Pebble says: E
volution could prove more resilient than you appear to think. I have seen no sign of a superior theory to displace it. All you have done to date is to point to the fact that we do not have evidence of species jumps recorded at present. However, neither have we seen continents colliding. The fact that one can measure incremental continental drift if generally regarded as proof when backed by other evidence from mountains and volcanos etc.
So in evolutionary terms - here is some evidence of studies into the potential mechanisms of such seizmic events.
PNAS 2009; 106: 1869 - 1874
Emergence of species in evolutionary “simulated annealing”
- <LI id=contrib-1>Muyoung Heo, <LI id=contrib-2>Louis Kang and
- Eugene I. Shakhnovich1
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138
- Edited by Harold A. Scheraga, Cornell University, Ithaca, NY, and approved November 20, 2008 (received for review October 1, 2008)
Which factors govern the evolution of mutation rates and emergence of species? Here, we address this question by using a first principles model of life where population dynamics of asexual organisms is coupled to molecular properties and interactions of proteins encoded in their genomes. Simulating evolution of populations, we found that fitness increases in punctuated steps via epistatic events, leading to formation of stable and functionally interacting proteins. At low mutation rates, species form populations of organisms tightly localized in sequence space, whereas at higher mutation rates, species are lost without an apparent loss of fitness. However, when mutation rate was a selectable trait, the population initially maintained high mutation rate until a high fitness level was reached, after which organisms with low mutation rates are gradually selected, with the population eventually reaching mutation rates comparable with those of modern DNA-based organisms. This study shows that the fitness landscape of a biophysically realistic system is extremely complex, with huge number of local peaks rendering adaptation dynamics to be a glass-like process. On a more practical level, our results provide a rationale to experimental observations of the effect of mutation rate on fitness of populations of asexual organisms.