Human evolution; new older time line for humans (Introduction)

by David Turell , Thursday, July 14, 2022, 21:32 (644 days ago) @ David Turell

At the Sterkfontein caves in South Africa:

https://bigthink.com/the-past/human-evolution-challenged-older-fossils/?utm_source=mail...

"In 1936, South African doctor and paleontologist Robert Broom made a historic discovery in the Sterkfontein caves in South Africa. Broom discovered the first adult specimen of the genus Australopithecus, a group of early hominins from which our own genus, Homo, emerged.

"Since 1936, the Sterkfontein caves have become ground zero for Australopithecus research and fossil finds. The complex cave system runs 60 meters deep, and it has revealed hundreds of Australopithecus fossils within its sediment. From these rocks emerged notable discoveries, such as the nearly complete skeletons of specimens dubbed “Little Foot” and “Mrs. Ples.”

***

"The complex cave system still houses many secrets, but the discoveries already made retain mysteries of their own. Among the most debated issues is the age of the fossils found in Member 4. Researchers have estimated the age of Australopithecus in the lower Member 2 section at 3.7 million years, which jars with the estimated age of the fossils found higher in the cave. Researchers originally estimated the fossils in Member 4 to be between 2 million and 2.4 million years old. The geological peculiarities of the cave challenge traditional methods of aging fossils, casting further doubt on the accuracy of these estimations.

***

"Recently, Granger and a team of scientists from France and South Africa endeavored to redate the famous fossils using a new method. They published their results in the Proceedings of the National Academy of Sciences.

"The team discovered that scientists were right to doubt the original findings. The Australopithecus fossils in the Member 4 cave sediments date from 3.4 million to 3.7 million years ago, making them about a million years older than initially thought. With the famous fossils finally placed in the correct timeline, scientists can better picture the lives of these early hominins, including the environmental conditions in which they lived. The findings also increase the geographic range and diversity of our earliest ancestors, reigniting debates surrounding the story and timeline of human evolution.

***

"Combining their isotope results with an extensive geological survey of the area, the researchers concluded that the fossils are between 3.4 million and 3.7 million years old — at least a million years older than the original estimate of 2 million to 2.4 million years. This estimate makes the Member 4 Australopithecus the wise elders of the most well-known Australopithecus, “Dinkinesh” (also known as “Lucy”), which experts date as 3.2 million years old. The results also are consistent with the ages of the older specimens found in the lower reaches of the cave. With the discrepancy corrected, we now know that the entire Australopithecus assemblage at the South African site dates to between 3.4 million and 3.7 million years old.

***

"These findings challenge East Africa’s recognition as the first location humans evolved. South Africa is suddenly a contender for the most likely area of early human evolution — genuinely living up to the moniker Cradle of Humanity."

Comment: this seems like a more reasonable timeline for our development. But in contrast to whales our evolution is like a speedboat. They look fifteen million years or more:

https://en.wikipedia.org/wiki/Evolution_of_cetaceans

"The evolution of cetaceans is thought to have begun in the Indian subcontinent from even-toed ungulates 50 million years ago (mya) and to have proceeded over a period of at least 15 million years."