'Modern birds' result of Earth's geography

The power of flight gives birds the edge over most other creatures. Evolution of birds is thought to have begun in the Jurassic Period, and now scientists believe that the Avian evolution is greatly shaped by the history of our planet's geography and climate.

A new research led by the American Museum of Natural History reveals the DNA-based work finds that birds arose in what is now, South America, around 90 million years ago.

They had radiated extensively around the time of the Cretaceous-Paleogene extinction event that killed off the non-avian dinosaurs.

A research associate in the Museum's Department of Ornithology, Claramunt said that ,With very few exceptions, fossils of modern birds have been found only after the Cretaceous-Paleogene (K-Pg) extinction.

The new research suggests that birds in South America survived this event and then started moving to other parts of the world via multiple land bridges while diversifying during periods of global cooling. This has led some researchers to suggest that modern birds didn't start to diversify until after this event, when major competitors were gone.

Many times, these small populations will end up going extinct, but fragmentation also provides the opportunity for speciation to occur and for biotas to expand when environments get warm again. This work provides pervasive evidence that avian evolution has been influenced by plate tectonics and environmental change.

The study appears in Science Advances.