New research uncovers the negative link between flight-worthiness and fight-worthiness in birds. Evolutionary pressure demanded that birds could either fly or arm themselves — but not both. Furthermore, the new research suggests that developing wings and not bony spurs involved both sexual and natural selection. This insight helps us better understand how the enormous diversity of life and earth came to be.
Click here for original story, Fight or flight? How birds are helping to reveal the mysteries of evolution
Source: ScienceDaily