Flatfish Support Darwin's Evolutionary Theory, Research Claims

September 24, 2009

Release from: Telegraph UK

The discovery removes a major argument used by advocates of intelligent design, which suggests that evolution alone cannot account for some of the surprising adaptations found in the natural world. The flatfish group, which includes the flounder and sole, is often characterised by having both eyes on one side of the head. Darwin, author of On The Origin Of Species, believed animal evolution occurred gradually over millions of years and fossil records revealed this ''transitional'' process. But the Victorian scientist was troubled by the flatfish order because during the time of his studies the group's fossil record was incomplete and it was unclear how the gradual migration of one eye could have come about. But now, a study of 50-million-year-old fossil fishes from Europe has provided a clear picture of the origins of the flatfish group - supporting Darwin's theories. Dr Matt Friedman, the author of the study who recently took up a post at Oxford University, investigated the prehistoric fish - known as acanthomorphs - from Italy and France. Addressing the Society of Vertebrate Palaeontologists' (SVP) annual meeting at the University of Bristol today, Dr Friedman said: ''Flatfishes and their profoundly asymmetrical skulls have been enlisted in many arguments against gradual evolutionary change, precisely because it is difficult to imagine how intermediate forms might have been adaptive. ''My work provides clear evidence of the kinds of intermediates deemed 'impossible' by earlier workers and answers this long-standing riddle in vertebrate evolution.'' Dr Friedman's study of the ancient specimens revealed how the positions of the creature's eyes gradually changed over millions of years. The most ancient acanthomorphs had asymmetrical skulls, but retained eyes on both sides of the head. Intermediate species then show how one eye gradually moved across the head so that both eyes eventually ended up on the same side. This discovery points to a gradual evolution of the unusual skull anatomy of modern flatfishes, Dr Friedman contends. The spiny-finned fishes represent a huge percentage of modern biodiversity - roughly one in three backboned animals is an acanthomorph fish. Dr Friedman's study of more than 1,200 fossil specimens and more than 600 species is the first to examine large-scale patterns of anatomical change in this group.