Abstract:
Understanding how different forms of reproductive isolation contribute to the
process of speeiation is important in understanding how new species arise, which is .i
fundamental a~pect of evolution. Reproductive isolating barriers continue to accumulate
as ti.1r, \ species diverge, so the process of speciation exists along a continuum, and when
J ;fferent barriers evolve can shed light on how two species diverge from one another.
The 'ipecies Mimu/us aurantiacus is an excellent system to use for studying the
evolutionary processes that drive speciation, as it contains several closely related taxa
that are geographically and morphologically distinct from one another, and yet still
hybridize where their ranges overlap. I performed crosses between taxa to test for postmating
isolation in this system by analyzing fruit and seed weight for each cross, in
order to ultimately answer two questions: I) what is currently maintaining the
c.livergt!nce berween taxa? And 2) where are these ta~a found along the speciation
continuum? l found no evidence of post-mating isolation between taxa. implying that
these measure!,: of post-mating isolation are not currently maintaining the divergence
between taxa and that these taxa are early in the speriation process, as they have not yet
accumulated enough divergence to show genetic incompatibilities.
Description:
31 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2016.