Chapter 6

Primates are characterized by

arboreal adaptation, dietary plasticity, and parental investment.

The eminent British anatomist Sir Wilfrid E. Le Gros Clark (1895-1971) identified three prominent tendencies in primates. They are

arboreal adaptation, parental investment, and the presence of dietary plasticity.

The cladistic approach to primate classification is

based on the use of anatomical and genetic evidence to establish ancestral relationships.

A sagittal crest is

found along the sagittal suture along the midline of a cranium of some primates.

In primates, rounded lower cusps indicate a diet of

fruit

A skull with a foramen magnum positioned at the back of the skull belongs to an individual that is

fully quadrupedal, such as a dog.

Primate females

give birth to fewer offspring than do many other mammals.

On a visit to the zoo, you overhear a teacher correctly telling a young student that the chimpanzees climb and swing on branches because their

good sense of touch lets them grip trees.

A sectorial premolar

has a single dominant cusp with a sharp edge adapted for cutting.

Which is the correct ordering, from heel to toe, of different kinds of bones in the primate foot?

tarsals; metatarsals; phalanges

According to the British anatomist Wilfrid Le Gros Clark, what are the main tendencies that help to define a primate?

the ability to eat a wide variety of foods, parental investment, and arboreal adaptations

Dietary plasticity in primates refers to

eating a wide variety of foods.

Phylogeny refers to

evolutionary relationships that are based on shared characteristics including physical traits, genetics, and behavior.

Preadaptation is

the use of an anatomical feature in a way unrelated to the feature's original function.

What can distinguish primates that are adapted for eating large amounts of plants and leaves?

their sagittal crests

Which of the following fall under the cladistic classification of apes and humans?

three subfamilies within hominids: pongines, gorillines, and hominines

Strepsirrhines have a special lower incisor called a

tooth comb.

Brachiation refers to

using the forelimbs to move from tree limb to tree limb.

The gluteal medius and gluteal minimus

pull the leg in different directions depending on the type of locomotion.

While at the zoo you see an exhibit with a small group of primates and notice they have wet, snout-like noses. This indicates a species of

strepsirrhine, because they retain a rhinarium.

What are the two suborders of primates?

strepsirrhini and haplorrhini

Which of the following is the major cladistic division of primates?

strepsirrhini and haplorrhini

What is the dental formula for Old World primates, including humans?

2/1/2/3

The typical dental formula of lorises and lemurs is

2/1/3/3

Your sister, who lives in Ohio, calls you crying because she just hit an animal with her car, and she thinks it was a black-and-white colobus monkey. What is a correct statement you could tell her to calm her down?

Black-and-white colobus monkeys are Old World monkeys and are not found in North America. She probably hit a skunk.

You are watching the 1995 film Outbreak. In it, a capuchin monkey, who has a prehensile tail, is believed to be the carrier of an African disease that begins killing humans. What is wrong with this scenario?

Capuchin monkeys are New World monkeys.

Baboons have thirty-two teeth, spider monkeys have thirty-six teeth, and the hypothetical primitive mammal has forty-four teeth. Given these facts, which of the following is likely true?

Catarrhini gave rise to Platyrrhini.

Which trait differentiates hominoids from other primates?

Hominoids do not have tails.

Which of the following would be an accurate classification following the gradistic (traditional) classification scheme?

Lorises, lemurs, and tarsiers are grouped together in the prosimians.

Living lemurs are found only in

Madagascar

While observing primates at the zoo, you notice that the particular monkey you are watching uses its hands, feet, and tail to grasp branches while moving throughout the trees in its enclosure. This is MOST likely a(n)

New World monkey, because many of these species have a tail with grasping abilities similar to those observed in nonhuman primate hands and feet.

At the primate exhibit at the zoo, you notice a slew of monkeys dangling from branches by their tails. The information plaque notes that they are colobus, macaques, and baboons. When you read this, you immediately seek out the zookeeper to complain there is an error. What is wrong with the plaque?

None of those monkeys have prehensile tails.

Primates have an enhanced sense of vision. How do primatologists think this evolved?

Primate eyes converged toward the front of the skull, giving enhanced depth perception. Later, nocturnal primates shifted to become diurnal, and in this context, color vision evolved.

For which of the following statements did the reintroduction project of lemurs on St. Catherines provide more evidence?

Primates exhibit remarkable levels of adaptability under many circumstances.

We observe a remarkable increase in brain size in the order primates. With what is this associated?

Primates have long growth and development periods to accommodate the development of complex behaviors in individuals.

What is one way the vision of primates is different from that of other animals?

Primates have overlapping vision fields.

One of your friends is originally from Ecuador. When he was a kid, he would sneak into the forest and watch howler monkeys. On one of these trips, though, he insists that he and his friends found a human skull. What would be a valid distinction why the skull was not actually human?

The foramen magnum was not located at the bottom of the skull.

You are watching a program about animals and the narrator incorrectly identifies a lemur as a haplorrhine. How did you determine the narrator made a mistake?

The lemur has a tooth comb, which is only found in strepsirrhines.

In the Linnaean taxonomy, how do you know that humans are closely related to chimpanzees?

They are both in the subfamily Homininae.

How do haplorrhines differ from strepsirrhines?

They are more sexually dimorphic than strepsirrhines are.

Colobine primates are well adapted for eating leaves. What leaf-eating traits have evolved in these monkeys?

They are very arboreal; have high, pointed molars good for shearing leaves; and have a three- or four-chambered stomach similar to that of a cow.

How can you identify suspensory primates from their skeletons?

They have very long arms compared to their legs.

In your primate anatomy lab you are shown the mandible (jawbone) of a species of primate. While looking at the teeth you notice a large space between the canine and first premolar. What do you note in your lab book?

This might belong to a species of Old World monkey or ape, as the space in the teeth of the mandible suggests the presence of a canine-premolar honing complex.

In class your professor shows you an MRI scan of a primate brain. The professor points out the relatively large size of the olfactory bulb beneath the frontal lobe. What does this suggest?

This primate must be a species of strepsirrhine, as that suborder of primates relies heavily on the sense of smell.

A feature unique to human teeth and their hominin ancestors is

a canine that shows wear on the tip.

What is the presence of a rhinarium in a primate an example of?

a primitive characteristic retained in only some primates

What features does a strepsirrhine have?

a wet nose, a snout, a tooth comb, and a grooming claw

Arboreal adaptation is

adaptation to life in the trees.

Which of the following fall under the suborder strepsirrhini?

all of the primates of Madagascar

Compared to other primates, strepsirrhine adaptations include

an enlarged olfactory bulb and enlarged scent glands.

Old World monkeys have ________ molars.

bilophodont

Which is the correct ordering, from top to bottom, of different parts of the primate spine?

cervical; thoracic; lumbar; sacrum; coccyx

The Y-5 molar morphology is present in

chimpanzees

Catarrhines' nostrils are

close together and face downward.

Prehensile tails are

common in platyrrhines.

High, pointed crowns indicate a diet of

insects.

The canine-premolar honing complex

involves a diastema, a projecting canine, and a sectorial premolar.

Knuckle-walking

is only found in primates with longer arms than legs.

Relative to body size, primate brain size is

larger among great apes than among other primates.

The attempt to introduce zoo-raised lemurs to St. Catherines Island along the U.S. Atlantic Coast demonstrated that

lemurs can invent new predator alarm calls if a natural predator exists in their new environment.

The strepsirrhines include

lemurs, lorises, and galagos

The generalized skeletal structure of primates

means that limbs and joints are separate from each other, providing flexibility.

Which of the following are considered haplorrhine?

monkeys and apes, including humans

The variation in living primates provides models for understanding

morphology, behavior, and adaptation in the evolutionary past.

Modern primates are characterized by arboreal adaptations, including

opposable thumbs.