Archive for January, 2015

Jan 13 2015

Chimp and Human DNA

Published by under Creationism/ID

I was recently asked to respond to an apologist page that  challenged the scientific claim that human and chimpanzee DNA are very similar, which is evidence that we are descended from a recent common ancestor. You have probably heard the claim that human and chimp DNA are 96% the same. The apologist was referencing the work of Jeffrey Tomkins in his “peer reviewed” study showing that there is only 70% similarity. In fact, the the DNA of chimps and humans are so different, Tomkins claims, that there would not have been enough time for evolution to account for all the changes.

This is what I like to call, “sophisticated nonsense.” The very purpose of pseudoscience such as this is to confuse the public with complicated arguments that only scientists are likely to understand. We can turn such pseudoscience, however, into teachable moments.

For background, it is helpful to understand that there is no completely objective way to come up with one number that represents the percent similarity between the DNA of two species. There are just too many different choices to make in terms of how to count similarity. For example, how do you count chromosomal differences? Do you just compare the sequences of genes in common? What about insertions, gene duplications, and deletions? Do you line up sequences to their best match and just count point mutations? Do you count non-coding segments?

There is no one right way to do it to give a definitive answer of similarity. However, if you have a specific question in mind, then the method you choose should be designed to answer the question.

Continue Reading »

Like this post? Share it!

24 responses so far

Jan 12 2015

Another Salvo in the Mammoth Extinction Controversy

Published by under General Science

There are many enduring controversies within science, and they are fun to follow. There are raging debates about the so-called Hobbit or Homo floresiensis, is it a new species or a diseased human? You may be surprised to hear that there is still a controversy over whether or not the dinosaur extinction was due to a meteor impact or other terrestrial factors (although I think this one is heavily tilting toward the impact theory).

One controversy I have been following, here and on the SGU, concerns the Young Dryas and whether or not the cooling characteristic of that period was due to melting glaciers or a local comet impact.

Such controversies always raise a few general issues for me. The first is how the mainstream media covers them, which I always find disappointing. Properly covering genuine scientific controversies is challenging, but that is what science journalists are supposed to do. What I find is that they tend to present each new study in the debate as if it is definitive and has ended the debate, rather than putting it into the proper context of the ongoing controversy.

Another common mistake is to rely on one expert rather than getting a reasonable sample. They tend to weight the story toward the side of the expert on which they relied, and maybe provide only token coverage of other views. There is also, of course, the issue of proper balance. Reporting should reflect the balance of opinion in the scientific community. It’s OK to present minority opinions but they should be presented as such.

Continue Reading »

Like this post? Share it!

3 responses so far

Jan 09 2015

Antibiotic Resistance and New Antibiotics

Humans have a massive footprint on our ecosystem. Enough so that we have to think carefully about anything we do on a large scale, such as agriculture, industry, shipping (because of invasive species), and using drugs to fight bacterial infections.

The development of antibiotic resistance is a particular worry of mine, and one that I feel does not get proportional attention in the media. It is quite possible that in the future more people will die from antibiotic resistant bacteria than global warming, food shortages, or disrupted ecosystems (depending on how each of these things develop).

We are already seeing more deaths from drug-resistant bacteria, longer hospital stays, and greater costs. I have seen this change during my career. When I round in the hospital I now have to don protective garments before entering many patient rooms because they are infected or even just colonized with a resistant strain of bacteria.

There is no way around the fact that were are engaged in a war with the subset of bacterial species on this planet that are capable of infecting humans. We have been winning for a while, but the bacteria are now rallying.

Continue Reading »

Like this post? Share it!

19 responses so far

Jan 08 2015

The Science of God

Recently Eric Metaxas wrote an opinion piece in the Wall Street Journal in which he argues that, “Science Increasingly Makes the Case for God.” (Sorry, it’s behind a paywall, but I will quote the salient parts.) Metaxas is an author and speaker, but not a scientist, and it shows in his writing.

His essay is based on two instances of the anthropic principle, which simply notes that in order for life to exist the universe must possess conditions compatible with life. He applies the anthropic principle to the Earth specifically and to the universe as a whole. Starting with the Earth he writes:

As factors continued to be discovered, the number of possible planets hit zero, and kept going. In other words, the odds turned against any planet in the universe supporting life, including this one. Probability said that even we shouldn’t be here.

Today there are more than 200 known parameters necessary for a planet to support life—every single one of which must be perfectly met, or the whole thing falls apart. Without a massive planet like Jupiter nearby, whose gravity will draw away asteroids, a thousand times as many would hit Earth’s surface. The odds against life in the universe are simply astonishing.

Continue Reading »

Like this post? Share it!

105 responses so far

Jan 06 2015

Ancient Indian Airplanes

Published by under Pseudoscience

Being an activist skeptic means being reminded, almost on a daily basis, that there is no idea so absurd that there will not be those who fervently believe it.

At the most recent meeting of the Indian Science Congress Association, Captain Anand J Bodas, apparently under the aegis of Mumbai University, gave a lecture in which he claimed that airplanes existed in India 7,000 years ago, that they were able to fly to different continents, and even to different planets.

These claims are obvious nonsense (although I will link to resources which painstakingly demonstrate this). What is more interesting is that such a talk was able to infiltrate what is apparently a science conference. This is a disturbing phenomenon, all too common, in which rank pseudoscience is able to work its way into the domain of respected science.

Continue Reading »

Like this post? Share it!

26 responses so far

Jan 05 2015

Cancer Risk Largely Bad Luck

This is one of those glass-half-full / glass-half-empty news items. Different headlines reporting on the same study present the results in opposite ways. The BBC, for example, writes, “Life choices ‘behind more than four in 10 cancers.'” Meanwhile the press release from Johns Hopkins states, “Bad Luck of Random Mutations Plays Predominant Role in Cancer, Study Shows.”

The Hopkins headline is more accurate. The BBC headline is not just focusing on life choices vs bad luck, it actually gets the data wrong.

What the researchers did was look at the replication rate of stem cells in different tissue types (they did not include breast cancer and prostate cancer as they could not find published replication rates). They then compared differences in these rates to differences in adult cancer rates in the same tissues. For example, colon cancer is more common than cancer of the small intestine, and colon cells replicate more frequently than small intestine tissue. (In mice, this is reversed, but the correlation holds.)

Continue Reading »

Like this post? Share it!

65 responses so far

Jan 02 2015

How To Create a Fad Diet

Fad diets pop up on a regular basis. I believe that is because they are so easy to manufacture and there is a ready made market for them. Add to that the fact that it is difficult to lose weight. There is also a great deal of misinformation out there about diet and health, so the environment is very friendly to pop pseudoscience.

If you want to create your own fad diet, here is a handy formula. These things pretty much write themselves.

#1 – You need a catchy title, usually taking the form of “The blank Diet.” You can fill in the blank with almost anything. For example, a recent fad diet is called “the bulletproof diet.” This doesn’t say anything about the diet itself, it’s just a catchy phrase, a brand. You can fill in the blank with a title that does reflect the diet itself, but this is optional. Creating a catchy title is actually the most creative work you have to do in making a fad diet.

Continue Reading »

Like this post? Share it!

15 responses so far

Jan 01 2015

2014 Was a Bad Year for Homeopathy

I have been saying for several years that if there is a pseudoscientific medical treatment that is especially vulnerable to critical analysis it’s homeopathy. There’s a lot of nonsense in the world of medicine, but homeopathy takes the prize. First, it is complete and utter nonsense.

There is no need to equivocate. Homeopathy violates basic scientific knowledge in physics, chemistry and biology. It is transparent witchcraft that cannot possibly work by any known or even semi-plausible mechanism. Further, clinical studies unsurprisingly show that it does not work, for anything.

And yet the public does not generally understand what homeopathy actually is. The most common belief is that homeopathy is natural or herbal medicine. Rather, homeopathy is based upon several dubious notions. The first is that like cures like, and idea based on sympathetic magic and not science or any knowledge of the real world. Further, the actual starting ingredients are based upon a fanciful and often absurd interpretation of this dubious notion, leading to things like using duck liver to treat the flu.

None of this actually matters, however, because most homeopathic remedies are diluted beyond the point that there is any chance of a single molecule of starting ingredient remaining. All of this is supposed to work, however, because the potion is “activated” by shaking it.

Continue Reading »

Like this post? Share it!

12 responses so far

« Prev