Teaching Evolution: Sewall Wright: Evolution in space

March 9, 2019 • 10:30 am

by Greg Mayer

Our next installment of Teaching Evolution for this spring concerns Sewall Wright. His contributions were wide-ranging, but he is most noted for his integration of population structure (population size, migration) and selection into what he called the “shifting balance” theory. In this theory, genetic drift, migration, and selection interact to produce what he saw as the most favorable conditions for evolutionary advance. The reading is a brief precis of his much longer 1931 paper in Genetics, but in many ways was more influential, as it exposed a wider audience to his ideas. Modern appreciations of the shifting balance theory are given by Nick Barton (2016) and Norm Johnson (2008).

Sewall Wright, with guinea pig.

Sewall Wright (1889-1988) was, along with R.A. Fisher and J.B.S. Haldane, one of the founders of theoretical population genetics, which synthesized Mendelian inheritance with Darwinian natural selection, thus laying the foundations of modern evolutionary biology. His classic paper “Evolution in Mendelian Populations” (Genetics, 1931) laid out his synthesis, and led to his election to the National Academy of Sciences while still a young man. Like Darwin, Wright studied carefully the work of animal breeders, and this strongly influenced his ideas on evolution, which he called the “shifting balance” theory. Although sometimes caricatured as a theory emphasizing random genetic drift, Wright stressed the importance of the interaction of drift, selection, and migration in adaptive evolution. Wright strongly influenced Dobzhansky, and he coauthored five papers in the latter’s “Genetics of Natural Populations” series. Beginning with his graduate studies at Harvard, Wright’s organism of choice for genetic studies throughout his career, which ended with a very productive 33 year retirement at the University of Wisconsin, was the guinea pig (note what is in his left hand in the photo). He is author of the monumental four volume Evolution and the Genetics of Populations (1968-1978). William Provine has edited a collection of Wright’s most important papers, Evolution: Selected Papers (1986), and written an insightful and analytic biography, Sewall Wright and Evolutionary Biology (1986).

Reading:

Wright, S. 1932. The role of mutation, inbreeding, crossbreeding, and selection in evolution. Proceedings of the Sixth International Congress of Genetics 1:356-366.

Study Questions:

1. In this paper, Wright introduces the idea of a fitness surface or adaptive ‘landscape’ (see esp. Fig. 2). What do the x and y axes (the two dimensions of the ‘map’ on the paper) represent? What does the ‘altitude’ of a point on the landscape represent? What does a peak in the landscape represent? What does a valley in the landscape represent?

2. In one sentence in the first half of the paper, Wright succinctly states the Hardy-Weinberg equilibrium for allele frequencies, and its cause. Find and quote the sentence. Show that Wright understands the H-W principle.

3. Why is it difficult for a species to evolve across a valley from one peak to another if selection is the only evolutionary force? How does this lead Wright to argue for the importance of drift (inbreeding) and migration (crossbreeding), as well as selection, in allowing species to reach the highest adaptive peaks?

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Jerry addendum:  While Wright’s theory was influential, and was incorporated by Theodosius Dobzhansky into his view of the Modern Evolutionary Synthesis (see his book Genetics and the Origin of Species), I find the theory deeply flawed. With two colleagues, Nick Barton and Michael Turelli, I wrote a long critique of that theory in 1997. Our paper was in turn criticized in two papers, one by Mike Wade and Charles Goodnight, and the other by Steven Peck et al.  We then rebutted these papers in another Evolution paper in 2000. All four references and links are below.

In my biased estimation, our critique did stem the tide of enthusiasm for Wright’s theory; in fact, Wright’s colleague James Crow at Madison said that our paper prompted him to stop accepting that theory. I’m not sure whether Greg mentions the critiques and attempted rebuttals in his lecture, but I’m putting them here for readers.

Coyne, J. A., N. H. Barton, and M. Turelli.  1997.  A critique of Sewall Wright’s shifting balance theory of evolution.  Evolution 51:643-671.

Wade, M. and C. J. Goodnight. 1998. The theories of Fisher and Wright in the context of metapopulations: when nature does many small experiments. Evolution 52:1537–1553.

Peck, S. L., S. P. Ellner, and F. Gould. 1998. A spatially explicit stochastic model demonstrates the feasibility of Wright’s shifting balance theory. Evolution 52:1834–1839.

Coyne, J. A., M. Turelli, and N. H. Barton.  2000.  Is Wright’s shifting balance process important in evolution? Evolution 54: 306-317.

 

Caturday felid trifecta: Realistic cat masks; cat burgler steals dosh from the milkman; computer-generated cats that don’t exist

March 9, 2019 • 9:00 am

Reader Steve sent me this first, but since then I’ve gotten this or similar links from many readers (thanks, all!). At this site you can see the products of a Japanese company that produces realistic cat masks. They take a picture of your cat that you’ve sent in, and, for a considerable fee (about $2700), will produce a realistic head mask of your cat that you can use to scare the bejeesus out of both people and felids.  They use the photo to make a mold of your cat, and then apply the fur and finishing touches:

 

 

This cat doesn’t look too pleased. . . . 

. . . and a video! This doesn’t show much about the cat mask, except that a dude wearing one narrates a cute video about a mother cat and her four new kittens:

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From the BBC we have this story about another cat burglar, this time one that steals MONEY. (Click on the screenshot):

An excerpt:

A kleptomaniac cat notorious for stealing items from its neighbours has “finally brought home something of real value” – £25.70 in cash.

Pilfering puss Theo became known for thieving Christmas decorations and toys in Ipswich, which owner Rachael Drouet would then try to return.

She had joked it might be useful if he brought home cash instead of “tat”.

So he did. The eight-year-old Siamese cross stole the money a neighbour had left out for the milkman.

Ms Drouet and her family recently moved to a new house in the town and thought Theo might have left his thieving habits behind him.

Far from mending his ways, the filching feline upped his game and stole a plastic bag containing the cash.

Luckily there was a note inside with an address, and Ms Drouet’s partner Paul Edwards was able to return the money to their neighbour.

“He explained we have an Asbo cat,” Ms Drouet said.

“The young lad smiled, took the money and acted like that kind of thing happened all the time.”

Now I have no idea what “tat” is, nor what an “Asbo cat” might be, so British readers might help out. At any rate, all’s well that ends well. Here’s the dosh that Theo brought home:

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When I was a kid, my father used to tell me, “Jerry, try to think of a face you’ve never seen before.” This is very hard, as your imagination always calls up faces of people you’ve met. But, using computer technology, you can do this by morphing different faces. Now, the DevopStar site describes how you can produces not only the faces of humans that don’t exist, but also of cats.  Here are some cat faces generated this way. Most aren’t bad, but that monstrosity at the lower left is clearly a glitch, as is the asymetrically-eyed cat right above it:

h/t Kevin, Graham

Readers’ wildlife photos

March 9, 2019 • 7:30 am

Today we have a selection of insect photos from regular Mark Sturtevant, whose comments and IDs are indented:

Here is the final batch of photos taken over the summer of 2017. Enjoy!

We begin with a picture of some very tiny flies that were feeding from flowers. They’re clearly not mosquitoes, although they do somewhat resemble them right down to having a long proboscis. They were eventually identified as members of the bee fly family (Bombyliidae), so named because larger species resemble bees. Adult bee flies are important pollinators, while their larvae are parasitic on a range of insect hosts. This species is in the genus Geron.

The weird little fly shown in the next picture would have stumped me, but with the above bee fly identification I knew the family and that led to identifying it. This is a scaly bee fly (Lepidophora lepidocera). It was sipping the sweat off the arm of a friend of mine while we were out photographing insects. He could not get its picture because of its location, but I made him hold still so I could!

Moving on, I always find something to see in the Magic Field. Three species of tiger beetles are to be found in this field, and my favorite is this one: the festive tiger beetle (Cicindela scutellaris). Their colors can be pretty amazing (and variable), as shown in the link, but most of the ones around here are much darker. The first picture was of an individual that allowed me to get barely close enough for pictures. The much closer picture is of a beetle that allowed me get as close as I wanted. But that individual was pretty dusty.

Tiger beetles are clearly active predators, and long as I can remember they were placed in their own family while also being closely related to the ground beetle family. They are divided into two groups, and the most familiar group is known as the ‘flashy tiger beetles’. The festive t.b. is clearly a member of that crowd. Other tiger beetles are black or some other plain color, and they closely resemble ground beetles. I had recently learned that the entire tiger beetle family has been placed within the ground beetle family(!) I am probably out of the loop on many other revisions of this sort.

Next are pictures of a garden spider (Argiope aurantia) who was completing her egg sac near the end of the season. I had not seen this since I was a wee kiddo, and it was nice to observe. She was single-mindedly going ‘round and ‘round her enormous parental investment, carefully securing her “preciousss” for the long winter that was fast approaching.

On one of my last outings before winter, I found this nice big ‘n bristly Tachinid fly (looks like Juriniopsis adusta) on one of the last blooming goldenrods. These flies are of course parasitic on other insects, and this species is parasitic on caterpillars.

Finally, on the same plant was this nice surprise: an oötheca from a Chinese mantis (Tenodera sinensis). This will stand over the winter, and about a hundred little mantids will emerge all at once the following spring. This is a cheering thought.

 

Saturday: Hili dialogue

March 9, 2019 • 6:30 am

It’s the weekend at last, and I think the scent of Spring is in the air on this ninth of March, 2019. It’s National Crab Day, and I could use a batch of blue crabs, a mallet, and a pitcher of beer. That’s one of the best American meals you can get.

On this day in 1500, the fleet of the Portuguese explorer Pedro Álvares Cabral left Lisbon , heading for the Indies. The fleet discovered what is now Brazil in South American, and that’s why the country speaks Portuguese.  On March 9, 1566, the secretary to Mary, Queen of Scots, David Rizzio, was murdered in her presence in Holyrood Palace, Edinburgh.  On this day in 1776, Adam Smith published his famous book The Wealth of Nations.  On March 9 of 1916, Mexican revolutionary Pancho Villa, along with 500 raiders, attacked the border town of Columbus, New Mexico (note that Wikipedia’s “Pancho Villa” page says only 100 raiders, so again we have a discrepancy). He was after arms and ammunition, but got General Pershing and the U.S. Army on his tail, though he eluded capture.

On March 9, 1946, the Bolton Wanderers Stadium Disaster took place in Bolton, when a barrier collapsed under a packed crowd (estimated at 85,000), resulting in the death of 33 fans and injuries to hundreds. Oddly, they continued the game after the bodies were covered. Here’s a  12-minute video about that event, with interviews of many who were at the game:

On March 9, 1954, CBS News with Edward R. Murrow (produced by Fred Friendly) produced the “See it Now” episode describing the malfeasance of Senator Joseph McCarthy, which helped bring him down. It was also influential in how future television investigations would be structured. In his famous summary, Murrow said this, which still resonates today:

No one familiar with the history of his country can deny that Congressional committees are useful; it is necessary to investigate before legislating. But the line between investigating and persecuting is a very fine one, and the junior senator from Wisconsin has stepped over it repeatedly. His primary achievement has been in confusing the public mind as between the internal and the external threats of communism. We must not confuse dissent with disloyalty; we must remember always that accusation is not proof, and that conviction depends upon evidence and due process of the law.

Here is the entire show, well worth watching:

On this day 60 years ago, the Barbie doll was introduced at New York’s International Toy Fair.

Notables born on this day include Vita Sackville-West (1892), Samuel Barber (1910), Mickey Spillane (1918), Ornette Coleman (1930), Yuri Gagarin (1934, first human in space), Bobby Fischer (1943), Bobby Sands (1954), Ornella Muti (1955).

Sands, an IRA member died on May 5, 1981 during a prison hunger strike; 9 others died in the same episode. Sands was only 27.  Here were their demands:

Those who expired on this day include Cardinal Mazarin (1661), Mary Anning (1847), Leopold von Sacher-Masoch (1895), Robert Mapplethorpe (1989), Charles Bukowski (1994), George Burns (1996), Notorious B.I.G. (1997), and John Profumo (2006).

Meanwhile in Dobrzyn, Hili’s comment is a bit opaque. Malgorzata explains:

“Wisła is the biggest river in Poland, it flows through the whole of Poland. Hili is a tiny cat and has absolutely nothing to do with the river and its flow. The idea that a tiny cat should be, on the one hand, proud, and, on the other, a bit patronizing towards this huge river seemed funny to us.”
The dialogue:
Hili: I’m proud of my river.
A: Why?
Hili: Because it continues to flow in spite of all obstacles.
She does look proud, doesn’t she?
In Polish:
Hili: Jestem dumna z mojej rzeki.
Ja: Dlaczego?
Hili: Bo dalej płynie, mimo wszystkich przeszkód.

A tweet from reader Nilou. Imagine trying to rock climb in a full-length skirt! Pinker was right!

Tweets from Grania, the first showing a beautiful and adventurous Bengal cat:

https://twitter.com/AMAZlNGNATURE/status/1103906100225564672

Nick Cohen speaks truth to the benighted and the Woke. Many Brits contest the accusation that Labour has adopted an anti-Semitic cast.

. . . and God gets wise:

Man, viruses are SMALL!

https://twitter.com/MichaelGalanin/status/1102226924364095490

Okay, which muscle is this?

https://twitter.com/MichaelGalanin/status/1102316844315303937

Tweets from Matthew. Can you really eat a pineapple this way? Please, somebody try this!

https://twitter.com/DenzBenzi/status/1103958443050889216

So much for Michael Behe’s contention that only broken genes can promote adaptation:

Matthew retweeted this and commented, “Cool! But you might get frog spunk on your fingers.”

This is the opposite of a cat in so many ways:

 

 

My review of Behe’s book in the Washington Post

March 8, 2019 • 3:20 pm

Well, I read Michael Behe’s new intelligent-design book Darwin Devolves a long time ago, as I was asked to review it for the Washington Post. But I couldn’t say that, of course, for it would reveal that I had a prepublication copy, and that means I was going to produce a review. One can’t say that in advance. Up to this point, instead of giving my own take on the book, I gave the take of others: Rich Lenski, Josh Swamidass, Nathan Lents, and so on. At last my own review is out.

Well, we all agree: the book is, as ID books always are, junk science.

But Behe makes some truly outrageous statements in this one, especially his claim that mutations involved in distinguishing new families and similar higher-order taxa are those created by the Designer (aka God), while mutations creating lower level taxa like species and genera are random, non-Goddy mutations. To any biologist who knows how subjective groups like genera, families, and so on really are, this is arrant nonsense, bordering on lunacy.

Behe also claims (and I didn’t say this in my review), that the fossil record shows that “higher categories of classification such as phylum and class [precede] new lower levels of classification such as order and family” (p. 196), which is also ludicrous. All taxa begin as new species that result from the splitting of populations, and species themselves often continue to split and diverge to the point where groups of them (preferably with a common ancestry) can be called genera, families, and so on.

I didn’t get to mention that in my review, nor did I describe Behe’s ludicrous claim that disulfide bonds in proteins (cysteine-cysteine) are “irreducibly complex” because they hold proteins together but both of them must be in place before you get that bond. Ergo, God is required.  But there are plenty of single, free cysteine residues in proteins, which is a perfectly adaptive first step in forming those disulfide bonds. No irreducible complexity needed.

Sorry, but Behe’s book is dreadful. And that is what my review says. He and the Discovery Institute will be furious, but too damn bad. They’ve lied for Jesus too long.

Click on the screenshot to read my take on the book.

Naturalist communes with bears

March 8, 2019 • 2:30 pm

It’s the end of the week, which means it’s time to enjoy some animal cuteness. In this case we have a momma American Black Bear (Ursus americanus) and her two adorable cubs (or is it three?), all filmed by a biologist who gets along with them swimmingly.  This three-minute video from BBC Earth shows something I wouldn’t have thought possible: a man approaches a bear with her cubs and doesn’t get attacked! He even gives her treats and pets her! Here are the YouTube notes:

Natural World: Black Bears Of The Northwoods

Forty years ago Lynn Rogers began studying the black bears of the American Northwoods. During this time, he has formed a unique relationship with the bears, allowing him to spend time in close proximity with them, revealing more about their habits and characters than ever before. Through his research, Lynn Rogers hopes to prove that bears can live alongside people happily. Natural World follows Lynn and the bears for a year, revealing the nature of his relationship with his research subjects, including intimate footage of a bear and her new-born cubs.

As Andrew Sullivan might say, see you tomorrow!

h/t: Michael