Geologic Time Scale

Flashcards covering key concepts from the Geologic Time Scale lecture.

What is the geological time scale a record of?

It is a record of the life forms and geological events in Earth’s history.

How was the geological time scale developed?

By studying rock layers and fossils worldwide.

What helps determine the absolute divisions in the geological time scale?

Radioactive dating.

What are the largest sections of geological time called?

Eons.

How are eons divided?

Eons are divided into eras.

What are the two eons mentioned in the notes?

Cryptozoic (Precambrian) and Phanerozoic.

What is the duration of the Archean era?

It lasted from 4600 mya to 2500 mya.

What significant event occurred during the Paleozoic Era?

The evolution and development of various life forms, including the first organisms with hard parts.

What period is known as the 'Time of Reptiles'?

Mesozoic era.

What major extinction event occurred during the Permian period?

The largest mass extinction, affecting 90% of ocean life and 78% of land life.

What is significant about the Cretaceous period?

It marked the end of the Mesozoic Era and the extinction of dinosaurs and many other species.

What is the significance of the Quaternary period?

Humans evolved as the most intelligent creatures of Earth during this time.

What are the two epochs of the Quaternary period?

Pleistocene and Holocene.

What evolutionary developments occurred in the Jurassic period?

First birds and mammals were formed; dinosaurs reached their peak.

What was a key feature of the Carboniferous period?

Formation of the first reptiles and pteridophytes, and significant coal formation.