Reason For Peacock’s Colorful Tail
Even Charles Darwin struggled to explain why the bird should have this burdensome trait. When there are many potential danger related to the colourful tail, why this bird got this trait. Darwin finally got the idea of sexual selection, which provides an advantage in the competition for mates and that outweighed other disadvantages. While humans are attracted to symmetrical faces and other outward signs of fitness, these birds are attracted to colourful tails. The male specific traits are evolved with the changing preferences of females. When the female tastes change, these traits go away.
Image credit : http://blog.oregonlive.com
Evolution Of Facial Expression
A research done by Joshua Susskind of University of Toronto, suggests that different changes on the face would lead to different amounts of sensory intake. When fearful objects were shown, subjects breathed in more air, saw a wider field of view, and could visually track targets more quickly.
On the other hand, expression of disgust seems to produce the opposite effect, that is reducing the sensory intake, which means when pinching noses and squinting eyes in disgust, subjects saw and smelled less. This finding supports Darwin’s idea of emotional facial expressions might have evolved for a reason.
