Is there more diversity in marine species? I was reading about how life emerged from oceans, and the following question occured to me. Do land species suffer from the founder effect and is there more (genetic) diversity in marine species? A quick google search pointed to the fact that a majority of species live on land. Is that a paradox?

I know that marine habitats have a higher phylogenetic diversity (see also Faith 2006) than terrestial habitats, even though they host far fewer species, which is a result of their deeper evolutionary history. Unfortunately, I cannot find a good reference to this claim right now (see < for some support though).

I wouldn't really call the difference in species numbers a paradox though, since speciation rates depend on habitat complexity and dispersal rates (which are generally higher in marine habitats). In either case, the knowledge of marine habitats and species living there are much poorer than for terrestial habitats, so differences in species numbers are highly tentative.