
https://www.livescience.com/animals/bird...s-reptiles
EXCERPTS: Anyone who has watched a rooster stalking around a farmyard might agree that there is something very dinosaur-like about birds. That may come as no surprise, given that birds are dinosaurs. But in terms of classification, this raises a question: Since dinosaurs are reptiles, does that mean that birds are reptiles, too?
"I would say that any modern biologist would, or should, say that birds are reptiles," Martin Stervander, an evolutionary biologist and senior curator of birds at National Museums Scotland, told Live Science.
It wasn't always this way. Before the 1940s, biologists relied on a system called the Linnaean method to classify all life on Earth. This approach was developed by Carl Linnaeus in the 1730s, and it works by grouping animals that have similar physical characteristics. Linnaeus determined that all reptiles share two key features: They have scales, and they are ectothermic, or "cold-blooded," meaning they must rely on external sources of heat to regulate their body temperature.
Because warm-blooded, abundantly feathered birds lack these features, "birds were considered their own branch on the tree of life" under the Linnaean system, said Klara Widrig, a postdoctoral fellow in the Vertebrate Zoology Department at the Smithsonian's National Museum of Natural History in Washington, D.C. Linnaean classification accurately describes many relationships and helped to establish the broad branches of the tree of life we use today. Yet this classification system overlooks something that can reveal a lot more about an organism: its genes.
From the 1940s, the ability to examine genetic material gave rise to a new type of classification, called phylogeny...
[...] "All of these guys — snakes and turtles and crocodiles and birds, and the dinosaurs when they were around — they all come back to one common ancestor," Stervander explained, and so under the phylogenetic grouping system, "that simply means that since birds are in [that clade], they are, per definition, reptiles." This is why phylogeny is valuable, because it can reveal that organisms that look very different are, in fact, very close to one another genetically and belong in the same group... (MORE - missing details)
EXCERPTS: Anyone who has watched a rooster stalking around a farmyard might agree that there is something very dinosaur-like about birds. That may come as no surprise, given that birds are dinosaurs. But in terms of classification, this raises a question: Since dinosaurs are reptiles, does that mean that birds are reptiles, too?
"I would say that any modern biologist would, or should, say that birds are reptiles," Martin Stervander, an evolutionary biologist and senior curator of birds at National Museums Scotland, told Live Science.
It wasn't always this way. Before the 1940s, biologists relied on a system called the Linnaean method to classify all life on Earth. This approach was developed by Carl Linnaeus in the 1730s, and it works by grouping animals that have similar physical characteristics. Linnaeus determined that all reptiles share two key features: They have scales, and they are ectothermic, or "cold-blooded," meaning they must rely on external sources of heat to regulate their body temperature.
Because warm-blooded, abundantly feathered birds lack these features, "birds were considered their own branch on the tree of life" under the Linnaean system, said Klara Widrig, a postdoctoral fellow in the Vertebrate Zoology Department at the Smithsonian's National Museum of Natural History in Washington, D.C. Linnaean classification accurately describes many relationships and helped to establish the broad branches of the tree of life we use today. Yet this classification system overlooks something that can reveal a lot more about an organism: its genes.
From the 1940s, the ability to examine genetic material gave rise to a new type of classification, called phylogeny...
[...] "All of these guys — snakes and turtles and crocodiles and birds, and the dinosaurs when they were around — they all come back to one common ancestor," Stervander explained, and so under the phylogenetic grouping system, "that simply means that since birds are in [that clade], they are, per definition, reptiles." This is why phylogeny is valuable, because it can reveal that organisms that look very different are, in fact, very close to one another genetically and belong in the same group... (MORE - missing details)