Complex sentence: From a Neo-Darwinian perspective, evolution refers to the changeing frequency of alleles within a population of interbreeding organisms, for example of the allele for black colour in a population of moths becoming more common.
Split into simpler sentences: From a Neo-Darwinian perspective, evolution occurs when there are changes in the frequencies of alleles within a population of interbreeding organisms. For example, the allele for black colour in a population of moths becoming more common.