Ecology and Evolution of Development

Eggs, larvae, and juveniles of marine invertebrates offer many opportunities to explore how organisms interact with their current environment and have evolved over geological time. What happens to these early stages in their environment may be essential for determining patterns of life cycle evolution, current patterns of population dynamics, and the evolution of new forms and body plans. In my laboratory, we explore many facets of these early stages in invertebrate life cycles. We focus on the interactions of the organism with its environment. The laboratory is part of the University of Oregonís Institute of Marine Biology (OIMB ) located in coastal Charleston (2.5 hours from Eugeneís main campus).

Marine invertebrates have such amazing life styles, innovations, and life histories!

- The differences between adult forms and larval forms are staggering, yet complete and reliable explanations for patterns are lacking.

- Why do so many marine invertebrates have biphasic (pelagic larva and benthic adult) life-cycles?

- What are the specific form and function requirements for being successful as pelagic larvae? - What new form and function requirements do newly metamorphosed juveniles have to meet?

- Closely related species of invertebrates often have very different development : some have pelagic, feeding larvae, others have pelagic, nonfeeding larvae, and others brood their young. Why are there such differences and how might these differences arise? In some cases a feeding larval form may have been lost repeatedly. In others feeding larvae may have evolved from nonfeeding ones.

Brief Background on my research:

My research has focused primarily on how extrinsic factors, such as global change, environmental, populational and organismic forces, can act to constrain or direct evolution of both life history characteristics and developmental processes either through natural selection or through stochastic events. This effort requires an interdisciplinary approach, integrating organismal biology with earth history and developmental mechanisms with form, function, and ecology.

I have studied sea urchin larvae and developmental patterns for almost 20 years. These studies have taken me out of North America, on research trips to Panama, Japan, Australia (many times), New Zealand, and Europe. One of several ongoing themes is examining the geological and historical patterns of developmental evolution in sea urchins.

I have explored aspects of larval form and function in echinoderms, examining swimming mechanics, influences of temperature and viscosity on movement, and functional reasons for form change when larvae evolve nonfeeding development.

I have studied a few aspects of polychaete larval form and function.

Summary of recent focus in the laboratory:

Most recently I, and people in my laboratory, have been exploring connections between larval and juvenile periods. If larvae survive to settle and metamorphose their success in the new benthic environment may be determined , in part, by factors during the larval period that affect condition at and after metamorphosis. We have studied various aspects of larval-juvenile connections with sea urchins, snails and barnacles. We approach these studies as ecologists with quantitative skills and by conducting replicated, experimental manipulations (in the field when possible), as evolutionary biologists by using a phylogenetic framework to explore trait changes and as functional morphologists by applying principles of fluid and solid mechanics to analyze form and function.

In experiments we place newly metamorphosed juveniles, obtained from laboratory-reared larvae exposed to different larval food rejimes, into the field to explore how they perform.

I continue to be interested in larval fuctional morphology and comparative biology, larval and juvenile ecology, and in regulation and dynamics of marine populations.