See the Football Diving Hall of Shame for some Oscar-worthy performances.

Since I work on speciation, I’m often asked how many species there are on Earth. You’d think that we have a pretty good idea of this, but we don’t. Most species of viruses and bacteria—indeed, if there are such things as viral and bacterial “species”—can’t be easily seen in the field or grown in the lab, and most other species are nematodes or insects hidden in the forests of the tropics.

According to Robert May, who took up this issue without resolution in a 1988 paper in Science, biologists have named roughly 1.5 million species, with 15,000 more named each year.  This, of course, is only a fraction—perhaps a small one—of all species living on earth.  And, given the predominance of arthropods among all species, this effort is patchy.  As May points out in a note in this week’s Science, one third of taxonomists work on vertebrates, which are only about 1% of all species, another third work on plants (around 10% of all species), and the remaining third work on the other 89% of taxa.

Estimates have varied between 5 and 50 million species on Earth, and that’s a big range.  At the upper end of this range come calculations from biologist Terry Erwin, who, in a short but famous paper in 1982 in The Coleopterists Bulletin, tried to estimate the number of species of beetles in the world’s tropics.  (One third of the world’s species are insects, and of these about a third are in the order Coleoptera—beetles.  There’s a possibly apocryphal story about biologist J. B. S. Haldane, who was once asked what one could infer about the nature of the Creator from his creation.  “An inordinate fondness for beetles,” Haldane supposedly replied).

Erwin fogged  (sprayed with toxic chemicals) 19 individuals of the tropical tree Luehea seemannii in Panama, killing everything in their canopies, and carefully counted all the beetles he found.  There were 1143 species represented, most of them leaf-eaters.  Erwin then made some calculations.  Assuming that a certain percentage of these beetles were “host-specific,” found only on that species of tree (this percentage ranged from 5% for predatory and scavenging beetles to 20% for herbivores), he calculated that this species of tree harbored 163 species of host-specific beetles.

Erwin then parlayed these data into an estimate of the total number of tropical, host-specific arthropods in the world.  This involved making assumptions about not only the proportion of beetles that are host-specific, but the number of trees in the tropical forests (50,000), the proportion of arthropods that are beetles (40%), and the number of total beetle species per hectare of tropical rain forest canopy (12,448). Erwin came up with an astounding figure: thirty million species of tropical arthropods in the world!  And that’s just arthopods!  This suggested to many that there were far more species in the world than previously thought.  Erwin later (1988) produced an even larger estimate–one hundred million species of arthropod.

To be sure, Erwin recognized that this estimate was very rough, based on untested assumptions.  As he said, “I hope that someone will challenge these figures with more data.”

Well, someone has—not just with more data, but with better statistical analysis, too.  As May reports in this week’s Science, Andrew Hamilton and his colleagues have, in a new paper in The American Naturalist, used new data on species numbers, and have varied the parameter estimates that Erwin saw as fixed, to come up with new estimates of the number of tropical arthropods.

I w0n’t belabor the methods, which themselves involve assumptions, but they yield estimates of arthropod species much lower than that found by Erwin. Hamilton, using probability distributions for various estimates (such as the proportion of beetle species that specialize on a certain tree), come up with a range of species numbers, each having a relative likelihood.   The two separate models give a median species number of 2.5 million (90% confidence interval: 1.1-5.4 million) and and 3.7 million (c.i. 2.0-7.4 million) tropical arthropod species in toto; Erwin’s estimate of 30 million or more has a probability of less than 0.001% of being true.

Using these medians, Hamilton et al. estimate that, since only 855,000 species of arthropods have been described, 66%-77% of the world’s species are still unknown.  As they say, “This represents an enormous amount of work for taxonomists that will take hundreds of years to complete at the current rate that species are described, taxonomists are trained, and funding is allocated for invertebrate taxonomy.

They leave out one consideration: at the current rate of deforestation, we won’t have any rainforest left in a hundred years, and most of those species will vanish without ever having been seen by humans.

So how many species are there on Earth?  It’s still murky, but a fair back-of-the envelope estimate, including all those nematodes and the unknown parasites of living species (but not including bacteria), would involve tripling the estimate of total tropical arthropods, to make about ten million species.  And that’s what I’ll tell people if they ask, making sure to add that it’s a very rough estimate.

Fig. 1. The goliath beetle, Goliathus orientalis, one of many tropical insects. Males can reach 4 inches in length and weight 3.5 oz.

_________

Erwin, T. L.  1982.  Tropical forests: their richness in Coleoptera and other arthropod species.  Coleopterist’s Bull. 36:74-75.

___________.  1988.  The tropical rain forest canopy: the heart of biotic diversity.  pp. 123-129 in E. O. Wilson and F. M. Peter, eds.  Biodiversity. National Academy, Washington D. C. (Note: I haven’t read this paper).

Hamilton, A. J.  Yves Basset, Kurt K. Benke, Peter S. Grimbacher, Scott E. Miller, Vojtech Novotný, G. Allan Samuelson, Nigel E. Stork, George D. Weiblen, and Jian D. L. Yen. 2010.  Quantifying uncertainty in estimtion of tropical arthropod species richness.  Amer. Natur.  176:90-95.

May, R. M.  1988. How many species are there on Earth? Science 241:1441-1449.

May, R. M. 2010.  Tropical arthropod species, more or less?  Science 329:41-42.

I’m still not convinced of the value of Twitter, and so don’t (ugh) tweet, but I’ve started an account that links to each post on this website.  You can find it at Evolutionistrue.

I’m not sure what’s going on at the Templeton-funded accommodationist website BioLogos, but lately they seem to be reviving Biblical literalism.  First there was the website’s waffling about whether Adam and Eve were real people, and now, as reported by commenter Scott on yesterday’s “Tea Party Jesus” post, BioLogos is retreating from the notion of Genesis as metaphor.

You’d think that, for a website devoted to reconciling faith with the facts of science, the idea of Genesis as inspirational fiction would not be negotiable.  If anything is absolutely, rock-bottom true, it’s that life evolved, beginning about 4 billion years ago, and that the creation myth of Genesis is completely wrong.

Yes, you’d think that, but it isn’t so.  To buttress the idea of a literal Genesis, BioLogos has posted a short video, “The danger of preaching on Genesis, by Joel Hunter, a preacher at the oddly named “Northland, a Church Distributed.”

Here’s BioLogos‘s characterization of the piece:

In this video Conversation, Joel Hunter acknowledges the risk that pastors take when preaching on Genesis—and in particular, when they approach it with an attitude of humility, allowing the possibility that the text was not meant to be understood in literal terms.

What?? Humility is bad??? At first I thought that this was a mistake, but it’s not:

Hunter notes that a large number of congregants in our churches today are uncomfortable with the literal narrative of creation in six twenty-four hour days. In fact, many believers are open to the notion that God used alternative means of creation. Those with this viewpoint are not convinced of the all-or-nothing mentality that pervades contemporary evangelicalism, but rather, they see the possibility of evolutionary creation as a testament to God’s abilities.

Hunter emphasizes, however, that one must avoid being dismissive or derisive of those who do hold to a literalist view of Genesis because for some, reconsidering the traditional creation narrative introduces questions to which they are unsure of how to respond. Many with this viewpoint feel that if Genesis can’t be understood in straightforward terms, then we cannot know how to read the story of the Resurrection—as a historical account, or simply as a metaphor? Questions like this have the potential to cause them to wonder if they must now question the whole truth of Scripture.

Without “bullying” literalists into a new scriptural interpretation, we should still provide Christians with the space—and permission—to more completely consider the “fullness” and the “great mystery” of God.

The purpose of the video, it seems, is to tell preachers to be careful when telling their flocks that Genesis might be a metaphor.  Why is that “dangerous”? Because it might scare “uneducated” people into questioning other parts of the Bible, like the Resurrection.  And we can’t have that!  No questioning! “Humility”, once a virtue, is now seen as a problem.  And, “bullying”, apparently, means “telling people that Genesis might be metaphorical and not literally true.”

Here’s Hunter: (this is a screenshot, not a link; to see the video go here):

Here are quotes from Hunter, soft-spoken but oozing intellectual arrogance:

“When people say, look if the scripture’s not plain to the uneducated mind, if the scripture can’t be understood by what it says to somebody like me, then is the Resurrection really just a story?  Is it just a metaphor for rising up out of constraints, and overcoming the death that we face in everyday life and so on and so forth and was there really a Resurrection? And so that’s what’s at risk for many people, and I don’t, again, want to dismiss or denigrate those who hold a literalist view because they honestly believe that if they vary off that, then they themselves, will have to question the truth of scripture. . .

. . . there are those with a lot more capacity intellectually than they’re using, and they need to be given permission to use that intellectual capacity to understand the fullness of God and the great mystery of God.”

Okay, here’s my translation of Hunter’s words into plainspeak.

“Look, fellow preachers, there are a lot of dumb people in our pews who can’t be told that Genesis is wrong because if they see that, then they may start questioning the foundational claims of our faith that are equally bogus, like the Resurrection. Where would we be then?  So don’t even intimate that Genesis might  be wrong.

On the other hand, we don’t want to alienate the smart people either—those who realize that the claim of a six-day creation is ludicrous, in plain contradiction to the facts of biology and geology.  So don’t say anything about Genesis! You’ll put us all out of business!”

By giving preachers a platform to say that Adam and Eve might really have existed, or to warn against questioning Biblical literalism in the face of science, BioLogos has abjured its mission to bend faith to the facts.  Their mission now seems to be hiding the facts so they don’t disturb the faithful.  As many have pointed out, this attitude treats religious people as if they were delicate and befuddled little children who simply can’t bear to hear their beliefs questioned.  Question their politics, sure, but their religion? Never!

But if you don’t do that, of course, you’ll never convert them to accepting evolution.  Isn’t it possible that those “uneducated minds” could be educated?

It’s possible to bend over backwards so far that your head goes up your butt.

Here’s an idea: take the words of Tea Party activists and right-wing commentators, and put them in the mouth of Jesus.   That’s the idea behind a new website, Tea Party Jesus.  Here are two:

Over at the site, click on the pictures to get the original quote.  This one is from Glenn Beck.

And this is Bill O’Reilly:

God bless America.

What a bummer!  Prayers aren’t in the offing, but many good wishes are.

Michael Ruse has spent a lot of time trying to explain to Christians how they can reconcile their faith with the advances of science.  This effort has sometimes reached risible lengths.  In his book Can a Darwinian be a Christian?, for example, Ruse tries to reconcile Christianity with the possibility of extraterrestrial life. He winds up telling the concerned faithful that there might have been an “intergalactic Jesus” who, like a travelling doctor, moved from planet to planet dispensing salvation.  What’s curious about all this is that Ruse claims not to believe any of the Christian myths—he’s an atheist.

But he’s finally run into a tenet of Christianity that can’t be reconciled with science:  the inevitability of humans. Ruse describes the problem in a piece at HuffPo, “A Darwinian can be a Christian, too”:

To my great surprise, however, I found what I thought then and still think now a major problem with reconciling Darwinism with Christianity. It is an absolute bottom-line claim of the Christian that the existence of humans is not contingent — if we did not exist then the Christian story could not be. It might be that we are blue and that we have twelve fingers. Possibly, although I am not sure, it might be that we don’t have sex. But intelligent beings, with moral awareness, able to act in this world, have to exist if Christianity is true. Otherwise, what is the point of all of that stuff about being made in “His Image”? However, Darwinism stresses that change is random and non-directed. For Darwin and his followers this has always been an absolute. Obviously humans are pretty complex animals, but our arrival has always been in some sense a matter of chance.

And Ruse gives a pretty good explanation for why scientists see the evolution of humans as contingent rather than inevitable:

Today’s Darwinians would make the case for non-directionality on two grounds. First, natural selection is always opportunistic, relative. What works in one case might not work in another. There are no absolutes, no fixed goals. Humans are pretty good organisms, but they have their drawbacks. For a start, their brains need massive amounts of protein, usually dead animals. There was no guarantee in the wild that such protein was always available or that we might not have been better eating grass albeit a bit dumb. Buffalo were doing pretty well until humans turned up. For a second, the building blocks of evolution, the mutations, are random, not in the sense of being without cause, but without regard for what their possessors need. Things can go any which way.

Indeed, this is a major roadblock in the accommodationist program, one that I’ve emphasized for a long time.  Claiming that the evolution of humans was inevitable violates every tenet of not only modern evolutionary biology, but of naturalism as the methodology of science.

One solution, as Ruse recognizes, is to claim that, well, maybe evolution occurred, but that God somehow either directed it or set it all up to culiminate in the appearance of humans.  This is the foundational claim of theistic evolution. And many real scientists who claim to accept evolution, like Kenneth Miller, Simon Conway Morris, and Francis Collins, buy this view.  They don’t seem to realize, as Ruse does, that

. . . this seems to me to be at total variance with the spirit of modern Darwinism.

True, but you won’t hear Miller, Conway Morris, or Collins pointing this out. At least Ruse has the intellectual decency to admit that this is a problem.

Indeed, more Americans accept theistic evolution than they do real (i.e., purely naturalistic) evolution: recent polls show that when Americans are asked how they account for the existence of humans, around 50% say that God created us directly, 30% say that we evolved but that God guided this process, and only 15% say that we appeared via unguided evolution.

So if we tell Christians that this is a way to reconcile science with their faith, we have to admit that we’re offering a bogus, nonscientific solution. Theistic evolutionists don’t really accept evolution, at least not the way scientists see it.  They’re buying a bastardized hybrid theory that is rejected by virtually all working biologists. Can we really count those 30% of theistic-evolutionist Americans as being on our side?

What does Ruse offer as a solution? He doesn’t have one, although he suggests that some version of the “multiverse” hypothesis may obtain:  if evolution occurred enough times on enough planets, or in enough universes, eventually one of them would cough up a smart, God-fearing creature.  In the end, though, he admits:

My suspicion is that if the problem is to be solved, then it has to be done with a theological solution rather than a scientific one.

And that’s the real job of theology: it’s a philosophical sausage mill for converting intellectual necessities into spiritual virtues.

h/t: (and goodbye for the nonce): Jason Rosenhouse