LEARNING TO WALK: Young visitors imitate the walking of apes in front of a human evolution chart at the Paleozoological Museum of China in Beijing (LIU BIN)
Fossil discoveries across China are contributing, as well as offering new insights, to the ever-evolving theories presented by English naturalist Charles Darwin a century and a half ago.
"Great scientists are those thinkers who inspire revolutions of the whole of mankind; just like Charles Darwin, who overthrew the theory of God creating human beings," said Shu Degan, a professor of paleontology at Northwest University in Xi'an, capital of Shaanxi Province. Regarding Darwin as his spiritual mentor, Shu twice presided over the translation of Darwin's landmark work, On the Origin of Species, into Chinese.
Shu is better known for discovering fossils of the world's earliest vertebrates. In 1996, Shu and his colleagues found a blurry fish imprint measuring less than 2 cm long and half a centimeter wide on a rock in fossil-rich Chengjiang County in south China's Yunnan Province. Later Shu and his fellow scholars named the fossilized fish Myllokunmingia.
In 1999, Shu discovered Haikouichthy, which together with Myllokunmingia pushed the known origin of vertebrates back by 50 million years. Shu's discovery was awarded as one of China's 10 most important scientific achievements of 1999, an award elected by 524 members from the country's prestigious Chinese Academy of Sciences and Chinese Academy of Engineering.
All animals can be classified as either invertebrates (animals without backbones) or vertebrates (animals with backbones). But an important question to be unraveled by paleontologists is the evolutionary link between the two. "Scholars around the world have universally recognized that the fish discovered in Yunnan is the oldest and most primitive vertebrate, but the remaining question is what invertebrates spearheaded the evolutionary transition into the fish," said Shu.
Finding fossils to support his theory had always been a scientific headache for Darwin, as if nature were trying to hide evidence from him.
"A challenge facing Darwin's theory of evolution was that if all diversity in nature resulted from gradual adaptive evolution, why hadn't people found remains of intermediary forms of life? Although Darwin's theory explained the whole evolutionary process, the grave objection came from the lack of transitional fossils," said Shu, who believes Myllokunmingia provides an anatomical link between invertebrates and vertebrates. "Since Myllokunmingia has developed the most primitive vertebra and a simple and small skull, the logical interpretation is that it is human beings' oldest ancestor with a vertebra and head," Shu said. His thesis on the discovery was published in the prestigious Nature magazine in 1999.
In the popular science book The Ancestor's Tale, author Clinton Richard Dawkins, a former professor at Oxford University, follows the path of humans backward through evolutionary history, introducing humanity's cousins as they converge with common ancestors. Dawkins commented that Myllokunmingia is close to humanity's 18th generation of ancestors.
Explosion of life
Shu's series of theses in Nature has provided rich material for reevaluating the Cambrian Explosion's nature and scale.