It has been said numerous times to this board that microevolution is the only thing that is proven, and that macroevolution could or could not be true. The only way that we can prove macroevolution is if we can prove all the evolutionary pathways that have resulted in the species that we have today. This, in the past, was virtually impossible. New technology though is allowing us to see the similarities between the many different species. Reptiles and Birds We have known for many years now, through sketal factors, that reptiles and birds are related. In a paper published THIS YEAR, in THIS MONTHS "Current Opinion in Genetics and Development" there is a paper published entitled Evo-Devo of feathers and scales: building complex epithelial appendages. The many point of the paper (I won't go into the biological mumble jumble) is this: To prove the connection between feathers and scales and the connection between birds and reptiles. It was found that Retinoic acid can cause feather formation on all the three types of foot scales in reptiles. As well, the reverse is true in terms of scales can form where feathers are on birds. In all species of animals we have Hox genes, which are our master control genes that stimulate the growth of all our appendages while we are still but little embryos. Thus, the presence of retinoic acid is all it would have taken to develop feathers along the evolutionary pathway. Mammals and Bird There was also a study done that was published in Science magazine that indicates the connection between birds and mammals along the evolutionary line. Apparently, according to the paper, hens have not had teeth for 100 million years. This is caused because they do not have one inducing signal to activate a gene that will form the teeth. In this study, the researchers toke the tooth inducer from a mouse and placed it in the hen. The mouse inducer was able to cause the hen to grow teeth. Thus, between two very distinct and seperate species there is a common factor: they use the same receptor to grow teeth. Are all these examples coincidences? I think not. I don't know what else could prove macroevolution better than these cross-species examples... except more. And I'm positive more will be found. Philosophy