For such reasons, we can assume that there must be an important random factor in neural development, and in particular, that errors must and do occur in the development of all normal brains.
The floor had the biggest bacteria party, revealing what the authors called "diverse bacterial communities" of organisms, including several typically found in soil.
"Exploring that far below the earth surrounded by bats, beautiful rock formations and billions of organisms that you can't see but you know are there," she says - "that's awesome."
Indeed, there is loose talk of life having originated more than once in the distant past, and of there being entire shadow biospheres of organisms completely unrelated to anything on the surface.