Hello and welcome to my page! On my website you will be learning about the geologic time scale. A geologic time scale is a timeline stating the different life and geologic events of earth's history in eras and periods. There are 4 different eras; Precambrian, Paleozoic, Mesozoic, and Cenozoic.
You might wonder how do scientists know what life form goes into what era? Well scientists take fossils and use those as evidence. Once they have the fossils they see what rock layer they are from. Using that evidence they then use radioactive data and thats when they find what era the life form comes from. Scientists also use the Law of Superposition, which helps them identify and interpret stratigraphic layers.
Another question you might have is why is there 4 different eras? Precambrian time is the earliest, it was when earth formed. Many organisms started to evolve and then later died. Later the Paleozoic era came and new organisms evolved, but soon died at the mass extinction. So basically after every period a mass extinction happens and later a new era comes which means new organisms.
You might wonder how do scientists know what life form goes into what era? Well scientists take fossils and use those as evidence. Once they have the fossils they see what rock layer they are from. Using that evidence they then use radioactive data and thats when they find what era the life form comes from. Scientists also use the Law of Superposition, which helps them identify and interpret stratigraphic layers.
Another question you might have is why is there 4 different eras? Precambrian time is the earliest, it was when earth formed. Many organisms started to evolve and then later died. Later the Paleozoic era came and new organisms evolved, but soon died at the mass extinction. So basically after every period a mass extinction happens and later a new era comes which means new organisms.