Convergence of Life History Phenotypes in Two Species of Topminnows, <i>Fundulus notatus</i> and <i>Fundulus olivaceus</i>

<p>Convergent evolution is the independent evolution of similar characteristics by means of natural selection. Convergence is a well-known phenomenon, but convergence resulting from equivalent environmental gradients has only been pursued in a few cases. The main purpose of this study was to look for evidence of convergence of life history traits between two sympatrically distributed topminnows. The two species typically separate along a stream size gradient with <em>Fundulus notatus</em> inhabiting the downstream environment, and <em>F. olivaceus</em> inhabiting the upstream headwater environment. However, there are at least three known drainages where the normal distribution pattern is reversed, and <em>F. notatus</em> is found upstream of <em>F. olivaceus</em>. Divergent life history traits are displayed in drainages with the normal distribution pattern, leading to the prediction that life history traits of headwater <em>F. notatus</em> (reversed distribution) will converge on those of headwater <em>F. olivaceus</em> (normal distribution). A field study and an energetics experiment were used to look for convergent life history traits. These data reveal convergent life history traits of headwater <em>F. notatus</em> on downstream <em>F. olivaceus</em>.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Discipline thesis:degree_discipline

Biological Sciences

Year dc:date.available

2013

Author dc:creator

• Harris, Jared Aubin

Contributors dc:contributor

• Jake Schaefer
• Carl Qualls
• Nathan Franssen

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/501

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1571