Alligators and crocodiles died out in Europe as the climate cooled in the Pliocene Epoch. The modern species Alligator mississippiensis, having evolved in the Miocene, continued into the Pliocene, except with a more northern range; specimens have been found in very late Miocene deposits of Tennessee.
Precambrian time - The period in the geologic time scale from the formation of the Earth to the beginning of the Palezonoic era, from about 4.6 billion to 543 million years ago.
Periods on the geologic time scale represent units of time that divide eras into smaller segments. They typically last tens of millions of years and are defined by distinctive rock layers and characteristics of the Earth's environment. Each period is marked by significant shifts in global climate, the evolution of life forms, and geological events.
the record of life forms and geologic events in earth's history is actually called the "Geologic time scale" fine sir. good day
The geological time scale is the geologic history of the planet from formation to the present. It starts with large divisions of time called eons and is subdivided into successively smaller units of time based on dominant lifeforms, extinction events, even climate. The development of the geologic time scale was initially based on the observation and reasoning that deeper layers of rock are generally older than less deep layers in what is called the "Law of Superposition".Paleontologists look for index fossils in fossil bearing sedimentary rock. Index fossils are organisms that were widespread, rapidly evolving, and only existed for a short period of time as evidenced by their appearance in the fossil record of specific rock strata. The appearance of a fossil alongside an index fossil gives a rough approximation of the age of the fossil in relative terms as it would appear on the geologic time scale. The appearance of the same fossil alongside index fossils of different geologic ages means that the fossil organism spanned multiple geologic time periods. Associations of specific strata alongside radiographically datable igneous and metamorphic rock determines the absolute age of a fossil.A period of around 4,600,000,000 years, the largest groupings of geologic time are eons, followed in descending order by era, period, epoch, and age.The geologic time scale is very important, especially in fields involving the exploration and retrieval of fossil fuels, which are geologically date range specific.
Geologists determined the division of the geologic time scale through the study of rock layers and the fossils contained within them. By examining the different types of fossils and their distribution in the rock record, geologists were able to identify distinct time periods based on changes in the Earth's environment and the evolution of life forms. This process of relative dating helped establish the framework for the geologic time scale.
precambrian times
This period is called holocene.
an era uhm NO ^ an eon . (apex)
Cenozoic is not a major period of the geologic time scale. The scale is broken down into eras. Cenozoic, Mesozoic and Paleozoic are all part of the Phanerozic era.
A period is smaller than an era in the geologic time scale. It is further subdivided into epochs and ages.
geologic time scale
The two basic divisions following the Precambrian on the geologic time scale are the Paleozoic Era and the Mesozoic Era. These eras are further divided into periods, such as the Cambrian, Devonian, and Permian in the Paleozoic Era, and the Triassic, Jurassic, and Cretaceous in the Mesozoic Era.
an era uhm NO ^ an eon . (apex)
The 4 eras are Cenozoic era, the mesozoic era, the paleozoic era, and the precambrian era.
The divisions of the geologic time scale are divided into four eras. from earliest to closer to the present is the Precambrian, Paleozoic, Mesozoic, Cenozoic. During these time periods, there were several major evolutionary events. Most commonly known are the dinosaurs and humans. Hope that helped :)
Cenozoic Era
On the geologic time scale, an era is longer than a period. There are 12 geologic eras in total and they are composed of geologic periods. For instance, the Mesozoic era is composed of the Triassic, Jurassic and Cretaceous periods.