Growth Rate and Mature Function of Skeletal Muscle: A Constraint on the Evolution of Avian Life Histories

研究人员将检验出生后生长速度与骨骼肌功能能力成反比的假设。如果鸟类在发育过程中受到这种关系的约束，它们应该能够根据新孵出的小鸡的早熟和父母提供的照顾的质量和程度来解释生长速度的变化。他们将直接通过小鸡在冷应激下产生热量的能力来衡量功能能力，间接通过肌肉的生化特性，特别是酶活性来衡量。该项目将晚熟物种与早熟物种进行了比较，晚熟物种需要父母的强烈照顾，而早熟物种在孵化后不久就能保持体温并自给自足。该项目将是迄今为止为数不多的考虑生命史适应优化的生物体水平限制的研究之一，应该有助于更普遍地理解生物体的设计。

The investigators will test the hypothesis that postnatal growth rate is inversely related to the functional capacity of skeletal muscle. If birds are constrained by such a relationship during the course of development, they shall be able to interpret variation in growth rate in terms of the precocity of the newly hatched chick and the quality and extent of care provided by the parents. They will measure functional capacity directly by the ability of chicks to generate heat in response to cold stress, and indirectly by the biochemical attributes of muscle, particularly enzyme activities. The project compares altricial species, which require intense parental care, to precocial species, which can maintain body temperature and feed themselves soon after hatching. The project will be among the few studies to date to consider organism-level constraints on the optimization of life- history adaptations and should help in understanding the design of organisms more generally.