All animals in the phylum Chordata share which of the following features?

The size and shape of the vertebrate skull can reveal a great deal about an animal's lifestyle and evolutionary relationships. Consider your own skull. If you put your finger in your ear and move your jaw up and down, you can feel the space near the hinge of your jaw. Nestled in this space are the tiny bones that make your hearing possible: the malleus, incus, and stapes. All mammals have these three ear bones, but reptiles such as this T. rex don't.

Where did ear bones come from?

A marine biologist has dredged up an unknown animal from the seafloor. Describe some of the characteristics that could be used to determine the animal phylum to which the creature should be assigned.

Which of the following nested monophyletic groups are correctly organized from largest (most inclusive) to smallest (least inclusive), showing your place in the tree of life?

a. Deuterostomes>Chordates>Vertebrates>Mammals

b. Animals>Mammals>Vertebrates>Primates

c. Chordates>Primates>Mammals>Hominins