but one giant leap for life on Earth. 地球生物一大步
the oceans are bountiful, bursting with life... 海洋丰饶 充满生机
...giving them the best possible start in life. 让它们有一个尽可能好的起点
...it's no wonder that the most famous predator in the history of life on our planet 难怪地球史上最著名的捕食者
in the eternal game of life and death. 进化出的极端情况
of what life may have been like for some of those ancient mammals. 古代哺乳动物可能的生活形态
these small creatures were limited to a life in the margins. 这些小生物局限在边缘生活
Combined with the surge in plant life, 再加上植物的激增