Basal (phylogenetics) Updated 2025-07-16
When a characteristic is basal, it basically means the opposite of it being polyphyletic.
E.g. monotremes laying eggs did not evolve separately after function loss, it comes directly from reptiles.
Marsupial Updated 2025-07-16
They split up from the rest of the mammals after the monotremes.
Every other mammal has a placenta.
This baby in pouch thing just feels like a pre-placenta stage.
Theria Updated 2025-07-16
Every mammal except the weird monotremes, i.e. marsupials and the placentalia.
The name is completely random, "wild beast". Are platypuses not "wild beasts"? They have a freaking poison!!