Dating fossils and rock

11-Sep-2019 13:44

They include fishes, frogs, reptiles, birds and mammals.

Ancestral relatives of vertebrates are found in the 505-million-year-old Burgess Shale deposits, while the earliest known vertebrate is from China and dates to about 525 mya.

A mass extinction occurs when over 75% of species go extinct within a short span of time (in geological time scales this equates to roughly within 2 million years).

Cambridge’s Indigenous Knowledge Library series offers a wealth of readily available, exciting and accessible material as a resource for high school learners and teachers for researching this invaluable aspect of our heritage.

Dinosaurs and mammals co-existed during most of the 160 million years that dinosaurs dominated land environments in the Mesozoic period.

During this time, mammals stayed small (no bigger than a house cat), unlike dinosaurs that diversifi ed into a wide range of shapes and sizes.

From these humble beginnings Africa’s fossil record shows how life became increasingly complex and diversified into a wide array of forms.Palaeontologists generally accept that there are background ‘normal’ extinctions that occur among life.Usually species live for about 5–10 million years, and extinctions happen at a rate of about one every 200 years.Carbon dating, a technique that estimates the radioactive decay of carbon in samples of charcoal found with the fossils helped establish their age.The charcoal also showed they knew how to use fire.

From these humble beginnings Africa’s fossil record shows how life became increasingly complex and diversified into a wide array of forms.

Palaeontologists generally accept that there are background ‘normal’ extinctions that occur among life.

Usually species live for about 5–10 million years, and extinctions happen at a rate of about one every 200 years.

Carbon dating, a technique that estimates the radioactive decay of carbon in samples of charcoal found with the fossils helped establish their age.

The charcoal also showed they knew how to use fire.

However, it is worth noting that mammals also took advantage of opportunities as they arose: a few years ago, a rare find was made in China of a fossilised skeleton of a mammal with the remains of a baby dinosaur in its belly region!