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 good scientific hypothesis is based on existing evidence and leads to testable predictions. What hypothesis did the paleontologists who discovered Tiktaalik test? What evidence did they use to predict where they would find fossils of transitional forms?

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?Researchers studied mice embryos as a model organism to determine whether the cells of the ear bones originated from the same embryonic cells as the cells that form the jaw in other vertebrates. Why would the researchers use mice instead of humans? Do the results from mice tell you something about your own ears? Why or why not?

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?Evolution often results in the co-option of a preexisting structure for a new use. Cite three examples from this chapter to support this statement. Evolution can also result in the loss of a trait. Cite three examples from this chapter.

Recall that hemophilia is an X-linked recessive disease. If a woman with hemophilia had children with a man without hemophilia, what is the chance that their first child will have the disease? What is the chance that their first child will be a carrier?

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.

If an animal has segments, bilateral symmetry, pharyngeal clefts, a post-anal tail, and deuterostomic development, it must be a member of the __________.

A __________ is a chordate but not a vertebrate.

Which of the following chordate characteristics contributes most to the formation of your ears?