Redefining Evolutionary Relationships

The evolutionary tree of life may undergo a makeover in the next decade or so.

In the past, the primary sources of information about the evolutionary relationships between organisms came from the fossil record or from comparative anatomy, physiology, or biochemistry. But now a new scientific field called phylogenomics (the study of the evolutionary history of organisms based on genetics) has emerged, thanks to the increased availability and cheap cost of sequencing DNA.

How does comparative DNA sequence data tell us anything? By tracing specific differences in the nucleotide sequences of the genes of closely related species, phylogeneticists can tell just how closely related two species are and when they most likely split from a common ancestor. That’s because when a mutation (a change in nucleotide sequence) occurs by random chance in a common ancestor, that mutation should still be present in all subsequent descendants of that ancestor. So when exactly the same mutation appears in the same gene in two species, the mutation most likely occurred before the two species split from a common ancestor – i.e. the two species are related to each other by a common ancestor.

The DNA sequences of a wide variety of species are now known, and more are being determined every day. We can expect challenges to the current tree of life (also called the phylogenetic tree) as the data are analyzed and debated.

Save the date

The Department of Molecular, Cellular and Developmental Biology at  UCSB cordially invites all faculty, staff and students to attend:
MORSE SYMPOSIUM
Honoring Dan Morse and his ongoing contributions to the UCSB campus and the at-large research community

Friday, April 15, 2011
100 PM - 530 PM
Loma Pelona Center, UCSB Campus

DRAFT SCHEDULE (speakers confirmed):
100 PM -- coffee/tea/cookies
115 PM -- Opening Remarks hosted by Dr. Joel Rothman, Chair, MCD Biology
130 PM -- Talk #1 (Dr. Bernie Degnan)
230 PM -- Talk #2 (Dr. Jen Cha)
315PM -- BREAK (refreshments)
330 PM -- Talk #3 (Dr. Angela Belcher - Giving Life to Materials for Energy, the Environment and Medicine)
415 PM -- Closing Remarks
430-530 PM -- RECEPTION (libations, hors d'ouevres)

A final schedule will be posted on the MCDB website
(http://www.lifesci.ucsb.edu/mcdb/ ).


Angela Belcher is one of CCS Bio's more famous alumni, director of the Biomolecular Materials Group at MIT and a 2004 MacArthur Fellow (aka the Genius award).

Career opportunities

Who knew that panda impersonator was even a valid career option?

From a Time Photo-story: Giant Panda People - scientists don costumes for good cause.

In 1980, the Chinese government teamed up with the World Wildlife Fund to establish the China Conservation and Research Center for giant pandas. Since then, with 100,000 visitors a year, it has become the most popular place on the planet to see giant pandas in their habitat. The reserve's mission is to observe, study and breed the endangered species to increase their chances of survival. So far the reservation has successfully bred 66 panda cubs.

Part of the reserve's mission includes placing the pandas it has bred back into the wild. Because previous attempts to reintroduce captive pandas into the wild have been largely unsuccessful, the researchers have developed the novel technique of dressing as the animals to acclimate them to the wild.

I think we need one more picture but you should check them all out at the Time website.

Is the 'panda' on the left eating bamboo? That seems to be taking method acting a bit too far...

Dilemma

The world’s largest set of shark jaws is going up for auction. The jaws, which once belonged to a megalodon, will be placed up for bid in Dallas, Texas in June at the Heritage Auction Galleries. The asking price is set at $625,000. The previous owner, the late Vito Bertucci, spent 16 years gathering the right shaped teeth to fit the jaw. So paleontologically this may be a specimen of many parts but realistically it is just awesome.

Magalodon is an extinct species of shark that lived roughly about 25 to 1.5 million years ago, during the Cenozoic Era.

It is thought that megalodon looked like a bigger version of the great white shark. Much bigger.

Furthermore a paper in 2008 suggested that Magalodon had the most powerful bite that has yet been discovered.

Personally I think this would look awesome placed around my front door. Assuming it doesn't go for much more than the asking price I guess I could sell my house and buy it but then I wouldn't have a front door... It's a pity CCS doesn't have a large slush fund or a generous benefactor because these jaws would also look great as the entrance to CCS. I'm not sure if they would send the right message but they'd look fantastic.

The Sixth Mass Extinction

Over about 3.5 billion years, evolution (descent of species over time, with genetic modification) has produced the astonishing variety and number of life forms found on Earth today. Punctuating this natural evolutionary process of speciation have been five mass extinctions – periods characterized by the rapid (compared to evolutionary processes) loss of over 75% of all species. Past causes of mass extinctions include major changes in ocean and atmospheric chemistry, changes in climate, periods of volcanic activity, and an impact with an asteroid.

According to a recent review article in Nature, we may be about to enter a sixth mass extinction, meaning that over the next 300 to several thousand years we can expect that over 75% of all current species will become extinct. Somewhat disturbing is the suggested cause – humans. Won’t THAT be an interesting and contentious debate over the next 300 years or so!

This is a well-referenced review in a high-quality journal. It’s worth reading if you’re interested in this subject. The notion that the next mass extinction may be caused by humans is only a small part of it.

Lotusland 2011

Unlike last year when it rained we had beautiful weather this year. The rain did lead to some great pictures last year though. Check out the posts here and here for some photos of the gardens last year in the sun and rain.

Post some pictures from this year if you took some good ones (when you click the photo icon in the posting screen this will give you the option to upload a photo).

Here are two articles about the Lotusland gardens and their founder, Ganna Walska, Forget About Rubies – She Wanted Cycads from the Christian Science Monitor and What The Diva Wrought, published in the Wall Street Journal. Both are short and well worth a read. The second article is hosted at the Lotusland website so click the links on the left for further information about Lotusland. 

Early earth tectonics

This National Geographic video showing plate tectonics during the early earth covers a surprisingly large number of topics we have mentioned in this class - from the surprisingly early appearance of life before the end of the massive asteroid bombardment, to the generation of heat via radioactivity within the earth and the movement of the continents. Notice that they go much further back than Pangaea. Evidence for these early super continents is much weaker than the evidence for Pangaea.

'Here's how it might have happened...'

The UC Museum of Paleotology at Berkeley has some neat animated gifs of Plate tectonics, I like this one that ends with the present day. Check out India smashing into the rest of asia.