Major

Biology

Anticipated Graduation Year

2022

Access Type

Open Access

Abstract

This study examined two questions in a fossilized lineage of threespine stickleback fish (Gasterosteus doryssus) sampled across 15,000 years. (1) Did speciation take place, which would help answer Darwin’s sharpest critique of his own theory? (2) How did differences between males and females (sexual dimorphism) change over time? We compared evolution in fossils to data collected from living population pairs of a closely related threespine stickleback. We found divergence in endpoints of the lineage, suggesting that the end population should be considered a different species from its founder. We found that dimorphism evolves rapidly, likely in response to environmental change.

Faculty Mentors & Instructors

Dr. Yoel E. Stuart, Department of Biology; Samantha Swank, Laboratory Technician, Department of Biology; Franklin Joaquin, Laboratory Technician, Department of Biology

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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Anagenetic Speciation and Sexual Dimorphism in Fossil Samples of Threespine Stickleback Fish (Gasterosteus doryssus)

This study examined two questions in a fossilized lineage of threespine stickleback fish (Gasterosteus doryssus) sampled across 15,000 years. (1) Did speciation take place, which would help answer Darwin’s sharpest critique of his own theory? (2) How did differences between males and females (sexual dimorphism) change over time? We compared evolution in fossils to data collected from living population pairs of a closely related threespine stickleback. We found divergence in endpoints of the lineage, suggesting that the end population should be considered a different species from its founder. We found that dimorphism evolves rapidly, likely in response to environmental change.