Chapter 6: Survey of Living Primates

members of the mammalian order Primates which includes lemurs, lorises, tarsiers, monkeys, apes, and humans
members of the primate infraorder Anthropoidea which includes monkeys, apes, and humans.
Evolution is not a
goal directed process
Humans represent the finals stages of evolutionary lineage. T/F
False, the only creatures who do have already become extinct
List of primate evolutionary trends- including distinctive (primitive and derived) anatomical, behavioral, and or ecological characteristics or features of primates. Start with limbs and locomotion.
A. Limbs and Locomotion
1. A tendency toward an erect posture (especially in the upper body) (Derived Trait) also includes sitting, standing, and bipedal walking
2. A flexible, generalized limb structure, which allows most primates to practice various loco motor behaviors. Primates have a series of hip and shoulder morphology that provides them with a wide rand of limb movement and function. Thus, unlike horses, primates are not restricted to one form of movement like many other mammals.
3. Prehensile hands (and some times feet) (capable of grasping (Derived trait) Primates can use there hands and feel to manipulate objects.
a. Retention of five digits on the hands and feet, some species don’t even have fingers or thumbs.
b. An opposite thumb and, in most species, a divergent and partially opposable big toe. Thumb can come in contact with other fingers.
c. Nails instead of claws
d. Tactile pads enriched with sensory nerve fibers at the ends of digits.the sense of touch is enhanced
the form, shape, and size of anatomical structures, can also refer to the entire organism.
Talk about the Diet and Teeth patters of primates:
1. There is a lack of dietary specialization in primates. They tend to eat a wide assortment of food items. In general they are omnivorous meaning that they have a diet consisting of many food types, such as plant materials, meat, and insects.
2. A generalized detentition: Primates teeth are not specialized for processing only one type of food, a characteristic related to a general lack of dietary specialization.
C. Senses and the brain: Primates (Diurnal ones in particular; meaning active during the day) rely heavily on vision and less on olfaction (sense of smell) especially when compared with other mammals. This emphasis is reflected in evolutionary changes in the skull, eyes, and brain.
1. color vision: this is a characteristic of all Old World diurnal primates. Some new world species don’t have the full range of color vision, and nocturnal primates lack color vision.
2. Depth Perception: Primates have stereoscopic vision or the ability to perceive objects in three dimensions. This is made possible through a variety of mechanisms, including:
a. Eyes placed toward the front of the face and not to the side. This position provides for overlapping visual fields, or binocular vision: vision characterized by overlapping visual fields provided by forward facing eyes. Binocular vision is essential to depth perception
b. Visual information from each eye transmitted to visual centers in both hemispheres of the brain. see figure 6-2 on page 146 or look at picture on phone.
C. Visual information organized into three dimensional images by specialized structures in the brain itself.
3. Decreased reliance on olfaction: This trend is expressed as an overall reduction in the size of olfactory structures in the brain. It leads to an increased reliance on vision.
4. Expansion and increased complexity of the brain. Most evident in the neocortex (portions of the bran where information from different sensory modalities is combined) Expansion in regions involved with sensory and motor function of the hand is seen in many primate species, especial humans.
D. Maturation, learning, and behavoir:
1. A more efficient means of fetal nourishment, longer periods of gestation, reduced number of offspring (with single births being the norm) delayed maturation, and extension of the entire life span.
2. A greater dependence on flexible, learned behavior. Apes spend longer amounts with their parents during the maturation process, and are more dependent on learned behavior.
3. The tendency to live in social groups and the permanent association of adult males with the group.
4. The tendency toward diurnal activity patterns. Most are active during the day.
Old World Prmates
The Old World monkeys are native to Africa and Asia today, inhabiting a range of environments from tropical rain forest to savanna, shrubland and mountainous terrain, and are also known from Europe in the fossil record. However, a (possibly introduced) free-roaming group of monkeys still survives in Gibraltar (Europe) to this day. Old World monkeys include many of the most familiar species of nonhuman primates, such as baboons and macaques.
New World Primates
the five families of primates that are found in Central and South America and portions of Mexico: Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae. The five families are ranked together as the Platyrrhini parvorder and the Ceboidea superfamily, which are essentially synonymous since Ceboidea is the only living platyrrhine superfamily.[3] They differ from other groupings of monkeys and primates, such as the Old World monkeys and the apes.
active during the day
sense of smell
active during the night
Stereoscopic vision
The condition whereby visual images are superimposed. They get smaller and bigger the farther away they are to your face. This provides for depth perception or viewing the environment in three dimensions.
Binocular vision
Vision characterized by overlapping visual fields provided by forward facing eyes. This vision is essential to depth perception.
The two hales of the cerebrum that are connected by a dense mass of fibers.
the more recently evolved portions of the cortex of the brain that are involved with higher mental functions and composed of ares that integrate incoming information from different sensory organs.
sensory modalities
different forms of sensation (e.g, touch, pain, pressure, heat, cold, vision, taste, hearing, smell)
tree living, adapted to life in the trees
Adaptive niche
An organism’s entire way of life: where it lives, what it eats, how it gets food, how it avoids predators, and so on.
Describe the arboreal environment on primate evolution
Originally, primates were arboreal or that they were tree living animals. While many other animals were arboreal as well, they tended to go looking for food on the ground level. Primate however, began implementing the trees themselves in order to find food. Over time, this led toward omnivory, which eventually evolved into general primate characteristics we see today. This involved things such as reliance on vision, grasping of the feet and hands, and other adaptions to the arboreal lifestyle.
compare and contrast the arboreal hypothesis with the visual predation hypothesis.
In contrast to the aboreal hypothesis is the visual predation hypothesis. This brings up the point that squirrels are also aboreal, yet they have not evolved into primate like adaptions such as prehensile hands or forward facing eyes. The visual predation hypothesis argues that traits such as forward facing eyes (which facilitate binocular vision), grasping hands and feet, and the presence of nails instead of claws may not have come about solely as adaptive advantages in a purely aboreal setting. Rather they arised from insectivorous predators resembling tarsiers, subject to the same selection pressure for frontal vision as other predatory species. He also uses this hypothesis to account for the specialization of primate hands, which he suggests became adapted for grasping prey, somewhat like the way raptors employ their talons. It also states that since basic primates traits were developed in conjunction with the appearance of flowering plants that provided numerous resources for primates, including nectar, seeds, and fruits, forward facing and grasping hands and feet and of course omnivory and color vision arose to accommodate for this environmental change. Certainly, this type of discrimination was necessary when feeding on small food items such as berries, seeds, and other things.
work out the dental formulas for ancestral mammals, monkeys, apes, and humans
Old world primates are mainly found in
Africa, India, Southeast Asia, and Japan
New World Primates are found mainly in
Mexico, Central America, and parts of South America
Old world monkeys, for example baboons, spend most of the day on the
ground, where trees are sparsely distributed. The same is also true for African Apes (gorillas, chimpanzees, and bonobos)
All primates spend time in
trees, none are adapted to a fully terrestrial lifestyle.
Work out the dental formulas of ancestral mammals, monkeys, apes, and humans
see below
Dental formula for all old world monkeys, apes, and humans
2 incisors, 1 canine, 2 premolars, and 3 molars. over
First is Upper, second is lower
New World monkeys dental formula
Dental formula
Numerical device used to indicate the number of each type of tooth in each side of the upper and lower jaws.
the bumps on the chewing surface of premolars and molars. Primates have low rounded cufs, allow them to chew meat if needed.
Primates have developed a dentition adapted to a varied diet, and the capacity to exploit many foods has contributed to their overall success.
they have a very specialized diet meaning that they
can eat many foods
Almost all primates are _________ meaning that they use all four limbs to support the body during locomotion.
Primates, however, are able to use more than one form of locomotion.
example of quadrupedal primate would be
a savanna baboon
Vertical clinging and leaping
another form of locomotion, and is characteristic of lemurs and tarsiers. It is where they support themselves by vertically grasping onto trunks of trees or other large plants while their knees and ankles are tightly flexed.
arm swinging, a form of locomotion used by some primates. It involves hanging from a branch, and moving by alternately swinging from one arm to the other. Apes and humans are capable of such a locomotion.
found in some new world monkeys such as spider monkeys and muriquis because it is a practice of a combination of leaping with some arm swinging.
Prehensile tail
also spider monkeys, locomotion through a grasping tail
Knuckle walking
found mainly in gorillas and chimpanzees, this is a special form of quadrupedal locomotion because the weight of the upper body is supported on the knuckles and not the palm of the hand. Bent fingers.
The suborder of primates are divided into 2 smaller categories
1. Strepsirhini: lemurs, and lorises
2. Haplorhini: Tarsiers, monkeys, apes, and humans
How does taxonomic classification in primates reflect biological relationships?
At the suborder level for example, lemurs and lorises are distinct as a group from all other primates. This classification makes the biological and evolutionary statement that all the lemurs and lorises are more closely related to one another than they are to any other primates. Likewise, humans, apes, monkeys, and tarsiers are more closely related to one another than they are to lorsies than lemurs. Using a system which groups them based on physical similarities, such as the old system, isn’t fool proof because Some Old and New World monkeys resemble each other anatomically but are not closely related even remotely. It is based, rather, on genes. If you say that lemurs and Lorises are the most primitive of all primates, this only means that they are the most anatomically similar to their earlier mammalian ancestors than are the other primates. (Tarsiers, monkeys, apes and humans)
a type of primate that include lemurs, lorises, bushbabies, and tarsiers, but not simians, e.g. monkeys and apes (including humans). They are considered to have characteristics that are more “primitive” than those of monkeys and apes.[1] Prosimians are the only primates native to Madagascar, but are also found throughout Africa and in Asia. With the exception of tarsiers, all extant prosimians are in the suborder Strepsirrhini. Because simians (including all monkeys and apes) are not included in the prosimian group even though they also descend from the prosimian most recent common ancestor, prosimians are a paraphyletic group and not a clade.
Lemurs and Lorises
Included in the suborder Strephsirhini, and it is the most primitive living primates (meaning most similar to the earliest primates). They have more ancestral characteristics such as more pronounced reliance on olfaction. This is reflected in the presence of a moist, fleshy pad, called a rhinarium at the end of their nose. They are also different from other groups due to their eyes placed more to the side, differences in reproduction physiology, and shorter generations and maturation periods. Lemurs and Lorises also have a unique, derived trait called a dental comb formed by forward projecting lower incisors and canines. These modified teeth are used in both grooming and feeding. They also have a retention of a claw called the grooming claw on their second toe.
Found only on the island Madagascar. They are the only non human primates on Madagascar. They represent a kind of lost world. Can be anywhere from 5 inches, to 2-3 feet. Small lemurs are nocturnal and insectivorous, and the large ones are diurnal and eat a wide variety of foods. Some are arborial but others are more terrestrial. Some arboreal species are quadrupeds and others (ring tail lemurs) are vertical clingers and leapers. Some live in groups, some live in just small families, others are simply solitary.
moist, hairless pad at the end of the nose seen in most mammalian species. The Rhinarium enhances an animal’s ability to smell. Range from the
Primates which somewhat resemble lemurs. They were able to survive in mainland areas being nocturnal. They are found in tropical forest and woodland habitats of India, Asia, and Africa. Included in this are bush babies. Locomotion some species is slow, cautious, climbing form of quadrupedalism. They can hang, and they use their hands to feed. Some other species however, such as the Galago or bush baby, are fast vertical climbers.
Some Insectivorous, others omnivorous
Lorises and Galagos feed alone mainly, but sometimes together.
Known for “infant parking,” leaving young alone.
Good grasping and climbing
well developed visual apparatus.
Vision is not completely stereoscopic, and in diurnal species color vision si not very good as in anthropoids.
Primate species that are restricted to islands of Southeast Asia
live in topical forest to back yard gardens
Nocturnal insectivores
Vertical clingers and leaping
Live with mated pairs and young offspring
What is the problem with classifying Tarsiers
Highly specialized animals with unique characteristics
In past, believed to be most closely related to lemurs and lorises because of shared traits.
In reality, they present a complex blend of characteristics not seen in other primates.
One of them is big eyes that are immobile
Rotate head like owls 180 degrees
Poses certain anthropoid characteristics and
DNA studies- more related to monkeys, apes, and humans
Despite Debate, classified in the sub order Haplorhini, along with anthropoids
Monkeys, Apes, Humans
Difference between them and lemurs or Lorises:
1. Larger average body size
2. Larger brain in absolute terms and relative to body weight
3. Reduced reliance on olfaction, indicated by absence of a rhinarium and a reduction in relative size of olfactory related structures in the brain
4. Increased reliance on vision, with forward facing eyes placed more to front of the face
5. greater degree of color vision
6. Back of eye socket protected by a bony plate
7. Blood supply to brain different than from lemurs or lorises
8. Fusion of two sides of mandible to form one bone. (in lemur or Lorises they’re two distinct bones joined by cartilage at the middle of the chin.)
More generalized dentition, as seen in absence of a dental comb and some other features
9. Differences in female internal reproductive anatomy.
10. Longer gestation and maturation period
12. Increased parental care
13. More mutual grooming
85 percent of all primates are
Monkeys are divided into two groups separated by geographical area as well as about 40 million years of separate evolutionary history
1. new world (Ceboidea and Catarrhini) (monkeys)
2. old world (Cercopithecoidea, and Hominoidea) (apes and humans)
New World Monkeys
70 species found in a wide range of arboreal environments throughout the world
Mainly forested areas in southern mexico and Central and South America
Wide range in size, diet, and ecological adaptation.
Exclusively Arboreal, some never come to ground
All are diurnal (except howler monkey)
Differ from Old world because of shape of nose
New World: broad noses with outward facing nostrils
Old World: narrower noses with downward facing nostrils
Marmostes and Tamarins: see below
other species
Squirrel monkeys
diet varies
combination of fruits, leaves, insects
Prehensile tails for some used for hanging and locomotion
Most live in mid sexed groups
flat nosed primates Old world
downward nose primates New World
Marmosets and Tamarins
smallest of the new world monkeys (smallest of all monkeys even)
claws instead of nails
usually give birth to twins instead of single births
use claws for climbing
Live in mated pairs and offspring
infant care
That taxonomic family that includes all old world monkeys
taxonomic family that includes all old world monkeys
Common name for members of the subfamily of Old World Monkeys that include baboons, macaques, and guenons
Common name for members of the subfamily of Old World Monkeys that include the African colobus monkeys and Asian langurs
Old World Monkeys
except for humans, most widely distrusted of all living primates. Found in Africa, Asia, ranging from tropical jungles, to desert, to snow covered areas in Japan.
Placed in Cercopithecidae
two subfamilies:
most are quadrupedal and primarily arboreal, but some such as baboons are also adapted to life on the ground.
spend time feeding, sleeping, grooming
also have hardened skin called ischial calosities that serves as a sitting pad.
locomotion includes
arboreal quadrupedalism in guenons, macaques, and langurs
terrestrial quadrupedalsim in baboons and macaques
also semibrachiation and acrobatic leaping in colobus monkeys
sexual dimorphism mark differences in body size or shape between sexes
example: terrestrial species in baboons have males being way larger
Females in some species such as baboons have cyclical changes in genitalia. It is swelling and redness associated with estrus, basically to show to males that they are sexually ready. ovulation
Live in different social groups
Colobines: small groups, 1 adult and 2 males
Savanna baboons: large social units comprising of several adults of both sexes and offspring of all ages.
Monogamous pairing as well.
subspecies of Old Monkeys more general of the old world monkeys. They are more omnivorous and they have cheek pouches for storing food like a hamster.
They eat almost anything.
The majority of the species are mostly arboreal guesons
more terrestrial savanna and hamdryas baboons found in Africa.
Also macaque species found in Asia and India
Colobine species
2nd subspecies of old monkeys.
Narrower range of food
mainly mature leaves
leaf eating monkey
Found in Asia, Africa
Boscis monkey of Borneo
sexual dimorphism
Differences in physical characteristics between males and females of the same species. For example, in humans where males are larger, and taller than females. Very prevalent in species such as gorillas
Ischial callosities
patches of tough, hard skin on the buttocks of old world monkeys and chimapnzees
Explain why New and Old World monkeys are so similar- an example of parallel evolution
the facts are, they’re all monkeys!
Similar primarily arboreal way of life.
except for owl monkey, all diurnal
all live in social groupings
all are omnivorous to varying degree
all are quadrupedal
variations of this
crazy considering both followed separate evolutionary paths.
hypothesized that both arose in Africa from a common monkey ancestor.
members of the primate superfamily (Hominoidea) that includes apes and humans.
Apes and humans differ from monkeys in numerous ways
1. Generally larger body size (except for gibbons and siamangs)
2. no tail
3. lower back shorter and more stable
4. Arms longer than legs (only in apes)
5. Anatomical differences in the shoulder joint that facilitates suspensory feeding and locomotion.
6. more complex behavior
7. more complex brains and enhanced cognitive abilities.
8. increased period of infant development and dependency
Gibbons and Siamangs
smallest of the apes, with a long slender body.
anatomical features are adaptations to feeding while hanging from tree branches or brachiation where they excel
more dedicated to brachiation than any other primate
very long arms
permanently curved fingers
short thumbs
and powerful shoulder muscles
so long arms, they have to walk bipedally by raising arms to the side
eat mostly fruit, but also leaves, flowers, and insects
basic social unit of them is adult male and female with dependent offspring
sometime monogamous
highly territorial and protect their territory
represented by two subspecies found today in only heavily forested areas on the Indonesian islands of Borneo and Sumatra.
threatened by poaching by humans which could lead them to extinction
slow, cautious climbers
locomotion: four handed-use all four limbs for grasping and support.
almost completely arboreal, but do travel on the ground.
sexual dimorphism-males very large.
in wild- live solitary lives for the most part
female with offspring though
Frugivorous but also eat bark, leaves, insects, and sometimes meat.
diet composed mainly of fruit
the largest of living primates in the Hominoids group. possibly might go extinct. Mountain gorillas most endangered. Adult gorillas, mainly males, are primarily terrestrial. Like chimps, they practice knuckle walking.
live in groups consisting of one or two large silver back males and a variable amount of females and offspring.
Typically but not always, they leave their natal group as young adults. females join other groups or form their own.
exclusively vegetarian.
natal group
group in which animals are born and raised
auditory bulla
The region of the skull that contains the structures of the middle ear is completely encircled by a bony structure called this. In primates, the floor of this is derived from segments of temporal bone. It is one of the best diagnostic traits of the primate order. It encloses parts of the middle and inner ear.
Binocular vision
vision characterized by overlapping visual fields provided by forward facing eyes. It is essential for depth perception
arm winging, a form of locomotion used by some primates. It involves hanging from a branch and moving by alternately swinging one arm to another.
animals are those that are active primarily during twilight (i.e. dawn and dusk).
derived traits
refers to characters that are modified from the ancestral condition and thus diagnostic of particular evolutionary lineages
active during the day
ecological niche
The position of a species within its physical and biological environments. Defined by such components as diet, terrain, vegetation, type of predators, relationships with other species, and activity patterns, and each niche is unique to a given species. It makes up an ecosystem.
home to lost world of lemurs
parallel evolution
is the development of a similar trait in related, but distinct, species descending from the same ancestor, but from different clades
postorbital bar
is where the zygomatic bone and the frontal bones join to form a lateral strut which, with the exception of Tarsiers runs around the eye socket of most Prosimians and some other mammals, such as the hyracoids. This is in contrast to the higher primates, Anthropoids, who have evolved fully enclosed sockets to protect their eyes.
having five toes or fingers, or derived from such a form, as characteristic of all tetrapods.
using all four limbs to support the body during locomotion, the basic mammalian (and primitive) form of locomotion.
the moist, hair less pad at the end of the nose seen in most mammalian species. It enhances an animals ability to smell.