A Sense of Planetary Proportion

I don't get tired of watching these. Need I say more?

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The Vaccine-Autism Wars

There is an article in this month's PloS Biology titled, "A Broken Trust: Lessons from the Vaccine–Autism Wars." It does a nice job of explaining how the recent controversy over vaccines and autism came to be.

Now, more than ten years after unfounded doubts about vaccine safety first emerged, scientists and public health officials are still struggling to set the record straight. But as climate scientists know all too well, simply relating the facts of science isn't enough. No matter that the overwhelming weight of evidence shows that climate change is real, or that vaccines don't cause autism. When scientists find themselves just one more voice in a sea of “opinions” about a complex scientific issue, misinformation takes on a life of its own.

The article would have been even better if it had listed the main studies addressing the autism question along with summaries of the findings. But since it didn't, I found a site that has at least some of them: The National Network for Immunization Information.

• Studies on MMR and autism
• Studies on thimerosal and autism

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Macroevolution

Macroevolution (see also here) refers to a broad view of evolution that encompasses--at a minimum--multiple species. It is not so much a process as a scale of study, and is in contrast with microevolution--evolution within a species. Anti-evolutionists often claim that they accept microevolution, but reject macroevolution (as though macroevolution is some kind of special process that is different from those operating in microevolution).

The journal Evolution: Education and Outreach has a brand new edition that focuses on macroevolution, and contains what look like excellent articles written by experts, for educators.

Below are the articles whose titles got my juices flowing, and that I plan to read. Feel free to explore the rest. The contents of the journal are currently free, but my understanding is that that will change later this year. So get them while you can.

1. Understanding Natural Selection: Essential Concepts and Common Misconceptions

2. The Fish–Tetrapod Transition: New Fossils and Interpretations

3. The Evolution of Marine Reptiles

4. Downsized Dinosaurs: The Evolutionary Transition to Modern Birds

5. From Land to Water: the Origin of Whales, Dolphins, and Porpoises

Fact: Anti-evolutionists have long pointed to a lack of transitional fossils from land animals to whales as casting doubt on evolution. For example, Michael Behe once wrote,

"...if random evolution is true, there must have been a large number of transitional forms between the Mesonychid and the ancient whale. Where are they? It seems like quite a coincidence that of all the intermediate species that must have existed between Mesonychid and whale, only species that are very similar to the end species have been found."

6. Evolutionary Transitions in the Fossil Record of Terrestrial Hoofed Mammals

7. Transforming Our Thinking about Transitional Forms

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Tyson on Pluto and Science Education

Neil deGrasse Tyson is an astrophysicist and the director of the Hayden Planetarium at the American Museum of Natural History. In March he was interviewed on Point of Inquiry about his recent book, The Pluto Files: The Rise and Fall of America's Favorite Planet. The interview is available here. I haven't read the book, so my comments are based on the interview.

Tyson was indirectly involved in the change of Pluto's status as a planet to a dwarf planet. Back in the 1990's, the museum was re-building the astronomy section, and as he and his staff looked at the current science they decided that Pluto really had more properties in common with objects in the Kuiper belt than with the rest of the planets. Sparks began to fly when the New York Times ran a front-page story pointing out that in the display Pluto was not grouped with the other planets, nor was it referred to as a planet. The rest is history, with Pluto currently classified as a dwarf planet.

Tyson points out that the whole fight has been over nomenclature, not over the actual properties of Pluto, and he thinks that the reason for the attachment of many people to Pluto as a planet has to do with how we learn about the solar system in school. Rather than comparing and contrasting the objects in the solar system and discussing the process of discovery, the solar system is presented as a finished product with a mnemonic to help in memorization. This scheme becomes cemented in people's minds such that they feel a sense of betrayal when it is altered.

Science is exploratory, and as new discoveries are made we have to find or invent words to describe or label them. But often as discovery continues it becomes clear that the old system of labels is inadequate. As Tyson points out, originally planets were just lights in the sky that wandered relative to the other stars. As their capabilities grew, astronomers identified and named more and more wanderers until we reached nine, with Pluto as the last. But as astronomers learned more about Pluto, it became clear that it was rather different from the terrestrial planets (Mercury, Venus, Earth and Mars) and the gas giants (Jupiter, Saturn, Uranus, and Neptune), and they found that it was much like objects in the Kuiper belt (which was discovered in 1992(!)).

Ultimately, Tyson puts it this way: Pluto is not the last of the planets; it is the first of a new class of objects.

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Quackery Roundup: Oprah and Chiropractic

Newsweek takes Oprah Winfrey to the woodshed for the various quacks and quackery that have been promoted on her show. There have been complaints about Oprah on science/skeptic blogs and podcasts for a while now, so it's nice to see more mainstream criticism of some of the empty and potentially dangerous advice given on the show. Although the diet and fitness tips are apparently generally good, be very skeptical of the medical advice--especially promises of easy solutions or revolutionary methods.

Meanwhile there is an ongoing legal skirmish in the U.K. over chiropractic. A New Scientist opinion piece, "What you should know about chiropractic," briefly reviews the origins of chiropractic and the controversy surrounding it. I'm willing to grant that there may be a legitimate place for chiropractic in health care when it hews closely to mainstream medicine. Unfortunately, many chiropracters make claims beyond the evidence and actually steer people away from effective treatment. As an example, chiropracters are historically--and apparently still commonly--anti-vaccination.

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Keeping Time

[The following was brought to my attention by Jerry Coyne's book, Why Evolution is True.]

Earth is old--about 4.5 billion years old. We know this primarily from radiometric dating of rocks, which is based on the fact that certain elements decay into other elements at a constant rate. We also know that Earth is slowing down in its rotation due to tidal forces exerted by the moon, which is at least one reason that leap seconds are occasionally added to our official time. This observed slowing implies that millions of years ago Earth's rotation was faster with shorter days and more days per year.

But is this all just unwarranted extrapolation into the past? After all, as young-earth creationists like to remind us, none of us was there.

In the early 1960's, paleontologist John Wells published a paper describing his study of fossil coral from several ancient periods. As corals grow, they lay down a skeleton of calcium carbonate with a regularity such that distinct layers can be seen, analogous to tree rings. These layers can be discerned as yearly--or even daily--layers. The geological periods had been dated radiometrically, so the expected number of days per year could be calculated. Wells looked at the growth layers of fossil coral and determined how many daily layers were in each year. Lo and behold, he found that the coral daily layers per year correlated nicely with the astronomically calculated days per year.

This represents just one method of independently checking the reliability of radiometric dating. We may not have been there, but coral were; and dead coral tell tales.

For more information on coral timekeeping, see Can Corals Tell Time?

For a nice explanation of radiometric dating and a response to creationist claims, see Radiometric Dating: A Christian Perspective.

For more information on a number of dating methods see Dating Methods in Science.

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One Way of Getting a Link

S. Faux at Mormon Insights gives his perspective on being a Mormon evolutionist. It's a nice read, and my opinion is in no way biased by the fact that he says nice things about me and my blog.

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Great Primate Fossil; Great Hype

Everyone seems to agree that this 47-million-year-old primate fossil, named Darwinius masillae, is a remarkable find. The preservation is fine enough to reveal the stomach contents and the outline of the fur.

But it's also supposed to be a source of revenue--this may be the first fossil whose publication was accompanied by a press conference, a History Channel film, and a book--and is being hyped (i.e. marketed) as a revolutionary find that's going to change everything about our understanding of primate evolution.

For cooler heads, see here, here, and here.

Bottom line: Neat? Yes. Important? Yes. Revolutionary? Not so much.

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