What does the statement "Phylogeny recapitulates ontogeny." mean?

Answer 1

Ernst Haeckel coined this phrase. It's a different name for the theory of recapitulation. This theory says that the development of an embryo (ontogeny) repeats the evolutionary development of the species (phylogeny).
The theory is quite old (1866). Nowadays this theory is not accepted anymore.

Answer 2

"Ontogeny recapitulates phylogeny" is a catchy phrase coined by Ernst Haeckel, a 19th century German biologist and philosopher to mean that the development of an organism (ontogeny) expresses all the intermediate forms of its ancestors throughout evolution (phylogeny). His theory was later proved wrong, but the catch phrase remains.

check this site: http://mcraeclan.com/Graeme/Language/OntogenyRecapitulatesPhylogeny.htm

Answer 3

The statement is really "Ontogeny recapitulates phylogeny". Check this link at Wikipedia:
http://en.wikipedia.org/wiki/Ontogeny_recapitulates_phylogeny

Answer 4

It means that the development of the embryo resembles evolutionary development. For example, at some stages of development, human embryos look very similar to chimp embryos and even fish embryos. As the embryos develope, however, the fish embroys start to look much different while the chimp embroys continue to look similar to human embryos. This reflects the fact that we are much more closely related to chimps than fish.