Field of Science

Not the Model of Monophyly

Physcomitrella patens is our little model organism moss. It has recently had all of its DNA sequenced. Think the human genome project, but for mosses. The speed at which scientific information is transmitted has been greatly increased by the internet. Some scientific journals even publish papers online before they even come out in print. One of these articles in the journal Evolution focuses on the genus Physcomitrella and some of its closest relatives.

Mosses were collected and identified as a particular species by their morphology (their outward appearance to the eye). Using similarities in appearance as an initial hypothesis for species relationships is often where scientists start. These hypotheses were then tested using DNA data to examine relationships among the moss species.

The Bottom Line - All moss populations that are identified as members of the genus  Physcomitrella were not found to be each others closest relatives using DNA information.

Thus the genus does not descend from a single common ancestor. Species or genera that do descend from a single common ancestor are said to be monophyletic or to demonstrate monophyly. Often this is a rule that is used when determining the names of organisms. Think of a genealogy. If you traced back to your grandmother and then you diagrammed all of her children and their children and their children, everyone who is descendant from her by blood, not marriage, you would have a monophyletic group. It works the same way in plants and in the same genus all the members hopefully form a monophyletic group.    

Since the genus Physcomitrella is not monophyletic, name changes are in order with some of these species needing to me moved into a different genus. Their data also show that some of the species are forming hybrids. Crossing a horse with a donkey to get a mule would be an example of a hybrid you might know. However unlike a mule, which cannot reproduce, some of these hybrid species are able to make offspring and continue their reproductive lines.

Their paper explores a basic question that I am very interested in: Are plants that look the same morphologically actually each other's closest relatives? Or have plants that look the same evolved from different ancestors?

Darwin's not that Cool

Charles Darwin's work On the Origin of Species is celebrating its 15oth birthday/publication-day today. A lot of news outlets are talking about the influence of this book on our scientific thinking about evolution. Checkout NPR, BBC and NYTimes for more info. I really don't have much more to add to that information-wise about Darwin. I've read parts of On the Origin and as a thinker he was way ahead of his time with some really great thoughts.

But honestly, just between you, me, and the blogosphere he is not my favorite historic (aka. dead) scientist. Beating him out by a long shot is Wilhelm Hofmeister. Ok, so you have probably never heard of Hofmeister. His position as an unknown underdog is one of the reasons I like him and his scientific discoveries. I study mosses. I tend to like the underdogs and migrate toward championing them.

Hofmeister's major discovery was to observe and outline the alternation of generations in many different kinds of plants from bryophytes to flowering plants. Basically he figured out how different parts of the plant life cycle go from gametophyte to sporophyte and then back again. He was the first scientist to figure out and discribe this important plant phenomenon.

He only had a basic education equivelent to trade school through age 15 and was entirely a self-taught botanist. Also he was very near-sighted. So much so that he sometimes did not recognize people walking down the street. However this sort of turned his eyes into magnifying lenses enabling him to see tiny plant parts and mini mosses.

Check out this scientific journal article to read more about Hofmeister and his scientific contributions.
The Genius of Wilhelm Hofmeister: The Origin of Causal-Analytical Research in Plant Development. Donald R. Kaplan and Todd J. Cooke. American Journal of Botany, Vol. 83, No. 12 (Dec., 1996), pp. 1647-1660.

Hofmeister also has a well-referenced wiki entry that appears to be accurate considering its wiki-ness.

A Mossy Embrace

A fellow graduate student forwarded along this link to a BBC news page reporting on the results of a photo competition. The photo that won the student category is a pair of moss sporophytes sticking out of the snow. (#13 in the series.) The photo is entitled Embrace. It is a great picture with nice imaginative imagery in the quote from the photographer. Some of the terms that she uses in the caption are not entirely bryologically accurate or maybe they are just not the terms that I would use. However I am trying to not be such a scientist, so I am not going to critique them here. I encourage you to suspend reality and any terminology hangups that you might have and to enjoy the beauty of these snowy sporophytes.

An additional news source that reported on the competition is the Guardian News. Click here for the link to another version of the moss image and its associated caption. (Photo #7)

(We are reading the book Don't Be Such a Scientist: Talking Substance in an Age of Style in the Science Communication seminar I am taking. Thus I am trying to relax into my science communication and not be so picky about terms especially when the above photo is art. We shall see how it works.)

Moving and Mossing

A couple of weekends ago I helped one of my grad student pals move into his new house. I arrived a little early and explored the moss diversity on the property. There was an old well behind the house that was covered by mosses. It has a nice bit of species diversity. I have included some of the photos below.

I was on a photo spree and did not do any collecting to identify the specific species. I think that I will have to visit again to do a more through survey.

Blogging Pause

October has been a busy month for me with a trip to Virginia and juggling a number of projects here in the lab. All the balls are still in the air and I am feeling pretty good about that. However as you can see the blogging has suffered, with my last post being over a month ago. I have been amassing ideas for new posts over the month and am planning to write some of those during the upcoming weekend.

For now...

- The latest edition of the plant blog carnival Berry Go Round is up at Beetles In The Bush (#21) for your perusal. My favorite article of the bunch was the post at The Natural Capital about wild grapes. It is a well written post with a good hook at the beginning. Then great facts on identifying wild grapes and tips on avoiding other fruiting plants that you might mistake for grapes.

- The trip to Virginia was to see a friend and former Grad Student from my department who now lives in Virginia. I left the shutter-bugging to the other gals so I don't have any pictures of our outing to the Shenandoah National Park. It was a great autumn day and there were tons of mosses to be seen! If you would like to see some photos and the tale of hiking adventures with four botanists you can check out Em's blog post here.