Question

Geological evidence indicates that two landmasses, separated by a deep ocean channel, have been moving apart since 45 million years ago. You are studying a group of organisms that has widespread populations on both of the landmasses. Which is the most likely hypothesis for the group's evolutionary history

Answer 1

A) It depends on the dispersal abilities of the organism. If the organism cannot move across the open ocean, it is very likely that the groupʹs ancestors were present on the original land mass before it broke up.

Step-by-step explanation:

A) It depends on the dispersal abilities of the organism. If the organism cannot move across the open ocean, it is very likely that the groupʹs ancestors were present on the original land mass before it broke up.

B) The groupʹs ancestors cannot have been present on the original land mass before it broke up.

C) The groupʹs ancestors were definitely present on the original land mass before it broke up.

D) The groupʹs ancestors must have independently colonized each of the land masses from a third location within the past 45 million years.

The two land masses are separated by deep ocean channel which are purported to have been moving apart since 45 million years ago. Hence, for the organisms to have a widespread population on both land masses, either of two things are possible:

• The ancestors of the organisms had a wide range of dispersal mechanism to cover the two land masses as they were moving apart or
• The ancestors were present on the original land mass before it broke up into two. When it broke up, each land mass has some parts of the ancestors.

The correct option is A.