1 [I,T] (formal 正式) to develop or to make sth develop gradually, from a simple to a more advanced form （使）演化，形成: His style of painting has evolved gradually over the past 20 years. 20年来，他的画风一直在慢慢地演变。

2 [I] develop (from sth) (used about plants, animals, etc) to develop over many thousands of years from simple forms to more advanced ones （指生物）进化