Fossils and Geological Eras

The Permian-Triassic extinction event was the most severe in Earth's history, resulting in the extinction of approximately 95% of marine species and 70% of terrestrial vertebrate species.

The Permian-Triassic extinction, occurring at the end of the Paleozoic era, is considered the largest mass extinction in Earth's history.

Early Earth is thought to have been covered by a global ocean, with very little land mass exposed compared to today.

The earliest evidence of life on Earth dates back approximately 3.5 to 3.8 billion years ago.

Evidence for the earliest life forms, such as stromatolites, dates back to approximately 3.8 billion years ago.

The Earth is estimated to have formed approximately 4.5 to 4.6 billion years ago.

The Cenozoic Era is often called the Age of Mammals because mammals became the dominant land animals following the extinction of the dinosaurs.

The Mesozoic Era is known as the Age of Reptiles, during which dinosaurs were the dominant terrestrial vertebrates. The Paleozoic preceded it, and the Cenozoic followed it.

The Paleozoic Era began with the Cambrian Explosion, a period characterized by a rapid diversification of life forms. The PreCambrian came before this event.

The PreCambrian accounts for the vast majority of Earth's history, spanning from the formation of the planet until the beginning of the Paleozoic Era.

Index fossils are fossils of organisms that lived for a short, well-defined period and were geographically widespread, making them useful for dating rock layers.

Fossils are the preserved remains, impressions, or traces of organisms that lived in the past.

Relative dating determines the age of a fossil by its position in rock strata, where lower layers are generally older than upper layers.

An endangered species is one that is at high risk of becoming extinct due to low population numbers or loss of habitat.

Charles Lyell was a geologist who argued for uniformitarianism, the idea that the same geological processes observed today have shaped Earth over vast time scales.