Why is the Tm of DNA and RNA so high (around 90 C) if it
wasn't selected in a very hot environment?
Quoted message said:From "Life on the Edge" M. Gross
"As the earth was a reasonably stable body with oceans,
continents and an atmosphere, and the meteorite impacts
became less frequent and less catastrophc, the evolution of
life began. At that time, the luminosity of the Sun
presumably was only three quarters of what it is today; but
the greenhouse effect of the carbon dioxide-rich atmosphere
must have overcompensated for this difference. However, the
details of the climate changes during the first two billion
years of our planet remain controversial."
Also in Lovelocks, "Healing Gaia" he suggests " (CO2) fell
from it's pre-life level of about 30 %, to around 10% after
the start of life..."
Comment?