LEC 25 Regulating Protein Synthesis -- Eukaryotes - ORIGIN...

ORIGIN OF GENES

Last impact heating
~3500
Geological stratigraphy,
together with radioactive
dating, show the
sequence of events in
the history of the Earth.
Note the entry for
“cyanobacteria” and
“stromatolites” only one
billion years after the
formation of the Earth.
How did life arise so quickly
after the end of the Hadean
Period?

A New Picture of the Early Earth
Left, Bruce Watson; right, Don Dixon
AGES AGO Analyses of crystals in rocks in Australia, left, have formed a new picture of the early Earth, depicted with young
oceans in the painting at right.
New York Times, Tuesday, December 2, 2008
Isotope composition of ancient zircons suggests that Earth was cooler and
wetter in the Hadean Period, giving more time for prebiotic evolution.

If the minimal requirements for life are catalysis and heredity (Can we
envision life without reproduction? Can we envision reproduction without
catalysis and heredity?), what are the most basic molecules that satisfy the
minimal requirements?
If they are proteins and DNA, how are the two connected? Is there an
alternative?
How did the genetic code evolve?
How are genomes organized? Do they evolve for efficiency?