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Anthropology Class

Biological Classification of the Living Primates


  • Analogy = a feature that evolves independently in different groups as a result of similar evolutionary pressures resulting in similar adaptations.



  • Homology= a characteristic that is similar in various groups of organisms because of their origin from a common ancestor possessing that characteristic.


Primitive vs. Derived

  • Primitive feature = features that are similar in form to that of an ancestor.
  • Derived feature = features that have undergone change from the ancestral form.


Biological Classification

  • Binomial nomenclature = classificatory system for organisms devised by Linnaeus featuring the binomen (genus and species).
  • Genus = taxonomic level above species and bellow subfamily; a group of closely related species.
  • Species = a group of individuals that can potentially interbreed and produce fertile offspring (biological definition of species).


Biological Classification

How do we determine taxonomic relationships?

  1. Recency of divergence – how recently two groups shared a common ancestor.

For example, Homo sapiens and Pan troglodytes last shared a common ancestor 5-7 mya.

  1. To what extent the groups diverged – how much each group has changed in the time since they shared a common ancestor.


The Order Primates

  • Kindom: Animalia
    • Phylum: Chordata
      • Subphylum: Vertebrata
        • Class: Mammalia
          • Order: Primates
            • Family: Hominidae
              • Genus: Homo
                • Species: sapiens


The Order Primates

  • Order originated approximately 65 million years ago.
  • Habitat: tropics and subtropics in South America (New World) and Africa/Asia (Old World).
  • Dietary Specializations:
    • Folivory (leaf-eating)
    • Frugivory (fruit-eating)
    • Gramnivory (seed-eating)
    • Gummivory (gum-eating)
    • Insectivorous (insect-eating)
    • Omnivorous (eat a variety of plants, fruits, nuts, protein, etc.)


Characteristics of Primates

1.) Retention of unspecialized limb structure:

  • Retention of five fingers and five toes
  • Retention of clavicle

2.) Nails rather than claws

3.) Grasping hind feet with opposable first toes

4.) Increased emphasis on vision:

  • Forward facing eyes (allowing for better depth perception)
  • Expanded occipital and temporal lobes of the brain.
  • Color vision (in most primates)

5.) Complete ring of bone around the orbit:

  • postorbital bar

6.) Enlarged brain relative to overall body size.

7.) Less emphasis on olfaction:

  • Shortened snout
  • Small olfactory bulb

8.) Longer period of fetal nourishment/development.

  • Intrauterine development
  • Prolonged stages of lifespan

9.) Longer period of infant dependency.

10.) Most live in social groups with well-developed communication systems.


Two Suborders

  • Strepsirhini Prosimians
  • Haplorhini Anthropoidea


Infraorder Strepsirhini


  • Among oldest living primates.
  • Developed sense of smell
    • Enlarged olfactory bulb & scent glands
  • Combination of nails and claws
  • Less dexterity
  • Geographic range: Madagascar and Southeast Asia.
  • Lemurs (ring-tailed, black and white ruffed), indri, safakia, lorises, galagos, pottos).


Infraorder Strepsirhini

  • Relatively smaller brain
  • No postorbital closure
  • Orbits with more lateral orientation
  • Unfused mandible
  • Longer snout
  • Moist rhinarium (nose)
  • Toothcomb
  • Grooming claw




Infraorder Tarsiiformes

  • Vertical clingers and leapers.
  • Huge eye orbits for nocturnality.
  • Tapetum lucidum
  • Unfused mandible.
  • Grooming claw
  • Molars with sharp, pointy cusps.
  • Categorized differently depending upon the textbook!


Sub Order Haplorhini

  • Relatively larger brain
  • Postorbital closure
  • Orbits with more forward orientation
  • Fused mandible
  • Molars with flatter cusps
  • Shorter snout
  • Continuous upper lip
  • Nails on all digits


Infraorder Platyrrhini

New World Monkeys

  • One subfamily:
    • Ceboids
    • Spider monkeys, squirrel monkeys, capuchins, tamarin, marmosets, howler monkeys, woolly monkeys, saki, uakari
  • Side-directed nostrils
  • Dental formula: 2-1-3-3
  • No bony ear tube
  • Prehensile tail.
  • Lower levels of sexual dimorphism
  • Geographic Range: Central and South America


NWM: Prehensile Tails


Infraorder Catarrhini

Old World Monkeys, Apes, Humans

  • Terrestrial and arboreal
  • Geographic Range: Africa and Asia
  • Two subfamilies:
    • cercophithecoids
    • colobines
  • Baboons, macaques, mandrills, geladas, vervet monkeys, guenons colobus moneys



Old World Monkeys

  • Forward or down-directed nostrils
  • Dental Formula: 2-1-2-3
  • Higher levels of sexual dimorphism.
  • Bony ear tube
  • Bilophodont molars (two cusps)
  • Narrow thorax
  • Tail (but not prehensile)
  • Ischial callosities (tough sitting pads on the rear)


Colobus Monkeys and Langur

Bilophodont or Y-5?

Molars have different numbers of cusps.

  • Bilophodont (two lobes). (found in Old World Monkeys)
  • Y-5 (cusps in the shape of a “Y”). (found in Superfamily Hominoidea)


Ischial Callosites

  • Tough sitting pads on the rear (ischial callosities).
  • Old World Monkeys tend to rest in the sitting position.


Superfamily Hominoidea

Apes and Humans

  • Largest relative brain size
  • Y5 molar pattern
  • Broad thorax
  • No tail


SuperFamily Hominoidea

Lesser Apes:

(gibbon, siamang)

  • Skilled brachiators.
  • Long arms in comparison with legs.


Superfamily Hominoidea

Great Apes:

Orangutan, Chimpanzee, Bonobo, Gorilla

  • Sagittal crest in gorilla, orangutan
  • Chimpanzees and Humans omnivorous
  • Humans characterized by skeletal structure for bipedalism


Sagittal Crest (Gorilla)














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Anthropology 111 – Lab Human Biological Evolution

1.  Biological Anthropology as a Science

2.  Genetics

3.  Genetics: The Basics

4.  Natural Selection

5.  Microevolution and Limits on Natural Selection

6.  Human Osteology

7. Living Primates