We all (except a handful of fanatics) agree that evolution happens. What is not fully clear are the details of how it happens. These days two new researches challenge some conceptualizations and support others instead.
Evolution is not constant but punctual.
That is what Stephen A. Smith (left) and colleagues have discovered when analyzing the phylogeny of angiosperms (flowering plants). They found that the conceptualization of evolution as punctuated rather than constant seems to be correct, and also that the characteristics of a new taxon evolve in a single population or root species before diversification (radiation) occurs.
The research has been published in the American Journal of Botany (open access) and a synthesis appears at Science Daily.
Perfectly fit? Maybe not needed.
A simplistic school promotes the idea that given enough evolutionary time in a simple ecological niche only one competitor will survive: the fittest one.
However this does not seem to be the case. Research by Robert E. Beardmore and colleagues, published in Nature (ppv), vindicates previous research in which optimal efficiency coexists with suboptimal one:
The fit use food well but they aren't resilient to mutations, whereas the less efficient, unfit consumers are maintained by their resilience to mutation. If there's a low mutation rate, survival of the fittest rules, but if not, lots of diversity can be maintained.
Full story at Science Daily.