Transcript Chapter 5 Overview of Living Primates

Chapter 6
An Overview of the Primates
Chapter Outline
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Characteristics of Primates
Primate Adaptations
Primate Classification
Survey of the Living Primates
Endangered Primates
Primates As Mammals
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There are approximately 190 species of
nonhuman primates
Primates belong to:
 Vertebrate class - Mammalia
 Subgroup of placental mammals.
Characteristics of Primates
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Fur (body hair)
Long gestation followed by live birth
Homeothermy, the ability to maintain a
constant body temperature
Increased brain size
Capacity for learning and behavioral
flexibility.
Primate Limbs
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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
Primate Senses and the
Brain
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Color vision is a characteristic of all diurnal
primates, nocturnal primates lack color vision.
Depth perception is made possible by eyes
positioned forward on the front of the face.
Decreased reliance on the sense of smell.
The brain has expanded in size and become
increasingly complex.
Binocular Vision in Primates
Primate Maturation
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Longer periods of gestation
Reduced numbers of offspring
Delayed maturation
Extension of the entire life span.
Primate Learning and
Behavior
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Have a greater dependence on flexible,
learned behavior.
Tend to live in social groups.
Males are permanent members of many
primate social groups, a situation unusual
among mammals.
Arboreal Hypothesis
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Arboreal living was the most important
factor in the evolution of primates.
Prehensile hand is adapted to climbing in
the trees.
A variety of foods led to the omnivorous
diet and generalized dentition.
Visual Predation Hypothesis
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Primates may have first adapted to
shrubby forest undergrowth and the
lowest tiers of the forest canopy.
Forward facing eyes enabled primates to
judge distance when grabbing for insects.
Flowering plants may have influenced
primate evolution.
Primate Habitats
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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
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Generally omnivorous, reflected in their
generalized dentition.
Most eat a combination of fruits, leaves,
and insects.
Most have four types of teeth: incisors,
canines, premolars and molars.
Primate Locomotion
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Most are quadrupedal, using all four limbs
in their locomotion.
Arm swinging is found among the apes.
Prehensile tails, found only among the
new world monkeys, are used as an aid to
locomotion.
Alternative Classifications of
Great Apes and Humans
Revised classification
(more evolutionarily
accurate)
Great apes—separate
family (Pongidae)
Orangutan
Gorilla
Chimpanzee
Bonobo
Humans—separate family
(Hominidae)
Traditional
classification
One family only
(Hominidae), including all
large-bodied apes and
humans; more detailed
distinctions made at lower
taxonomic categories
Prosimians
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The most primitive of the primates.
Characteristics:
 Reliance on olfaction
 Laterally placed eyes
 Shorter gestation and maturation
periods
 Dental specialization called the "dental
comb”
Lemurs
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Found on the island of Madagascar and other
islands off the coast of Africa.
Extinct elsewhere in the world.
Characteristics:
 Larger lemurs are diurnal and eat vegetable
foods: fruit, leaves, buds, and bark.
 Smaller lemurs are nocturnal and
insectivorous (insect -feeding).
Lorises
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Found in tropical forests and woodlands of
India, Sri Lanka, southeast Asia, and Africa.
Characteristics:
 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.
Tarsiers
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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)
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Common traits:
 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
 Fused mandible
Monkeys
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Represent about 70% 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
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Almost exclusively arboreal.
Found in southern Mexico and central and
south America.
Two families: Callitrichidae and Cebid
New World Monkeys:
Callitrichidae
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Give birth to twins
Live in families composed of a mated pair
or a female and two adult males, plus the
offspring.
Males are involved with infant care.
New World Monkeys: Cebid
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Possess prehensile tails.
Most live in groups of both sexes and all
ages.
Others live as monogamous pairs with
subadult offspring.
Old World Monkeys
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Habitats range from tropical forests to semiarid
desert to snow-covered areas in Japan and
china.
Characteristics:
 Most quadrupedal and arboreal
 All belong to the Cercopithecidae family.
 Divided into subfamilies, the cercopithecines
and the colobines.
Hominoids
(Apes and Humans)
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Characteristics distinguishing hominoids from
monkeys:
 Larger body size
 Absence of a tail
 Shortened trunk
 More complex behavior
 More complex brain
 Increased period of infant development and
dependency
Gibbons and Siamangs
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Found in the tropical areas of southeast Asia.
Adaptations for brachiation may be related to
feeding while hanging from branches.
Diet is largely fruit with leaves, flowers, and
insects.
Basic social unit is a monogamous pair and
their offspring.
Males and females delineate their territories
with whoops and “songs”.
Orangutans (Pogo pygmaeus)
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Found in heavily forested areas of Borneo
and Sumatra.
Almost completely arboreal.
males = 200 lbs, females = 100 lbs
Pronounced sexual dimorphism.
Solitary
Principally frugivorous (feed-eating).
Gorillas (Gorilla Gorilla)
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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.
Chimpanzees
(Pan Troglodytes)
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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)
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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)
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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)
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Flexible limbs and grasping hands
Omnivorous diet
Cognitive abilities are the result of
dramatic increases in brain size.
Bipedal
Endangered Primates
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Over half of all living primates are
endangered, many face immediate
extinction.
Three reasons:
 Habitat destruction
 Hunting for food
 Live capture for export or local trade
Hunting of Primates
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In West Africa the most serious problem is
hunting to feed the growing human
population.
Estimated that thousands of primates, are
killed and sold for meat every year.
Primates are also killed for commercial
products.
Quick Quiz
1. Which of the following is NOT a primate
characteristic?
a) stereoscopic vision
b) highly developed sense of smell
c) orthograde or upright posture
d) prehensility
Answer: b
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A highly developed sense of smell is
NOT a primate characteristic.
2. Binocular vision in primates contributes
to
a) color vision.
b) lateral vision.
c) panoramic vision.
d) stereoscopic vision.
Answer: d
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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.
Answer: c
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Tarsiers do not live in groups of 10-12
individuals.
4. The _________________ is the
largest living primate.
Answer: gorilla
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The gorilla is the largest living primate.
5. Which of the following is NOT a reason
that nonhuman primates are
endangered?
a) habitat destruction for logging, mining,
and agricultural land
b) hunting for food
c) live capture for either the exotic pet
trade or biomedical research
d) establishment of biological reserves
Answer: d
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The establishment of biological
reserves is NOT a reason that nonhuman
primates are endangered.