International Journal of Molecular Evolution and Biodiversity 2024, Vol.14, No.3, 133-146 http://ecoevopublisher.com/index.php/ijmeb 141 6.2 Morphological adaptations High-altitude birds exhibit distinct morphological traits that enhance their survival in extreme environments. Larger body size and specific anatomical features, such as increased wing length and tarsometatarsi length, are common among these birds. For example, snowfinches have evolved larger body sizes and exhibit variations in DNA repair mechanisms, which are crucial for coping with high UV radiation and cold temperatures. These morphological adaptations are accompanied by genetic changes that have been positively selected to support these traits. 6.3 Behavioral adaptations Behavioral adaptations are critical for the survival of birds in high-altitude environments. These adaptations include changes in habitat use, feeding strategies, and territorial behaviors. High-altitude sparrows, for instance, exhibit enhanced metabolic and thermogenic capacities in their pectoralis muscles to maintain body temperature during cold conditions, while also showing shifts in habitat and dietary preferences during different seasons (Nabi et al., 2021). These behavioral adaptations reduce interspecific competition and allow efficient utilization of available resources, promoting coexistence in extreme environments. These combined physiological, morphological, and behavioral adaptations underscore the complex and multifaceted strategies that high-altitude birds have developed to thrive on the Qinghai-Tibet Plateau. 7 Case Studies of Endemic Bird Species 7.1 Blue Eared Pheasant (Crossoptilon auritum) The Blue Eared Pheasant (Crossoptilon auritum), an endemic bird species of the Qinghai-Tibet Plateau, exhibits significant genetic differentiation attributed to climatic oscillations during the Quaternary period. These climate changes have shaped the population genetic structure, leading to distinct subpopulations in different regions of the plateau (Gu et al., 2013). By analyzing mitochondrial DNA sequences and eight autosomal microsatellite loci, the population genetic structure of the Blue Eared Pheasant was revealed, identifying four distinct subpopulations: the central Huzhu and Taizishan group, the southern Ruoergai group, the southernmost Wanglang group, and the northernmost Helanshan group (Figure 3). These subpopulations formed during the Pleistocene, corresponding to geological changes along the eastern edge of the Tibetan Plateau and climatic oscillations between interglacial and glacial periods. The findings indicate that these subpopulations constitute primary conservation units, particularly the isolated Helanshan subpopulation. Furthermore, the study explored how climatic and environmental changes drive population differentiation by comparing timelines of paleoclimate changes with species divergence times, underscoring the importance of phylogeographic studies for conservation efforts. This provides valuable information for understanding and preserving the biodiversity of the Tibetan Plateau’s marginal areas (Gu et al., 2013). 7.2 Tibetan Bunting (Emberiza koslowi) The Tibetan Bunting (Emberiza koslowi) displays unique phylogenetic relationships to other bunting species. Phylogenetic analyses have placed it within a distinct clade, illustrating its evolutionary divergence from related species. The origin of the Tibetan Bunting can be traced back to the early Miocene, around 20 million years ago. During this period, multiple colonization events into and out of the Qinghai-Tibet Plateau have shaped its current distribution and genetic structure. Intraspecific lineage separation and ecological segregation have further driven the diversification of the Tibetan Bunting. Different lineages have adapted to distinct ecological niches, leading to variations in habitat preference and resource utilization (Lei et al., 2014).
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