In 520 BC he speculated that life had a single origin and that it was simpler in the past and has become more complex.

He published Zoonomia, in which he agreed that all living things were descended from a single ancestor and that they had diversified into the various forms seen today due to competition and social interaction

Georges Cuvier believed what?

He proposed an early definition of a species and that individuals of a species are similar due to descent from a common ancestor in his book, History of Plants

He proposed a hierarchical scheme that he felt revealed a divine order of living things in his book on classification

This developed from modeling of inheritance of multi-factorial phenotypes

This developed from modeling of evolution of genes in populations

This involves wealth of discoveries about genes and genomes integrated into genetic theory

Its concept focuses on new species originated when they mutated from pre-existing species, but this process was independent of natural selection, which only affected the composition of populations.