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

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

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 (economy); 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