G5 Doctoral dissertation (article)
Adaptation to fluctuating and extreme temperatures (2024)
Sopeutuminen lämpötilan vaihteluun ja äärilämpötiloihin
Räsänen, E. (2024). Adaptation to fluctuating and extreme temperatures [Doctoral dissertation]. University of Jyväskylä. JYU Dissertations, 822. https://urn.fi/URN:ISBN:978-952-86-0287-3(external link)
JYU authors or editors
Publication details
All authors or editors: Räsänen, Emmi
eISBN: 978-952-86-0287-3
Journal or series: JYU Dissertations
eISSN: 2489-9003
Publication year: 2024
Number in series: 822
Number of pages in the book: 1 verkkoaineisto (71, 9 sivua, 4 numeroimatonta sivua)
Publisher: University of Jyväskylä
Place of Publication: Jyväskylä
Publication country: Finland
Publication language: English
Persistent website address: https://urn.fi/URN:ISBN:978-952-86-0287-3(external link)
Publication open access: Openly available
Publication channel open access: Open Access channel
Abstract
Climate change forces species to tolerate heat and faster fluctuations in temperature. The speed of thermal change is expected to affect species ability to adapt, as there should be fitness trade-offs and evolutionary constraints between constant and fluctuating temperatures. However, there is no certainty about the factors that could facilitate or limit adaptation to temperature at different timescales. In this thesis, my aim was to investigate the trade-offs in adaptation to constant mean and extreme temperatures, and fluctuations of varying speed. My study species were fungi and bacteria. First, I used quantitative genetics and association mapping to study if different genes affect thermal tolerance at constant and fluctuating temperatures. Second, I used experimental evolution to test the differences in adaptation to constant and fluctuating temperatures, and the efficacy of adaptation in large and small populations. Third, I used competition experiments to investigate if thermal fluctuations select for populations that are better competitors against other species. The results indicated only weak trade-offs between constant and fluctuating temperatures at genetic level, in adaptation with different population sizes, or in competitive ability of evolved populations. Based on my results, trade-offs do not seem to determine species ability to adapt to increased variation, as some individuals and populations are able to perform well across temperatures. However, the tolerance to extreme heat might be more evolutionary constrained due to little genetic variation in some species. On the other hand, high temperatures can form strong selection pressures that lead to fast adaptive responses in populations. In addition, present thermal fluctuations can affect species competitive ability, and hence should be considered when predicting species survival in future. To conclude, the results of this thesis highlight a need for reconsidering some of the hypotheses that emphasize the role of trade-offs and evolutionary constraints in adaptation to constant and differently fluctuating temperatures.
Keywords: temperature; variation; heat; adaptation (change); biochemistry; heat resistance; populations; size; genetic factors; environmental factors; competition (phenomenon); doctoral dissertations
Free keywords: competition; experimental evolution; fitness trade-off; genetic architecture; population size; temperature fluctuation; thermal adaptation
Contributing organizations
Ministry reporting: Yes
VIRTA submission year: 2024