Dollo’s Law Tuesday, May 29, 2007
Posted by Henry in anti-creationism, biology, Dawkins, Dollo's Law, evolution, genetics, Richard Dawkins, science, sea snails, Stephen Gould.1 comment so far
Dollo’s law is one interesting hypothesis in the theory of evolution. In its original form, it states that evolution is irreversible – that is, once an organism has lost or discarded a structural feature during the course of evolution, then it cannot regain that feature.
This law was proposed firstly in 1890 by a biologist named Louis Dollo. In its modern form, this law should be understood as one that hypothesises that evolution is highly unlikely reversible – that is, it is highly improbable that an organism would regain a lost feature.
This law kind of makes sense under the first impression – life evolves from simple to complex, and it seems that there is no known case of organisms regrowing a previously discarded feature. However, on a second thought, one must pause and examine the issue further. None of the evolution mechanisms – natural selection, sexual selection, genetic drift, genetic mutation, genetic recombination, symbiogenesis and so on – dictates that organisms cannot completely regain lost features. In fact, scientists have argued that at least theoretically there is no block to evolutionary reversion.
