By Dr. May Chi, Clinical Psychologist
My statistician supervisor has been involved in everything from gathering evidence for a planetary mass orbiting a binary star to understanding how bush turkeys and echidnas like to cross the road.
My favourite article of hers is about the potential inbreeding of a small population of Xanthorrhoeaceae. I like it for the paper title: Is Your Mother My Father?
Ten years ago, the book Evolution in Four Dimensions by evolutionary biologist Eva Jablonka opened my eyes to more than just genes. She and Marion Lamb proposed four distinct inheritance systems: genetic, epigenetic, behavioural, and symbolic.
Humans uniquely benefit from symbolic inheritance. Words, language, pictures, and songs are all examples of our symbolic inheritance. It allows information to be transmitted, interpreted, and recombined in infinite ways. We can construct elaborate cultural systems, imagine futures that do not yet exist…! And yes, lots of people use it to share inappropriate memes online.
As with the other dimensions of evolution, symbolic transmission follows the same steps: variation, mutation, selection, and retention. Variation is the natural differences within a population. Some people say toe-may-toe, others say toe-mar-toe. Mutation is when a new variation emerges, like how the youth keep creating new slang words, such as ‘rizz’. Mutation is random and may or may not be useful.
Selection, on the other hand, isn’t random. It’s based on how useful something is in the environment you find yourself in. And the interesting thing is, when there is more than one useful approach, such as approaching with compassion or approaching with contempt, we get to choose. Finally, retention is the inheritance. If retained, our selection guides the trajectory of what happens next.
For those holding their breath about the fate of that little cluster of Xanthorrhoeaceae, don’t worry; there was pollen transfer across close and distant plants. High genetic diversity was found, with no dominant paternal genotypes. They’re doing ok.
