Lecture 2: Describing Microbial Diversity: the ... - MCD Biology

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1) Chloroplasts recognized as derived from "Blue-Green algae" (now “cyanobacteria” – one of ~100 bacterial
“phyla” (“divisions”, deepest clades in bacterial domain).
2) Mitochondria were thought probably derived from some sort of bacteria.
Note that the “endosymbiotic” origins for the organelles had been in the air since the 19th century -- for
comprehensive overview of this history (and controversy) see J. Sapp, “Evolution by Association: A History of
Symbiosis” (Oxford, 1994).
D. Still, there are many problems with this Five-kingdoms story:
1) Relationships among microbes, both “procaryote” and eucaryote were speculative, at best
2) There were no criteria to relate organisms between “kingdoms” (even between e.g. phyla of animals)-- a
universal phylogeny was impossible.
3) Implicit timeline remained -- “procaryotes”, “protists” “primitive.”