我相信比较高级的动物是由比较低级的动物进化而来的这一学说。

I believe in the theory that the higher animals developed from the lower ones.

youdao

寻找这种基因在小鼠和果蝇中以同样的方式起作用是很重要的，因为它意味着这种基因是保守的，或者说是从低级动物向高级动物中进化的。

Finding that it works in the same way in mice and fruit flies is important because it means the gene is conserved, or has evolved from "lower" to "higher" animals.

youdao