The rule from GMAT Grammar book states the following: If the object of the preposition is singular, use a singular verb. If the object of the preposition is plural, use a plural verb.
Half of the dresses are
Half of the sugar is
A high percentage of the population is
A high percentage of the people are
The majority of Congress has
voted for the bill.
The majority of Senators have
However look at this sentence from Kaplan
Contrary to popular belief, extinction is a common phenomenon in nature; in fact, the majority of the species that have existed on our planet are already extinct, with most disappearing long before Homo sapiens evolved.
Shouldn't it be: the majority of the species has existed?
Is there a set of words that fall under that rule?