25 – Split of Neandertal and Denisovan lineages from modern humans (per genetic evidence)
500,000 years ago
One question that fascinates us to this day is that of our closest fossil relatives. If humans were able to survive to the present, why were the Neandertals and Denisovans unable to do the same? While this is still unclear and represents a complicated, multifaceted question, we do know that the genetic lineage of the Neandertals and Denisovans first diverged from the human lineage about 500,000 years ago. This was determined using the molecular clock model, a framework that allows the estimation of speciation events using both DNA mutation rates and well-dated fossil evidence in combination. Read more about Denisovan DNA.
Image credit https://www.nature.com
Environmental and Climate Changes
Intensification of cold glacial/warm interglacial cycles 1.2 Ma to 600,000 Ya
Earth’s climate remains relatively stable with alternating glacial and interglacial periods