During much of the Paleocene and early Eocene, the global mean temperature appears to have risen by as much as 5-8°C to an average temperature as high as 73°F. (today's globa average is shy of 60°F.) This may have resulted from a massive release of carbon dioxide into the atmosphere, at least doubling or possibly even quadrupling the background concentrations. During such periods of warming, organisms would likely have adapted by producing and -chain fatty acids in order to increase their Tm. wont GREENLAND 85 56 million years ago Cartoon by Emily Greenhalgh NOAA Cimago O More saturated; longer O Less saturated; shorter O Less saturated; longer O More saturated; shorter

A mitochondrion is a cellular organelle that serves as the site for cellular respiration and energy production (ATP or Adenosine Triphosphate). It is a double-membrane-bound organelle and is only present in eukaryotic cells.