09 June 2005

Diversity — it's not just a good idea


What's happening to the Tasmanian devil right now is a good example of why diversity in a species is a Very Good Thing.

The animals are suffering from facial tumors which grow so large that they are unable to eat. Interestingly, and devastatingly for the Tasmanian devil, these tumors seem to be infectious, with the agent being the tumor cells themselves.

This doesn't, as far as I know, happen with cancer in other species, because the immune system will normally recognize a foreign cell and destroy it. But Tasmanian devils have very little genetic diversity, and so the invading tumor cells aren't recognized as foreign.

Half of the Tasmanian devil population has already died from this disease; the species may be wiped out in the wild. As the biodiversity of our food supply diminishes year by year, thanks to the efforts of the agro-giants, it becomes more and more susceptible to the same kind of system failure that the Tasmanian devil is dying from.

Think about it the next time you walk into a grocery store and see the rows and rows of identical produce.