Primates share several behavioral and biological characteristics,

which indicates that they evolved from a common ancestor.

Section 1: Primates

K

What I Know

W

What I Want to Find Out

L

What I Learned

Essential Questions

• What are the characteristics of primates?

• What are the similarities and differences between major primate groups?

• How can the evolution of primates be traced?

PrimatesCopyright © McGraw-Hill Education

Review

• extinction

New

• opposable first digit

• binocular vision

• diurnal

• nocturnal

• arboreal

• anthropoid

• prehensile tail

• hominin

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Vocabulary

PrimatesCopyright © McGraw-Hill Education

Characteristics of Primates

• Humans, apes, monkeys, and lemurs belong to a group of mammals called

primates.

• Primates share traits such as high levels of manual dexterity, keen eyesight,

complex brains and behaviors.

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Characteristics of Primates

Manual dexterity

• Primates typically have five digits on each hand/foot.

• An opposable first digit, one that can brought across the palm or foot to

touch other digits, is a unique primate feature.

PrimatesCopyright © McGraw-Hill Education

Characteristics of Primates

Senses

• Rely more on vision, less on smell than many other mammals

• Primates have binocular vision, eyes with overlapping fields of vision.

• Greater depth perception

• Can judge relative distance and movement

PrimatesCopyright © McGraw-Hill Education

Characteristics of Primates

Senses

• Most primates are diurnal, or active during the day

• Diurnal primates have color vision, reduced sense of smell

• Some primates are nocturnal, or active at night

• Black and white vision

• Most primates have unspecialized teeth, suitable for a diverse diet.

PrimatesCopyright © McGraw-Hill Education

Characteristics of Primates

Locomotion

• Flexible bodies, limber shoulders and hips

• Rely primarily on hind limbs for locomotion

• All primates except humans walk on all four limbs, but many can walk on two

legs for limited distances.

PrimatesCopyright © McGraw-Hill Education

Characteristics of Primates

Complex brain and behaviors

• Primates have large brains for their body size.

• Less brain area devoted to smell, more to vision

• Many primates have problem-solving abilities and complex social behaviors.

PrimatesCopyright © McGraw-Hill Education

Characteristics of Primates

Reproductive rate

• Compared to other mammals, primates:

• Have fewer offspring (usually one at a time)

• Have long pregnancies

• Have newborns with a longer period of maternal dependency

Primates

Characteristics of Primates

Reproductive rate

• Low reproductive rates combined with habitat loss has resulted in a large

number of endangered primate species.

Copyright © McGraw-Hill Education

PrimatesCopyright © McGraw-Hill Education

Primate Groups

• Primates are a large, diverse group of over 200 species.

• Most are arboreal, or tree-dwelling

• Primates are classified into two subgroups:

• Strepsirrhines: more primitive, “wet-nosed” primates

• Haplorhines: “dry-nosed” primates, include the anthropoids, large-

brained, diurnal monkeys and hominoids.

Visualizing Primates

Animation

FPO

Add link to animation from page 454 (Figure 3) here.

PrimatesCopyright © McGraw-Hill Education

PrimatesCopyright © McGraw-Hill Education

Strepsirrhines

• Identifiable by their large eyes and ears

• Only primates that rely predominantly on smell for hunting/ social interaction

• Primarily found in Madagascar, some in SE Asia and Africa

Characteristics of Strepsirrhines

Interactive Table

FPO

Add link to interactive table from page 455 (Table 1) here.

PrimatesCopyright © McGraw-Hill Education

PrimatesCopyright © McGraw-Hill Education

Haplorhines

• Include tarsiers, monkeys, and apes

• Tarsiers are found only in Borneo and the Philippines – small, nocturnal,

arboreal

• The anthropoids (monkeys and apes) are split into the New World monkeys,

Old World monkeys, and apes.

Haplorhines

New World monkeys

• The New World monkeys refer to the species found in the tropical

forests of Mexico, Central America, and South America.

• Diurnal, arboreal, live together in social bands

• Distinguished by their prehensile tails – a strong, fifth limb-like

structure used for grasping and balance.

PrimatesCopyright © McGraw-Hill Education

PrimatesCopyright © McGraw-Hill Education

Haplorhines

Old World monkeys

• Old World monkeys live throughout Asia and Africa – forests, mountains,

grasslands

• Diurnal and live in social groups

• None have prehensile tails, and some have no tails.

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Haplorhines

Apes

• Apes have longer arms than legs, barrel-shaped chests, no tails, and flexible

wrists.

• Highly social and have complex vocalizations

• Classified into two subcategories: the lesser apes and the great apes

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Haplorhines

Apes

• Lesser apes: Arboreal, move through the trees

using a hand-over-hand swinging motion called

brachiation.

• Great apes: Largest primates, include gorillas,

orangutans, chimpanzees, humans

• Humans are in a separate subcategory of

hominids called hominins – humanlike primates

more closely related to modern humans than to

the rest of the great apes.

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Primate Evolution

Arboreal advantage

• Primates may have evolved from

ground-dwelling animals that

searched for food in the branches of

forest shrubbery.

• Rise of flowering plants could have

provided a new niche for primates

to exploit.

PrimatesCopyright © McGraw-Hill Education

Primate Evolution

Primate ancestors

• Genetic data suggests the first primates lived ~85 mya.

• The earliest primate fossils appear in the fossil record ~60 mya, at the

beginning of the Eocene epoch.

• Early primates were small, lemur-like, nocturnal animals that ate fruits and

insects.

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Primate Evolution

Diverging primates

• 50 mya, lemur-like primates were widespread and existed on all continents

except Australia and Antarctica.

• Around this time, arthropods began to diverge, and were widespread by 30-

35 mya.

PrimatesCopyright © McGraw-Hill Education

Primate Evolution

Displacement

• By the end of the Eocene, many early strepsirrhines became extinct.

• Extinction could have been driven by geological/climatological factors, or by

diversion of anthropoids

• Larger anthropoids with bigger brains could have outcompeted

strepsirrhines.

• This is supported by modern observations where strepsirrhines and

anthropoid habitats overlap.

PrimatesCopyright © McGraw-Hill Education

Review

Essential Questions

• What are the characteristics of primates?

• What are the similarities and differences between major primate groups?

• How can the evolution of primates be traced?

Vocabulary

• opposable first digit

• binocular vision

• diurnal

• nocturnal

• arboreal

• anthropoid

• prehensile tail

• hominin