The fossil evidence for early Archaean.

Brasier, M, N McLoughlin, O Green, D Wacey. 2006. A fresh

look at the fossil evidence for early Archaean cellular life. Philos. Trans. R. Soc. B-Biol. Sci. 361:887-902.

https://www.researchgate.net/publication/7027640_A_fresh_look_at_the_fossil_evidence_for_early_Archaean_cellular_life_Philos_Trans_R_Soc_Lond_B_Biol_Sci_361_887-902

1.  What is the essence of the arguments in Brasier et al (2006)?

2.  Which fossils (at what dates) do Brasier et al (2006) accept as biogenic and which does he reject?  Why?

3.  What should we take away from Figure 2 and related discussion?

4.  In their conclusion, Brasier et al (2006) argue that the earliest life forms were hyperthermophiles.  What evidence do they provide to support this claim?

Schopf, JW, AB Kudryavtsev, AD Czaja, AB Tripathi. 2007. Evidence of archean life: Stromatolites and microfossils: PreCambrian Research 152: 141-15

https://www.sciencedirect.com/science/article/pii/S0301926807001209
1.  What is the essence of the arguments in Schopf et al (2007)?  (e.g. Fig 1 and 5)

2.  What do you think of the claim by Schopf et al (2007) that: “.. it is precisely during this period of Earth history, prior to 2000 Ma, that most workers have assumed that prokaryotic microbes originated and diversified to comprise Earth’s earliest biosphere” (p. 141)?

3.  What do you think of the idea of a ‘test for biogenicity?” (section 5.6)

Comparison:
1.  Which paper do you find most compelling and why?