I was impressed by Zuk's argument that about how agriculture might have led to more genetic adaptation at the same time as it led to health problems for our species. First, she acknowledges that the advent of agriculture resulted in an increase in bacterial and viral infections for humans. The close proximity of humans and their livestock allowed bacteria and viruses to switch readily between species, which created a number of new illnesses for humans. These bacteria and viruses are not only more able to adapt to humans because of the new proximity between humans and animals, but are also able to spread between humans because agriculture results in humans living in closer proximity to each other. Agriculture, Zuk argues, requires many people working together to make the process worthwhile. When all these people come together, the transfer of disease becomes more probable.
However, despite these advantages, Zuk argues, the human population was able to explode. This rapid increase in population size carries with it an increase in the total genetic variation, which may have resulted in humans, as a species, being more able to adapt to new pathogens and environmental changes than was possible with the limited genetic variation present before agriculture.
Zuk therefore argues that while agriculture may have brought with t a higher risk of disease, it may have also provided humanity with the genetic diversity to withstand the new pathogens present in the environment. This almost paradoxical argument is fascinating. What do you think? Did agriculture expose us to new pathogens, or did it provide us with the genetic machinery to combat even worse maladies?
No comments:
Post a Comment