The project

The theory of punctuated equilibria, derived from palaeontological evidence, sustains that evolution proceeds by episodic changes followed by long periods of stasis. Two of the assumptions of the theory are a) that reproductive isolation is linked to morphological change and b) that speciation follows the peripatric model; however, the first assumption can only be tested in living systems and geologic time lacks the fine resolution to track the small, ephemeral, localized changes that characterize the diversification periods. Support for the aforementioned assumptions can only come from extant taxa and from them the fine resolution of short time change can be detected as well.

To see it in living taxa, one should spread the time axis two-dimensionally, that is: select a perfectly contained clade whose members can be assigned to discrete time frames. The model predicts that the members of the clade living in older, stable areas will exhibit less intraspecific diversity and be genetically less close interspecifically (stasis), whereas those living in younger, perturbed areas will be intraspecifically more diverse although genetically closer interspecifically (diversification). The Azores islands, with ages ranging from 250.000 to 8 million years and recent, recorded volcanic activity as well, provide the geological framework. The endemic molluscan subgenus Drouetia, which anatomy and morphology varies according to the ages of the islands, assures the biological settings to test punctuated equilibrium in a living system.

The main objective is the testing of the theory of punctuated equilibria on those assumptions that it draws from living systems.

Discrete platforms derived from the stepwise procedure to reach that main objective are:

1. To establish a phylogeny for Drouetia, through molecular (DNA) approach, using as reference the morphological and anatomical findings that support this proposal.
2. To establish a phylogeography for the taxon.
3. To correlate morphological/anatomical diversity with genetic diversity.
4. To correlate diversity with phylogeography and, in the process, to find a molecular reference that could relate change with time with space.