Darwin in Old Age

I have just posted a video about what Darwin might have thought about old age. He walked on his thinking-path (the sandwalk) every day that he could even in old age. He was pretty much an invalid when he died, but not as much of an invalid as he would have been had he not walked on his thinking path so often.

First, in the video, Darwin speculates on why walking improved his thinking. I have already summarized this in an earlier essay. Gentle walking increases blood flow to the brain. Also, thinking, like walking, is a series of steps.

Second, in the video, Darwin speculates on why old age evolved. Humans are unique among animals in having decades of post-reproductive life span. One explanation is that natural selection has provided us with whatever we need to be young, but not whatever we need to be old. But if old age is just the dumping ground of bad genes and defective body parts, why hasn’t evolution gotten rid of it?

The more likely reason that humans grow old, rather than just dying, is that old people provide important benefits to their offspring and to their tribe. Old people are repositories of knowledge and wisdom (well, knowledge, anyway) especially before books and AI. Us old people know things that young people haven’t even thought to ask about. Also, old people help to take care of the grandkids while the parents are searching for food or status. This is also the time when old people can pass on a lot of culturally important information to later generations. Finally, old people may not travel very far but they can forage for food near the camp.

Old age doesn’t seem quite so bad when Darwin explains it to you.

Live Fast and Die Young: Another Message from Fluff the Cottonwood Tree

This is Fluff the cottonwood tree (she/her/hers). I think this is my fifth message that Stan has agreed to post for me on his blog. I live about a half block away from his house in Oklahoma.

I know Stan is the one with the botany Ph.D., but I know a thing or two myself. And today I am going to tell you about the evolution of life cycles.

Cottonwoods like me are the James Deans of the tree world. We live fast and die young. In contrast, many of the oak trees that grow here in Oklahoma, like the post oaks up on Turkey Mountain, live for several centuries. They grow slowly and invest in the future: they have strong wood, for example. They produce large seeds (acorns). They grow in stable forests where long life and big seeds are important in winning the game of competition. But us cottonwoods live along rivers, creeks, and lakes. I live near Joe Creek, a quintessentially Okie name, although it is a rip-rap lined drainage ditch. We cottonwoods do not have a future to invest in.

The margins of rivers, creeks, and lakes are very unstable habitats. Every few years, a major flood will come along and sweep many of us away into the oblivion of death. I am a little luckier than most; I live far up on the bank. But the flood waters almost got me—and Stan’s house—in 2019. Still, the cumulative risk of death from flooding is very great, and it is a rare cottonwood that is able to enjoy his or her hundredth birthday. Why build strong wood, when we do not live very long? And why invest in big seeds to compete against trees, most of which will get swept away in a flood anyway? We live fast and die young. We reach our full height after maybe fifty years. After that, our trunks keep growing but our roots are not very deep. We are just asking to get knocked over in a flood. But even if we do not, we fall over as our weak wood rots away. From where I stand, I can see a house with a new roof. The old one was damaged by one of my fellow cottonwoods falling on it during an unremarkable storm. If you want to plant a tree near your house, you should probably choose an oak instead of a cottonwood.

We reproduce like crazy as soon as we are about fifteen years old, which is young for a tree. We need to get as much reproduction finished as possible, in case we die even sooner than we expect. Stan took this photo of some of my seeds in 2019.

All these characteristics fit together. In order to grow fast, we have large xylem vessels in our wood, which conduct water rapidly to the leaves at the top of the tree. The very fact that we have lots of big, hollow vessels in our wood is what makes the wood weak. Oak trees have stronger wood, but the price they pay for it is slower growth.

I do not recommend the James Dean strategy in general, but my species lives in a habitat in which trees get destroyed quite often. For us, the James Dean approach works very well. The same is true for all species. If a disaster happens frequently, it is better to grow up fast and reproduce early. One such disaster is predators. Research has shown that fishes that live where there are predators will grow fast and reproduce young. But in the absence of predators, they grow larger and more slowly, reproducing later. The same pattern has been observed in opossums. It sounds like a law of nature, a spectrum of life cycles, and I am at the James Dean end of it.

Despite this, trees almost always live longer than animals, even most tortoises. I will probably outlive Stan.

Science is Alive and Well in Oklahoma, part one.

I posted the following on the Oklahoma Academy of Sciences blog a few weeks ago, but the rest of you might want to know about this too.

The Oklahoma Academy of Science held its 2014 Technical Meeting at Northeastern Oklahoma State University (Broken Arrow campus) on November 7, preceded by the Executive Council meeting on November 6. As president, I enjoyed watching and occasionally coordinating the good and enthusiastic work of so many students and faculty from around the state. Nobody had to be there. It was sheer enthusiasm for science that made the meeting a success.

I wanted to mention one paper that really got my attention. Lois Ablin, a chemist at Oral Roberts University, talked about advances in “green chemistry,” particularly in student organic chemistry laboratories. I took organic chemistry in 1976 and it has been downhill from there. Back then, we poured toxic chemicals all over the place (including benzene on our hands), and all of them ended up down the drain and probably out in the ocean (I was at UC Santa Barbara). Today, thankfully, we have many rules that preserve personal and environmental safety. One of the easiest ways to reduce the amount of waste produced by student labs is simply to use small-scale reactions. In my day we used whole flasks and beakers of toxic chemicals. But in green chemistry, the same reactions can be performed in small vials, heated in a microwave oven instead of over a burner or in a hot glove. It saves time, too: you can microwave a reaction for eight minutes with the same result that you would get with an hour-and-a-half reflux. Some universities have even gone so far as to carry out reactions on filter paper, rendering fume hoods unnecessary.

There were lots of student posters. This is an time for faculty to see the excellent work done by students at other universities. I barely had time to glance at them and take grainy photos. I got to stop and look at a poster from a student at Cameron University who had studied the stomach contents of a mammoth that had lived in what is now southern Oklahoma during the last ice age (in case you didn’t know there were mammoths here). The mammoth had eaten horsetails.

  

Bruce Carnes, from the University of Oklahoma Health Sciences Center, gave the luncheon presentation about the evolution of aging. What an interesting topic, especially for people who might have wondered what evolution has to do with medicine. For those who might have thought that aging is simply a problem that can be solved by some magic medical bullet, Bruce (who described himself as a disappointed optimist) had some bad news. Natural selection has indeed produced a human species that is guaranteed, in the absence of intrinsic and extrinsic accidents, to live for about 55 years, which is enough time not only for nearly all reproduction to be completed but for a person in tribal society to discharge their grand-parental duties as well. Fifty-five years, then, is our “warranty period.” After age 55, the body starts to break down in multiple ways. There’s no way to stop it, even though we try very hard to prolong our lives as much as possible. It makes more sense, Bruce indicated, to try to have a healthy old age rather than simply a long one. Once the “expiration date” has passed, a car or a person might keep running for a long time, but will require more and more intervention. Old age is not a problem to be solved but a process to be managed.

In the next entry, I will write about the symposium about science-related issues in the afternoon. It was one of the most exciting things the Oklahoma Academy of Sciences has ever done, I think.

Attention All Investors

Attention all investors: the United States is not where you want to make long-term investments. The reason is obvious. You cannot know from one week to the next whether there will be a functioning government. And this is a situation created by the government itself. Therefore the only kind of American investment that you might wish to consider is something extremely short term, where you can make a quick killing and get out.

Evolution has fashioned the life histories of organisms, which is largely the stories of their investments. How long do they live? How sturdy are their bodies? How many offspring do they produce? These are all investment questions. And oak trees answer these questions differently than cottonwood trees do. Oaks invest in strong wood and produce relatively few seeds over the course of centuries because they live in stable environments. Cottonwoods invest in cheap wood and produce many seeds during their short lives (by tree standards) in unstable, flood-prone, riverside environments.

Investing in the American economy today requires a cottonwood mentality. It is no place for you to trust your life’s savings, unless you do not plan to live very long. Of course, most of us have little choice; this is where we live, and it is very inconvenient for us to invest in, say, Japan or South Korea or Singapore. My own, admittedly imperfect, solution is to put most of my money in bank accounts and retirement funds, the purpose of which funds is to sit around and do very little, slowly accumulating value; in my health, so that I will not need to spend money on health care; in my house, since I actually live there; and in my daughter, who is my future. I will not consider putting my money into the floodplains of the general economy, where it will end up as flotsam and jetsam amidst the corpses of fish.

I think the American economy is even more tumultuous than the environment of cottonwoods. It is more of a bacterial economy. As soon as an animal dies, the bacteria begin to rot it. The bacteria have a wild population explosion. Then they die once they have finished decomposing the animal.

Another image that might serve for our American economy is the Permian extinction. Ecological communities around the world were collapsing 250 million years ago. One of the pieces of evidence for this is that the fossil record for that time period has a sudden spike of mold spores, which indicates that the world was rotting. We are in the economic equivalent of the Permian extinction. The world eventually recovered from that period of death; but it took about a hundred million years to recover its biodiversity! Right now (as of 11:00 central time) the Dow is high, which sounds like economic health—but remember that the Permian extinction was also a period of high and fast living, for fungi.

Congress passes laws that authorize, even require, certain expenditures, then they refuse to fund them. Congress forbids us to do what they require us to do. This is either so stupid as to be the product of pre-human cognition or else it is deliberate.

It really doesn’t matter if or when Congress resolves the budget impasse or whether the government defaults. America has already shot its credibility. America now has no more credibility for long-term investment (I’m talking to you, China) than does a shack built out of cottonwood or the brief pungent decomposition of a corpse.

Have a nice day.

Cottonwood Investments

This essay appeared on my website on February 15, 2009.

How many of you would build a home out of cottonwood? I doubt that anybody would do this. This kind of wood is not strong. Although cottonwood trees grow tall and their trunks are large, they do not live very long. They live along creeks and rivers, where periodic floods turn trees into floating logs.

In contrast, most oak trees have very strong wood. Strong wood is more expensive for a tree to produce than is weak wood. Oaks live for centuries, and strong wood is a necessary investment, but it would be a wasted investment for a cottonwood, which would be probably be killed by a flood before a century has passed. Cottonwood trees follow the James Dean philosophy of life: live fast and die young. Oak trees grow slowly and live a long time. Both patterns of life are adaptations to their circumstances: the first to a temporary habitat, the second to a stable habitat.

Yet another approach to life is found in alder trees. Alders, like cottonwoods, live in streamside habitats where floods frequently destroy them. The 2007 floods in Oklahoma destroyed almost every alder tree that I could see. But alders produce numerous small trunks from a strong underground rootstock. Within a couple of months of the floods, nearly all of the alders had resprouted. An alder clump may persist for centuries, even though each of its trunks may live only for a few decades.

The near-collapse of the financial sector resulted from cheap investments that were not intended to last. For a brief time, these investments yielded immense profits to a few people, but failure was built into the system. Financial markets invested like cottonwoods. The problem is that a nation is supposed to survive for a long time, like a forest of oaks, not like a streamside with cottonwoods. If the United States intends to persist, the correct way to invest is for the long term.

In nature, cottonwoods cannot survive in oak forests. But on Wall Street, all of the biggest corporations followed the cottonwood type of investment and, in effect, forced it on the entire system. By investing in the short term, banks and other financial firms forced their environment to become unstable, and took billions of dollars down with them. Their approach to life turned a country, and a world, into a habitat that lives fast and dies young.