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03/01/2015
Faster than Darwin Would Have Expected
CHAPTER 54 From a Comet to Pig Poop
Last month I discussed E-cigarettes, and some of their pluses and minuses. After posting my column, I read Brian Trumbore's Week in Review column posted on January 31. In it he mentioned fires caused by E-cigs packed in airline baggage. As noted in my column, E-cigs work by using a lithium battery to heat up a nicotine-containing liquid, vaporizing the nicotine as the E-cig is smoked, or "vaped". I should have anticipated that, if left on and unattended, especially packed in baggage, they can heat up and cause fires.
So, what to write about this month? Given my obsession with the universe and space-related topics, the appear4ance in the January 23 issue of Science of the first published papers on the European Space Agency (ESA) Rosetta mission to a comet certainly merits attention. Also, the ESA's Planck satellite mission has been in the news. Combining data from the Planck mission with data from the so-called BICEPS project has put the nail in the coffin of the widely heralded detection of gravitational waves resulting from the inflation of the universe in the first tiny fractions of a second after the Big Bang. The swirly polarization patterns of the light in the cosmic background radiation are actually due to cosmic dust. We'll have to look further for those gravity waves.
But let's get back to the comet. Somehow, I'd always pictured comets as round objects spewing their trails of stuff as they came closer and closer to the Sun. Now Rosetta's great pictures of comet 67P/Churyumov-Gerasimenko (67P) show it to be a scraggly looking thing resembling a rubber duck, with a head, a neck and a body. One of the questions raised by its shape is was it formed by two comets coming together or is the shape a result of erosion of the comet as it sheds material, especially when it's closest to the sun? Hopefully, Rosetta will provide an answer to the question by determining whether the composition of the head and body are the same or different, which would imply a joining of two different comets. I was surprised to learn that the comet's density is only about half that of water, more like cork! It's a fluffy thing.
The surface of 67P is rich in organic material, compounds of carbon, oxygen and/or hydrogen. I gather the comet rotates and has seasons. It also has grains of material orbiting it, with some of the orbiting clumps being around a meter in size. Rosetta has also measured the ratio of deuterium to ordinary hydrogen in the water and finds about three times as much deuterium compared to the ratio here on Earth. All in all, even with the Philae lander unable to charge its batteries, the orbiting Rosetta is transmitting a wealth of information about the comet and its composition - a truly remarkable mission.
In addition to space, I have another obsession - evolution. Specifically, I just can't understand why, according to various polls, a huge number of people in our country don't believe in it. And it really bugged me when I saw in the news recently that possible presidential candidate Scott Walker, when asked in the UK if he believed in evolution, said he would "punt" on the question. I haven't read it yet, but I see that the cover of the March 2015 issue of National Geographic is headlined "THE WAR ON SCIENCE". As I would expect, some of the highlighted issues are evolution, climate change, vaccination and even the moon landing. Flipping the pages of the article in the magazine, I found the statement that a third of Americans believe that humans have existed in their present form since time began. I'm sorry, but God would have to be an unbelievably knowledgeable and talented chemist to create even a single cell, with its DNA with billions of base pairs and all the proteins and cellular structure, let alone a whole human being.
For me, one of the best examples of evolution in our time is MRSA, Methicillin-resistant staphylococcus aureus. This bacterium is just one of those that have evolved in my lifetime to become resistant to treatments designed to kill them before they kill us. Accordingly, I was intrigued by an article titled "Life in the Fast Lane" by Jane Braxton Little in the March 2015 issue of Discover magazine. The article discusses the work of David Reznick and others showing that various fish and other creatures can evolve in remarkably short periods of time to adapt to differing environmental conditions. Darwin himself would no doubt be shocked and surprised by how fast evolution can take place in certain species. He thought evolution required hundreds of thousands of years.
Reznick was among the first to show that significant evolution can occur in only 6 or 8 generations. This was in studies of small fish, guppies, in Trinidad. Specifically, he wanted to see if these small fish could adapt to the introduction of predators or, conversely, to the removal of predators already present in the guppies' environment. In 1981, he went to Trinidad to a site where the guppies had to contend with larger fish called cichlids. The cichlids had wide mouths and apparently liked to eat the guppies. Reznick took a bunch of guppies from this site and moved them to another site where there were no cichlids. In only four years, the guppies in the new site had grown to mature later and they reproduced more slowly. So, what do you expect would happen when predators are introduced to guppies that had been living in a site without predators? Sure enough, these guppies began maturing earlier, having to hurry up and have babies before the predators ate them. We humans are consummate predators. The article cites the case of Chinook salmon becoming smaller and shorter-lived after commercial fishing increased back in the 1920s.
It seems clear that climate change will require quite a bit of evolution for many plants and animals to survive. An example cited in the article is the case of tawny owls in Finland. The dominant color of these owls was a pale gray, which helped them blend in with the snowy landscape, minimizing the possibility of being eaten by predators. Now, however, reddish brown tawny owls are steadily increasing in proportion as the winters get warmer and the snowy season is shorter.
One of the problems with the public's perception of science is one of the fundamental characteristics of the scientific field, namely the continuous questioning of previous results and theories by scientists as a matter of course. I've already mentioned the demise of the work on gravity waves that was proved wrong. Surprisingly, the paper announcing that the effect was actually due to dust was co-authored by members of both the BICEPS team and the ESA. Evolution is no different in that as more and more work is done and, especially with the advent of DNA and fabulous work decoding DNA of ancient fossils, various evolutionary paths can be revised with sometimes startling results. For example, an article by Elizabeth Pennisi in the January 16 issue of Science tells of the work of Jon Harrison and others on insects and crustaceans. The article has a picture of the compound eyes of the horsefly and a shrimp. They look the same. When researchers looked at DNA and other features of insects and crustaceans, the old view that insects were closely related to centipedes and millipedes has fallen by the wayside. Now it seems that both insects and crustaceans actually arose from what are now termed pancrustaceans. So that lobster you had for dinner and the butterfly hovering outside your window are really quite closely related.
Finally, I mentioned MRSA as an obvious example of evolution. I just finished reading an article by Christina Larson in the February 13 issue of Science and find there's an alarming case in China of bacteria evolving to contain genes for resistance to antibiotics. There's a huge demand for pork products in China, where about half a billion pigs are consumed annually. And those pigs poop! The article estimates over 600 billion kilograms of pig manure a year, much of which ends up in rivers and lakes. The problem is that the pigs are fed an estimated 150 to 200 thousand tons of antibiotics a year to keep them healthy. That's about ten times more antibiotics than used in the United States to promote healthy animals. As a result, a number of rivers in China are loaded with antibiotic-resistant bacteria. China has more problems than its widely publicized air pollution problem.
Well, now I plan to read the article on the war on science. Not looking forward to it. Next column, hopefully, on or about April Fool's Day, when our local par-3 golf course is supposed to open. Hopefully, the snow/ice will have melted by then!
Allen F. Bortrum
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