"Nature's House has many Niches" --- and many different creatures to fill them

John 14:2 probably says all that needs to be said in proof of the 'survival of the MANY fittest' over the claim of the 'survival of the one most all-around fit'.

Survival of the MANY fittest

Short of successfully terraforming Earth into one big uniform niche (and don't think muscular modernity hasn't tried many times !) our world continues to be made of an incredibly wide selection of very different niches - and hence - an equally incredibly diverse selection of beings, each able to be the fittest key for each of those niche locks....