Incompatibility and Speciation within & between Species

iii Acknowledgements I would like to use this space to thank and acknowledge all those who contributed their skill, knowledge, help, and mental and emotional support to make this thesis a reality. I thank Dr. Patrick Phillips for his mentorship and guidance in designing and carrying out this experiment, as well as his patience and support in helping me to analyze and synthesize my findings. I thank both Dr. Wetherwax for their participation on my thesis committee and their general advising and support over the past couple of years. I would like to sincerely thank and acknowledge Valerie Haskins, Chris Hanson, and Addison Kaufman all of whom contributed many volunteered hours of their time in the lab helping me transfer, hatch off, and count the 71,335 worms and 277,850 eggs I analyzed (as well as the extras that weren't used). I would like to sincerely thank both Miriam Rigby and Christine O'Connor for contributing their computational skills, time, and knowledge and making all of the data figures and edits possible. I thank John Willis and Janna Fierst for working to help me begin the genomics analysis that didn't quite make it in time to be included. And lastly, but absolutely not least, I thank all of my friends and family who have feigned or expressed real interest in hearing about " my worms " and who have provided their support and encouragement throughout the past three years of data collection and the entire thesis process.