Monthly Archives: April 2015

Polemics

How brief was the period in which the Cambrian phyla suddenly appeared?

Leave a comment

The Cambrian explosion refers to the sudden appearance of new body plans in the fossil record. ID proponents think that the period is between 5-10 million years at the most. Naturalists want to stretch out the period in which the body plans appear to tens of millions of years. The two sides can’t both be right. What’s the truth?

Evolution News has the answer.

Excerpt:

To establish the length of the most explosive period of innovation within the Cambrian explosion itself, Meyer cites the work of MIT geochronologist Samuel Bowring and his colleagues as well the work of another group led by Smithsonian paleontologist Douglas Erwin. The Bowring-led study showed that (in their words) “the main period of exponential diversification” within the Cambrian lasted “only 5-6 million years” (emphasis added). Meyer explains:

An analysis by MIT geochronologist Samuel Bowring has shown that the main pulse of Cambrian morphological innovation occurred in a sedimentary sequence spanning no more than 6 million years. Yet during this time representatives of at least sixteen completely novel phyla and about thirty classes first appeared in the rock record. In a more recent paper using a slightly different dating scheme, Douglas Erwin and colleagues similarly show that thirteen new phyla appear in a roughly 6-million-year window. (p. 73)

[…][T]ake a look first at the following figure that Bowring and his colleagues included in their definitive 1993 article, published in the journal Science. They use radiometric methods to date the different stages of the Cambrian period, including the crucial Tommotian and Atdabanian stages in which the greatest number of new animal phyla and classes arise. Note that the so-called Manykaian stage of the Cambrian period lasts about 10-14 million years. Note also that the main pulse of morphological innovation didn’t begin during this stage but rather during the Tommotian and Atdabanian — a period that they describe as taking between “5 to 10 million years,” and in a more detailed passage as taking about 5-6 million years.

[…]In the figure above, the Tommotian and Atdabanian stages of the Cambrian period together span only about 5 million years, starting at about 530 and ending about 525 million years ago. Bowring’s figure also depicts the total number of classes and orders present at any given time during the Cambrian period. The biggest increases in morphological innovation occur during the Tommotian and Atdabanian stages. Indeed, during this period the number of known orders nearly quadruples. Moreover, Bowring and his colleagues also make clear that this period corresponds to the main pulse of Cambrian morphological innovation as measured by the number of new phyla and classes that first appear. They note that, while a few groups of animals do arise in the earliest Manykaian stage of the Cambrian, the most rapid period of “exponential increase of diversification,” corresponding to the Tommotian and Atdabanian stages, “lasted only 5 to 6 m.y.”

You can see the figure they are reference in the Evolution News article.

Also, check out these clips that explain the Cambrian explosion:

Part 1:

Part 2:

The first clip features James Valentine, a professor of biology at the University of California who just co-authored a new book on the Cambrian explosion and is not a proponent of intelligent design.

The consensus among scientists regarding the period of time in which the new body plans appear is 5-6 million years. Biologically speaking, that’s a blink of an eye. You aren’t going that kind of complexity and innovation in such a short period of time any more than you can expect to win the lottery by buying 5-6 million tickets when the odds of winning are 1 in a googol (10 to the 100th power – 1, followed by 100 zeroes). You don’t have enough lottery tickets to make winning the lottery likely. Similarly, 5-6 million years is not enough time for naturalistic mechanisms to code brand new body plans from scratch. It would be like trying to research and write a Ph.D thesis during a single lunch hour. It’s just not enough time to produce the amount of information that’s required.

News

New study: tiny songbirds fly over the Atlantic ocean and back each year

1 Comment
Blackpoll Warbler- so tiny and so cute!
Blackpoll Warbler- so cute!

I love birds! I really, really do! A lot!

So here is the latest study, reported in Science Daily about our amazing feathered friends.

They write:

For more than 50 years, scientists had tantalizing clues suggesting that a tiny, boreal forest songbird known as the blackpoll warbler departs each fall from New England and eastern Canada to migrate nonstop in a direct line over the Atlantic Ocean toward South America, but proof was hard to come by.

Now, for the first time an international team of biologists report “irrefutable evidence” that the birds complete a nonstop flight ranging from about 1,410 to 1,721 miles (2,270 to 2,770 km) in just two to three days, making landfall somewhere in Puerto Rico, Cuba and the islands known as the Greater Antilles, from there going on to northern Venezuela and Columbia. Details of their study, which used light-level, or solar, geolocators, appear in the current issue of Biology Letters.

First author Bill DeLuca, an environmental conservation research fellow at the University of Massachusetts Amherst, with colleagues at the University of Guelph, Ontario, the Vermont Center for Ecostudies and other institutions, says, “For small songbirds, we are only just now beginning to understand the migratory routes that connect temperate breeding grounds to tropical wintering areas. We’re really excited to report that this is one of the longest nonstop overwater flights ever recorded for a songbird, and finally confirms what has long been believed to be one of the most extraordinary migratory feats on the planet.”

While other birds, such as albatrosses, sandpipers and gulls are known for trans-oceanic flights, the blackpoll warbler is a forest dweller that migrates boldly where few of its relatives dare to travel. Most migratory songbirds that winter in South America take a less risky, continental route south through Mexico and Central America, the authors note. A water landing would be fatal to a warbler.

[…]For this work the scientists fitted geolocator packs on 20 birds in Vermont and 20 more in Nova Scotia. They were able to recapture three birds from the Vermont group and two from the Nova Scotia group for analyses.

So-called light-level geolocators use solar geolocation, a method used for centuries by mariners and explorers. It is based on the fact that day length varies with latitude while time of solar noon varies with longitude. So all the instrument needs to do is record the date and length of daylight, from which daily locations can then be inferred once the geolocator is recaptured. “When we accessed the locators, we saw the blackpolls’ journey was indeed directly over the Atlantic. The distances travelled ranged from 2,270 to 2,770 kilometers,” DeLuca says.

Evolution News has more on the discovery.

They write:

More record-breaking discoveries may be in store. Oskin says that some of the blackpoll warblers spend their summers in Alaska and Canada instead of New England. If they fly east before joining the southern route to Colombia and Venezuela, it would add three thousand more miles to their annual migration.

[…]But that’s not all. Lest we forget, there are the Monarch butterflies, much smaller and lighter than birds, that travel three thousand miles from Canada to Mexico each year, as detailed in Illustra’s film Metamorphosis. Even though butterflies don’t fly non-stop, that’s — well, we need an adjective beyond “extraordinary.” And more recently, British scientists found that another butterfly, the painted lady, flies triple that distance — nine thousand miles — in its annual migration from the UK to Africa.

Think of all the integrated systems that have to be in place to make these migrations possible. The birds or butterflies need elegant flight systems, with all the attendant muscles, nerves, and structural supports required. They require digestive systems to sustain them, circulatory systems, thermal systems, sensory systems, and protection from the elements. Most astonishing are the navigational systems, including sensing the stars or the earth’s magnetic field, to take them unerringly to their destination and back over routes of thousands of miles. To pack all that in a tiny animal is a masterpiece of miniaturization. Oh — and then there’s a reproductive system, and a battery of instincts to operate all the systems.

It seems fair to say these engineering marvels are beyond the reach of unguided Darwinian evolution. The birds don’t have to fly that far. Warblers could stay inland along the coast, and feed on the way, or learn to get by through the winter like other birds do. Butterflies, too, could stay with other species that don’t migrate. Natural selection would take the easy road, get rid of the wings, and let them grovel in the dirt to eke out a living. These migratory abilities are gratuitous and superfluous to the requirements of mere survival. Such over-design, right on the “brink of impossibility,” speaks of design so beyond our comprehension, we can only stand in awe.

Butterflies are OK, but birds are much better – you can actually make friends with birds. Anyway, if you like birds as much as I do… well, no one likes them as much as I do… but if you like birds a lot, then you should get Illustra’s documentary Flight: The Genius of Birds and watch it. And share it with your friends.

News

Should Christian apologists avoid political, moral and cultural issues?

9 Comments

 

The Sexual Revolution and the decline in religious affiliation
The Sexual Revolution and the decline in religious affiliation

Here’s an article from The American Conservative, by moderate conservative Rod Dreher, dated April 2013.

He writes:

Twenty years ago, new president Bill Clinton stepped on a political landmine when he tried to fulfill a campaign promise to permit gay soldiers to serve openly. Same-sex marriage barely registered as a political cause; the country was then three years away from the Defense of Marriage Act and four years from comedian Ellen DeGeneres’s prime-time coming out.

Then came what historians will one day recall as a cultural revolution. Now we’re entering the endgame of the struggle over gay rights and the meaning of homosexuality. Conservatives have been routed, both in court and increasingly in the court of public opinion. It is commonly believed that the only reason to oppose same-sex marriage is rank bigotry or for religious reasons, neither of which—the argument goes—has any place in determining laws or public standards.

The magnitude of the defeat suffered by moral traditionalists will become ever clearer as older Americans pass from the scene. Poll after poll shows that for the young, homosexuality is normal and gay marriage is no big deal—except, of course, if one opposes it, in which case one has the approximate moral status of a segregationist in the late 1960s.

[…]When they were writing the widely acclaimed 2010 book American Grace, a comprehensive study of contemporary religious belief and practice, political scientists Robert D. Putnam and David E. Campbell noticed two inverse trend lines in social-science measures, both starting around 1990.

They found that young Americans coming into adulthood at that time began to accept homosexuality as morally licit in larger numbers. They also observed that younger Americans began more and more to fall away from organized religion. The evangelical boom of the 1970s and 1980s stopped, and if not for a tsunami of Hispanic immigration the U.S. Catholic church would be losing adherents at the same rate as the long-dwindling Protestant mainline.

Over time, the data showed, attitudes on moral issues proved to be strong predictors of religious engagement. In particular, the more liberal one was on homosexuality, the less likely one was to claim religious affiliation. It’s not that younger Americans were becoming atheists. Rather, most of them identify as “spiritual, but not religious.” Combined with atheists and agnostics, these “Nones”—the term is Putnam’s and Campbell’s—comprise the nation’s fastest-growing faith demographic.

Indeed, according to a 2012 Pew Research Center study, the Nones comprise one out of three Americans under 30. This is not simply a matter of young people doing what young people tend to do: keep church at arm’s length until they settle down. Pew’s Greg Smith told NPR that this generation is more religiously unaffiliated than any on record. Putnam—the Harvard scholar best known for his best-selling civic culture study Bowling Alone—has said that there’s no reason to think they will return to church in significant numbers as they age.

Putnam and Campbell were careful to say in American Grace that correlation is not causation, but they did point out that as gay activism moved toward center stage in American political life… the vivid public role many Christian leaders took in opposing gay rights alienated young Americans from organized religion.

In a dinner conversation not long after the publication of American Grace, Putnam told me that Christian churches would have to liberalize on sexual teaching if they hoped to retain the loyalty of younger generations. This seems at first like a reasonable conclusion, but the experience of America’s liberal denominations belies that prescription. Mainline Protestant churches, which have been far more accepting of homosexuality and sexual liberation in general, have continued their stark membership decline.

It seems that when people decide that historically normative Christianity is wrong about sex, they typically don’t find a church that endorses their liberal views. They quit going to church altogether.

That’s why I am somewhat underwhelmed with the pure apologetics approach of most apologists.The real reason that drives atheist “apologetics” is, to be frank, the desire to dispense with rules around sexuality. The sexual freedom comes first, and then the speculative smokescreens follow. Close behind the sexual freedom is leftist economic policies (which are seen as more “fair”) and anti-business environmentalist policies. So there’s more turf to defend here than just the existence of God, the resurrection and the reliability of the Bible. That’s not what’s behind the drift of young people away from Christianity.

That’s why on this blog, you get a ton of politics and tons of studies and arguments against premarital sex, no-fault divorce, single motherhood by choice, same-sex marriage, and everything else that comes before traditional apologetics. (And you also get lots of apologetics, too!) We need to get better at defending Christian sexual ethics using purely secular arguments and evidence, e.g. – showing people how premarital sex undermines marital stability or how gay parenting harms the well-being of children. There are reasons for these rules we have, and we have to go beyond “The Bible Says…” if we expect to be convincing to young people.

And when we go against the Sexual Revolution, we have to bring secular arguments and secular evidence and bring it to bear squarely against radical feminism, and the Sexual Revolution. In particular, we have to put the burden of responsibility for poor sexual decisions back on the shoulders of young people. Young men must reject a cultural standard of what a “good” woman is. Young women must reject a cultural standard of what a “good” man is.  Men and women who reject traditional Christianity, traditional morality, and traditional notions of male leadership and male roles are bad people to have relationships with. We have to persuade both men and women about the harm that poor choices cause – abortion,  divorce, fatherlessness, expensive welfare programs. There is no point in blaming bad men and women – they are already bad. We have to teach young people to choose good men and good women. We have to teach them that choosing mates poorly, and making poor sexual choices, is their responsibility. They are not victims! And we shouldn’t be blaming one sex for the others poor choices, i.e. – we should not be blaming bad men when women chose them and make bad choices with the bad men. Those men were bad before the women chose them, and those women are only victims of their own poor choices.

When it comes to same-sex marriage, we have to defend traditional marriage using secular arguments and secular evidence. We have to show how same-sex marriage undermines religious liberty. We have to show how same-sex marriage undermines marital norms like exclusivity and permanence. We have to show how same-sex marriage harms children by depriving them of a mother or a father or both. And so on. We have to defend the goodness of traditional marriage.