Question

Cladograms are branched diagrams representing evolutionary relationships. A cladogram with representative animals is shown given.
The traits M, N, O and P would represent

• A. M: Nails, N: Jaws, O: Fur, P: Opposable thumb
• B. M: Lungs, N: Vertebral column, O: Bipedal locomotion, P: Mammary glands
• C. M: Vertebral column, N: Jaws, O: Mammary glands, P: Nails
• D. M: Lungs, N: Claws, O: Fur, P: Opposable thumb

Answer 1

Answer: (D)

Cladogram shows evolutionary relationship between different organisms. In the given diagram, traits M, N, O and P represent the difference between the the organisms before and after that point. For examples, Salmon fish lacks lungs. However, salamander, lizard, mouse and chimpanzee posses lungs. Similarly, claws or nails are absent in salmon fish and salamander but present in lizard, mouse and chimpanzee. Fur is absent in salmon fish, salamander and lizard. However, it is present in mouse and chimpanzee. Opposable thumb is present only in chimpanzee and absent in other organisms. All these are adaptations seen in successive organisms but absent in primitive organisms.

Thus, the correct answer is option D.