http://www.whoi.edu/oceanus/viewArticle.do?id=3807&archives=true&sortBy=printed

The Deeps of Time in the Depths of the Ocean*

Complex tree of Life
Illustration by Jayne Doucette, WHOI

Microbes are living archives of Earth’s evolutionary history. The discovery of a great variety of deep-sea microorganisms (using diverse metabolic strategies to live in diverse habitats) indicates that they evolved along different evolutionary pathways. Using genetic analyses, scientists can trace these pathways to reconstruct when various microbial biochemical and metabolic machinery developed, diverged, or intermingled in the three major domains of life: bacteria, archaea, and eukaryotes.

I dug this out after KingBoy sent me this interesting article: From bacteria to us: What went right when humans started to evolve?

*I don’t know why I kept the original title. I really don’t like it.