Environment & Energy
Related: About this forumThe dinosaurs in your garden
Birds really are dinosaurs, and a sparrow or a blackbird is every bit as much a dinosaur as Tyrannosaurus or StegosaurusThe dinosaurs first arose in the Late Triassic period about 225m years ago. No specific ancestral species is identified, but we recognise that there is a distinct lineage of animals that can be grouped together by shared features of their anatomy that we call dinosaurs. This group has three main lineages: the huge sauropodomorphs, the herbivorous and diverse ornithischians and the (mostly) carnivorous theropods.
Modern birds are the direct descendants of dinosaurs and so are part of the dinosaur group (or more technically, the dinosaur "clade" . Living birds are literally dinosaurs by definition.
This means several things, most obviously the fact that dinosaurs are not actually extinct. Most lineages of course have gone: every dinosaur lineage except the birds is extinct (and indeed various birds are no longer with us). Second, this means that when biologists and palaeontologists talk about dinosaurs, they actually generally mean all dinosaurs except the birds. This often goes unsaid in public communications (and occasionally the odd paper) but really when we say "dinosaurs" we should say "non-avian dinosaurs".
This is something I myself have avoided to date on the Lost Worlds, but it was always a point I intended to raise and introduce and then try and maintain. It's really quite relevant as accuracy is an inherent part of science communication and the statement that "dinosaurs are extinct" is incorrect, whereas "non-avian dinosaurs are extinct" is correct. Third and most amazingly, we have dinosaurs everywhere around us.
http://www.guardian.co.uk/science/lost-worlds/2012/sep/06/dinosaurs-garden-birds
gordianot
(15,226 posts)Speck Tater
(10,618 posts)...we insult them here on a regular basis.
gordianot
(15,226 posts)I could see them someday feeding off the population if that is what it took to survive.
Cleita
(75,480 posts)Aren't they related to dinos too?
intaglio
(8,170 posts)Closer to Republicans than the more evolved dinosaur
Scootaloo
(25,699 posts)Birds and crocodiles - along with pterosaurs, dinosaurs, and a handful of other extinct oddballs - are a group called archosaurs. They're descended from reptiles, as are Synapsids (which includes mammals and a bunch of old dead critters) but thye are not themselves easily classifiable as "reptiles."
In fact, the "Reptiles" class is kind of a defunct category, since it excludes creatures descended from reptiles. Aves and mammalia are good Classes, since they include everything descended from a common ancestor. "Reptilia," however, excludes birds and mammals, which do share a common ancestor with reptiles. The same problem is found with Pisces and Amphibia, since those Classes exclude all Reptiles, birds, and mammals, despite sharing ancestry with those groups.
Linnaean taxonomy gets really weird when you add evolution to the mix. Poor Carol Linne, he had no idea...
Also, the further back we go, we keep finding more birds; it may be safer to say that dinosaurs are extinct birds, than saying birds are living dinosaurs.
Odin2005
(53,521 posts)The only one that most people know about is Dimetrodon, and most think it's a dinosaur.
There were an incredibly diverse group that dominated the large land animal fauna in the Permian period. The later Permian forms were almost certainly warm-blooded and may have already have had fur.