Topic: Biology

A team of scientists from Oxford University and Yunnan University in China discovered a fossil site in southwest China that is changing our understanding of how complex animal life developed on Earth. The fossils date back to the Ediacaran period, around 554-539 million years ago.

The discovery shows that many major animal groups were already present before the Cambrian Period began. This period marked a dramatic shift from simple organisms to a wide variety of more advanced life forms.

The research was led by teams from Oxford University's Museum of Natural History and Department of Earth Sciences, along with Yunnan University in China. The study was published on April 2 in Science.

For years, scientists believed that the rapid rise of diverse and complex animals, known as the Cambrian explosion, began around 535 million years ago. However, this new study indicates that this transformation started at least 4 million years earlier, during the late Ediacaran period.

The fossils were uncovered in the Jiangchuan Biota in Yunnan Province, where researchers collected more than 700 specimens dating from 554 to 539 million years ago. This site reveals a rich and varied Ediacaran ecosystem, including previously unknown species as well as animals once thought to appear only later in the Cambrian.

Among the most important findings are fossils believed to be the oldest known relatives of deuterostomes, a major group that includes vertebrates such as humans and fish. These discoveries extend the fossil record of this group back into the Ediacaran Period for the first time.

The collection also includes early relatives of starfish and their close counterparts, the acorn worms (the Ambulacraria). These organisms had U-shaped bodies and were anchored to the seafloor by a stalk. Tentacles near their heads were likely used to capture food.

Why It Matters

This discovery is important because it helps us understand how life on Earth evolved over time. It also shows that many animal groups that exist today have been around for millions of years, which can help us better understand the diversity of life on our planet.

Key Facts

• The fossils were found in the Jiangchuan Biota in Yunnan Province, China, and date back to the Ediacaran period, around 554-539 million years ago.
• The discovery shows that many major animal groups were already present before the Cambrian Period began.
• The study was published on April 2 in Science and was led by teams from Oxford University's Museum of Natural History and Department of Earth Sciences, along with Yunnan University in China.
• The fossils include early relatives of deuterostomes, a major group that includes vertebrates such as humans and fish.
• The discovery extends the fossil record of this group back into the Ediacaran Period for the first time.

Key Terms

Ediacaran period

A geological period that occurred around 554-539 million years ago, during which complex animal life began to develop.

Implications

This discovery is important because it helps us understand how life on Earth evolved over time. It also shows that many animal groups that exist today have been around for millions of years, which can help us better understand the diversity of life on our planet.