Evolution

The Texas Board of Education is voting this week on a new science curriculum designed to challenge the guiding principle of evolution, according to the Wall Street Journal. The proposed curriculum change would prompt teachers to raise doubts that all life on Earth is descended from common ancestry. Texas is such a huge textbook market that many publishers write to the state's standards, then market those books nationwide. "This is the most specific assault I've seen against evolution and modern science," said Steven Newton, a project director at the National Center for Science Education,…

Weeds, trees or tomatoes; no matter the plant genome of interest, Yves Van de Peer and associate Bioinformaticians at the VIB-Ugent research institute repeatedly observe that the last genome duplication to have occurred in all extant plants happened at the same time—65 million years ago.  This is a rather peculiar date considering it coincides with earth's last mass extinction event.  With this factoid in mind, an inference can be made; duplicated chromosome mutants (polyploids) have a strong advantage during times of environmental hardship. Although we…

There is a conversation about evolution that I’m apparently doomed to replay over and over with various family members, friends and acquaintances. I tell a friend that the evidence for evolution is overwhelming - everywhere in biology you find the signature of evolution; in every little bizzare, unexpected nook of biology you find unmistakeable evidence that all life is related, descended from common ancestors that lived long ago and took forms that were very different from what we observe in today’s organisms. We swim in a deluge of evidence, and I’m baffled that anyone can disregard the…

Humans belong to a sub-clasification of animals called deuterostomes (or second-mouth). During embryological development there is a period where part of the tissue “folds” back into itself creating what’s called a blastopore. The blastopore, in insects (and other members of the “other” group called protostomes, or first-mouth), forms the mouth. Not so for us and other deuterostomes. Oh, no. Our blastopore develops into the anus. We come out butt first. For discussion on such phylogenetic fun and sillyness, I stumbled across this tidbit from Greg Morrow: So that’s it for our animal family…

How did life begin, anyway?      I am a research professor at the University of California, Santa Cruz, and over the past 30 years my students and I have been working to understand how cellular life arose. The unit of all life today is the cell, a molecular system of functional polymers (proteins and nucleic acids) that is bounded by a membrane composed of lipid.      We and others have discovered ways to fabricate what we call protocells, artificial molecular systems that have some of the properties of life. In the next few years I am reasonably confidant that…

Professor Lynn Margulis is the biologist who had the incredible insight that the cells of modern organisms were originally formed by the symbiotic combination of prokaryotic cells and colonies of bacteria, and then had to battle for years to have this recognised by the science community. The idea is so outlandish, but so significant, that it puts her right up there as one of the greats of biology. We owe a huge debt to Margulis, but it’s not only for this that we owe her. Margulis has described neo-Darwinism as; "a minor twentieth century religious sect within the sprawling religious…

Show Me The Science Month Day 25 Installment 25 In nature, there is a sucker born every day. We humans may think that we're clever, but evolution has produced con games that would put Bernie Madoff to shame. One common natural swindle is mimicry, when one species tries to pass itself off as another. Orchids and cuckoos are classic examples of nature's swindlers, but mimicry isn't limited to plants and animals. A recent study has looked at how a fungus outsmarts a termite by dressing up as a termite egg. Male insects aren't particularly bright, and some orchids famously have figured out how…

Show Me The Science Month Day 24 Installment 24 How do new genes arise? One common way is through gene duplication - the creation of a second copy of a gene when the DNA replication or repair machinery goes awry, followed by the the evolution of a new function for one copy. How genes are accidentally duplicated is reasonably well understood, but once a gene is duplicated, but how does the new copy acquire a new function? A pair of researchers in New York have looked at the role of a class of reproductive proteins in the mating behavior of different species of flies. One thing you can learn…

Want to start an argument among shark paleontologists?   Ask whether Carcharodon carcharias, the great white shark, evolved from the line that produced Carcharodon megalodon, the largest carnivorous fish known, or from the broad-toothed mako shark. The mako camp contends megalodon, which grew to a length of 60 feet, should have its genus name switched to Carcharocles to reflect its different ancestry.  A study in the Journal of Vertebrate Paleontology says the mako proponents are right and concludes megalodon and modern white sharks are much more distantly related than…

Show Me The Science Month Day 23 Installment 23 Thanks to your parents, you have two copies of each chromosome, which means that you have maternal and paternal copies of every gene. In most cases, having two copies of a gene is no problem, but in some cases, two is too much, and your cells have to shut one copy down. How does a cell do it? Shutting down one copy of a gene (or an entire section of a chromosome) is called genomic imprinting. (This is not the same thing as the newly hatched duckling that latches on to the first thing it sees, obviously). Genomic imprinting is a critical process…