Good day everyone!Today, we were going to talk aboutThe GeologicTimescale
perfecto !
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taken by a process or sequence of events.
Do you have any idea what a Timescale is?
what are those four-level hierarchy of time intervals, sir?
The geologic time scale is the “calendar” for events in Earth history. Moreover, it is a system of chronological dating that classifies geological strata in time.
Geologic time is divided into a four-level hierarchy of time intervals
moving forward
1.) Eons - are the longest portions of geologic time 2.) Era – smaller time interval that divides the eon.
Those are the definition of Four-level hierarchy in Geologic Timescale
3.) Period – eras are subdivided into periods.4.) Epoch – finer subdivision of time is possible and the periods are frequently subdivided into epochs.
Next, I will give you an example of significant events that happen using geologic time scale
~ Eon ~ Era ~ Period ~ Epoch
The first appearance of plant life on Earth
The first land plants appeared around 470 million years ago, during the Ordovician period. They were non-vascular plants.
EXAMPLE #01
The first appearance of Animals on Earth
The first animals- including the common ancestor of all animals today, evolved in the sea. Cooperating cells eventually became the first animals, which DNA evidence suggests evolved around 800 million years ago
EXAMPLE #02
The formation of Earth's mountains
The world's tallest mountain ranges form when pieces of Earth's crust—called plates—smash against each other in a process called plate tectonics