The Number of Cervical Vertebrae Is Nearly Constant in All

question 22

Essay

The number of cervical vertebrae is nearly constant in all animals,whether the neck is short or long.Explain this evolutionary phenomenon.Could it simply be related to an ancestral condition?

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Definitions:

Hypothalamus

A complex structure near the lower center of the brain that has direct connections to many other parts of the brain and is involved in the production of psychologically important hormones; thought to be important for mood and motivation.

Electroencephalography (EEG)

A technique for measuring the brain’s electrical activity by placing electrode sensors on the outside of the skull.

Magnetoencephalography (MEG)

A technique for using delicate magnetic sensors on the outside of the skull to detect brain activity.

Positron Emission Tomography (PET)

A technique for creating images of brain activity by injecting a radioactive tracer into the blood and then, using a scanner, finding where in the brain the blood is being metabolized.