who first observed living cells

In the 1970s, Carl Woese explored microbial phylogenetics, studying variations in 16S ribosomal RNA. This helped to uncover the origin of the eukaryotes and the symbiogenesis of two important eukaryote organelles, mitochondria and chloroplasts.

How did the first living thing form?

Prokaryotes were the earliest life forms, simple creatures that fed on carbon compounds that were accumulating in Earth’s early oceans. Slowly, other organisms evolved that used the Sun’s energy, along with compounds such as sulfides, to generate their own energy.

Is Luca an archaea?

That is, the bacteria are rooted in an archaeal outgroup and vice versa. Genes present in LUCA contain information about their lineages and about the groups of bacteria and archaea that branched most deeply in each domain. In both cases, the answer was clostridia (bacteria) and methanogens (archaea).