Transcript Primate Studies 2

Primate Studies 2
Taxonomy
Development
There are approximately 190 sepcies of
non-human primates.
prosimians
monkeys
apes
Primate Development and Taxonomy
Origins—where did primates
come from?
A proliferation of mammalian forms from the
end of the Cretaceous period (ca. 65 Mya)
opened new econiches
The major evolutionary trends that distinguish
primates and their generalized mammalian
form came as a result of adaptation to
arboreal living.
Trees: The Primate Adaptive Niche
Other placental mammals
tended to adapt to grasslands,
marine or other environments
Adaptive niche for primates was the trees
Provided many challenges and opportunities
– Depth perception and binocular vision crucial
– Climbing using prehensile hands and feet instead of claws
– Varied diet led to omnivorous adaptation and generalized
dentition
– Longer life span, increased intelligence and more
elaborate social system needed to cope
Arboreal vs. visual
predation vs. mixed diet
Tarsier
Tarsier
Matt Cartmill criticized the arboreal hypothesis
• He proposes a visual predation hypothesis
• First adaptation was to the lower tier of the forest canopy and the
brush, as "stealthy" eaters of insects who quickly “pounce” from
branch onto insect
• Needed foward-facing eyes and partially grasping hands to do so
Visual predation and the arboreal hypothesis
are not mutually exclusive explanations
The visual predation traits developed as the
primates moved to the trees.
Whatever the case, we know they eventually
moved to the trees.
Weakness?
Prosimians, considered to be closer to the
ancestral form of all primates, exhibit
lower reliance on visual information for
locomotion and predation
Mixed Diet Hypothesis
Prosimians emphasize olfactory and auditory
cues in the pursuit of prey.
Indriidae
Robert Sussman proposed the Mixed Diet
Hypothesis
• Increased exploitation of angiosperms
(flowering plants) selected for modern
primate characteristics.
• Enhanced visual acuity, color vision, and
characteristics amenable to exploiting
terminal branch resources all allowed for
efficient acquisition of resources.
• The emergence of flowering plants in the
Paleocene roughly coincides with the
emergence of the earliest primate ancestors.
Tupaiidae
Tree shrews
Primate Classification
Linnean taxonomic system
Highest level: order Primates
Next level down:
Prosimii (lemurs, lorises, and usually the tarsiers)
Anthropodiea (monkeys, apes and humans).
At successively lower levels (infraorder,
superfamily, family, genus, and species), see
chart
Suborder
Infraorder
Superfamily
Lemuroidea
Lemuriformes
Prosimii 2
(prosimians)
Subfamily
Lorisoidea
Tarsioidea 3
Common Names
Madagascar and
Comoro Islands
indris, avahis, and
sifakas
Madagascar
aye-ayes
Madagascar
Lorisinae
lorises, pottos, and
angwantibos
lorises--India and
Southeast Asia;
others--Africa
Galaginae
galagos (or bush
babies)
sub-Saharan Africa
and Zanzibar
tarsiers
Philippines, Borneo,
Celebes Islands, and
Sumatra
marmosets and
tamarins
Panama and north
and eastern South
America
squirrel, howler, owl,
and spider monkeys;
capuchins; etc
Central America and
north and eastern
South America
guenons, baboons,
macaques, etc.
guenons and
baboons--Africa;
macaques--northwest
Africa, Gibraltar, South
and East Asia
colobuses, langurs,
and proboscis
monkeys
colobuses-- Central
Africa; langurs-- India
and Southeast Asia;
proboscis monkeys-Borneo
gibbons and siamangs
Southeast Asia
Daubentoniidae
Lorisidae
Tarsiidae
Platyrrhini
(New World
monkeys)
Callithricidae
Ceboidea
Cebidae 4
Cercopithecinae
Cercopithecoide
a
(Old World
monkeys)
Anthropoidea
(anthropoids)
Cercopithecidae
Colobinae
Catarrhini
(Old World
monkeys, apes
and humans)
Hylobatidae
Hominoidea
(apes and
humans)
Pongidae
Panidae
Hominidae
Distribution
ring-tailed, ruffed, and
mouse lemurs, etc.
Lemuridae
(true lemurs)
Indriidae
Daubentoniodea
Lorisiformes
Family
orangutans
5
Sumatra and Borneo
chimpanzees,
bonobos, and gorillas
Central and West
Africa
humans
throughout the world
Primate taxonomy based on morphology:
Criticisms
Tarsiers have both prosimian and anthropoid traits and are
biochemically closer to anthropoids.
Hominoids have traditionally included four species in one family
(the Pogidae-gorillas, chimpanzees, bonobos, and orangutans),
as separate from humans (Hominidae) but seem actually to
have both Asian and African branches.
DNA studies have complicated it further, indicating the closeness
of humans and chimpanzees, with gorillas further away. Some
have even suggested that chimps be labelled Homo
troglodytes.
The point is that the taxonomic system is in flux as new data are
utilized. Most experts still use the traditional system.
Prosimians
• The most primitive of the true primates: lemurs and
lorises
• more reliance on olfaction (smell), with moist, fleshy
pad (rhinarium) at the end of the nose and a long
snout
• mark territories with scent (other primates don't)
• somewhat more laterally placed eyes
• differences in reproductive physiology, shorter
gestation and maturation
• the dental comb, formed by forward-projecting lower
incisors and canines, used in grooming and feeding
Dental
comb
Rhinarium
Lemurs
Found only on the Island of Madagascar and
adjacent island off east Africa, they are
extremely diversified into a range of niches-22
surviving species
Size range from the mouse lemur with head and
trunk length of only five inches to the indri a bit
over two feet long.
Larger lemurs are diurnal and eat a variety of
leaves, fruits, buds, bark and shoots; smaller
are nocturnal and insectivorous
Considerable variation in behavior. Some are
arboreal while others are terrestrial.
Socially several species live in groups of 10-20
animals. Some like the indri live in
monogamous family units. Some nocturnal
forms are solitary.
Lorises
Similar in appearance to lemurs, but survived in continental areas
of India, Sri Lanka, Southeast Asia, and Africa.
Five species, largely nocturnal. Galagos are included as well, with
6-9 additional species.
They are slow, cautious, quadrupedal climbers who can suspend
themselves on hind limbs leaving hands for feeding.
Some are entirely insect eaters while others supplement the diet
with leaves, fruits, and slugs. Food foraging is often solitary.
• Lemurs and lorises are at the same adaptive level. Good
grasping and climbing abilities and well-developed visual
ability, though stereoscopic ability not as developed as it is in
anthropoids.
• Most have a claw-grooming claw on second toe.
• Life span is about 14 years for loris and 19 years or lemurs.
Tarsiers
Three species restrcted to island areas in SE Asia. They live in a
wide range of habitats.
They are nocturnal insectivores, and leap onto prey from
branches and shrubs.
They form pair bonds, with the social unit being the mated pair
and offspring.
Unlike loris and lemurs, they have no rhinarium and they have a
eye sockets enclosed by bone t back and sides.
This is more like an anthropoid. Eyes are enormous, compared
to the rest of the body.
They have taxonomically mixed traits
.
Anthropoids
The traits that distinguish anthropoids from prosimians include:
• generally larger body size
• larger brain (in absolute terms as well as relative to body
weight)
• more rounded skull
• complete rotation of eyes to front of face with full binocular
vision
• bony plate at back of eye orbit
• no rhinarium (less reliance on smell)
• increased parental care
• increased gestation and maturation periods
• more mutual grooming
Monkeys
• The monkeys represent 70% (about 130 species) of
all primates and are the most varied.
• New species are still being discovered and there are
debates about taxonomy.
• Two main groups, New and Old World monkeys,
have several million years of distinct evolutionary
history.
• They had a strikingly parallel evolution with similar
selective pressures in tropical arboreal
environments
• Some say they evolved independently while others
claim a common ancestor sometime before 50
million years ago.
New World
Monkey
Old World
Monkey
New World Monkeys
• A wide range of size, diet and ecological adaptation. Marmosets
and tamarins weigh about 12 ounces at the small end, and
howlers weigh up to 20 or so pounds.
• Almost exclusively arboreal, some never coming to the ground
• All but one species in diurnal, living in most forested areas of
southern Mexico into Central and South America.
• Major characteristic is the shape of the nose.
• New World have broad, widely flaring noses with outwardfacing nostrils—sometimes called platyrrhine or flat-nosed
Marmoset
Tamarin
Two families: Callitrichidae and Cebidae
• Callitrichidae are the most primitive monkeys: marmosets and
tamarins as examples
– with claws instead of nails
– giving birth to twins instead of one offspring
– usually insectivorous
– quadrupedal locomotion with claws used in tree climbing, but
with leaping too
– males heavily involved in infant care (the only primates to do
so)
– family groups of mated pair and offspring.
• Cebids--at least 30 species ranging from foot-long squirrel
monkey to the howler (2 ft.).
– diet varies, with most eating fruit and leaves with some
insects
– most are quadrupedal, but some can brachiate a bit
– powerful prehensile tails used for moving and for suspending
while eating
– socially live in small mixed-sex groups, but some live as
monogamous pairs with offspring
Old World Monkeys
Much more variety in morphology and behavior
than New World monkeys
They have downward facing noses and are called
catarrhine
Only one recognized family: Cercopithecidae
Two subfamilies: cercopithecines and colobines
subfamily:
species:
Cercopithecinae
baboons
guenons
patas
monkeys
macaques
Colobinae
colobus
langurs
proboscis
monkeys
Old World Monkey Traits
• The most widely distributed of non-human primates,
ranging from tropical forests to semi-arid deserts
and seasonal snow-covered areas in northern Japan.
• Most are quadrupedal and primarily arboreal, but
some (like baboons) are well adapted to the ground
• Most hold their upper bodies erect for long periods
of time while feeding, sleeping, and groomingassociated with it is hard skin on the buttocks called
ischial callosities-serve as sitting pads
• Most have a great deal of manual dexterity
Most have tails that are used in both balance and
communication.
Ischial callosities
(gelada baboons)
Old World Monkey Traits
• Locomoton varies from arboreal to terrestrial quadrupedalism
to semibrachiation to acrobatic leaping.
• Sexual dimorphism is typical of land species like baboons, with
male weight (80 lbs.) often twice that of females
• Females often exhibit pronounced cyclical changes of the
external genitalia with swelling and redness during estrus, a
hormonally initiated period of sexual receptivity correlated with
ovulation.
• Several types of social groups:
Colobines tend to live in small gropups with only one or two
adult males, whereas cercopithecines live in large groups with
several adults of both sexes and offspring of all ages.
Female hamadryas
baboon in estrus
(note the sexual skin)
Hominoids
• Superfamily Hominoidea includes placed in the family
• Hylobatidae: gibbons and siamangs (the "lesser" apes)
• Pongidae: orangutans, gorillas, chimpanzees and bonobos (the
“great” apes
• Hominidae: humans
Locations of Ape Habitats
Hominoid Traits
Apes and humans differ from monkeys in many ways
including:
• generally larger body size, except in gibbons and
siamangs
• absence of tail
• shortened trunk (lumbar area relatively shorter and
more stable)
• differences in position and musculature of shoulder
joint (adapted for suspensory locomotion)
• more complex behavior
• more complex brain and cognitive abilities
• lengthened period of infant development and
dependency
Gibbons and Siamangs
• Eight gibbon species are found in tropical areas of SE Asia.
• Small, weighing 13 pounds for gibbon and 25 for saimang.
• Extremely good brachiators due to very long arms,
permanently curved fingers and powerful shoulders.
• Mostly a fuit diet, supplemented by leaves, insects.
• Social unit is monogamous pair and offspring.
• Both males and females are highly territorial.
Siamang
Gibbon
Orangutans
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Represented by two subspecies in heavily forested areas of
Indonesian islands of Borneo and Sumatra.
They face extinction due to poaching and diminution of their habitat.
The are slow, cautious climbers who use all four limbs for locomotion.
Almost completely arboreal, but do travel quadrupedally on ground for
short distances.
Very large animal that may weigh 200 lbs. for males, 100 for females.
They are frugivorous, but supplement with leaves, insects and some
meat.
Gorillas
• The largest of all living primates,
now confined largely to forested
regions of central Africa.
• Two varieties: lowland and highland.
• They exhibit marked sexual
dimorphism with males up to 400
pounds and females at 200 pounds.
• Weight makes them primarily
terrestrial, and semi-quadrupedal
knuckle walkers.
• Family groups consist of one or
more large silverback (due to white
hair patch across back) males, a few
females and subadult offspring.
• They are not the King Kong
stereotype, but are gentle, shy
vegetarians.
• Males will display when provoked,
and may attack to defend their
group.
• Probably only 40,000 lowland and
620 highland left due to poaching
and habitat problems.
Chimps
• Best known of the non-human primates.
• Structurally similar to gorillas, but
ecological adaptations differ.
• They are mostly terrestrial knuckle walkers,
but also can brachiate in trees.
• May walk bipedally for sort distances.
• Chimps are highly excitable, active and
noisy.
• Males are about 100 pounds and females
around 80.
• They tend to live in flexible communities of
as many as 50 individuals.
• They are very territorial.
• They are omnivouous, and even hunt
communally to kill small mammals and even
other chimps.
Bonobos
• Found only in limited area of Zaire
River, they weren't recognized as
separate from chimps until the 1920s.
• Least studied of the great apes.
• They are "pygmy" chimps due to
small size, but some claim this is not
warranted in that size can be as large
as most chimps.
• They have a more linear build. They
are more arboreal than chimps, but
less excitable and aggressive.
• Little physical violence.
• We know little about them though
recent work by de Waal is intriguing.
Chimpanzees & Bonobos
Our closest relatives
Why are they so different?
Genetics
• Karyotyping of apes has not demonstrated the evolutionary
sequence
• Suggests that humans and chimps share a more recent
ancestry after splitting from gorillas.
• Despite 99% similarity at the level of DNA sequence between
humans and our nearest relative, chimpanzees, the locations of
DNA swapping between chromosomes, known as
recombination hotspots, are nearly entirely different.
• More controlled study may clarify.
Human
HAS=Human, PPA=Chimpanzee PPY=orangutan GGO=gorilla