[From many - one.]

Yes, there are uncertainties but the basics are known.

Here's a sample article:
THE GENETICS OF MAIZE EVOLUTION - Annual Review of Genetics, 38(1):37 - Abstract
http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.genet.38.072902.092425

[muawiyah]

Yup ~ plenty of uncertainties ~ mainly the total absence of proto-corn. Presumably there were such plants, but alas, they vanished ~ due to what? The classical evolutionary position would be that they "failed to adapt".

Yet, corn, as we know it, has not only "adapted" it has virtually abandoned its reproductive life to a different species, mankind!

Point I was making was that there are highly successful species whose forebear species were shortlived, and who have all disappeared. At the same time there are other species that don't seem to change over tens, or even hundreds of millions of years.