Tag: Evolution

Richard Feynman — Take the World From Another Point of View

In this clip from a documentary film shot in Yorkshire in 1973, physicist and philosopher Richard Feynman (1918-1988) talks with Fred Hoyle, an accomplished astronomer from the United Kingdom.

Feynman poses the question: “What, today, do we not consider part of physics, which may ultimately be part of physics?”

His answer (which should be cued up here at the 7:10 mark) is the initial conditions of the universe, as well as the possibility that the physical laws themselves, evolve with time.

As he explains, there was a time when we considered the properties of substances to be chemistry, but as the quantum mechanical understanding of the atom evolved, we came to discover that this was actually all a part of physics.

In physics, our acceptance of the way things are (i.e. given conditions) without wondering why they’re like that is akin to playing chess without asking where the pieces should be placed before the game even starts.

It’s as though we’re doing a chess game and we’re working on the rules but we’re not worrying about how the pieces are supposed to be set up on the board in the first place. We tell ourselves, that’s not our business, that’s the business of cosmology and how the universe came to be. It’s interesting that in many other sciences, there’s a historical question. Like geology, we ask “How did the earth evolve into its present condition?” In biology, it’s “How did the various species evolve to get to be the way they are?” But the one field that has not admitted any evolutionary question is physics. “Here are the laws!” we say. We don’t even think about how they got that way. We think, well it’s been that way forever, it’s always been that way. It’s always been the same laws. And we try to explain the universe that way. So it might turn out that they’re not the same all the time, and that there is a historical, evolutionary question.

 

This fascinating conversation between two great minds continues in the follow-up video. Listen on to hear Feynman explain why he’s afraid to speculate about things.

The evolutionary roots of human behaviour

Anthony Gottlieb writing in the New Yorker:

Indeed, the guilty secret of psychology and of behavioral economics is that their experiments and surveys are conducted almost entirely with people from Western, industrialized countries, mostly of college age, and very often students of psychology at colleges in the United States. This is particularly unfortunate for evolutionary psychologists, who are trying to find universal features of our species. American college kids, whatever their charms, are a laughable proxy for Homo sapiens. The relatively few experiments conducted in non-Western cultures suggest that the minds of American students are highly unusual in many respects, including their spatial cognition, responses to optical illusions, styles of reasoning, coöperative behavior, ideas of fairness, and risk-taking strategies. Joseph Henrich and his colleagues at the University of British Columbia concluded recently that U.S. college kids are “one of the worst subpopulations one could study” when it comes to generalizing about human psychology. Their main appeal to evolutionary psychologists is that they’re readily available. Man’s closest relatives are all long extinct; breeding experiments on humans aren’t allowed (they would take far too long, anyway); and the mental life of our ancestors left few fossils.

He concludes:

Barash muses, at the end of his book, on the fact that our minds have a stubborn fondness for simple-sounding explanations that may be false. That’s true enough, and not only at bedtime. It complements a fondness for thinking that one has found the key to everything. Perhaps there’s an evolutionary explanation for such proclivities.

Still curious? Check out Barash’s book, Homo Mysterious: Evolutionary Puzzles of Human Nature, for yourself.

“When we encounter pain, we are at an important juncture in our decision-making process.”

It is a fundamental law of nature that to evolve one has to push one’s limits, which is painful, in order to gain strength—whether it’s in the form of lifting weights, facing problems head-on, or in any other way. Nature gave us pain as a messaging device to tell us that we are approaching, or that we have exceeded, our limits in some way. At the same time, nature made the process of getting stronger require us to push our limits. Gaining strength is the adaptation process of the body and the mind to encountering one’s limits, which is painful. In other words, both pain and strength typically result from encountering one’s barriers. When we encounter pain, we are at an important juncture in our decision-making process.

Most people react to pain badly. They have “fight or flight” reactions to it: they either strike out at whatever brought them the pain or they try to run away from it. As a result, they don’t learn to find ways around their barriers, so they encounter them over and over again and make little or no progress toward what they want.

Ray Dalio

David Quammen on Why Big Populations Survive and Small Ones Go Extinct

“Big populations don’t go extinct. Small populations do.
It’s not a surprising finding but it is a significant one.”

***

Why do small populations go extinct?

While the answer is simple to outline the scientific details are more nuanced. For now, lets stick to the outline version.

“Small populations go extinct because (1) all populations fluctuate in size from time to time, under the influence of two kinds of factors, which ecologists refer to as deterministic and stochastic; and (2) small populations, unlike big ones, stand a good chance of fluctuation to zero, since zero is not far away.”

Deterministic factors are those involving straightforward cause-and-effect relations that to some extent can be predicted and controlled: hunting, trapping, destroying habitat, introducing new animals that compete with or prey on existing ones, etc.

Stochastic factors “operate in a realm beyond human prediction and control, either because they are truly random or because they are linked to geophysical or biological causes so obscurely complex that they seem random.” We’re talking things like weather patterns, epidemic disease, infestation of parasites, forest fires, etc. Each might cause a downward fluctuation in the population of some species.

In Song of the Dodo, David Quammen gives the following illuminating example.

Think of two species that live on the same tiny island. One is a mouse. Total population, ten thousand. The other is an owl. Total population, eighty. The owl is a fierce and proficient mouse eater. The mouse is timorous, fragile, easily victimized. But the mouse population as a collective entity enjoys the security of numbers.

Say that a three-year drought hits the island of owls and mice, followed by a lightning-set fire, accidental events that are hurtful to both species. The mouse population drops to five thousand, the owl population to forty. At the height of the next breeding season a typhoon strikes, raking the treetops and killing and entire generation of unfledged owls. Then a year passes peacefully, during which the owl and the mouse populations both remain steady, with attrition from old age and individual mishaps roughly offset by new births. Next, the mouse suffers an epidemic disease, cutting its population to a thousand, fewer than at any other time within decades. This extreme slump even affects the owl, which begins starving for lack of prey.

Weakened by hunger, the owl suffers its own epidemic, from a murderous virus. Only fourteen birds survive. Just six of those fourteen owls are female, and three of the six are too old to breed. Then a young female owl chokes to death on a mouse. That leaves two fertile females. One of them loses her next clutch of eggs to a snake. The other nests successfully and manages to fledge four young, all four of which happen to be male. The owl population is now depressed to a point of acute vulnerability. Two breeding females, a few older females, a dozen males. Collectively they possess insufficient genetic diversity for adjusting to further troubles, and there is a high chance of inbreeding between mothers and sons. The inbreeding, when it occurs, tends to yield some genetic defects. Meanwhile the mouse population is also depressed far below its original number.

Ten years pass, with the owl population becoming progressively less healthy because of inbreeding. A few further females are hatched, precious additions to the gender balance, though some of them turn out to be congenitally infertile. During that same stretch of time the mouse population rebounds vigorously. Good weather, plenty of food, no epidemics, genetically it’s fine—and so the mouse quickly returns to its former abundance.

Then another wildfire scorches the island, killing four adult owls, and, oh, six thousand mice. The four dead owls were all breeding-age females, crucial to the beleaguered population. The six thousand mice were demographically less crucial. Among the owls there now remains only one female who is young and fertile. She develops ovarian cancer, a problem to which she is susceptible because of the history of inbreeding among her ancestors. She dies without issue. Very bad news for the owl species. Let’s give the mouse another plague of woe, just to be fair: a respiratory infection, contagious and lethal, causes eight hundred fatalities. None of this is implausible. These things happen. The owl population—reduced to a dozen mopey males, several dowagers, no fertile females—is doomed to extinction. When the males and the dowagers die off, one by one, leaving not offspring, that’s that. The mouse population fluctuates upward in response to the extinction of the owls, a rude signal that life is easier in the absence of predation. Twelve thousand mice. Fifteen thousand. Twenty thousand. But while its numbers are so high it will probably overexploit its own resources and eventually decline again as a consequence of famine. Then rise again. Then decline again. Then …

The mouse population is a yo-yo on a long string. Despite all the accidental disasters, despite all the ups and downs, the mouse doesn’t go extinct because the mouse is not rare. The owl goes extinct. Why? Because life is a gauntlet of uncertainties and the owl’s population size, in the best of times, was too small to buffer it against the worst of times.

Still curious? Read The Song of the Dodo.

Born, and Evolved, to Run

Daniel Lieberman, author of The Evolution of the Human Head, sat down with the NYT for an interesting conversation.

Some years ago, I was doing an experiment where I put pigs on treadmills. The goal was to learn how running stressed the bones in the head. One day, a colleague, Dennis Bramble, walked into the lab, watched what was going on, and declared, “You know, that pig can’t hold its head still!”

This was my “eureka!” moment. I’d observed pigs on treadmills for hundreds of hours and had never thought about this. So Dennis and I started talking about how, when these pigs ran, their heads bobbed every which way and how running humans are really adept at stabilizing their heads. We realized that there were special features in the human neck that enable us to keep our heads still. That gives us an evolutionary advantage because it helps us avoid falls and injuries. And this seemed like evidence of natural selection in our ability to run, an important factor in how we became hunters rather than just foragers and got access to richer foods, which fueled the evolution of our big brains.

So I got interested in how we developed these stable heads. I’m a runner myself. It’s always interesting to study one’s passion. By 2004, we’d found enough evidence to publish a paper in Nature where we declared, “Humans were born to run.” We cited the many dozens of adaptations in the human body that had made us into superlative endurance runners, even compared to dogs and horses.

Before bows and arrows and before horses were tamed, we did “persistence hunting” where we ran kudu, wildebeest and zebra into exhaustion. These animals can’t pant when they gallop. They overheat. People would find a big animal and chase it till it collapsed. You need no technology to do this, just the ability to run long distances, which all of us have.

You can see proof of this capability every November when 45,000 people run for many hours through the streets of New York.

Continue Reading

In his treatise The Evolution of the Human Head, Daniel Lieberman sets out to explain how the human head works, and why our heads evolved in this peculiarly human way.

Why is it so Hard to Kill a Cockroach with your Shoe?

The Cockroach Papers by Richard Schwied is an interesting book if you are looking to learn more about biology or evolution. Cockroaches are built for survival no matter what the world throws at them. Their ability to adapt is just amazing.

Here are some of my notes from the book.

Food and Water
German cockroaches, Blattella germanica, the most common domestic roach in the United States, have been observed to live 45 days without food, and more than two weeks with neither food nor water.

Cockroaches will eat almost anything including glue, feces, hair, decayed leaves, paper, leather, banana skins, other cockroaches, and dead or alive humans. They will not, however, eat cucumbers. They are particularly fond of dried milk around a baby’s mouth.

The roaches are not confined to any particular environment and live in a tremendous variety of places, from underneath woodpiles in Alaska to high in the jungle canopy in the tropics of Costa Rica. They are even found in the caves of Borneo and under the thorn bushes in arid stretches of Kenya. Wherever they live, they are masters at surviving. They are, Schwied writes, “undeniably one of the pinnacles of evolution on this planet.”

Why is it so hard to kill a cockroach with your shoe?
Schweid observes that “when a cockroach feels a breeze stirring the hairs on its cerci, it does not wait around to see what is going to happen next, but leaves off whatever it is doing and goes immediately into escape mode in something remarkably close to instantaneous fashion.” Studies show that a cockroach can respond in about 1/20th of a second, so “by the time a light comes on and human sight can register it, much less react by reaching for and hoisting something with which to squash it, a roach is already locomoting towards safety.”

Blood
Cockroach blood is a pigments, clear substance circulating through the interior of its body, and what usually spurts out of a roach when its hard, , outer shell—its exoskeleton—is penetrated or squashed is a cream-colored substance resembling nothing so much as pus or smegma.

Brains
Cockroaches have two brains—one inside their skulls, and a second, more primitive brain that is back near their abdomen.

Copulation
Schweid says “Pheromones, chemical signals of sexual readiness, operate between a male and female cockroach to initiate courtship and copulation. A sexually receptive female assumes a posture with her abdomen lowered and her wings raised and gives off a pheromone that attracts males.” If he finds a virgin female, a male cockroach after some antenna rubbing foreplay will turn away from the female and raise his wings, “an invitation to her to mount.”Copulation frequently lasts an hour. After sex, female cockroaches store the sperm and use them as needed. The sperm may last her a lifetime.

“The evolutionary strategy employed by cockroaches to reproduce is considerably more efficient than that employed by humans.” Oddly, there are certain species of cockroaches that can, at least for a generation or two, reproduce without any sperm. Schweid says “the females unfertilized eggs will develop and hatch—always producing new females.”

Partying
Betty Faber, the former staff entomologist for the New York Natural History Museum, says “Females go to bed—by which I mean disappear back to the harborage—at night earlier than males.”

Socialness
Schweid writes, “cockroaches, while not social insects in the entomological sense of bees or ants with clearly assigned tasks that benefit the whole community, do clearly take pleasure in the company of other roaches, and the aggression pheromones draw them together, eliciting their effects regardless of the sex or age.” Cockroaches reared singly develop more slowly and take longer between molts than do those reared in a group. Although those groups can be too big “just as development is delayed in young cockroaches if they are isolated, over-crowding also extends the time between molts. So there is yet another kind of pheromone, called a “dispersal pheromone,” and it serves as the chemical signal that it is time to look for a new, slightly roomier harborage. This chemical is found in the insects’ saliva, and has just the opposite effect of the aggression attractant, in that it repulses cockroaches and causes them to look elsewhere for harborage.”

Radiation
In case you’re thinking we can just nuke the little critters you should know that cockroaches survived the atomic bombs test blast at Bikini. “There is such a thing as a lethal dose of radiation for a cockroach, but it is a lot higher than our own.”

Predators
“While few humans may eat them, the roach has both external and internal predators and parasites. There are centipedes that have a primary diet of cockroaches. Mantises, ants, and scorpions will eat them, as will a variety of larger animals including toads, frogs, possums, hedgehogs, armadillos, mongooses, monkeys, lizards, spiders, mice, cats, and birds”

Sleeping
Roaches are nocturnal and pass their days sleeping.

Male aggression
“Cockroaches, like so many other species including our own, have male aggression rituals. They have their own inventory of aggressive behaviors, a scale of conflict that begins with threatening postures. Beyond that they graduate to antenna lashing—a form of which is also present in male/female encounters to determine if a female is sexually receptive–and biting. Sex and territory seem to be the primary motivations for fighting between male cockroaches: These clashes never end in death, but always in the retreat of one fighter.”

Trapping a cockroach
“Stale while bread moistened with warm, slightly soured beer” is the most reliable and effective. “This is typically placed at the bottom of a small jar—a Gerber’s baby food jar, say—around the interior rim of which a petroleum jelly like Vaseline has been applied. The cockroach can climb in from the outside but can’t climb back out.”

What should you do if you get a cockroach stuck in your ear?
“It is, according to all accounts, painful and horrifying, although a little mineral oil or lidocaine sprayed into the ear is usually enough to dislodge the intruder.”

Exterminators
Exterminators primarily employ two methods to kill the cockroach: gas and gel. The gel is way more effective but many still rely on the spray. Why? “The major problem that exterminators have with the gel is that it has no immediate knockdown effect.”

John Wickham, an English pest control consultant defined knockdown as: “The inability of the insect to move in a sufficiently coordinated manner to right itself and progress normally.” When a roach eats gel bait—the safer of the two methods—it heads home before the active poison kills it.

“Customers who are paying $75 an hour like to see these roaches struggling to get up, in agony and convulsions, and the sprays, with substantial knockdown effect, provide them that gratifying visual reassurance that the problem is being solved and that they are getting their money’s worth.

It’s unlikely this poison will have much long term impact. “Almost as soon as an effective poison goes into widespread use, cockroaches begin to develop Resistance. And, typically, the most efficacious products developed, those that do the best job, turn out to be more detrimental to our own health than are the roaches.”

If you want to learn more about cockroaches read The Cockroach Papers.