A tiny organism alone on a vast world, its multifarious shape and very nature incomprehensible to human eyes: such is the ancestor of all Earthly life. LUCA (Last Universal Common Ancestor) is hard to discern from our time, nearly 3 billion years later given the lack of a good fossil record. But scientists keep trying to limn the ur-thing.
For instance, the monster was possibly some kind of meta-domain entity:
LUCA [eventually] split into the three domains of life: the single-celled bacteria and archaea, and the more complex eukaryotes that gave rise to animals and plants
Maybe that "one primordial form" (Darwin) also used RNA instead of DNA.
Poole has studied the history of enzymes called ribonucleotide reductases, which create the building blocks of DNA, and found no evidence that LUCA had them...
Instead, it may have used RNA: many biologists think RNA came first because it can store information and control chemical reactions.
The form could have been tiny, or vast. Researchers use "mega-organism" to describe it. Plus there's this Solaris-ish language: "this living primordial ocean essentially functioned as a single mega-organism."
A living ocean, a sprawling incompehensible monster - surely life didn't have a Lovecraftian horror origin, did it?
(thanks to Ed Webb's mad Twitter organelles; photo from Machete Red)
Comments