Snakehead Homework

My dad gave me homework. He asked me to tell him all about snakeheads (Family Channidae) when I came down on Friday for a visit. So I did what any good daughter would do and I did a search on the greater snakehead fish (Channa micropeltes) and the northern snakehead fish (Channa argus). Turns out they are kinda cool, speaking from an ecological perspective.

They are part of a family of freshwater fish native to Asia, from China to India and down into the islands of Indonesia. There are also species native to Africa, but I don’t think those are the ones my dad heard about, as the hubbub here in the US is that they are invasive species.

Anatomically, the fish are unremarkable, with a long dorsal fin running most of the length of it’s back, and fan-shaped tail fins. Their heads are kind of flattened, I suppose like a snake head, and the mottled blotchy brown coloration reminds me of patterns on snakes bodies, like pythons or boa constrictors.

They grow quickly and can get quite large, as evidenced by this video courtesy of National Geographic.

Snakeheads were brought to America for food and as aquarium fish. However, as people are wont to do they release them in nearby ponds, rivers or streams when they get too large or they no longer need them, and the snakeheads settle and begin making more snakeheads.

They caused a stir in 2002 in Maryland, where an angler caught one in a pond. He took it to a local wildlife and fisheries office for identification. The authorities visited the pond and subsequently caught some hatchlings, indicating the population was well-established. This wouldn’t be such a problem, but the snakeheads are sneaky.

They are one of the few species of fish that need to breathe air. Yes, I said breathe, meaning they don’t use just their gills; they also have what is called a “suprabranchial organ”, which is a kind of a branch of their vascular system allowing them to oxygenate their blood via inhalation of atmospheric oxygen.

While snakeheads don’t actually walk, they do have a decidedly un-fishlike ability to scoot or flop themselves from one body of water to another. Thus, the concern of wildlife and fisheries agents.
There is plenty more I could say about invasive species but I think I should wait, or this will become a longwinded entry.

So, there you have it Dad, everything you wanted to know about snakeheads.

Warm Blooded Dinos?

I am not a paleontologist, but I am a big fan of scientific controversy. I love it when two sides argue about how flight originated or how new fossils may be related to our own hominid lineage. That’s why the recent findings that large bi-pedal dinosaurs like the beloved Tyrannosaurus rex may not have the typical large lizards we have long thought really caught my attention.

It’s generally consensus these days that some dinosaurs were birds rather than lizards, and the lineage has been split to include non-avian and avian branches. But there is still controversy among experts as to whether or not these dinos were warm-blooded like their birdy brethren or cold-blooded like their lizardy links. A new study published in the online scientific journal PLoS ONE on Nov. 11th brings to light some new information.

Say the study authors, endothermy, or warm-bloodedness, was widespread “in at least larger non-avian dinosaurs.” The results of their study seem to indicate that the ability to maintain a constant internal temperature may have originated earlier than previously believed.

What this essentially means is that once again we are rethinking how these extinct giants behaved. For the longest time, large dinosaurs like the T-rex were considered unwieldy, hulking and awkward. Now there’s evidence that there was more power and precision behind their lumbering movements.

So why is this such a point of contention? Because being warm-blooded and cold-blooded are very different and require different energy expenditures, different rates of respiration, and different natural histories altogether.

Cold-blooded animals (termed ectothermic), such as amphibians, reptiles and the ilk, rely on the environment to maintain body heat. They generally adapt behaviors to soak up as much heat and sun as possible to run their metabolic processes.

Warm-blooded animals are everything else—including birds (or avian dinosaurs). We can maintain homeostasis (i.e., regulate and maintain a constant body temperature through metabolism). But doing this requires much more energy consumption and output, and requires different anatomical and physical traits. It also means we can live anywhere, hunt for food anytime, and not have to worry about the environment to meet our temperature regulation needs.

So the fact that there is evidence for endothermy among dinosaurs has huge ramifications. We may need to reconsider how we classify them, and even how they became extinct.

Reptiles, a lineage of animals dating back over 300 million years, include organisms such as the extinct dinosaurs and the extant (still living) species of lizards, crocodilians, turtles. It was later expanded to include birds, based on genetic and molecular evidence. These new findings could also lead to more accurate phylogenies, or evolutionary trees.

Your DNA damage looks great, did you get just get back from the beach?

My students in Biology 101 are learning about DNA right now and one asked me how UV radiation causes damage to our genetic material. I know the basics, but was unfamiliar with the process. So I, of course, was intrigued, and had to look it up. Bear with me, I’ve tried to make this as simple and bare-bones as possible, so don’t let your eyes glaze over (like those of some of my students) when you see big scientific words.
DNA structure consists of a backbone molecule made up of sugar (a deoxyribose sugar, what the D in it’s name stands for) paired with phosphate molecules. Attached to each of those sugars is a nitrogenous base: adenine (A), thymine (T), guanine (G) or cytosine (C). It’s the complimentary pairing nature of these bases that allows for such perfect replication of our genetic material; A pairs with T, and G pairs with C, and that is what gives DNA it’s structure, chemical properties, and it’s ability to replicate so faithfully.
DNA replicates, or copies itself, in a process that is nothing short of amazing. The double-helix structure unwinds (with the help of an enzyme) and each parent strand is faithfully copied via complimentary base pairing. Throughout the process are “checkpoints” to prevent errors and proofreaders that won’t allow the DNA to code for protein unless things are correct.
Most DNA damage interferes with the ability to proofread or prevent incorrect proteins from being made, which is the case with UV radiation. UVB light causes one of the nitrogenous bases, thymine, to pair with itself instead of with adenine. These thymine base pairs next to each other in genetic sequences bond together into thymine dimers, an incorrect sequence which disrupts replication in the strand and which enzymes cannot read or copy. This leads to the production of melanin--a tan, or in severe cases, sunburn. Sunburn is the body’s way to get rid of cells damaged by UV radiation.
Direct DNA damage is reduced by sunscreen, which prevents sunburn; it won’t necessarily keep you from getting a tan. On the skin’s surface, sunscreen filters the UV-rays, decreasing their intensity. When sunscreen molecules penetrate the skin, they protect against direct DNA damage because the UV-light is then absorbed by the sunscreen and not by DNA.
So, that beautiful golden color you get when you lay out in the sun, the one you think makes you look so good? Yeah, not so good. That damage accumulates in your DNA, and over time can lead to skin cancer.
We do need some sun, so I’m not advocating staying inside on beautiful afternoons, just be careful and use sunscreen to decrease your risks of skin cancer.

Fueling my new obsession with mitochondira

I'm currently reading a fabulous book that I found just laying all by it's lonesome (i.e., in the wrong place) in Barne's and Noble a couple of weeks ago. It's entitled Power, Sex, and Suicide (now do you see why I had to have it?). And, if a fabulous title isn't enough it's about my newest favorite organelle--the mitochondria.
Dr. Nick Lane, a British science writer, does a very admirable job with this subject, especially in light of all the research being done in this area. Unfortunately, I am not very far along in the book, but it's one of those I can't put down so far. It's interesting and inspiring (as a wanna be science writer), as Lane says things like "the living cell is a minute universe" (p. 8) and he calls mitochondria the "clandestine rulers of the world" (introduction). I love these descriptions!
As I get further in to it, I will share more, but I wanted to share the title and the fact that it's a good read, at least thus far.

Thesis writing

So the time is coming up fast for me to have a thesis written for my master's degree.  Bah.  I'm not so sure I can do this.  Oh, yeah, a year or two ago I was all gung ho and "I'm gonna be a science writer" and now that it's time to begin actually writing, and querying and publishing, I'm chickening out.  

I have my classes under my belt, and though it was not a traditional education, I feel quite well educated through the ILPS program at Antioch McGregor.  (Don't get me started on them, I will digress quite a while and wax poetic about their virtues.)  I'm scared, though, because not only do I need to live up to their standards, I have to live up to mine. 

I feel a little like Charlie Brown just as he gets ready to run toward Lucy holding the football.  

Doomed to a life of questioning everything

As a skeptic, the grassroots movement that espouses creation ‘science’ has what I believe are many flaws, probably equal to the gaps in evolutionary theory that creationists see. Chet Raymo, in his eloquent and subtle Skeptics and True Believers, explains both of these views. The two poles he describes fit well into the two niches of the creation and evolution debate, and I agree that it comes down to this: “It is not so much a matter of evidence as attitudes toward evidence. The astrologer and the scientist have different criteria for the truth—one anecdotal and personal, the other empirical and institutional” (87). One believes what they read is true, the other questions everything, “[t]there are people who prefer that things remain the same; there are people who like change” (137). I would argue, though, that instead of categorizing these two groups as “reactionaries and progressives” you could call them the creationists and the evolutionists (or perhaps scientists is a better, more all-encompassing term). These two views are characterized well in the two-model approach to the world espoused by this grassroots movement.
This approach sees things in only black and white, leaving out any possibility of an intermediate explanation. Creationists must discredit Charles Darwin, because when they do so it will prove special creation was the answer all along. But, they’re forgetting that there are fellow Christians that believe in theistic evolution, or that there are many other creation myths that could also be the answer. The academic freedom ID proponents are so fond of demanding would include these intermediate believes as well as the two extremes, and it would still include evolution. This argument is a categorical error; just because they believe it, doesn’t make it true. If you don’t believe in gravity, you don’t fall off the earth.
This mistake also plays out in the media representation of this debate. When reporters search for balanced treatment in stories concerning evolution, they alternately portray ID or creation ‘science,’ forgetting, or maybe not knowing, that the two are not scientifically equal. The politicization of this debate makes this sort of equal treatment unique to this subject, however, because you rarely see alternatives given when the report discusses quantum theory, astronomy, or thermodynamics. Raymo makes a valid point when he mentions that scientists are often inept at communicating their craft, at making clear why their research is important, or more specifically portraying it as important to humans and what we value. Humans want to know what science will be doing for them, despite the conflict this creates with their belief systems: “we warmly embrace the technological and medical fruits of science, but often hold religious beliefs that stand in flat-out contradiction to the scientific way of knowing” (7). Perhaps scientists, educators and the media need to focus on this way of knowing and give it the fair treatment that it so deserves rather than endlessly addressing the two extremes.
This may not happen though, as conflict is one of the best story-telling techniques, so comparing evolution and creationism, pitting Raymo’s Skeptics against his True Believers, makes for great copy. I would certainly agree when it comes to the books Summer for the Gods (Edward Larson, Basic Books, 1997) and Monkey Girl (Edward Humes, Ecco Books, 2007). This is an epic battle and portrayals of the players create ensuing conflict—it’s a writer’s dream, imaginations couldn’t come up with fodder this good. The nature of the two arguments, though, makes this an unending battle. Its like one is in fact imagination, the other truth; one has eons of believe on its side and the other centuries of empirical evidence. They argue apples and oranges, tom-ae-to/tom-ah-to, anthropocentric views versus natural phenomena. Most scientists (and most creationists too, I assume) don’t see how the two sides can reconcile, though Raymo has constructed a strong argument: “[n]one of the miracles I have been offered in my religious training were as impressively revealing of God’s power as the facts I was learning in science” (20). It should be the duty of scientists and the media (science writers, particularly) to convey these revealing facts, to foster understanding, to unearth this middle ground between the two approaches.
Raymo compares quantum physics to magic, miracles. I would have to disagree; nature is so much more extraordinary than any magic I have ever seen, and the explanations behind her phenomena so much more fantastic than any secrets magicians hide behind their capes. So, for me at least, a way of knowing the world is more incredible than any of the mere beliefs I have tried to understand, because “everything wonderful need not be true” (137). Even if it’s not true it can still be wonderful, you don’t have to disprove truth to convince someone of wonder.

Putting the "controversy" in context. Or not.

America wouldn’t be America without the freedoms it affords its citizens. This adage has been used to describe our country probably since its inception, and I doubt that anyone would argue this point with Ben Stein. After seeing his new documentary “Expelled: No Intelligence Allowed”, however, that may be the only unarguable point. I admit that as a zoologist and science enthusiast, I was biased going into the film, and I knew that it would get my hackles up. What surprised me though was that I found myself upset not just for the scientists that the film misrepresents—I expected that—but for someone who spends most of the movie preaching about freedom and free speech, Stein edited a lot of important information out of his film. For someone who espouses a movement asking for “equal time” for a religious theory in the science classroom he sure didn’t give science equal time in a movie to promote a religious theory. Not that I expected him to do so.

I could go on ad nauseum with my criticisms of this film, and my critiques of the standard anti-evolution arguments would take up pages themselves. I will leave that for another time, since they are becoming cliché anyhow. I have other criticisms, too, such as Stein’s stylistic choices. The footage of concentration camps and the Berlin Wall being erected as backdrops for his introduction to the “debate” were a bit overblown and, frankly, they aren’t fair comparisons, which becomes clear as the film drones on. The snippets of 1950’s propaganda films taken out of context between interviews with scientists made me weary. The references to the first amendment grew tiresome. The whining about the “witch hunt” that about a dozen scientists and journalists have had to endure—plus the “many more” who conveniently refused to speak on camera for fear of repercussions—was a purely rhetorical move to convince people who already believe that this battle between religion and science is proof of coming Armageddon. However, what I take most issue with is how a majority of those interviewed, as well as most of the arguments posed in the film, are out of context. Not that I didn’t expect this to be the case.

Stein interviews many scientists, including some who believe in Intelligent Design. He whines for them and with them about the persecution they have had to endure when they have tried to present ID research to scientific journals. Their articles aren’t accepted or printed, they were fired, they are now “black-listed”. This looks, to the casual or uneducated observer, like an injustice, like the big bad scientists are picking on the creationists yet again, but it is—shock!—taken out of context. What he predictably leaves out of these discussions is the fact that the research these scientists were presenting wasn’t science, and for that matter, he never explains why ID proponents think they have a scientific argument.

Stein also interviews evolutionary biologists and experts like Eugenie Scott from the National Center for Science Education (NCSE: www.ncseweb.org/). He allows them to explain that evolution by natural selection is a fact, but doesn’t let them describe that a fact in science has an airtight argument to support it, including empirical evidence that has been replicated in many experiments. He lets them try to explain the basics of the theory, but not the connotations that word carries in the scientific community. Stein even corners several scientists into saying that the more they learned about the theory of natural selection the less they believed in a creator. Scientists, by Stein’s conclusion (based on the 3-4 scientists who admitted this) are anti-God.

I expected to be irritated by the same tired arguments against evolution, the anti-atheistic attacks by the ID proponents, and even expected the scientists and science itself to be misrepresented. However, I was surprised by the misrepresentation of ID as well.

Perhaps misrepresentation is an overstatement, since the basis of the theory was never really elucidated from creationism. The chief experts on this position are The Discovery Institute in Seattle, WA, a “non-partisan public policy think-tank conducting research on technology, science and culture, economics, and foreign affairs” (www.discovery.org). They were key players in the anti-evolution court challenges in recent years, including the highly publicized Dover, PA trial. The crux of their “evidence” for an intelligent designer is the irreducible complexity in life and they are usually careful refer to this individual as a designer. It has always been my understanding that ID proponents work diligently to avoid using the terms Creator or creationism, so either that has changed or Stein is misrepresenting them as well. My friend, a non-scientist—yet not particularly religious either, said that she didn’t know much about ID going into the film, and she guessed she didn’t know much about it afterward. I actually felt myself getting angry for the Discovery Institute, who didn’t seem to get much face time in a movie based on ID. I most certainly did not expect this.

Despite the conclusions based on too-small sample size, the comparisons of scientists to Hitler, or the misrepresentation of the positions, I left the theatre less exasperated than I expected. I rolled my eyes at Stein’s inane attempts at humor, scoffed at his incessant whining, and all the while a Latin phrase was looping through my head: res ipsa loquitur (1). The movie wasn’t an attempt to explain the misunderstood underdogs who believe in Intelligent Design. Instead, like the propaganda films that act as filler and a poor attempt at humor, it was Stein’s diatribe against the establishment; a film meant to rally support from those who already see the world this way. Stein made a point of reiterating that America is free, there is freedom of speech and freedom of religion and freedom of press. He criticizes the scientific discipline for not letting people speak, but he leaves out the most important part: they weren’t speaking science. He should have worried less about the religious affiliations of scientists and more about how he looks like a hypocrite for editing the speakers in his own film. But really, in this never-ending argument between the natural and the supernatural, the believers and the non-believers, the thinkers and the non-thinkers, isn’t this to be expected?


1This literally means, "the thing itself speaks" but in general is translated "the thing speaks for itself" (www.wikipedia.com).