evolution
sporte | August 4, 2006Last week, we decided to compare a human mitochondrial DNA sequence with the mitochondrial sequences of our cousins, the apes, and find out how similar these sequences really are.
The answer is: really, really, similar.
And you can see that, in the BLAST graph, below the fold.
A quick glance shows that the ape with the most similar mitochondrial sequence is Pan paniscus, the pigmy chimpanzee. Next, is Pan troglodytes, the chimp that we see in movies, and last we have Gorilla gorilla.
Then we have a really curious, and unexpected, matching sequence.
Click the picture to see a larger…
mikethemadbiologist | August 4, 2006One of the lesser known microbiology facts is that the pathogen Shigella is actually E. coli. From the archives, here's an explanation (with a little modification).
As I mentioned in a previous post, Orac has two very good posts on MDs and creationism. In one of the posts, he links to a creationist medical student who writes the following:
Has anyone ever documented a plateful of Strep pneumo mutating into E coli? Or even into Strep pyogenes? I didn't think so. They mutate, and they exchange information. But they remain separate species, with their own unique characteristics. Staph aureus…
clock | August 3, 2006Predators Prefer To Hunt Small-brained Prey
Predators such as leopards and chimpanzees consistently target smaller-brained prey less capable of escape, research at the University of Liverpool has shown.They avoid more intelligent prey such as monkeys which have exceptionally large brains and are more capable of escaping attacks.
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Animals with small brains lack behavioural flexibility and are probably less capable of developing new strategies to escape predators, compared with larger-brained species.
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pharyngula | August 3, 2006Often, as I've looked at my embryonic zebrafish, I've noticed their prominent median fins. You can see them in this image, although it really doesn't do them justice—they're thin, membranous folds that make the tail paddle-shaped.
These midline fins are everywhere in fish—lampreys have them, sharks have them, teleosts have them, and we've got traces of them in the fossil record. Midline fins are more common and more primitive, yet usually its the paired fins, the pelvic and pectoral fins, that get all the attention, because they are cousins to our paired limbs…and of course, we completely…
mikethemadbiologist | August 2, 2006It looks like supporters of reason won out over sectarian ideologues in Kansas. Josh at Thoughts from Kansas writes:
The Board is back in moderate hands no matter what. The night is, on balance, a victory. It'd be nice to further marginalize the extremists by winning the remaining races in November, but we've got a majority that will implement the science standards recommended by the scientists, educators and parents of the science standards committee. The Board can focus on bigger issues. They can dig into ways to address the special challenges of rural districts, and to find solutions to…
loom | August 2, 2006This morning the Kansas State Board of Education is all shook up.
Last year the board voted 6-4 for much-criticised, creationism-friendly science education standards. Yesterday the primaries for the board elections took place, and on balance, the science-standards bloc lost two seats to Republic opponents. So it looks as if the balance is going to shift to 4-6, and the standards are going to go down.
The vote is all the more notable for the fact that the primaries saw a big media campaign carried out by the Discovery Institute, the main organization pushing intelligent design (a k a "the…
clock | August 2, 2006
This is a post from June 28, 2005, reviewing one of my favourite new evolution books:
Ever since I read Gould's Ontogeny and Phylogeny in about 1992 or 1993., I knew I wanted to do research that has something to do with evolution, development and timing. Well, when I applied to grad school, I could choose between evolution OR development OR timing, but not any combination of two or more - the true evo-devo folks were just not available for me at that precise moment in history. I chose timing and than worked dilligently to infuse my work with as much evolution and development as I could. I…
pharyngula | August 2, 2006If you're at work, I hope you have headphones; if you don't, check in once you get home. Here are a couple of audio recordings of good science.
John Rennie speaks out on stem cells on an Australian program, the Science Show.
I reviewed her new book a while ago, and now you can hear Christiane Nüsslein-Volhard lecture on basic developmental biology. She has a very nice light German accent that makes it especially pleasant to listen to, I think.
hrynyshyn | August 1, 2006Well, not clams. And not legs as such. But there's a neat piece out in Nature on the evolutionary leap, so to speak, between fish fins and the limbs of land critters. A team of researchers has "discovered that the median fin of Catsharks, although originating from different embryonic cells, uses the same genes (Hox and Tbx18) during development as limbs and paired fins."
It's not quite that simple, of course. But before we get to the details, allow me to quote from an AP story that appeared within 24 hours of the announcement of the fin-limbs paper. It's about the Creation Museum that's "…
grrlscientist | August 1, 2006I am sure that some of you have read this already, but here is a printable version of the cogent article published last year in the excellent magazine, The New Yorker, that discusses so-called "intelligent design". This article, entitled Why Intelligent Design Isn't, was published in May 2005 and is still relevant today.
This article should be required reading for all high school and college students who are studying biology.
Several issues it explains regarding "intelligent design", including the scientific refutations of these ID assertions;
ID is not Biblical literalism.
Behe's…
hrynyshyn | July 31, 2006While online polls are generally worthless when it comes to generating representative statistics - see this post and ensuing dicussion (sorry for being cranky, girlscientist) -- they can at time produce quite curious results. This self-described unscientific poll from the Australian science magazine COSMOS really has me wondering about the publication's readership.
"Are humans still subject to natural selection?" asks COSMOS. Fair question. And more than three quarters of the respondents selected one of two quite similar variations on a theme of "yes." But then there were the other responses…
pharyngula | July 30, 2006Carel Brest van Kempen has posted one of his paintings of Cambrian animals—be sure to click on it to get the larger size. I wish I had a pet anomalocarid in my aquarium.
pharyngula | July 30, 2006
Assuming that none of my readers are perfectly spherical, you all possess notable asymmetries—your top half is different from your bottom half, and your front or ventral half is different from you back or dorsal half. You left and right halves are probably superficially somewhat similar, but internally your organs are arranged in lopsided ways. Even so, the asymmetries are relatively specific: you aren't quite like that Volvox to the right, a ball of cells with specializations scattered randomly within. People predictably have heads on top, eyes in front, arms and legs in useful locations…
jrosenhouse | July 28, 2006Following up on yesterday's post, the July 21 issue of Science also contained this review article, entitled “Evolution of the Molecular Machines for Protein Import into Mitochondria.” The authors write:
Here we look at how protein import pathways were established to create mitochondria. The protein import pathway is driven by a set of molecular machines, and these machines are of modular design. Each machine has a core module that seems to be common to all eukaryotes. Additional modules have been added to each machine over time, with these add-ons being common only to particular…
clock | July 28, 2006As always, animal porn is under the fold:
You have probably heard that a female praying mantis eats her mate's head during the mating process. You may imagine the process to go something like this:
Actually, there are many species of praying mantises and in most of them sexual cannibalism is quite rare. It occurs much more often in the laboratory than out in the field. Apparently, the lights and sounds of a laboratory are stressful to the female so she acts aggressively in response.
The praying mantises are very aggressive predators and they can eat quite a lot of food, preferring soft-…
sporte | July 28, 2006We've had a good time in the past few last weeks, identifying unknown sequences and learning our way around a GenBank nucleotide record. To some people, it seems that this is all there is to doing digital biology. They would, of course, be wrong.
We can do much, much more than identifying DNA sequences and obtaining crucial information, like who left their DNA behind on that little blue dress.
Today, we're going to a deeper question about who we are and who are our relatives.
Drumroll, okay, here it comes:
How similar are DNA sequences between humans and apes?
Your assignment is to find…
jrosenhouse | July 27, 2006While the blathering know-nothings of ID pound their chests and predict the imminent demise of Darwin, real scientists are look to the future. A recent conference at Trinity College in England explored the future of Darwinian thinking in biology. Eors Szathmary (coauthor, with John Maynard Smith, of the excellent book The Major Transitions in Evolution) reports on the conference for Science. He writes:
Many regard the Darwinian theory of evolution by natural selection as one of the most important and powerful theories of our times, in the good company of the general theory of relativity…
pharyngula | July 27, 2006
I am going mildly nuts right now—somehow, I managed to arrange things so multiple deadlines hit me on one day: tomorrow. I've got a new lecture to polish up for our introductory biology course, a small grant proposal due, and of course, tomorrow evening is our second Café Scientifique. Let's not forget that I also have a neurobiology lecture to give this afternoon, and I owe them a stack of grading which is not finished yet. I'm really looking forward to Wednesday.
Anyway, so my new lecture for our introductory biology course is on…creationism, yuck. What I'm planning to do is to describe…
clock | July 27, 2006The latest AskTheScienceBlogger question is:
"I heard that within 15 years, global warming will have made Napa County too hot to grow good wine grapes. Is that true? What other changes are we going to see during our lifetimes because of global warming?..."
Answer under the fold....
I am not a big wine connoisseur, though I like an occasional glass of French burgundy, German riesling, Adriatic cabernet or Argentinian malbec. Also, I heard that wine is generally thought to be good for you (although you should take every claim in that article with a grain of salt, e.g., aboutmelatonin in wine…