They studied rock strata all around the world in order to figure out major events in geologic history. But what if you're talking about a bigger chore, like training for a marathon? And when we look at human history, we talk about it in terms of hundreds and thousands of years.
Over time, geologists and other scientists put all that information together to make the geologic time scale. You probably plan out your preparation on the scale of days, hours, weeks, and months. Obviously, it doesn't make sense to talk about everything on the same time scale. Years are made up of months, months are made up of weeks, weeks are made up of days, and so on.
Keep in mind that these three eras are all grouped within the Phanerozoic eon. Well, that one doesn't get to have any eras inside it.
We don't have a lot of information about it, so we leave it as one big chunk in geologic history.
You've probably seen pictures of giant prehistoric creatures, called 'megafauna', like the wooly mammoth, the giant ground sloth, and a Saber-tooth Cat.
So, in this lesson, we're going to learn how the time scale was created and how its major subdivisions fit together to tell the story of Earth's history.Free 5-day trial The geologic time scale is an essential tool for understanding the history of Earth and the evolution of life.In this lesson, explore the principal eons, eras, periods, and epochs that help us track major events in geologic history. How do we know when birds first appeared on Earth or when humans evolved? How was our planet formed and populated by living things over time?Before we learn the parts of the geologic time scale, let's first talk about how we measure time in our own daily lives. Geologists use the very same strategy to talk about the history of the earth.For instance, how do you measure the time it takes to get ready for work or school? They break up geologic time into larger and smaller chunks, so that major events are easier to talk about.