Evolution by natural selection requires three steps. New phenotypic variation 1) must arise, 2) must have an impact on fitness (survival or fecundity), and 3) must (ultimately) be heritable. The first step - how new variation arises - remains controversial. Traditionally, new phenotypes are ascribed to novel genotypes (mutants or recombinants). But developmental plasticity - the same genotype yields different forms in different environments - may be a much more important source of new phenotypes than generally recognized. This has renewed interest in its evolutionary significance.
Development & evolution of claw asymmetry in fiddler crabs (Uca)
(see Palmer Science 2004, Current Biology 2009)
Our work has yielded valuable insights into the causes and adaptive significance of several striking examples of developmental plasticity and our studies of the development, genetics and evolutionary history of right-left asymmetry variation have yielded some of the strongest evidence to date for a phenotype-leads mode of evolution (sometimes called genetic assimilation) -- a result that caught the attention of the Pharyngula blog. We continue to explore the interplay between developmental plasticity and evolution on both ecological time scales (via descriptive and experimental studies) and evolutionary time scales (via comparative studies).
Ongoing research includes:
West Side Bamfield & Barkley Sound, from BMSC
- developmental plasticity in starfish tube feet and body form.
- mating behavior in gooseneck and acorn barnacles.
- developmental control of shell sculpture in marine gastropods.
- environmental effects on nematocyst uptake by aeolid nudibranchs.
- handed behavior and induced asymmetry in crab claws.
- handed behavior in hagfish and other 'lower' vertebrates.
- role of learned, handed behavior in the evolution of morphological asymmetry.
- development and evolution of conspicuous biological asymmetries in many taxa.
Our research is funded by: