History of Life

With the huge debate on how/when life on Earth began for us 'humans' due to unique circumstances,then how do we account for the other many many thousands of species that have/still do inhabit this 'unique' planet?Or is it that we are just the many different variations of just one 'unique circumstance'?Kind RegardsKieron
- Kieron Farrell (age 50)
Birmingham England

I'm not sure I understand your question. Biologists and paleontologists are gradually filling in the story of human ancestry.  It's pretty interesting, with most of the genes coming from some bottleneck small African population that lived roughly 150,000 years ago. It's now clear that most or all of us also have some genes (typically a few percent) from populations (Neanderthal, Denisovan, some African groups,..) that branched off from that particular line around 800,000 years ago. A lot of details remain to be sorted out and no doubt to experts in the field the remaining question provoke "huge debates" over those details, but I don't think there are great uncertainties in the broad story. 

Most other species haven't been studied in as much detail. Some (e.g. cheetahs) seem to have simpler ancestral stories and some (many plants) have interesting mixed-ancestry stories. 

Mike W.

(published on 03/11/2017)