International Journal of Molecular Evolution and Biodiversity 2024, Vol.14, No.5, 252-262 http://ecoevopublisher.com/index.php/ijmeb 256 5.2 Evidence of Adaptive Evolution in Reptiles Evidence of adaptive evolution in reptiles in response to climate change is emerging, although it is often challenging to distinguish between genetic adaptations and phenotypic plasticity. The study by Telemeco et al. on the impact of developmental temperatures on reptile phenotypes demonstrates that early thermal environments can have significant and lasting effects on offspring phenotype and survival, suggesting a potential for adaptive responses to changing climates (Noble et al., 2018; Putman and Tippie, 2020). This highlights the role of phenotypic plasticity as a mechanism that can buffer populations against climate change, although it also points to the need for more research on genetic changes over time. Historical perspectives also provide valuable insights into adaptive evolution. The research on the early evolution and radiation of reptiles during successive climate crises in the deep past shows that climatic shifts have historically driven significant evolutionary changes in reptiles (Bodensteiner et al., 2020; Simões et al., 2022). This long-term view underscores the potential for reptiles to undergo adaptive evolution in response to current and future climate change. However, the pace of contemporary climate change poses a unique challenge, as the rate of environmental change may outstrip the ability of species to adapt through natural selection alone. 6 Case Study: Evolutionary Adaptation in the Sand Lizard (Lacerta agilis) 6.1 Background and Relevance of the Sand Lizard The sand lizard (Lacerta agilis) is a species of lizard that is widely distributed across Europe and parts of Asia (Zakharov et al., 2022). It inhabits a variety of environments, including heathlands, sand dunes, and grasslands, which are characterized by their sandy soils and sparse vegetation (Valero et al., 2021; Zakharov et al., 2022). This species is particularly notable for its adaptability to different climatic conditions, which makes it an excellent model for studying the impacts of climate change on reptilian species. The Swedish populations of Lacerta agilis, for instance, are considered relict populations from the post-glacial warmth period, indicating their long-term persistence in varying climatic conditions. The genetic diversity within these populations has been shaped by historical climatic events and more recent anthropogenic disturbances. Studies have shown that Swedish sand lizards have lower genetic variability compared to their Hungarian counterparts, likely due to a population bottleneck during post-glacial colonization. Despite this reduced genetic diversity, these populations exhibit a high level of observed heterozygosity, suggesting that they have maintained a degree of genetic health that could be crucial for their adaptability to ongoing climate changes. 6.2 Response to Warming Temperatures The response of Lacerta agilis to warming temperatures has been a subject of extensive research, revealing significant changes in their phenology, morphology, and reproductive cycles. One of the most notable phenological changes observed is the advancement of oviposition dates in response to higher spring temperatures. This shift is attributed to both population-level plasticity and individual-level variation, which together enhance the fitness and survival of offspring in a warming climate (Ljungström et al., 2015). Additionally, studies have shown that moderate warming can have beneficial effects on embryonic and hatchling development, particularly in low-latitude margin populations. These populations exhibit higher hatching success, growth rates, and survival rates under moderate warming scenarios, although extreme temperatures can have detrimental effects (Figure 1) (Cui et al., 2022). Morphological changes have also been documented, such as variations in dorsal patterns and coloration, which are influenced by local temperature conditions. For instance, in the common lizard (Lacerta vivipara), warmer climates have been associated with changes in the frequency of different morphotypes, suggesting that similar mechanisms could be at play in Lacerta agilis (Lepetz et al., 2009). These morphological adaptations, along with behavioral changes such as altered basking patterns and habitat use, are crucial for thermoregulation and overall fitness in a changing climate.
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