Welcome to the home page of the recently formed (January 2004) UCIRPEE.
evolution" we mean research in which populations are studied across
multiple generations under defined and reproducible conditions, whether
in the laboratory or in nature (for two recent short overviews,
and here). This intentionally general definition
subsumes various types of experiments that involve evolutionary
genetically based) changes. At one end of the continuum, the study of
evolutionary responses to naturally occurring events (e.g., droughts,
epidemics) may constitute a kind of adventitious experimental evolution,
especially if these events occur repeatedly and predictably enough that
the study can be replicated, either simultaneously or in subsequent years.
Next we have intentional "field introductions," in which a
population is placed in a new habitat in the wild, or a population's
habitat is altered
by adding a predator, a pesticide, a food source, fertilizer, etc. The
experimental population is then monitored across generations and compared
with an unmanipulated control population.
"Laboratory natural selection" denotes experiments in which the environment of a laboratory-maintained population is altered (e.g., change of temperature, culture medium, food) as compared with an unaltered control population. "Laboratory culling" involves exposing an experimental population to a stress that is lethal (or sublethal) and then allowing the survivors (or hardiest) to become the parents of the next generation. In all of the foregoing types of experiments, the investigator does not specifically measure and select individuals based on a particular phenotypic trait or combination of traits. Rather, selection is imposed in a general way, and the population has relatively great freedom to respond across multiple levels of biological organization (e.g., via behavior, morphology, physiology). "Multiple solutions" are possible and even probable, depending on the kind of organism and experimental design.
In classical "artificial selection" or "selective breeding" experiments, individuals within a population are scored for one or more specific traits, then breeders are chosen based on their score (e.g., highest or lowest). Depending on the level of biological organization at which selection is imposed -- and the precision with which the phenotype is defined in practice -- multiple solutions may again be common.
Domestication is an interesting (and ancient) type of experimental evolution that generally involves some amount of intentional selective breeding. In some cases, the process has been replicated enough times that general principles might be discerned (e.g., several species of rodents have been domesticated). Of course, whenever organisms are brought from the wild to the laboratory or agricultural setting some amount of adaptation to the new conditions will occur, and this may be studied. Once domesticated, organisms may be the subject of additional selective breeding programs, with varying degrees of control and replication, leading to multiple breeds or lines.
More recently, the unintentional effects of various actions by human beings have been studied from the perspective that they constitute selective factors whose consequences may be predictable. Examples include changes in commercial fisheries and in various ungulates that are hunted.
In any case, to qualify as experimental evolution, we require most if not all of the following fundamental design elements: maintenance of control populations, simultaneous replication, real-time observation over multiple generations, and the prospect of detailed genetic analysis. In short, experimental evolution is evolutionary biology in its most empirical guise.
Member Institutions and Host Units:
Department of Ecology & Evolutionary Biology
Francisco J. Ayala Example Pub. PDF
Albert F. Bennett Example Pub. PDF
Timothy J. Bradley Example Pub. PDF
Adriana D. Briscoe
Michael T. Clegg
Walter M. Fitch
Steven A. Frank
Anthony D. Long
Laurence D. Mueller Example Pub. PDF
Michael R. Rose, Director Pubs. on Experimental Evolution
Ann K. Sakai
Arthur E. Weis
Life Sciences Core Curriculum
John P. (Jay) Phelan, Associate Director Example Pub. PDF
Department of Biology
Daphne J. Fairbairn Example Pub. PDF Pubs. on Experimental Evolution
Theodore Garland, Jr., Assoc. Director & Webmaster Example Pub. PDF Pubs. on Experimental Evolution Jan. 2004 SICB Symposium
David Reznick, Associate Director Example Pub. PDF
Derek A. Roff Example Pub. PDF
Leonard Nunney Example Pub. PDF
Department of Entomology
Robert F. Luck
Department of Botany & Plant Sciences
Norman C. Ellstrand
Section of Ecology, Behavior & Evolution
Lin Chao, Associate Director Example Pub. PDF
Hopi Hoekstra Example Pub. PDF
Bernhard Ø. Palsson
Christopher J. Wills
Department of Ecology, Evolution, & Marine Biology
John A. Endler Example Pub. PDF
Todd Oakley, Associate Director Example Pub. PDF
William Rice Example Pub. PDF