Richard D. Campbell

Professor, Developmental & Cell Biology
School of Biological Sciences

PH.D., Rockefeller University, 1965

Phone: (949) 824-5322
Fax: (949) 824-4709

University of California, Irvine
4232 BS II
Mail Code: 2300
Irvine, CA 92697

Morphogenesis; biology of hydra; fractal geometry of biological forms.
Biological shapes arise by mechanical processes during embryogenesis and growth. I am interested in understanding the developmental causes of these shapes. Most animal tissues are intrinsically contractile because the cells themselves have a contractile cytoskeleton but no effective way to actively extend. Extension is usually accomplished by hydrostatic cavities around which nearly all embryonic tissues are organized. Animal tissues are in a state of balanced mechanical stresses arising from contractility due to the cytoskeletons and extension due to stretching around a hydrostatic chamber.

The freshwater polyp hydra consists of two epithelia stretched around a hydrostatic gastrovascular cavity. I am examining the organizations of the cells in order to understand which forces each cell might contribute to morphogenesis. The cells most important in morphogenesis have extensive processes containing microfilaments and these probably contribute the main cellular forces for shaping the hydra. Morphogenesis occurs to the extent that these forces and the gastrovascular pressure are out of balance.

Many biological forms are complicated. Understanding and describing form is a prelude to analyzing morphogenesis. Euclidean geometry provides a framework for describing simple shapes, such as ovals or cylinders. We usually view complex shapes as conglomerates of many small Euclidean shapes, but thiscan be unwieldy and loses the concept of wholeness of form. Fractal geometry offers a new framework for understanding complicated forms as single entities. l am studying the applicability of fractal geometry to describing biological shapes. The shapes of leaves of ferns are a natural model system with which to begin such a study because fern leaves have obvious characters of fractals: much detail which itself bears even smaller detail; and a similarity between the parts and the whole. Some computational algorithms for generating fractals produce leaf patterns. These provide succinct ways of describing these shapes, and also suggest ontogenetic pathways to achieve these patterns.

Another focus of my research concerns the general biology, taxonomy, and evolution of hydra.
Publications Campbell, R.D. (1985). Tissue architecture and hydroid morphogenesis: The role of locomotory traction in shaping the tissue. In The Cellular and Molecular Biology of Invertebrate Development (R.H. Sawyer and R.M. Showman, eds.), University of South Carolina Press, pp. 221-238.
  Campbell, R.D. (1987). The organization of the nematocyst battery in the tentacle of Hydra: Arrangement of the complex anchoring junctions between epithelial cells, nematocytes and basement membrane. Cell and Tissue Research 249, 647-655.
  Campbell, R.D. (1989). Taxonomy of the European Hydra (Cnidaria: Hydrozoa). Zoological lournal of the Linnean Society of London 95, 219-244.
  Campbell, R.D. (1996) Describing the shapes of fern leaves: a fractal geometrical approach. Acta Biotheoretica 44, 119-142.
  Campbell, R. D. (1999) The Hydra of Madagascar (Cnidaria: Hydrozoa). Annales de Limnologie/International Journal of Limnology 35, 95-104.
Graduate Programs Developmental Biology and Genetics

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Last updated 02/22/2002