To celebrate, today's photograph (courtesy of Nhu Nguyen, or xerantheum@Flickr -- original photo) highlights some "speciation in action".
Nhu writes in the accompaniment to the photograph:
"In celebration of Darwin's 200th birthday and the 150th anniversary of The Origin of Species, I have prepared this panel."
"This is a weedy species that grows in coastal (and some central) areas of California. According to research by Norman Ellstrand's group at UC Riverside, this species is evolving in a quantifiable manner. It is a hybrid between Raphanus sativus, the common radish, and Raphanus raphanistrum."
"Curiously, the same hybrid occurs elsewhere in similar climates such as that of South Africa, but something special about ecosytems in California allowed it to proliferate. It is now different enough from either of its parents that Ellstrand's group is considering describing this as a new species. This has occurred within the timespan that the two parents were brought together by humans in California."
"There are many color variations of this evolving species. It is exactly through this variation that the process of natural selection works. If allowed to go its own way, some of these color morphs may persist, others may perish, all depending on the selective forces present where they occur. Eventually, each of these via time and selection could become a species of its own. California thus would be the center of diversity for a new group of Raphanus species."
Daniel adds:
The paper from the Ellstrand group detailing "that California wild radish has now become an evolutionary entity separate from both of its parents" is here: Hegde, SG. et al. 2006. The Evolution of California's Wild Radish Has Resulted in the Extinction of its Progenitors. Evolution. 60(6): 1187-1197. doi:10.1111/j.0014-3820.2006.tb01197.x. From a read of the abstract, it seems that the wild parent species have become extinct (at least locally) and replaced by these hybridized descendants.
This is wonderful...!!! I used to see several of these colors on our ranches when I was a girl in Stanislaus and Lake counties in California. They were often growing near wild mustard, so I ''assumed'' it was a variety of the mustards...:) Beautiful display...Thanks so much!
Ah, wild radish is it's common name. It's interesting to have the latin nomenclature, but I do like it when the common name is included.
Wouldn't it be fun to have all these colors in one field!
hm, I wonder if there are differences other than just the flower color? Flower color does not seem to be something that would put a a great deal of selective pressure on the plants. It is an interesting concept that when a new species evolves there is more variation (genetic diversity) some of which is lost later on. Fascinating!
mr darwin still has us debating
his ideas yes no maybe or
the flowers are pretty just try
to enjoy and give your brain a rest
the write up is fine the montage
is just fine and intersting
this is friday the 13th beware of
black cats -thank you daniel and company
I love the daily dose of botanical thoughts, thanks Daniel! Makes me wonder about the big flap concerning "invasive species" here in Michigan. The plant community evolves unaware of man's intervention.
I just set Mr. Nguyen's beautiful montage as my desktop background...many thanks to him & to you for such wonderful daily diversions. I hope there is a CA plant breeder working to capture these outstanding colors, before the species settles on just a few and jettisons the rest.
While I always look forward to these posts, it is especially exciting to see plants from right out my back door! Point Reyes National Seashore will always have a special place in my heart, thanks for the write-up!
These are common plants around here near Monterey. The colors I recall are mostly purples and pinks. Beautiful even if they are weeds. Aside from their flowers, their "bottle gourd" fruits are also interesting.