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
Primates Classification
A 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.
Binocular Vision in Primates
Primate Limbs
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A tendency towards erect posture.
 Hands and feet possess grasping ability.
 Features of the hands and feet:
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5 digits on hand and feet
Opposable thumb
partially opposable great toe
Tactile pads enriched with sensory nerve fibers at
the ends of digits
Dental Formulae
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
(olfaction).
 The brain has expanded in size and become
increasingly complex.
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 (tree) 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.
– Some primates kill and eat small mammals.
– Some primates are dietary specialists on leaves.
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Most have four types of teeth: incisors,
canines, premolars and molars.
Primate Locomotion
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Most primates are quadrupedal, using all
four limbs in their locomotion.
 Arm swinging is found among the apes.
– Siamangs of southeast Asia use this exclusively.
– Monkeys that use a combination of leaping and
arm swinging are termed semibrachiators.
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Prehensile tails, found only among the new
world monkeys, are used as an aid to
locomotion.
Human and Chimpanzee
Chromosomes
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Human chromosome
2 has banding patterns
that correspond to
chimpanzee
chromosomes 12 and
13.
This suggests that
human chromosome 2
resulted from the fusion
of ape chromosomes
during the course of
hominid evolution.
Revised Partial
Classification of the Primates.
Alternative Classifications of
Great Apes and Humans
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).
Geographical
Distribution of Modern Lemurs
Lorises
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Found in tropical forests and woodlands of
India, Sri Lanka, southeast Asia, and Africa.
 Characteristics:
– Use a climbing form of 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.
Characteristics:
– 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.
Geographical Distribution of
Modern Old World Monkeys.
Hominoids (Apes and Humans)
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Characteristics distinguishing hominoids from
monkeys:
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Larger body size
Absence of a tail
Shortened trunk
More complex behavior
More complex brain and enhanced cognitive
abilities
– 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.
 Large
– males = 200 pounds
– females = 100 pounds
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Pronounced sexual dimorphism.
 Solitary
 Principally frugivorous (feed-eating).
Geographical Distribution
of Modern African Apes
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
 Most primates live in tropical rain forests that
are being destroyed for their natural
resources.
 Some primates are hunted for their meat.
 Others are victims of the exotic pet trade.
Tropical Rain Forests of the
World (Before Recent Massive
Destruction)
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.
Conservation Efforts
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Many developing countries have designated
areas as national parks or reserves.
 Private organizations, such as the rain forest
information center in Ecuador, have
set up biological reserves.
 Through conservation and educational
programs, primate species may have a
chance at escaping extinction.