Mr. Mysteries' So-True Histories Episode 9 - Paleogene Period

Hello Eager Learners! I am Mr. Mysteries, formerly of the Learned League, and this is my KARENcast series on the history of our Reality, Reality 69.
  Another episode, another mass extinction of life. Hopefully this does not foretell our own future. Our episode today will focus on the rapid spread of the mammalian survivors of the K-Pg extinction event.
  <A long breakdown of the cooling of the earth, spread of Conifers into even more regions, and the rapid diversification of mammalian and avian species to fill niches left empty by the die off of the previous era.>