Lecture 7: Geologic History of Life

• Oldest signatures of life in sedimentary rocks:

• Microfossils• Molecular fossils (mainly lipids)• Stromatolites• C and S isotopic signatures

• Pattern of nested similarity

A fossil cyanobacteriumin circa 1.5 Gyr old sedimentary rocks - (A. Knoll).

Signatures of early life on Earth

• Molecular Fossils and the rise of eukaryotes.

Sterol biosynthesis - A. Pearson, J.Brocks, M.Budin (2003)

Stromatolites

Phylogenetic Tree of Life

The 3 Domains of Life- Fig.2.1 - A. Knoll (2003).

Phylogenetic Tree of Life

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