Why Evolution is True is a blog written by Jerry Coyne, centered on evolution and biology but also dealing with diverse topics like politics, culture, and cats.
It’s October 24, 2016, and appears to be National Food Day. In honor of that, please have some food today.
Tom Hayden died last night at age 76 from the aftereffects of a stroke. One of my youthful heroes, he was a noted anti-war and pro-civil rights activist, and one of the Chicago Seven tried in 1968 for protesting at the Democratic National Convention in Chicago. Charged with conspiracy and incitement to riot in that highly publicized trial, Hayden and his co-defendants were later acquitted. Hayden spent the rest of his life as an activist, winding up as a California state senator. Those of a certain age will also remember he was married to Jane Fonda for a short while.
LOS ANGELES – APRIL 6: Former California State Senator Tom Hayden (D) arrives to the funeral services for lawyer Johnnie L. Cochran, Jr. at the West Angeles Cathedral on April 6, 2005 in Los Angeles, California. (Photo by Frederick M. Brown/Getty Images)
On this day in 1260, the Chartres Cathedral was dedicated. It has some of the most beautiful stained glass windows in the world, so if you go to Paris, don’t miss a day trip to Chartres. Also on this day in 1945, the United Nations was founded with great hopes; it’s now devolved into a largely useless organization. And on this day in 1947, Walt Disney testified before the House Un-American Activities Committee, giving them the names of his employees that he suspected of being Communists. Feel differently about Uncle Walt now?
Notables born on this day include Antonie van Leeuwenhoek (1632; see Matthew’s tribute a bit later today). Those who died on this day include Vidkun Quisling (1945; executed for treason), G. E. Moore (1958), Jackie Robinson (1972), Gene Roddenberry (1991), Rosa Parks (2009), and Maureen O’Hara (2015). Meanwhile in Dobrzyn, Hili makes her first comment on the American Presidential election. When I asked what Hili meant, Malgorzata explained:
It’s a choice between pest and cholera. What can someone, who – fortunately – doesn’t have to make this choice say about it? That the great America went crazy and wants to be governed either by a dangerous buffoon or by a dishonest, greedy politician who refuses to take responsibility for her actions?
And so Ms. Hili:
A: You’ve never said anything about the choice between Trump and Clinton…
Hili: I better say nothing.
In Polish:
Ja: Nigdy nie mówiłaś co sądzisz o wyborze między Trumpem i Clinton…
Hili: I lepiej, żebym nadal nic nie mówiła.
Reader Keira McKenzie from Oz sends a lovely portrait of her black cat, Plushie with a caption:
PuffHo’s frenetic demonization of Donald Trump (who’s already demonized himself out of contention for the Presidency) is growing—to the point of lunacy. Look, for instance, at the Entertainment section, where virtually every article is not about entertainment, but about how some entertainer has produced the “perfect” takedown of The Donald. Even “Weird News,” which used to have great nuggets of bizarreness, has jumped the shark, as witnessed by the article on “Grabby Donald” below (click on it, if you must, to see the piece)
But enough, as I’m trying to get PuffHo off my lawn. I call your attention instead to a recent piece by Glenn Greenwald, known to us as the mendacious and oliagenous atheist-hater and osculator of Islam, published at The Intercept. Called “The unrelenting pundit-led effort to delegitimize all negative reporting about Hillary Clinton,” the piece actually seems reasonable to me. Let us always remember that even those journalists whom we dislike, or whose ideology we reject, can sometimes produce something good. This may be one of them, but I invite readers to weigh in.
Greenwald is no fan of Trump, and clearly thinks Hillary is the far superior choice for President. I agree. But he also thinks, and I also agree, that the liberal media has gone overboard in trying to dismiss all criticism of Clinton, either out of some misguided form of Democrat worship, or—as we’ve I’ve seen from some readers—out of fear that criticizing Clinton could cause her to fall in the polls. (I hope you realize that the latter is no longer an issue.) He especially excoriates Paul Krugman for an unrelenting defense of Hillary (I’ve noticed that too, and wonder if Krugman isn’t angling for some Cabinet or government position), and takes the liberal media to task for the same behavior. I’ll give a few excerpts.
That American journalists have dispensed with muted tones and fake neutrality when reporting on Trump is a positive development. He and his rhetoric pose genuine threats, and the U.S. media would be irresponsible if it failed to make that clear. But aggressive investigative journalism against Trump is not enough for Democratic partisans whose voice is dominant in U.S. media discourse. They also want a cessation of any news coverage that reflects negatively on Hillary Clinton. Most, of course, won’t say this explicitly (though some do), but — as the wildly adored Krugman column from [Sept. 5] reflects — they will just reflexively dismiss any such coverage as illegitimate and invalid.
. . . . it would be journalistic malpractice of the highest order if the billions of dollars received by the Clintons — both personally and though their various entities — were not rigorously scrutinized and exposed in detail by reporters. That’s exactly what they ought to be doing. The fact that quid pro quoscannot be definitively proven does not remotely negate the urgency of this journalism. That’s because quid pro quos by their nature elude such proof (can anyone prove that Republicans steadfastly support Israel and low taxes because of the millions they get from Sheldon Adelson and the Koch brothers, or that the Florida attorney general decided not to prosecute Trump because his foundation and his daughter donated to her?). Beyond quid quo pros, the Clintons’ constant, pioneering merger of massive private wealth and political power and influence is itself highly problematic. Nobody forced them to take millions of dollars from the Saudis and Goldman Sachs tycoons and corporations with vested interests in the State Department; having chosen to do so with great personal benefit, they are now confronting the consequences in how the public views such behavior.
But none of it suggests that anything other than a bright journalistic light is appropriate for examining the Clintons’ conduct. . .
. . . The reality is that large, pro-Clinton liberal media platforms — such as Vox, and the Huffington Post, and prime-time MSNBC programs, and thecolumnists and editorialists of the New York Times and the Washington Post, and most major New York-based weekly magazines — have been openly campaigning for Hillary Clinton. I don’t personally see anything wrong with that — I’m glad when journalists shed their faux objectivity; I believe the danger of Trump’s candidacy warrants that; and I hope this candor continues past the November election — but the everyone-is-against-us self-pity from Clinton partisans is just a joke. They are the dominant voices in elite media discourse, and it’s a big reason why Clinton is highly likely to win.
That’s all the more reason why journalists should be subjecting Clinton’s financial relationships, associations, and secret communications to as much scrutiny as Donald Trump’s. That certainly does not mean that journalists should treat their various sins and transgressions as equivalent: Nothing in the campaign compares to Trump’s deport-11-million-people or ban-all-Muslim policies, or his attacks on a judge for his Mexican ethnicity, etc. But this emerging narrative that Clinton should not only enjoy the support of a virtually united elite class but also a scrutiny-free march into the White House is itself quite dangerous. Clinton partisans in the media — including those who regard themselves as journalists — will continue to reflexively attack all reporting that reflects negatively on her, but that reporting should nonetheless continue with unrestrained aggression.
Even on this site, I’ve had liberal readers tell me that I shouldn’t question the Clinton Foundation’s questionable contributors because “you can’t prove anything.” But as Greenwald says, “the fact that quid pro quos cannot be definitively proven does not remotely negate the urgency of this journalism.” And that’s precisely why ethical politicians avoid the appearance of a conflict of interest.
At any rate, if you read the piece you’ll see that by no means is Greenwald a flack for Trump. He despises the man. But I don’t think it’s kosher to withhold criticism from Clinton at this point because it might lead to Trump’s election. In fact, given what’s happening in the polls, I can’t see anything that could help Trump. The idea that now is not a good time to criticize Clinton, and that we should wait until after the election, strikes me as a way to permanently maim one’s moral antennae. After all, she’ll be the next President of the U.S.
But read Greenwald’s article and let me know what you think.
Speaking of hybridization, my friend Nicole L’Or Reggia sent me some ears she grew of what’s called “glass gem corn,” which are gorgeous. I had no idea this stuff existed, though of course I’d seen less variegated “Indian corn” that appears around Halloween. Here are 12 ears: all of them are small: up to about six inches long. Some are highly variegated like a pack of Jelly Belly jelly beans, while others have a dominant color scheme (bottom of the second picture and the third picture).
As the corn dries out, it becomes translucent, making it even more gemlike. The photos below show what my ears will eventually look like (photos are taken from various places, including the Glass Gem Corn Facebook page):
Now how are these produced? It’s hard to find much information about Glass Gem corn. It was clearly developed by breeding varieties of corn having different-colored kernels, but beyond that there’s little information about the breeding scheme. There’s a piece at Business Insider, and this from My Modern Met:
Nature often surprises us with the amazing things it produces, and Glass Gem corn is a fantastic instance of when the line between what’s real and fake is blurred. The rainbow-colored kernels resemble brilliantly-hued strands of jewels rather than something you’d find on your plate. They’re all natural, however, and are the result of heirloom-style farming as well as selective planting.
The story behind these special corn cobs started with an Oklahoma-based farmer named Carl Barnes. As an adult, the half-Cherokee Native American began growing older varieties of the crop as a way to reconnect to his roots. In doing this, he isolated heirloom corn seeds that were lost to Native American tribes when, in the 1800s, they were relocated to present-day Oklahoma.
Barnes shared and exchanged the ancient corn seeds with people he had met around the country, while he also selected and planted grains from the more colorful varieties. This is how the dazzling rainbow corn was born, but these weren’t crops that he kept to himself. Thanks to Barnes, fellow farmer Greg Schoen became acquainted with the vegetable in 1994 at a native-plant gathering in Oklahoma. Mesmerized by the colors, Barnes gave Schoen some of the seeds, who then planted the rainbow corn next to traditional yellow varieties. This mixture led to new and exciting hybrids.
Like Barnes, Schoen passed the seeds along to others, one being Bill McDorman. He owned an Arizona company called Seed Trust, and he’s now the Executive Director of Native Seeds/SEARCH. The non-profit conservation organization now sells the seeds online. [JAC: you can buy the seeds online for only $4.95 a packet.]
But beyond that, I see little information, though I’ve done only a cursory survey. I’m hoping a reader with botanical expertise can explain these, but here’s what I know about corn (I hope this is right!):
Each “kernel” is the result of a separate pollination event, which clearly accounts for the different colors (they come from genetically different pollen and ovules). Corn is wind-pollinated, but is effectively self-incompatible as the tassels (male parts) are physically separated from the ears (female parts). The many different colors surely reflect many different kinds of pollen impinging on each ear. Each “silk” on an ear is a style: the tube through which the pollen will grow to produce a single kernel. Each “cob” involves several hundred fertilization events. I could plant each kernel and, if I plant more than one together, get more ears like these.
I have no information about the color diversity among ears from the same plant. By all rules of genetics, they should resemble each other more than ears from different plants, since ears of a single plant have a single female genotype.
Many ears have a dominant “theme” color, like the purple and reddish ears depicted above. That may reflect a female genotype carrying “red” or “purple” genes, or perhaps limited pollination (Nicole grew about a dozen plants), the dominance relationships of some color alleles, or all of the above.
I know squat about corn genetics, and even less about corn color genetics. To work out how ears like the above are possible, one needs to be able to show that each of the kernels on a given ear reflects the female’s genotype in the ovule (limited to two alleles at each color locus) combined with a substantially larger variety of alleles in the pollen that fertilizes the female. And you’d have to know the dominance relationships as well as the number of genes producing each color.
And that’s where my knowledge stops. Readers who know about corn varieties or corn genetics are invited to weigh in.
Oh, and about its edibility. Apparently it’s not edible like regular corn on the cob, but you can cut the dried kernels off the cob to make popcorn. Then, however, the color disappears. Or I could plant the kernels, though growing space is sparse in my neck of the woods. I’d prefer to let my ears dry out, become gemlike, and then show off the ears as a lovely novelty.
Data show that the “normal” mode of speciation—the process in which one lineage divides into two or more species—involves the geographic isolation of populations of a single species. Over time, natural selection (and genetic drift) causes those populations to become more and more genetically different. When the genetic differentiation has gone to the extent that the separate populations evolved features that make them unable to produce fertile hybrids when they come back together in the same area (i.e. regain “sympatry”), then these populations have become separate species. They are now groups on distinct evolutionary trajectories, and their inability to exchange genes because of the evolved “reproductive isolating barriers” between them (e.g., behavioral differences in mating, preferences for different host plants or microhabitats, different times of mating, different pheromones, or the sterility or inviability of hybrids), is what makes nature “lumpy” rather than a continuum. The lumpiness of nature—the fact that, in a single geographic locality, in most groups you readily see distinct clusters of plants or animals (look at the birds outside your window, or look at a field guide)—is an important fact that can only be explained by connecting the formation of those “lumps” with the reproductive barriers that keep them from forming a continuum.
Geographic isolation is thought to be important because gene flow between diverging species tends to keep them from diverging. In our own species, humans in different places began the process of genetic divergence, as witnessed by the traits that distinguish human populations (these are correlated with geographic isolation, as the theory predicts), but this process was nipped in the bud by both population growth and the invention of forms of transportation that allow people to move much farther than they used to. There is now gene flow between many populations, and Homo sapiens is an example of a “polytypic” (variable) species that, if the populations had remained isolated for a million years or so, might have become more than one species of Homo.
One thing that biologists have discovered since the advent of DNA sequencing, though, is that gene flow between species is more common than previously thought. Reproductive barriers aren’t always complete (although they are now between our species and all other living species), and so sometimes hybrids are formed and genes can sneak between different species. In the group I used to work on, the closely related species Drosophila santomea and Drosophila yakuba, we and others discovered that the entire mitochondrion, with all of its own DNA, invaded D. santomea from D. yakuba, and there’s been a bit of other gene flow as well. (In most of the genome, however, the species remain distinct.) This could only have been due to hybridization, and it happened because although the species tend to live at different altitudes, there are areas of overlap where they can meet and hybridize, and the female hybrids (but not the males) are fertile.
So we know that genes sneak between species more often than we used to think.
Some biologists, however, have gone farther, and postulated that hybridization between two species can itself cause the formation of a third species, a process called “hybrid speciation.” This is somewhat common in plants, occurring through a special genetic mechanism called polyploidy. There are two forms. Allopolyploidy involves the hybridization of two species having different chromosome numbers, and since the different chromosomes can’t pair in the hybrids, those hybrids are sterile. However, if the chromosome number doubles in the hybrids, so that a new individual is formed with a chromosome number equal to the sum of the numbers in both parental species, one can get an “allotetraploid” populations whose members are fertile among itself but sterile when they mate with either parental species. (See any evolution textbook for an explanation.). This would, then, be a new biological species. A similar process can occur if chromosome number doubles within a single species, producing an autotetraploid. Further hybridization and chromosome doubling can lead to entire polyploid series of plants with hundreds of chromosomes, as in ferns.
As I said, polyploidy, both auto- and allo-, is a fairly common mode of speciation in plants. As Allen Orr and I noted in our book Speciation (read chapter 9), roughly 2-4% of speciation events in flowering plants involved polyploidy of one sort or another, and maybe as many as 7% of speciation events in ferns. This is a rough estimate, and the real frequency could be higher. But polyploid speciation in animals is much rarer, and I won’t go into the suggested reasons for it (see pp. 333-337).
There’s another form of hybrid speciation called “homoploid hybrid speciation” or “recombinational speciation.” In that process, a hybrid is formed between two species, and then, if it is at least partly fertile, the genes from the different parental species can sort themselves out into new combinations of genes or chromosome arrangements from the parental species. If the new sorted-out population is reproductively isolated from the two parental species that produced it, we have a new homoploid hybrid species.
Many biologists (I won’t name them) have posited that this kind of speciation is rampant in nature, so that it’s not just the occasional sneaking of genes between species that’s important, but also the wholesale formation of new species after hybrid formation. Lots of suggested examples of such species have been given.
However, it appears that most of the evidence for non-polyploid hybrid speciation is weak. That, at least, is the conclusion of Molly Schumer, Gil Rosenthal, and Peter Andolfatto in a 2014 paper in Evolution (link and free access below), a paper that I only learned about at CoyneFest. Schumer et al. argue that good evidence for a non-polyploid hybrid speciation event requires satisfying three conditions, and I quote:
To demonstrate that hybrid speciation has occurred given this definition, three criteria must be satisfied: (1) reproductive isolation of hybrid lineages from the parental species, (2) evidence of hybridization in the genome, and (3) evidence that this reproductive isolation is a consequence of hybridization. By contrast, a large number of empirical studies have simply used genetic evidence of hybridization (Criterion 2) as support for hybrid speciation. . .
The authors argue that there are many ways that a species can look as if it’s a hybrid without actually being the result of full-scale hybridization (or any hybridization); that in some cases a hybrid lineage hasn’t been tested to show that it’s interfertile with other members of that lineage and reproductively isolated from the parental species, and, especially, there are almost no demonstrations that the genes or chromosome arrangements of parental species have sorted themselves out in a way that has created a reproductively isolated homoploid hybrid. That is, few people have shown that the reproductive isolation of a putative hybrid species involves genes that came from the parental species rather than, say, genes that evolved via natural selection after hybridization.
You can read the paper for details, but Schumer et al. conclude that despite the big noise from some biologists, there are only four cases of homoploid hybrid speciation that meet their criteria. Three of them are in one genus: the wild sunflower Helianthus, which has formed three diploid species—all adapted to novel environments—by hybridization of pre-existing species and the sorting out of chromosome arrangements that, with their divergent genes, reproductively isolate the hybrid population from the parents. That superb work was done by Loren Rieseberg and his colleagues.
The other case is the butterfly Heliconius heurippa, which genetic evidence shows almost certainly resulted from hybridization between the species Heliconius cydno and Heliconius melpomene, H. heurippa has a hybrid wing pattern, which you can see below, and it’s been shown that each species, as well the “hybrid”, are reproductively isolated from the others because males mate almost entirely with females who have their own wing patterns. Thus H. heurippa (shown below with its parents) satisfies all three of the authors’ criteria, for the genes causing reproductive isolation are precisely the color-pattern genes derived from the two parental species.
H. heurippa (the hybrid species)H. melpomeneH. cydno
The upshot is that while the movement of individual genes between both plant and animal species is more common than evolutionists assumed before the gene-sequencing era, there is still scant evidence that entire new species of animals form via hybridization. Hybrid speciation is more common in plants, but only through the unusual mechanism of polyploidy, and homopoloid hybrid speciation (without an increase in chromosome number) doesn’t appear common in either plants or animals.
Today we’ll dispense with readers’ wildlife photographs, as I want to save some until I return from Asia in about 3 weeks. Instead, reader John O’Neall called my attention to Nikon’s Small World Photomicrography Champions, and I’ll like to present a few of the winners. They give us an idea of the marvels of nature that we don’t normally see.
First, the grand prize. Four-day-old zebrafish embryo (10x). Technique: Confocal. Photo by Dr. Oscar Ruiz, M. D. Anderson Cancer Center, Houston, Texas:
The second prize went to Douglas L. Moore at the University of Wisconsin at Stevens Point. It’s called “Polished slab of Teepee Canyon agate” (90x). Technique: steromicroscopy.
Fifth place went to Dr. Igor Siwanowicz from the Howard Hughes Medical Institute, Ashburn Virginia. It’s the front foot (tarsus) of a male diving beetle (100x), taken using confocal microscopy:
This photo of wildflower stamens won Samuel Silberman of Israel 8th place. It’s a 40x picture taken using fiber optic illumination:
This photo, by Geir Drange of Asker, Norway, took 15th place. It’s a head section of an orange ladybird (Halyzia sedecimguttata) (10x), taken using reflected Light and focus stacking.
This photo, by Charles Krebs of Issaquah, Washington, got an honorable mention. It shows the tail of a a small shrimp. 40x, reflected light:
There are many more photos at the site; go have a look.
It’s Sunday, October 23, 2016, and this morning all of Chicago is in jubilation about the Cubs’s clinching of the National League championship last night, shutting out the Dodgers 5-0. On Tuesday they’ll meet the American League champions, the Cleveland Indians, for the first game of the World Series. Chicago hasn’t won a league championship since 1945, and a World Series since 1908! That’s a record dry spell.
It’s also national Boston Cream Pie day. If you’re an American you’ll almost surely know what a Boston Cream pie is, but here’s a picture for all the uninitiated. It’s more like a cake, and proclaimed in 1996 as The Official Dessert of Massachusetts:
It’s good, but one rarely sees it any more. However, Dunkin Donuts does have a Boston Cream donut that approximates it.
And as I’m writing this, it just became a chemistry day: Mole Day (not the animal!), as explained by Wikipedia:
. . . . an unofficial holiday celebrated among chemists, chemistry students and chemistry enthusiasts on October 23, between 6:02 AM and 6:02 PM, making the date 6:02 10/23 in the American style of writing dates. The time and date are derived from Avogadro’s number, which is approximately 6.02 × 1023, defining the number of particles (atoms or molecules) in one mole of substance, one of the seven base SI units.
On this day in 1917, Lenin called for the October Revolution in Russia, and, in 1929, panic begin to set in on the New York Stock Exchange, ultimately triggering the Great Depression. On this day in 1942, the Second Battle of El Alamein began, which, according to William Shirer, and along with the German defeat at Stalingrad, marked the beginning of the end for Hitler’s Reich. Finally, on October 23, 1973, Nixon agreed to turn his Oval Office tapes over to investigators after a Supreme Court order. What was on those tapes ultimately led to his resignation.
Those born on this day include Felix Bloch (1905), Johnny Carson (1925), and Michael Crichton (1942). Notable people who died on this day include Zane Grey (1939), Al Jolson (1950), Mother Maybelle Carter (1978), and Jessica Savitch (1983 ♥). Meanwhile in Dobrzyn, Hili’s been very bad, snatching food from her staff:
A: Hili, who ate my sausage?
Hili: What sausage?
In Polish:
Ja: Hili, kto zjadł moją kiełbasę?
Hili: Jaką kiełbasę?
And out in icebound Winnipeg, Gus is doing serious nomming of his box? Why? Nobody has any idea, for he slept in it for several months without a single bite. Is he exercising his gums? Showing atavistic behavior of tearing up prey? Who knows? But given that the box is well aged, Gus certainly isn’t following the French instructions: “Mangez frais” (“Eat fresh”)!
Finally, since Halloween is coming up, here’s a rude cat pumpkin, found on Imgur and sent by reader Arno:
I have no idea if this true, or how you could be confident it was (or wasn’t) correct, but it could easily be right. Jack is Manager of the Grant Museum of Zoology at University College London.
Four out of every five individual animals on Earth today is a nematode worm. There are a lot of nematode worms.
In Polish:
