Question

A. What four traits unify you and tunicates in the same class?

B. What two traits aren't show in both you and tunicates at the same stage, and how are we developmentally similar when the trait loss occurs?

Answer 1

A)

Four traits that are common between us and tunicates are:

* Dorsal hollow nerve cord is found in both.

* pharyngeal gill slits are found both at larval stages.

* Both have bilateral symmetry.

* Both have complete digestive system.

* Both of them have notochord at their larval stages.

* Both of them have circulatory system.

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B)

Traits that are not common in tunicates and urochordates:

* Notochord is restricted to the tail region in tunicates at larval stages only where as notochord is replaced by vertebral column in the adults.

* Body is covered by tunic or test whereas our body is not covered by tunic or test.

* Larval stages is found in the development of tunicates but our developmental stages do not have larval stages.

Tunicate and we are developmentally similar because of following character:

* Post anal tail is found in both of them at larva.

* Both have notochord at larval stages.

* Dorsal neural tube is developed in both of them at developmental stages.

* The excretory pore is developed before mouth during development which is known as deuterstomy. Deuterostomy is found in tunicates and us.