The Cataclysmic History of Earth Revealed in Rocks

🌍The history of Earth and life is preserved in rocks, providing insights into past environments and organisms.

🦕The Cretaceous-Paleogene boundary marks the end of the dinosaurs and the rise of small mammals.

💥The Alvarez hypothesis suggests that an asteroid impact caused the extinction of dinosaurs.

🦠The Permian extinction was one of the most deadly mass extinction events in Earth's history.

🔴Banded iron formations formed when oxygen produced by photosynthetic bacteria reacted with iron in the ocean.

How do rocks preserve the history of Earth?

—Rocks contain fossils that provide evidence of past environments and the organisms that lived in them.

What caused the extinction of dinosaurs?

—The Alvarez hypothesis suggests that an asteroid impact was responsible for the extinction of dinosaurs.

What was the Permian extinction?

—The Permian extinction was a mass extinction event that wiped out a significant amount of Earth's biodiversity.

How did banded iron formations form?

—Banded iron formations formed when oxygen produced by photosynthetic bacteria reacted with iron in the ocean.

How did early photosynthetic bacteria adapt to oxygen?

—Early photosynthetic bacteria did not have a resistance to oxygen, which led to their demise in the presence of high oxygen levels.

00:00The history of Earth and life on the planet is written in its rocks, with fossils in rock layers providing insight into past environments and organisms.

02:10The Cretaceous-Paleogene boundary marks the end of the dinosaurs' reign and the rise of small mammals.

02:50The Alvarez hypothesis suggests that an asteroid impact caused the extinction of dinosaurs.

03:50The Permian extinction was a significant mass extinction event that wiped out a large number of Earth's species.

08:40Banded iron formations formed when oxygen produced by photosynthetic bacteria reacted with iron in the ocean.