Have you read “The 10,000 Year Explosion”? Cochran & Harpending (and Hawks and some others in the paper its based on) argue that evolution has accelerated recently. The reason is that there is a larger population, so more new mutations to be selected. Also, because our environment is not a steady state our genes don’t reach a steady state either (like horseshoe crabs or a number of other species). I’ve only read a bit past the first chapter, but it would seem relevant to your claim.
I’d be interested, but evolution over the past 20,000 years doesn’t affect the argument I’m making here, which looks at a long-term trend in evolution.
ADDED: There are some factors that will increase genetic exchange and selective pressure, as discussed in some comments below; but not that increasing genetic exchange often slows evolution. There’s a balance between being able to spread beneficial mutations, and reaching premature convergence; the “sweet spot” of that balance is with very small communities, much, much smaller than continent-sized. Some equations and data indicate that species diversity is much larger when the environment is fragmented into small areas with little communication (google “island theory of biogeography”).
It sounds as though they are talking about human evolution—plus maybe the evolution of rats, lettuces and pigeons. The numbers of many other species have dwindled.
Have you read “The 10,000 Year Explosion”? Cochran & Harpending (and Hawks and some others in the paper its based on) argue that evolution has accelerated recently. The reason is that there is a larger population, so more new mutations to be selected. Also, because our environment is not a steady state our genes don’t reach a steady state either (like horseshoe crabs or a number of other species). I’ve only read a bit past the first chapter, but it would seem relevant to your claim.
I’d be interested, but evolution over the past 20,000 years doesn’t affect the argument I’m making here, which looks at a long-term trend in evolution.
ADDED: There are some factors that will increase genetic exchange and selective pressure, as discussed in some comments below; but not that increasing genetic exchange often slows evolution. There’s a balance between being able to spread beneficial mutations, and reaching premature convergence; the “sweet spot” of that balance is with very small communities, much, much smaller than continent-sized. Some equations and data indicate that species diversity is much larger when the environment is fragmented into small areas with little communication (google “island theory of biogeography”).
It sounds as though they are talking about human evolution—plus maybe the evolution of rats, lettuces and pigeons. The numbers of many other species have dwindled.