So good they were invented twice

摘要

Evolution can repeat itself -even in producing complex structures like the mammalian middle ear. A fossil jawbone from an early Australian mammal proves that the hearing of at least two different groups of mammals developed independently in almost exactly the same way. The discovery raises both philosophical and practical questions. It challenges the claim made by the late biologist Stephen Jay Gould that replaying the evolutionary "tape of life" would produce different results. The finding that the same trait evolved more than once implies the contrary: that natural selection tends to converge on a limited range of options. Simon Conway Morris of Cambridge University, who famously clashed with Gould over the subject, described the findings as "music to my ears".