Consider what you have learned about the geologic timescale and geologic history to answer the following question.
Precambrian Time
Mesozoic Era Cenozoic Era
Paleozoic Era
CAMBRIAN
ORDOVICIAN
SILURIAN
DEVONIAN
PERAAN
TRASSIC
PERGO
CARBONIFEROUS
JURASSIC
CRETACEOUS
PALEOGENE
NEOGENI
QUATERNARY
4,600
TI
542
488
416
359
299
251
200
146
99
BE
YEARS AGO
5. How did major changes to Earth's systems, such as changes to the
atmosphere or climate, affect the way scientists organized Earth's history
into the geologic timescale? Use a specific example, such as the
introduction of oxygen or the K-Pg boundary, to support your answer.