<P> Vestigial structures have been noticed since ancient times, and the reason for their existence was long speculated upon before Darwinian evolution provided a widely accepted explanation . In the 4th century BC, Aristotle was one of the earliest writers to comment, in his History of Animals, on the vestigial eyes of moles, calling them "stunted in development" due to the fact that moles can scarcely see . However, only in recent centuries have anatomical vestiges become a subject of serious study . In 1798, Étienne Geoffroy Saint - Hilaire noted on vestigial structures: </P> <Table> <Tr> <Td> "</Td> <Td> Whereas useless in this circumstance, these rudiments...have not been eliminated, because Nature never works by rapid jumps, and She always leaves vestiges of an organ, even though it is completely superfluous, if that organ plays an important role in the other species of the same family . </Td> <Td>" </Td> </Tr> </Table> <Tr> <Td> "</Td> <Td> Whereas useless in this circumstance, these rudiments...have not been eliminated, because Nature never works by rapid jumps, and She always leaves vestiges of an organ, even though it is completely superfluous, if that organ plays an important role in the other species of the same family . </Td> <Td>" </Td> </Tr> <P> His colleague, Jean - Baptiste Lamarck, named a number of vestigial structures in his 1809 book Philosophie Zoologique . Lamarck noted "Olivier's Spalax, which lives underground like the mole, and is apparently exposed to daylight even less than the mole, has altogether lost the use of sight: so that it shows nothing more than vestiges of this organ ." </P>

How do vestigial structures remain in the population