Research Information
- O.U.R. Research Program: Undergraduate Research Assistant Program (UGRAP)
- Major(s): Biology
- Anticipated graduation year: 2022
- Title: The Evolution of Sensory Systems in Daphnia and Predator-Driven Evolution of Brain Size in Trinidadian killifish
- Faculty Research Mentor: Dr. Matthew R. Walsh
- Faculty Academic Department: Biology
Abstract
When changes in the environment occur, organisms exhibit changes in their behavior, expression of traits, and reproduction. The Walsh Lab is interested in the variation in both eye size and brain size. Shifts in these traits can influence fitness. Increases in eye size are associated with improved vision, whereas an increase in brain size is associated with enhanced spatial learning ability, as well as overall cognition. Improvements in vision, learning, and cognition can directly and indirectly influence fitness. The two model organisms that were used to conduct the projects were Daphnia and Trinidadian killifish (Rivulus hartii).
The Walsh Lab wants to address two questions while conducting both experiments. How much light availability influences the evolution of eye size in Daphnia and how brain structure and growth in Trinidadian killifish diverge between sites with and without predators. Using twelve forty-gallon mesocosms, we added a genetically diverse mixture of Daphnia as well as media. We have found that decreased light availability has significantly reduced the population size in Daphnia. Moreover, after analyzing the volume of each brain lobe of the Trinidadian killifish species, we have found that brain structures have all increased in males from Rivulus-only zones. We have also observed that this increase is present in small size classes however disappears in larger size classes.