the remaining descendants of Edd and Stella Hicks, sharecroppers in early twentieth century northeastern Oklahoma. I wonder if Stella gathered persimmons and cooked with them. There is no remaining family history to this effect, but it seems reasonable to suppose that she did. Persimmons, an aggressive early-successional clonally-spreading tree, would have been re-invading my grandfather Edd’s cleared farmland. This means that, after seventy years, persimmons have returned to our family.