RESUMEN
Mountains are among the most biodiverse places on Earth, and plant lineages that inhabit them have some of the highest speciation rates ever recorded. Plant diversity within the alpine zone - the elevation above which trees cannot grow-contributes significantly to overall diversity within mountain systems, but the origins of alpine plant diversity are poorly understood. Here, we quantify the processes that generate alpine plant diversity and their changing dynamics through time in Saxifraga (Saxifragaceae), an angiosperm genus that occurs predominantly in mountain systems. We present a time-calibrated molecular phylogenetic tree for the genus that is inferred from 329 low-copy nuclear loci and incorporates 73% (407) of known species. We show that upslope biome shifts into the alpine zone are considerably more prevalent than dispersal of alpine specialists between regions, and that the rate of upslope biome shifts increased markedly in the last 5 Myr, a timeframe concordant with a cooling and fluctuating climate that is likely to have increased the extent of the alpine zone. Furthermore, alpine zone specialists have lower speciation rates than generalists that occur inside and outside the alpine zone, and major speciation rate increases within Saxifraga significantly pre-date increased rates of upslope biome shifts. Specialisation to the alpine zone is not therefore associated with speciation rate increases. Taken together, this study presents a quantified and broad scale perspective of processes underpinning alpine plant diversity.
Asunto(s)
Saxifragaceae , Filogenia , Ecosistema , Clima , BiodiversidadRESUMEN
Introduction: Aging involves the loss of functional reserve with alteration of multiple systems. This influences the deterioration of various aspects of health and quality of life. To improve these aspects there are different types of interventions in which physical activity has a prominent role. Objective: To evaluate the effectiveness of one type of physical activity in improving the quality of life of an elderly population of the community. Subjects and methods: We recruited 71 subjects aged 60 years attending a club of elderly. Were randomized into 2 groups (intervention and control) by a blinded observer. The intervention was aerobic physical activity for 30 minutes and calisthenics exercises for heating and cooling, for 10 weeks and 3 times a week. We evaluated 8 dimensions of quality of life at the beginning and end of the intervention by the SF-36. Results: Both groups had similar values at baseline. The intervention group improved clinically (5 to 25 points) and statistically significant (p <0.05) in the 8 dimensions of quality of life. The control group showed a modest improvement in 3 items exploring psychosocial aspects of quality of life. Conclusion: The physical activity in the community is a therapeutic alternative economic, easy to implement, safe to apply and produces a great impact on improving the quality of life of the population over 60 years.