Bob Bales has claimed that no one has refuted the points that he has made about how scales

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Bob Bales has claimed that no one has refuted the points that he has made about how scales could have evolved into feathers. I find this puzzling, since I posted this to the net, from the same city, with his name prominently featured in the subject line. Bob, this is a refutation of your claim that feathers and scales arise from different skin layers. Please retract the claim above. :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Bob Bales claimed a few weeks ago that bird feathers and lizard scales 'came from different skin layers' and hence feathers could not have evolved from scales. Unfortunately, that does not match up with the data I have here before me: (detailed reference at end of article) - perhaps you could supply me with a more detailed reference for your assertion? "Skin consists of two layers, a superficial epidermis derived from the embryonic ectoderm, and an underlying dermis derived from mesoderm. The development of scales or other epidermal structures depends on inductive sig- nals from the dermis." - pg 160 In other words, both grow from the epidermis, under the con- trol of chemical signals from the dermis. Here is the interesting part: By grafting lizard epidermis over over chick and mice dermis, the scales can be made to grow in patterns corresponding to chick feathers, and mouse fur, even mouse whiskers - the code for the actual structure of hair and feather is not there, but the embryonic signalling system is so similar that: "Lizard epidermis responds to chick tarsometatarsal dermis to produce large scales indistinguishable in appearance and arrangement from chick tarsometatarsal scales. Lizard epidermis responds to chick dorsal dermis, which in chicks determines the arrangement and morphology of feathers. However, lizard epidermis is unable to interpret the specific signals for feather morphogenesis. Instead, the epidermis produces arrested scales arranged in a typical hexagonal feather pattern. In a like manner, lizard epidermis combined with mouse dermis forms not hair, but abortive scales arranged in typical mouse hair patterns..." [page 162] So: not only are feathers and fur coming from the same layer of skin, they respond to the SAME DEVELOPMENTAL CONTROLS in the embryo. What a coincidence. Regards, Max G. Webb _Embryos, Genes, and Evolution_, Rudolf Raff and Thomas Kaufman, (c) 1983 Rudolf Raff and Thomas Kaufman, Macmillan Publishing Company.


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