Disasters, Ecological Diversity, and the Future of Humanity
Professor Christopher Wills
How quickly can the world’s biological systems recover their diversity in the aftermath of ecological catastrophes that cause widespread local and global extinctions of species? This question can be answered by examining the forces that maintain and increase ecological and genetic diversity at the present time. Here I look at two of these processes: those that increase human genetic diversity, and those that maintain and increase tropical forest diversity. I suggest that both have been aided by a particular type of natural selection known as negative frequency-dependent selection, and I conclude that this type of selection may aid in the recovery of diversity following catastrophes.
The evolution of human intellect and of intellectual diversity has been driven by a feedback loop between our brains, our genes and our highly challenging environment. Negative frequency-dependent selection has made all of our brains slightly different from each other, so that collectively as a species we can accomplish far more than a single individual ever could.
We have recently shown that this same process of frequency-dependent selection has driven the evolution of tropical rainforests, allowing complex ecosystems to evolve that are capable of utilizing the environment far more efficiently than a single species could.Finally, the lecture will look at the fragility of these complex ecosystems. In collaboration with tropical ecologists worldwide, we have now demonstrated that a small reduction in the complexity of tropical rainforests will have a substantial negative impact on the growth and survival of the remaining species. Therefore the value of complexity and diversity in the natural world is high, and we put ourselves at risk if we do not maintain it.