在观赏鸟类时,人们可见雄鸟往往比雌鸟美丽。这是什么原因呢?现可用中学生物学中的有关知识来简析如下: 首先,是受到性激素控制的结果鸟类的外表美主要表现在冠的大小、羽毛的色泽等第二性征方面。而雄鸟的睾丸产生的雄性激素,雌鸟的卵巢分泌的雌性激素就具有分别去激发 When watching birds, people can see that males are often more beautiful than females. What are the reasons for this? The relevant knowledge in middle school biology can be used to briefly analyze the following: First of all, the results of sexual hormone control The appearance of birds is mainly reflected in the size of the crown, the color of the feathers and other secondary sexual characteristics. And male hormones produced by testes of males and estrogens secreted by ovary of females have to be stimulated separately.