ANTH 101 Lecture Notes - Lecture 5: Brachiation, Postorbital Bone, Postorbital Bar
19 Sep 2018
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PRIMATE TRAITS AND VARIATION
• How do we recognize primates?
o Important: traits that define primates are not unique to the group, we lack
specializations (we can make use of everything), all primates are arboreal (living
in trees)
o Taxonomy Order: Primates
• Phylogeny : study of evolutionary relationships between organisms; includes time
• Cladistics: classifies species of organisms hierarchically based on shared traits; does
NOT include time
o Cladogram
• 2 main suborders: Strepsirhines and Haplorhines
o Strepsirhines: Primates that look the most different from us; like lemurs; they
have wet noses; generally nocturnal; no complex social groups; don’t have
complex relationships, have tooth comb teeth, grooming claw
o Haplorhine (Anthroploids): large category, humans fall under this category, dry
nose, complex social groups, monkeys, apes
▪ Homnoidea: Super family of all apes and humans
• Ape or Monkey?
o If they’re an ape, they don’t have a tail, they are generally larger, greater range of
motion in arm
• Derived traits: something unique to group that keeps certain group on their own branch in
cladogram (study a cladogram)
• Defining traits of primates:
o Locomotion
▪ Particularly apes have semi erect or erect posture
▪ Modes of locomotion:
▪ Quadrapedalism
▪ Hanging below branches (suspensory locomotion) (brachiation)
▪ Leaping (jumping from branch to branch) (moving through
discontinuous supports)
▪ Bipedalism -humans are the only ones that can do this all the time
▪ Foramen magnum is at bottom of head bc we walk upright,
but behind head for cats or dogs
▪ Pelvis is wider in humans bc it makes it easier to balance
▪ Humans don’t have opposable big toes, but some monkeys
do
▪ Grasping of hands and feet
▪ We have 5 digits
▪ We have nails instead of claws
▪ We have tactile pads on digits
o Diet and Dentition
▪ Generalized, small teeth
▪ Lack of dietary specialization
▪ Lowered molar cusps
