[Campbell Biology P.621] Based on the character table Lancelet to Dolphin from Question 9, w... | Practice Question

Based on the character table Lancelet to Dolphin from Question 9, which of the following statements about evolutionary relationships is most accurate according to cladistic analysis?

  • A: Lamprey is more closely related to Lancelet than to Tuna, due to both lacking a hinged jaw.
  • B: Salamander and Turtle form a sister group defined by the shared presence of four limbs.
  • C: Leopard and Dolphin are sister species, as they are the only two organisms in the table that both possess milk and a dorsal fin (considering Dolphin's adult flippers and embryonic hind-limb buds as four limbs).
  • D: The shared presence of a dorsal fin is a synapomorphy uniting Tuna and Dolphin, distinguishing them from other tetrapods.

Explanation

In cladistics, sister species are the two most closely related groups that share a common ancestor not shared by any other group. Leopard and Dolphin both possess milk character 5 and four limbs character 3, with the note for Dolphin , which are shared derived characters within the mammalian clade shown. Among the organisms listed, they are the most recent to diverge from a common ancestor.