进化 (jìnhuà) is the general term for 'evolution' in both biological and social contexts — it's the most common word for Darwinian evolution and broad development. Its near-synonym 演化 (yǎnhuà) also means 'to evolve' but emphasizes a gradual, often natural or geological process, while 演变 (yǎnbiàn) focuses on a slow historical or social transformation. The simpler 演 (yǎn) as a standalone verb chiefly means 'to perform', not 'to evolve'.