Complex sentence: However, there is evidence for coevolution on the level of populations and species, for example, the concept of coevolution was briefly described by Charles Darwin in "On the Origin of Species", and developed in detail in "Fertilisation of Orchids".
Split into simpler sentences: However, there is evidence for coevolution at the level of populations and species. For example, the concept of coevolution was briefly described by Charles Darwin in "On the Origin of Species", and developed in detail in "Fertilisation of Orchids".