survival of the fittest
noun [ U ] uk/səˌvaɪ.vəl əv ðə ˈfɪt.ɪst/ us/sɚˌvaɪ.vəl əv ðə ˈfɪt.ɪst/
适者生存
the principle that animals and plants suited to the conditions they live in are more likely to stay alive and produce other animals and plants than those that are not suited
Compare: natural selection