The differences between the groups and the similarities within each group made it seem certain to most biologists that the tree of life had only two stems.
类群之间的差异和每个类群内部的相似性使大多数生物学家确信,生命之树只有两个树干。
Darwin's tree of life is evolving.
达尔文的生命进化之树也处在进化之中。
The tree of life (May 27).
《生命之树》(5月27号)。