Honors Theses


Karolyn Hansen, Ph.D.



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Honors Thesis


Humans are profoundly altering the abundance and distribution of organisms via climate change. Warming temperatures are affecting marine and freshwater ecosystems by increasing physiological stress, limiting growth, and decreasing dissolved oxygen. With all this change occurring, an understanding of how organisms are going to cope is crucial. Transgenerational plasticity – when parental experiences alter offspring traits - can allow organisms to rapidly adapt to environmental change. Previous literature has focused on the role of maternal experiences on offspring traits, but paternal experiences are just as important. Fathers can influence their offspring in multiple ways, including changes via both sperm and paternal care behaviors. Three-spined sticklebacks, Gasterosteus aculeatus, are a small fish found in freshwater and marine ecosystems with paternal-only care. Many populations are facing the threats of drought and wildfire, making it important to understand how they will adapt to climate change. To understand how paternal heat exposure alters offspring development, I exposed parents to cool (~17°C) or warm (~20°C) water temperature and then manipulated whether fathers provided paternal care or offspring were artificially aerated; this generated offspring that received cues of heat exposure from gametes alone versus from gametes and paternal care. I found that offspring survival was not affected by parental heat exposure but was lower when offspring themselves were exposed to warm temperatures. Additionally, parental care influenced the development of offspring traits and boldness in a novel environment. Overall, these results suggest that heat exposure alters both paternal and offspring traits, and that the effects on offspring depend on the mechanism of paternal effects (care versus sperm).

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Undergraduate research