BIODIVERSITY
Perhaps the most remarkable pattern of living things on the planet is the increase
in biological diversity towards the equator. Such latitudinal diversity patterns
occur in both the terrestrial and marine environments. Since I was a child, I always
wanted to know why things are the way they are. When I found out there are no
conclusive explanations for this question, I set out to tackle one small group of this
puzzle.
I chose cowries, a well-known and heavily collected group of marine snails.
The beauty of their shells and the animal itself comes as a bonus. I picked cowries
because a lot was already known about them. Pretty much all species are described,
meaning that when you go to the next island or biogeographic region you are not going
to all of a sudden discover ten or fifty new species you have to account for.
Also, their diversity profile (as seen below) is similar to other diversity contours for
more diverse groups that are too large to comprehensively sample. People had studied
their fossil record, their morphology and anatomy. I decided I could contribute a
molecular phylogeny for the group. With this framework of relationships, I can determine
the historical branching patterns and the relative timing of divergences. Hopefully,
cowries can be used as a model group to investigate the roles of various speciation
mechanisms in generating the remarkable tropical marine diversity.
