Barretts photo

Prof. Spencer C. H. Barrett
Evolutionary Biologist


My research is concerned with the ecology and evolution of plants with a particular focus on the evolution of mating systems, the ecology and genetics of invasions, and issues in conservation biology, such as genetic resource conservation and the problems posed by habitat fragmentation and small population sizes.

I have active research programmes in Canada, Australia, South America, and the Mediterranean involving graduate students and post-doctoral fellows. My research involves experimental and theoretical approaches to studying evolution, and ranges from molecular sequencing of genes to glasshouse and laboratory experiments to field studies.


BIO150Y: Organisms in Their Environment
Evolutionary, ecological, and behavioural responses of organisms in their environment at the levels of individuals, populations, communities, and ecosystems. A prerequisite for advanced work in biological sciences. Prerequisite: OAC Biology/Grade 13 Biology/BIO100Y. BIO150 Home Page.

BOT202Y: Plants and Society
The continuing impact of new scientific technologies on society through changes in agriculture, industry and the economy. Plant domestication, genetic resource conservation, environmental pollution, global warming, genetic engineering and biotechnology. Evaluation of the social implications of advances in modern plant science. Exclusion: All BIO courses except BIO100Y; all BOT and ZOO courses except ZOO200Y, if taken previously or at the same time. This course is intended primarily for Humanities and Social Science students.
BIO395H: Conservation Biology
This is a new course, offered for the first time starting September 1996. It teaches the principles and practices of conservation biology including biodiversity, rarity, exploitation, extinction, habitat fragmentation, gene pool, inbreeding and outbreeding, nature reserves, breeding programs, and the role of botanical gardens, zoos and museums. An in-depth case study, providing a conservation plan for an endangered species or community, is required of each student. Recommended preparation for this course is as many courses as possible in behaviour, ecology and evolution.

Recent Research Publications

Plant mimicry, in Scientific American 257: 76-83 (1987), by S. C. H. Barrett.

Waterplant invasions, in Scientific American 260: 90-97 (1989), by S. C. H. Barrett

Effect of a change in the level of inbreeding on the genetic load, in Nature 352: 522-524 (1991), by S. C. H. Barrett and D. Charlesworth.

The genetic and evolutionary consequences of small population size: implications for conservation by S. C. H. Barrett and J. Kohn. Pages 3-30 in Genetics and Conservation of Rare Plants, edited by D. Falk and K. E. Holsinger, published in 1991 by Oxford University Press.

The evolution and function of heterostyly, by S. C. H. Barrett (Editor). Published in 1992 by Springer-Verlag, Berlin.

Mating cost of large floral displays in hermaphrodite plants, in Nature 373: 512-515 (1995), by L. D. Harder and S. C. H. Barrett.

Floral biology: studies on floral evolution in animal-pollinated plants, edited by D. G. Lloyd and S. C. H. Barrett. Published in 1996 by Chapman and Hall, New York.


  • Born in Hertfordshire, U.K., in 1948.
  • Hons. B.Sc. in Agricultural Botany, University of Reading, U.K., in 1971.
  • Ph.D., University of California, Berkeley, in 1977.
  • Hired by the University of Toronto in 1977.
  • Awarded E. W. R. Steacie Fellowship in 1988 by Natural Sciences and Engineering Research Council of Canada for contributions to plant evolutionary biology.
  • Former chair of the Natural Sciences and Engineering Research Council of Canada (NSERC) grant selection committee in population biology.
  • Associate Editor for the following journals: Evolution, Plant Species Biology, Molecular Ecology

    Department of Botany
    University of Toronto
    25 Willcocks Street
    Toronto, Ontario M5S 3B2