Just came across a truly amazing website called TimeTree. You give it the names of two organisms and it goes away and looks at its database of published literature on molecular clock studies and calculates the time when they diverged.
I put in Oryza sativa and Oryza meridionalis and it returned a figure of 2 million years ago (Mya) based on a recent paper. Asian rice and maize diverged about 36.25 Mya. And Homo sapiens and rice last shared a common ancestor 1,397.06 Mya, in case you were wondering. The sheep and goat diverged about 9 Mya.
So much fun one could have… I hope they put in a lot more crop wild relative data, though.
