In the Oceans on Either Side of the Isthmus of Panama

question 51

Multiple Choice

In the oceans on either side of the Isthmus of Panama are 30 species of snapping shrimp; some are shallow-water species, others are adapted to deep water. There are 15 species on the Pacific side and 15 different species on the Atlantic side. The Isthmus of Panama started rising about 10 million years ago. The oceans were completely separated by the isthmus about 3 million years ago.
In the figure, the isthmus separates the Pacific Ocean on the left (side A) from the Atlantic Ocean on the right (side B) . The seawater on either side of the isthmus is separated into five depth habitats (1-5) , with 1 being the shallowest.

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Which of these habitats is likely to harbour the most recently diverged species?
Which of these habitats is likely to harbour the most recently diverged species?

• A) A5
• B) B4
• C) A3
• D) A1

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Definitions:

Arbor Vitae

The "tree of life" structure within the cerebellum of the brain, consisting of white matter that helps coordinate muscle movements.

Superior Peduncle

A band of nerve fibers connecting the cerebellum to the midbrain, involved in coordinating movements and proprioceptive sensory input.

Tentorium Cerebelli

Dural folds between the cerebrum and the cerebellum.

Vermis

The central part of the cerebellum that is involved in coordinating movement and controlling balance.