The geologic time scale organizes the history of the earth. which division in the geologic time scale is the shortest length of time?

Hiya!

So the geologic time scale (GTS) contains different ranks of times about Earth, obviously you know this already. However, the GTS has these different ranks in order from shortest length of time to longest length of time.
 (You can access the GTS on google maps btw if you wish to observe)

Look below!!

Longest to Shortest =

Eon: Phanerozoic  <--- Longest (542.0 million years ago)
Era: Cenozoic (65 million years ago)
Period: Paleogene (65-23 million years ago)
Epoch: Oligocene (33.9 million to 23 million years ago)
Age: Chattian + Rupelian <--- Shortest (The Chattian was 28.1 and 23.03 million years ago whereas the Rupelian was 33.9 and 28.1 million years ago)

These 'ranks/marks' are founded by the genomic revolution tracker. Researches use this little device to track our evolutionary phenomenas/times. Researchers are now able to sequence all of the DNA of an organism & it's genome. What they do with this information is compare the genomes of different organisms and populations. Then you have your list of times above.

Answer barren with few trees, in the northern hemisphere;