Well, classes start Monday and we'll get busy here. I'll be using this venue as a supplement for the classes I teach. Another, slightly less formal way to share information with students. Maybe spark some interest that might otherwise lie dormant. It's something that I think is important, and I'm more than willing to try some unorthodox approaches. A little music, some movie clips... Who knows - maybe I'll sing.

That said, the content will shift a little as I focus on particular subject areas. This semester, that means Zoology (of the general and vertebrate varieties) and Evolutionary Biology. (Hi guys. Come on in. I hope you find something you like.) Might also slip some Biogeography in here, for some of my online clients. If you're saying, "Man, that seems like a lot of classes", you'd be right. Maybe too many. But, truthfully, I manage to stay on top of them pretty well. By working pretty hard. Not that that makes me anything special here. A lot of my colleagues work very long hours. For very low pay. You might be interested in taking a look at a comparison of salaries for faculty at the various state institutions. You'll note some huge disparities between the big research universities and the smaller schools. Including (especially?) mine. Of course, there's a lot of pressure at the big schools to turn out research and generate grant dollars. The pressure on my colleagues and me is take high school students (who've spent the last few years cheering, playing baseball, sending text messages, and filling out the occasional worksheet while their teacher reads the newspaper) and turn them into biologists. Just sayin'.

So anyway....


If you see me coming, better step aside. Especially if it's Thursday - that's lab day.

You'll often hear those in the anti-evolution crowd express the viewpoint that evolution by natural selection can't operate to increase genetic diversity, only to decrease it. That's a clue to their fundamental misunderstanding of how the process works. It's driven by mutations, changes in the genome. Those changes create the variation on which selection can operate. No changes, no variation, no evolution.

So, it goes without saying that the faster the rate at which mutations accumulate, the greater the amount of variation in the genome. True, a lot of that variation will be selectively neutral, or even detrimental. But if we assume a more or less constant chance of a favorable mutation, then the rate at which evolution proceeds must be tied in some fashion to the mutation rate.

So, what is that mutation rate? A study just published in the new issue of the journal Science examines mutation rates in Arabidopsis, a small flowering plant in the mustard family which has become a significant model organism for geneticists and for which the entire genome has been sequenced. The researchers followed five lines of Arabidopsis thaliana for 30 generations, and identified in each line the the changes occurring between the original ancestor and the final generation.

They found, in each line, some 20 base pair changes. Taking into consideration the 120 million base pair size of the Arabidopsis genome, this indicates that the probability that any given base changes in a given generation is about one in 140 million, or that each seedling likely contains one mutated base in each of the two copies of the genome in its diploid state.

To some, this may seem like a vanishly small number, and suggest that evolution must proceed slowly. However, when you consider a large population of Arabidopsis, each producing vast numbers of seeds in each generation, it becomes clear that the raw material is there to allow selection to go to work to produce relatively rapid changes.

I'm walking...



Big news in the vertebrate water-to-land arena. In the new issue of the journal Nature, researchers report the discovery of a Devonian trackway in a mountainous region in southern Poland. The tracks are those of a relatively large animal, with the 10" wide tracks indicating a body length of some 7-8 feet. There is no indication 0f "body drag", indicating an animal using it's forelimbs and hindlimbs to lift its body clear of the substrate. The find is very significant in our understanding of the transition of vertebrate life from strictly aquatic environments to a terrestrial existence. These fossil tracks, well preserved and securely dated, are from rocks 395 million years old, almost 20 million years earlier than the oldest known tetrapod fossils and are some 10 million years older than fossils of tetrapod-like fish such as the famous Tiktaalik. The tracks seem to have been made by an organism with front and hind limbs of similar size, walking in much the way that a modern salamander might. Also of interest is that the deposits indicate a marine environment, rather than fresh water. This runs counter of most current thought regarding tetrapod origins.

Nature provides a fascinating video, in which one of the researchers, Per Ahlberg of Uppsala University in Sweden, describes the find and discusses its significance. Ahlberg is one of leading researchers in the area of early tetrapod evolution, and calls the Nature paper the most important one that he has worked on. The take home message is that the find changes our perception of the type of animal that might have been making its way across a prehistoric mudflat almost 400 million years ago - instead of a fish using its lobed fins to drag its body along, we've got a walker.

The tragic story of a mother and daughter killed by an elephant while on a walk in a Kenyan forest brings to mind a number of recent stories about lethal encounters between people and wildlife. The combination of recovering numbers of certain large species and the expansion of humans into their habitats can only serve to increase encounter rates, and a certain percentage of those encounters will go badly. That's just the nature of the beast. So to speak.

We don't have to worry about elephants in our part of the world, of course, but look for an increasing number of horror stories about the American alligator. Alligator numbers are on the rise across the lower tier of states, after reaching critical lows in the 1960s. When the first list of endangered species was developed in 1967 (under the Endangered Species Preservation Act of 1966, which preceded the Endangered Species Act of 1973), the American alligator was on it. With protection, they recovered rapidly, and were removed from the list in 1987. Now, estimates place Florida's alligator population at well over one million.

In addition to increasing numbers, we're seeing gators gradually extending their range into regions in which they were formerly found. Just in the last few years, alligators have been seen in reaches of the Tombigbee River where they had not been seen in decades.

Meanwhile, people have taken to the water in increasing numbers. The summer months see thousand of anglers, swimmers, water skiiers, and other aquatic enthusiasts taking advantage of recreational opportunities in our lakes and rivers. The result in predictable. In the 1970s, there were three fatal alligator attacks in the United States. In the last decade, there have been at least 13. Expect that number to go up, and expect the occasional horrific story to cross your television screen. You might exercise a little common sense when you go to the river, too.

Here it comes....

You may have heard about the invasive Australian spotted jellyfish, Phyllorhiza punctata, that have become abundant in the Gulf of Mexico in the last decade. The jellyfish are apparently taking advantage of dead zones in the Gulf and other environmental factors. The impact on the Gulf shrimping industry has already been significant, and promises to grow.

The problem is not limited to the Gulf. Recently, outbreaks of the nomura jellyfish, Nemopilema nomurai, in Japanese waters have become more frequent and more significant. The nomura is a much larger animal, reaching weights of over 400 pounds. It has also earned the honor of being the first jellyfish to sink a ship.

What's hot in biology right now? Well, an educated guess by even a casual observer would probably be pretty accurate. All you have to do is read the paper or watch the news. But, why guess? Check out Sciencewatch, a site hosted by Thomson Reuters which tracks trends in the sciences. They estimate the impact of a research paper by looking at the number of times it's cited in someone else's work. Take a look at the hot papers for 2009, and you'll see that they're dominated by stem cell work, human genome investigations, and AIDS research. The Scientist, an online life sciences magazine, tells us that the most cited paper in biology over the last couple of years was the work of Kazutoshi Takahashi and his colleagues, most of them in the Department of Stem Cell Biology at Kyoto University in Japan. It showed the pluripotent stem cells could be produced from adult human fibroblasts, and was cited over 500 times in 2009. If you're into stem cell research, check it our here.