Are birds a subset of reptiles and dinosaurs, or are they th

[Jupiter60]

are birds a subset of reptiles and dinosaurs, or are they their own class? traditionally they are considered their own class, has that changed?

 

[Bystander]

https://en.wikipedia.org/wiki/Dinosaur_classification

 

[Jupiter60]

wouldn't it be better just to consider birds to be their own class? saying "nonavian reptiles" and "nonavian dinosaurs" is cumbersome. better to reserve the words "reptile" and "dinosaur" for animals that aren't birds. after all, reptile stores don't typically sell birds. that shows that the word "reptile" doesn't typically include birds.

 

[Bystander]

"Just the facts, ma'am. Just the facts." You asked for the state of the taxonomic art, and now you're expecting "egg in your beer?"

 

[Ygggdrasil]

Are you using "class" in the layman's sense or in the sense of taxonomic rank (e.g. domain, kingdom, phylum, class, order, family, genus species)? Birds (class Aves) are their own class, though they fall within clades containing reptiles and dinosaurs.

Remember that scientific classifications don't always match up with popular classifications. For example, tomatoes are scientifically classified as fruits and peanuts are scientifically classified as beans, even though most would consider them as vegetables and nuts, respectively.

 

[BillTre]

There is a distinction between older ways of classifying things (within biology) taxonomically and the more recent cladistic methods.
Cladistics was popularized by Hennig and others in the 1960's.

Cladisitics focuses on clades, which amounts to grouping things together by relationship, no by looks or particular traits. Caldistic methods allow more critical data based decisions to be made about relationships than were formally done.
Cladisitics does not like groups that include everything in a group (dinosaurs in this case) except for one group which changed (birds in this case). The changed taxon (or taxonomic group; birds in this case) should remain in the larger group (dinosaurs in this case) because that is what was derived from.
It can however be made into a new sub-group (birds in this case).

If you are having trouble thinking about this by using the most commonly used phylogenetic tree imagery, it is equally correct and formally equivalent to use Venn diagrams. In this case, the birds would be a Venn diagram sub-group (circle within a circle) of the dinosaurs (the larger outer circle group).