Birds, dinosaurs, eggs and evolution

This video is called Hundreds of Dinosaur Egg Fossils Found in Spain.

From Wildlife Extra:

Egg shapes could be key to explaining evolution of birds

Research by scientists suggests that bird egg shape could be key in explaining their evolution

Next time you sit down to your breakfast of hard-boiled egg, you might want to take a moment to stop to consider why it is so perfectly ‘egg-shaped’. Evolutionary biologists have been studied [sic] the difference in the eggs of modern day birds compared to those of their extinct relatives, Theropod dinosaurs. The difference in their shape could be the key to explaining why some birds were able to survive the extinction event that wiped out the dinosaurs.

Researchers from University of Lincoln examined eggshells looking at the transition of Theropods into birds based on fossil records and studies of modern birds.

Their findings suggest that the early birds from 252 to 66 million years ago laid eggs that had different shapes to those of modern birds. This might suggest that embryonic development was different in the earliest birds, so could have implications for how some birds survived while the dinosaurs perished.

The author of the study was Dr Charles Deeming of Lincoln’s School of Life Sciences. He explains, “These results indicate that egg shape can be used to distinguish between different types of egg-laying vertebrates. More importantly they suggest Mesozoic bird eggs differ significantly from modern day bird eggs, but more recently extinct Cenozoic birds do not. This suggests that the range of egg shapes in modern birds had already been attained in the Cenozoic.”

The origin of the amniotic egg, which is an egg that can survive out of water, is one of the key adaptions underpinning the vertebrates’ transition from sea to land over 300 million years ago.

Dr Deeming suggests that the different egg shape of birds both past and present could be associated with different nesting behaviours or incubation methods, but points out that not much research has been carried out into this due to insufficient fossil data. “We hope that future discoveries of associated fossil eggs and skeletons will help refine the general conclusions of this work,” he says.