Of the 8.7 million species on Earth, why are human beings the only one that paints self-portraits, walks on the moon and ...

Given the diversity of social taxa, why do some species form complex societies, while other closely related species do not? Within these societies, why do some individuals attempt to reproduce ...

They are as distinct as though they were two separate species. Yet the entire complex of populations belongs to a single taxonomic species, Ensatina escholtzii. Ring species, says biologist David ...

Modern humans descended from not one, but at least two ancestral populations that drifted apart and later reconnected, long before modern humans spread across the globe.

Once determined, the phylogenetic tree resulting from this study can provide information on how diverse the species complex is and which species are most closely related to one another (Figure 3).