In: Biology
Consider the following as major groups of living Vertebrates: jawless fishes, cartilaginous fishes,
bony fishes, amphibians, reptiles, birds & mammals.
About how many species are recognized in each of these groups?
Two of these groups are paraphyletic. Identify which groups they are and explain clearly what makes each of them paraphyletic.
Jawless fish-100 species
Cartilaginous fish-980
Bony fish-28000
Amphibians-8000 where 90% are frogs
reptiles-10000
mammals-5450
Birds-10000
A paraphylectic group is a group of organisms that includes an ancestor but only some of its descendants.for example in your family your parents are the ancestors and you and your siblings are descendants.If any one of your siblings is left out of the group then the group is paraphylectic because it contains all ancestors not all descendants.
Jawless fish and reptiles are paraphylectic
Jawless fish comprise of all ray ray finned fish but exclude but exclude terrestrial descendants of fleshy finned fish.
Reptiles comprise of scaly tetrapods but exclude mammals and aves(birds)