Word: 20f
(lookup in dictionary)
(lookup stats)
Dates: during 1990-1999
Sort By: most recent first
(reverse)
...variety of habitats and climates. Yale paleontologist Elisabeth Vrba believes that their evolutionary success -- and the subsequent thriving of the genus Homo as well -- was tied to climate changes taking place. About 2.5 million to 2.7 million years ago, an ice age sent global temperatures plummeting as much as 20F, prompting the conversion of moist African woodland into much drier, open savanna...