Peter D Roopnarine | PubMed Health

PubMed2006

Comment on "Statistical independence of escalatory ecological trends in Phanerozoic marine invertebrates".

The analysis of Madin et al. (Reports, 12 May 2006, p. 897) of Phanerozoic diversity failed to support expected correlations between carnivores and noncarnivores, leading the authors to reject escalation as an important macroevolutionary process. The test, however, is based on a flawed model of causality, and the ecological groups are improperly delineated with regard to the hypothesis.

Adaptation, Biological↗

PubMed2003

Complex morphological variability in complex evaporitic systems: thermal spring snails from the Chihuahuan Desert, Mexico.

Thermal springs in evaporitic environments provide a unique biological laboratory in which to study natural selection and evolutionary diversification. These isolated systems may be an analogue for conditions in early Earth or Mars history. One modern example of such a system can be found in the Chihuahuan Desert of north-central Mexico. The Cuatro Cienegas basin hosts a series of thermal springs that form a complex of aquatic ecosystems under a range of environmental conditions. Using landmark-based morphometric techniques, we have quantified an unusually high level of morphological variability in the endemic gastropod Mexipyrgus from Cuatro Cienegas. The differentiation is seen both within and between hydrological systems. Our results suggest that this type of environmental system is capable of producing and maintaining a high level of morphological diversity on small spatial scales, and thus should be a target for future astrobiological research.

Animals↗