Olson Lab Research Page


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In my lab we are interested in the evolution of morphological diversity. Even the most cursory view of the living world reveals a remarkable diversity of shapes, sizes, and lifestyles. Where did this diversity come from? What makes  populations move from one part of morphospace, such at the one at right, to another? Natural selection is the most commonly cited cause, and the changes between morphologies are often  explained by adaptive evolution. At the same time, it is necessary to understand how the possibilities of ontogenetic systems permit or impede the formation of certain morphologies, and how evolutionary alterations in ontogeny permit movement through morphospace. In my laboratory, we are employing a comparative strategy to examine the causes of the relationship between organismal form and function. This approach allows us to examine questions such as: Can organisms be partitioned into "traits" in a biologically justified way? Are modules biologically real organismal subunits? How does organismal form and function covary across environments and why? To what extent do patterns of covariation between traits channel morphological evolution at the interspecific level? Because of their simple structure and because they can’t run away, we like to work on clades of woody plants of extraordinary morphological diversity. These systems include Moringa (Moringaceae), the simaruba clade of Bursera (Burseraceae), the Mexican clade of Manihot (Euphorbiaceae), and the Beaucarnea- Calibanus clade of Nolinaceae. We are also taking a complementary approach that examines the ways that entire communities fill morphological and functional space. For example, the plants of the Pedregal de San Ángel, which I can see from my office here in Mexico City, span a range greater than that seen by most anatomists in a lifetime: Sedum oxypetalum, whose wood is composed only of vessels and parenchyma, grows adjacent to Dodonaea viscosa, which has extremely reinforced wood that withstands extremely negative xylem pressures. How do the species of a community partition morphological and functional space? Does each species occupy a distinct region? Can guilds of species of similar structure and function be distinguished? We are currently generating phylogenetic, morphological, and functional data for this and other communities to examine these questions. We are also interested in  conceptual aspects of evolutionary biology. Current projects include understanding the differences between the ways that botanists and zoologists use the term homology, the problem of multiple explanations for the same observation in studies of adaptation, and a review of the conceptual foundations of comparative wood anatomy. Finally, as world petroleum production drops, it is clear that we need to reduce our energy consumption, and meet our needs for food, water, and health care locally. We are involved in exciting projects in rural communities to build a sustainable future together. See also: Our Publications page Courses page Mark's  CV

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Instituto de Biología, Universidad Nacional Autónoma de México
Tercer Circuito s/n, Ciudad Universitaria
Copilco, Coyoacán A. P. 70-367
C. P. 04510, México, D. F.
MÉXICO

(52) 5622-9124 fon (52) 55 5555-1760 fax
molson@ibunam2.ibiologia.unam.mx