But sometimes, we as humans intervene and prevent natural selection from taking its course. Take the bulldog. As animals go, the bulldog has to be one of the worst. Anyone who wants an argument against creationism and the idea that the world was perfectly designed by god only needs to look at the bulldog to see that not everything is quite so perfect. Many bulldogs have respiratory problems due to their unique squashed faces, and the folds in their face need to be cleaned daily to prevent infections. But most bizarrely of all, over 80% of bulldog litters have to be delivered by Caesarean section, because their large heads can get stuck in the birth canal.

What does all this have to do with plants? Well, it’s not just in the animal world that humans have intervened to keep alive plants that shouldn’t still exist.  Take the avocado, for example. Like most fruits, the avocado used to be propagated by animals eating them, defecating, and thereby spreading their seeds. This was all very well in the days of giant ground sloths and other prehistoric megafauna (that’s big animals to me and you). But these days, there aren’t any animals left that eat avocados – mainly because the big seed is quite a choking hazard to any animal whose name doesn’t begin with ‘giant’ or ‘mega.’

And avocados aren’t alone – there are a whole host of other ‘ghosts of evolution’ like mangoes, papaya and the stinking durian that have no other consumers apart from the humans who farm them, and daintily cut out their big stones with cutlery.

You can find out more about plants that are not in sync with the modern world in the book ‘Ghosts of evolution’.

Image Source: ceoln (some rights reserved)