Lecture 2 Notes - Time Scales & Origin of Life (Key Terms)

Eight vocabulary flashcards covering the key time-scale terms from Lecture 2, including planetary formation concepts and major geologic eons/eras.

Protoplanetary disk

A disk-shaped region of gas and dust surrounding a young star from which planets form as material clumps together.

Formation of our sun

The birth of the Sun from a collapsing solar nebula, forming a protostar that eventually ignited fusion in its core.

Protoplanet

A planetary embryo that grows by accreting material within a protoplanetary disk and can become a planet.

Precambrian supereon

The vast stretch of Earth's early history preceding the Phanerozoic, comprising the Hadean, Archean, and Proterozoic eons.

Paleozoic era

Early Phanerozoic era characterized by early animal diversification and the rise of land plants and vertebrates (Cambrian to Permian).

Mesozoic era

Middle Phanerozoic era known as the age of dinosaurs, including the Triassic, Jurassic, and Cretaceous periods.

Cenozoic era

Most recent Phanerozoic era, the age of mammals and birds, following the extinction of the non-avian dinosaurs.

Hadean eon

The Earth's earliest eon (roughly 4.6–4.0 billion years ago) with a molten surface, heavy bombardment, and formation of the crust/atmosphere—before life appeared.