[ExI] Swallows may be evolving to dodge traffic

[Anders Sandberg]

On 19/03/2013 18:47, Alfio Puglisi wrote:
> How about human beings? Are people better at crossing the street, or
> driving without rear-ending someone else?
Yes, but this is cultural evolution rather than biological evolution. 
Looking at the traffic fatalities data shows a rapid decline on a 
timespan of a decade, much less than a human generation time.

Suppose you have a dominant gene variant A which gives a fitness 
advantage h over the normal allele a, which we assumes has fitness 1. A 
has frequency f. So in the next generation (assuming random mating) the 
frequency will be f(1+h)/[f(1+h) + (1-f)] = f (1+h)/(fh+1). Traffic 
mortality is responsible for 2% of all deaths globally, so if we for the 
sake of argument assume a third of that turns into a fitness advantage 
thanks to A (a huge advantage - if you have this allele you will not be 
killed by a car before reproductive age) h will be 0.0066. If f is near 
zero the frequency will increase by a factor of 1.0066 every generation 
- it will take about a hundred generation to become dominant.

In practice you can get faster adaptation if there are multiple traits 
that can be affected, of if you have small populations.

-- 
Anders Sandberg,
Future of Humanity Institute
Oxford Martin School
Faculty of Philosophy
Oxford University