Which of the following groups of vertebrates is phylogenetically oldest and retains the ancestral type of heart?
A) Reptiles
B) Amphibians
C) Fishes
D) Birds
E) Mammals

Question

Quizplus · Accepted Answer

Fishes are phylogenetically the oldest group of vertebrates and their heart retains the ancestral type consisting of two chambers - one atrium and one ventricle. This type of heart is also found in some amphibians, while reptiles, birds, and mammals all have more complex hearts with separate pulmonary and systemic circuits.

Which of the Following Groups of Vertebrates Is Phylogenetically Oldest