Cape Town - A new study that investigated the evolutionary history of birds by examining fossils more than 100 million years old has shed light on how birds became so successful and why they live in such diverse climates.
The findings of the study by Jonah Choiniere, of the University of the Witwatersrand, and Roger Benson, of Oxford University, was published earlier this week in Proceedings of the Royal Society B.
By measuring early bird fossils from all over the world, Choiniere and Benson found birds first became “successful” about 130 million years ago after losing their “long, bony dinosaur tails”. Without the hindrance of a long, weighty tail, birds developed different leg shapes and were able to live in far more areas.
Some became waders, like modern-day herons, while others could develop strong legs and talons, like eagles.
“You might think once birds evolved powered flight there was little to compete with them, that they had a new niche to themselves,” said Choiniere of the Evolutionary Studies Institute at Wits. “But what we found is it wasn’t actually powered flight that led to their diversification.”
Diversification means changes in shape, like the length of a beak, that eventually lead to new species.
“There is this time lag between when they gained flight and when they diversified. The first burst of diversification is only after the tail shortened,” Choiniere said.
Once they diversified, birds could live in far more environments. Today, they are found from the Antarctic to the Kalahari Desert.
Choiniere and Benson travelled to China, South America, the US and Europe to measure fossils.
“The genesis of this paper happened in an enormous Mercedes truck in the middle of the Gobi Desert near the Chinese border. We were just blathering about science in the general, and we thought we should at least try to test some of these ideas about the evolution of birds,”
Choiniere said people had thought that birds diversified only after dinosaurs became extinct 65 million years ago.
“But we were able to show that even while dinosaurs were roaming the Earth, birds were successful.” - Cape Times