A "new" systematics will be forthcoming only when the urge to be "right" takes a back seat to the possibility that one is wrong. - Jeffrey H. Schwartz

There has been little morphological evidence offered since Darwin in support of the relatedness of humans and one or both of the African apes, but that, when the relationships among the extant humanoids are investigated cladistically in an evaluation of more than 200 morphological features, there are well over twice as many morphological synapomorphies in support of uniting humans with the orang-utan as with the African ape clad and very few in support of uniting the chimpanzee more closely with humans than with the gorilla.

Becoming a rock does not ensure safety. ...The blasting of windblown sands, the pummeling of waves, the corrosive secretions of mosses and lichens, and even the steady rhythm of a stream can, in time, reduce a seemingly indestructible boulder to a grain of sand.

If Walter Garstang's suggestion is correct, and chordates did arise from a tunicate-like form by retaining the chordate features of their larval stage of development into adulthood, then the first chordates must have been affected by a regulatory mutation that kept the Manx gene activated for a longer period of time.