个体选择、群体选择和亲系选择

Postembryonic development of myenteric flexuses of intestines in chicken

对国际行为生态学界最流行的三个学派：个体选择论，群体选择论及亲系选择论进行了介绍，并在较深的理论层次上作了评述．作者认为，生物种不同，时期不同，自然选择所作用的水平可以不同．但基因作为遗传的最小单位，具有一种内在的稳定性和“长寿”潜力，最可能成为自然选择的最终实体，因为进化是一个跨越地质年代的漫长历程．

The myenteric plexuses of the intestines of the chicken aged from 1 day to 7,21,42,70 days and the adult are observed and compared by Gross′s silver impregnation method. The result show that, in different age groups of the chicken from the aged 1 day to the adult, the myenteric plexuses of the intestines develop gradually, neurofibraes get gradually dense, ganglia become incresingly large, and there are more and more the neurones in ganglia. Big Dogiel′s cells become mature in chickens aged 42 days. The myenteric plexuses of thechicken aged 70 days are approximately similar to that of the adult chicken.