The reduced variability of small populations is not always due to accidental gene loss, but sometimes to the fact that the entire population was started by a single pair or by a single fertilized female. These 'founders' of the population carried with them only a very small proportion of the variability of the parent population. This 'founder' principle sometimes explains even the uniformity of rather large populations, particularly if they are well isolated and near the borders of the range of the species.
Ernst MayrIt seems to me that for Darwin the pulsing of evolutionary rates was a strictly vertical phenomenon.
Ernst MayrLiving in an entirely different physical as well as biotic environment, such a population would have unique opportunities to enter new niches and to select novel adaptive pathways.
Ernst MayrIsolating mechanisms are biological properties of individuals that prevent the interbreeding of populations that are actually or potentially sympatric.
Ernst MayrIn neither his definition nor the examples illustrating what memes are does Dawkins mention anything that would distinguish memes from concepts.
Ernst Mayr