Archived posting to the Leica Users Group, 2009/02/18
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 11:39 AM 2/17/2009, Walt Johnson wrote: >Mark > >Couple of points...I've never seen a flock of Canadian geese but am more >than familiar with Canadian tourists. ( Look dear, more Canadians...Where's >my shotgun?) > >As far as birds and dinosaurs go... Everything is related to primordial >ooze >so archsaurs be dammed, We're all from the early muck. (lawyers too) First, note the spelling: I am Marc, not Mark. Mark is generally Mark Rabiner. I am not Mark Rabiner, though we are friends and I find him a refreshing and insightful soul. Second, I had somehow managed to reach 59 years of age without realizing that the American Ornithologists' Union frowns on the use of the term "Canadian Geese". Here on the Atlantic seaboard, you would probably find yourself spending a few days in a rubber room if you insisted on terming them "Canada Geese". In these environs, they are Canadian Geese. I live about six or seven miles from one of their major winter nesting sites, and we have thousands of them in the area right now. Third, here is the condensed version of the evolution of modern tetrapods. Basal Tetrapods evolved from fish around the Carboniferous Era. These produced amphibians, which were the advanced life form in the late Carboniferous and early Permian Eras. Basal Amniotes either evolved directly from Basal Tetrapods or amphibians: the jury is still out on that one. Basal Tetapods dominated the mid Permian. They in turn evolved into Anapsids, which were the advanced life form in the later Permian and early Triassic. They then pretty much went away, leaving only turtles and tortoises, albeit those have been quite successful both in dominating fringe ecological niches and in their PR efforts. After all, COMCAST uses tortoises as spokes-animals and just today the Virginia General Assembly, hopeless deadlocked on killing off a ban on smoking in restaurants, adopted the Southern Box Turtle as the Official State Reptile. Synapsids. These guys evolved in the late Permian and briefly had a fling as the dominant terrestrial life form in the mid-Triassic. They were then pounded down into fringe ecological niches for 150 million years by the diapsids but rebounded in the Paleogene Era to again become the dominant terrestrial life form. There were four broad groupings, one of which, the Multituburculates, is now extinct, but the other three of which, the Monotremata, Marsupials, and Placentals, Yeah, us humans are synapsids. Diapsids. These guys evolved in the Permian but were fringe players for a couple of dozen million years until they radically expanded in the mid-Triassic, dished out the Anapsids and Synapsids, and ruled the earth for 150 million years. They had some groups which are poorly understood but, in the main, they were divided into pterosaurs, squamata (lizards and snakes, and probably including the aquatic mososaur), plesiosaurs, rhynocephalians (the Tuatara in New Zealand is the only survivor of these puppies), champsosaurs, and archosaurs (these include crocodiles and dinosaurs, of which birds are the sole survivors). Today, we have examples of squamata (lizards and snakes), rhynocephalians (the Tuatara) and archosaurs (crocodiles and birds). Note that there properly is not a group called "reptiles", as this violates cladistic properties by including animals not directly sharing a common ancestor. Anapsids and Diapsids are distinct groups separately evolved from Basal Amniotes. And, as a delectable tidbits for the day, microbats do not like to fly in the rain or snow, as the precipitation upsets their echolocation. Marc msmall@aya.yale.edu Cha robh b?s fir gun ghr?s fir!