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lemurs, lorises, tarsiers, monkeys, and apes
Primates Evolutionary Factors Changes in diet, reliance on vision with Forward-facing eyes (facilitate binocular vision, grasping hands and feet came about with
Rise of angiosperms (flowering plants)
Most live in tropical or semitropical areas of the new and old worlds.
Most are arboreal, living in forest or woodland habitats.
No nonhuman primate is adapted to a fully terrestrial environment; all spend some time in the trees.
Primate Diet and Teeth
Incisors for biting and cutting; premolars and molars for chewing and grinding
- Dental formula
- ¤Old World anthropoids have two incisors, one canine, two premolars, and three molars on each side in
- both upper and lower jaws: 220.127.116.11 (32 teeth total)
A tendency towards erect posture.
Hands and feet possess grasping ability.
- Features of the hands and feet:
- ¤5 digits on hand and feet
- ¤Opposable thumb
- ¤Partially opposable great toe
- ¤Tactile pads enriched with sensory nerve fibers at the ends of digits
Limbs and Evolution
A horse’s front foot, homologous with a human hand, has undergone reduction from 5 digits to one.
While raccoons are capable of considerable manual dexterity and can readily pick up small objects with one hand, they have no opposable thumb.
Many monkeys are able to grasp objects with an opposable thumb, while others have very reduced thumbs.
Quadrupedal, walk on all fours
Vertical clinging and leaping
Anatomy, Limb Proportions and Locomotor Patterns
Skeleton of a brachiator (gibbon).
Knuckle walking primate
Color vision is a characteristic of diurnal primates.
Nocturnal primates lack color vision.
Depth perception is made possible by eyes positioned forward on the front of the face.
Primates have a decreased reliance on the sense of smell.
The condition whereby visual images are superimposed on one another.
- This provides for depth perception, or the perception of the external environment in three
Stereoscopic vision is partly a function of structures in the brain.
Vision characterized by overlapping visual fields provided for by forward-facing eyes.
Binocular vision is essential to depth perception.
Two halves of the cerebrum that are connected by a dense mass of fibers.
The cerebrum is the large rounded outer portion of the brain.
The most primitive of the primates.
Lemurs and Lorises Characteristics:
- ¤Reliance on olfaction
- ¤Laterally placed eyes
- ¤Shorter gestation and maturation
- ¤Dental specialization called the "dental comb”
The moist, fleshy pad at the end of the nose seen in most mammals.
The rhinarium enhances an animal’s ability to smell.
Found on the island of Madagascar and other islands off the coast of Africa.
Extinct elsewhere in the world.
- ¤Larger lemurs are diurnal and eat vegetable foods: fruit, leaves, buds, and bark.
- ¤Smaller lemurs are nocturnal and insectivorous (insect -feeding).
Found in tropical forests and woodlands of India, Sri Lanka, southeast Asia, and Africa.
- ¤Use a climbing quadrupedalism.
- ¤Some are insectivorous; others supplement their diet with fruit, leaves, gums, and slugs.
Females frequently form associations for foraging or in sharing the same sleeping nest
Small nocturnal primates found on the islands of southeast Asia.
Eat insects and small vertebrates which they catch by leaping from branches.
Basic social pattern appears to be a family unit consisting of a mated pair and their offspring.
Anthropoids (Monkeys, Apes and Humans)
¤Larger brain and body size
¤Reduced reliance on the sense of smell
¤Greater degree of color vision
¤Bony plate at the back of the eye socket
¤Different female reproductive anatomy
¤Longer gestation and maturation periods
Represent about 85% of all primate species.
Divided into two groups separated by geography and several million years of evolutionary history:
¤ New World monkeys
¤ Old World monkeys
New World Monkeys
70 species almost exclusively arboreal.
Found in southern Mexico and Central and South America.
Two families: Callitrichidae and Cebid
Old World Monkeys
Habitats range from tropical forests to semiarid desert to snow-covered areas in Japan and china.
- ¤Most quadrupedal and arboreal
- ¤All belong to the Cercopithecidae family.
- ¤Divided intosubfamilies, the cercopithecines and the colobines.
The subfamily of Old World monkeys that includes baboons, macaques, and guenons.
Omnivorous, cheek pouches, majority found in Africa
The subfamily of Old World monkeys that includes the African colobus monkeys and Asian langurs.
Differences in physical characteristics between males and females of the same species.
For example, humans are slightly sexually dimorphic for body size, with males being taller, on average, than females of the same population.
Hominoids (Apes and Humans)
Characteristics that distinguishing hominoids from monkeys:
¤Larger body size
¤Absence of a tail
¤More complex behavior
¤More complex brain
¤Increased period of infant development
Orangutans (Pogo pygmaeus)
Found in heavily forested areas of Borneo and Sumatra.
Almost completely arboreal.
males = 200 lbs; females = 100 lbs
Pronounced sexual dimorphism.
Principally frugivorous (fruit-eating).
Largest of the living primates.
Confined to forested regions of central Africa.
Males can weigh up to 400 pounds, females 200 pounds.
Primarily terrestrial, using a posture called “knuckle –walking”.
Groups consist of one large silverback male, a few adult females, and their subadult offspring.
Confined to forested areas of western and eastern equatorial Africa
Found in equatorial Africa.
Anatomically similar to gorillas particularly in limb proportions and upper-body shape.
Locomotion includes knuckle-walking on the ground and brachiation in the trees.
Eat a variety of plant and animal foods.
Large communities of as many as 50 individuals.
Bonobos (Pan paniscus)
Only found in an area south of the Zaire River.
Population is believed to only number a few thousand individuals.
Exploit the same foods as chimps, including occasional small mammals.
Male-female bonds constitute the societal core.
Sexuality includes frequent copulations throughout the female's estrous cycle.
Humans (Homo sapiens)
The only living species in the family Hominidae.
Human teeth are typical primate teeth.
Dependence on vision for orientation to the world
Humans (Homo sapiens)
Flexible limbs and grasping hands
Cognitive abilities are the result of dramatic increases in brain size.
Mental capacity; ability to learn, reason, or comprehend and interpret information, facts, relationships, and meanings.
The capacity to solve problems, whether through the application of previously acquired knowledge or through insight.
- ¤Habitat destruction
- ¤Hunting for food
- ¤Live capture for export or local trade
Over half of all living primates are endangered, many face immediate extinction.
Why Primates Matters
Living nonhuman primates represent a lineage that goes back approximately 60 million years.
- They can provide us with information about how evolutionary processes have produced the diversity
- we see in our own lineage today.
- We can identify genetic causes for certain conditions (such as AIDS) that humans are
- susceptible to but chimpanzees are able to resist.
Which of the following is NOT a primate characteristic?
sense of smell
c)orthograde or upright posture
A highly developed sense of smell is NOT a primate characteristic.
Binocular vision in primates contributes to
Binocular vision in primates contributes to stereoscopic vision
3.Which of the following is NOT true of tarsiers?
a)They are nocturnal.
b)They are insectivorous.
c)They live in groups of 10-12 individuals.
d)They can rotate their heads almost 180 degrees.
Tarsiers do not live in groups of 10-12 individuals.