Here is a conversation starter for the next time you go out with your friends to eat lobster at your favorite seafood restaurant. Is the big crusher claw of a lobster an inherited trait, or is it a result of the environment?

Lobster lovers know that as a lobster grows, one of its two claws will develop into a larger crusher claw. According to classical Darwinian theory of evolution, this physical trait is inherited through genetics. In other words, having one bigger crusher claw is a selective advantage, so lobsters with this genetic trait survive better and pass on this trait.

However, Dr. Richard Palmer of the University of Alberta has published a paper in the October 29 issue of Science that challenges Darwin’s theory as the only explanation of how new species arise.

Palmer reviewed over 200 research papers, including a study on asymmetry – the difference between the left and right side of the body. He found that the environment plays just as key a role as genetics in explaining differences between species, also known as variations.

“Variations that do not initially have a genetic basis can still be important for evolution. They are 35 to 50 per cent as common as genetic variation, at least when it comes to the evolution of asymmetric forms,” Palmer said.

For the lobster example, baby lobsters have equal sized claws. As they grow, one claw transforms into a larger crusher claw as it is used more. There is supposed to be a genetic program that triggers this transformation. However, if one side isn’t stimulated enough, the program never kicks in and the crusher claw never develops.

Studies on many plant and animal species that exhibit asymmetry also support Palmers findings. For example, if two animals of a species with the same ‘handedness’ are mated, half their offspring will be ‘right-handed’ and half ‘left-handed.’ “Genetics made no difference in the direction of asymmetry. It’s a trait strictly determined by environment. From a evolutionary perspective, this means form arises first and the genes follow.”

So it turns out that lobsters not only make a good seafood dish. They can even stimulate our thinking and makes us reevaluate the theory of evolution.

This article was adapted from a news release from the University of Alberta.