Week 5

Our Evolution Over the Past 4 Billion Years

Phylogenetic trees help identify the most fundamental features of the last universal common ancestor of all cellular life on Earth. How many domains of life are there? Maybe a viral phylogeny can be grafted as a root onto the tree of cellular life? Did viruses, viroids or ribozymes play a role in the origin of life? Was the RNA world a viral world? The controversial claim is made that there is no minimal amount of information or minimal size to “life”.

Gaia: a new look at life on Earth
by James Lovelock, 1979, Oxford University Press

Revolutions that Made the Earth
by Tim Lenton and Andrew Watson, 2011, Oxford University Press

The fundamentals of life on Earth are probably the fundamentals of life elsewhere. Those fundamentals include...