When Darwin first published his seminal work ‘On the Origin of Species By Means of Natural Selection’ in 1859, Mendel’s work on heredity was largely unknown. Since then, the study of evolution has moved into the ‘modern synthesis’ combining evolutionary theory with current understanding of genetics. In fact, biological evolution is now defined as: changes in allele proportions within a population over time. Models in this section explore various mechanisms that affect allele proportions in populations. In this section there are models which simulate ‘gene pools’ of populations, you can manipulate various parameters and observe their effects on the populations.