Phelsuma

The theory of evolution is the cornerstone of modern biology. It provides an explanation for the extraordinary biological diversity of form and function on this planet. What is the best way to study this processóby focusing on the mechanisms producing variation, by seeking evidence of past evolutionary change in the phenotype, or by generating theory that fits with what we already know?


Tiny <i>Mantidactylus</i>

One approach is to look at evolution through the lens of development. We can consider evolution to be the change in populations and species that occurs over time, while development represents the change of an individual organism over time. Studies from the past two decades have revealed the somewhat surprising result that many of the genes involved in development are evolutionarily conserved. The ways in which these genes are used, however, appear to have been modified, to produce the adaptations that give rise to the diversity that we see. In this program, we will be studying evolution and development together, at both the morphological and molecular levels, in order to gain deeper insights into both processes.


During winter quarter, one strand will focus on the genetic logic of development. We will begin with a brief overview of the regulation of gene expression and the principles of cell signaling, and then move onto the study of early development in selected invertebrates and vertebrates. A parallel strand will focus on the history and diversity of vertebrates. By investigating each vertebrate clade in turn, we will be able to focus on some of the many innovations (e.g. brains, bone, the amniotic egg) and transformations of existing structures into new structures (e.g. swim bladder into lungs, hands into wings, scales into feathers), in vertebrate evolution.


Panamanian agouti

Laboratory exercises will include an introduction to techniques in molecular biology and embryology, and a weekly comparative anatomy lab. In the anatomy lab, we will dissect lampreys, cats, and sharks, and use them as our models to better understand the evolution of viscera, circulatory, muscle, and neurological systems through time.


During spring quarter, the emphasis will shift to later development, including the differentiation of muscle and the nervous system. We will also continue with our investigation of vertebrate evolution, perhaps including such topics as the re-evolution of aquatic from secondarily terrestrial forms, aestivation and hibernation, and the maintenance of circadian rhythms. We will also be considering selected topics that would particularly benefit from this interdisciplinary approach, such as the development of the tetrapod limb and the evolution of sex determination. Laboratory projects will be aimed at applying molecular biological techniques to study developmental or systematic questions. Field research projects which use theories or techniques covered in the program will also be possible.


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