clipped from: physorg.com   
Scientists have revealed what may well be the first pervasive ‘rule’ of evolution. In a study published in the Proceedings of the National Academy of Sciences researchers have found evidence which suggests that evolution drives animals to become increasingly more complex.

Looking back through the last 550 million years of the fossil catalogue to the present day, the team investigated the different evolutionary branches of the crustacean family tree.

They were seeking examples along the tree where animals evolved that were simpler than their ancestors.

Instead they found organisms with increasingly more complex structures and features, suggesting that there is some mechanism driving change in this direction.

“If you start with the simplest possible animal body, then there’s only one direction to evolve in – you have to become more complex,”

“This is the nearest thing to a pervasive evolutionary rule that’s been found.