Phylogeny

AP Biology· difficulty 3/5

A character matrix records presence (1) or absence (0) of derived characters in four taxa.

Taxon Hair Lungs Amnion Jaws Lamprey 0 0 0 0 Shark 0 0 0 1 Frog 0 1 0 1 Mouse 1 1 1 1

Using a parsimony approach with lamprey as outgroup, which character supports the most inclusive clade (most taxa)?

  • A

    Jaws (shared by shark, frog, mouse)

    check_circle
  • B

    Hair (mouse only)

  • C

    Amnion (mouse only)

  • D

    Lungs (frog and mouse)

Explanation

Jaws is present in 3 of 4 taxa (shark, frog, mouse) and absent in the outgroup. As a synapomorphy it defines the largest clade (Gnathostomes). The other derived traits unite smaller groups.

Want 10 more like this — adaptive to your weak spots?

Related questions