Primate ancestors and human origins Flashcards
What are the anatomical differences in the two types of suspensary species?
fast and slow species.
Often the thumb is reduced or gone completely to aid with brachiating. But thumb is used for grooming, so species compensate by cuddling instead.
What are the anatomical adaptations of primates?
- Pendactyl limbs
- Prehensile hands (Knuckle walkers have less prehensile hands)
- Opposable big tow
- tails are often present (Tails can be used as another limb or they’re just used as a balance)
- Sensitive tactile pads with ‘fingerprints’ on fingers/toes
- flat nails on hands and feet in most species.
Where can specialisations of primate species often be seen?
Forelimb or facial morphology
What species forelimb morphology is similar to homo sapiens?
Macaques hand is very similar to ours. They are specialist generalists. Can survive in lots of environments like humans.
What are the anatomical adaptations of an arboreal quadruped?
- Long tail
- Narrow thorax
- Laterally placed scapula
- Long Olecranon process
- deep ulna
- grasping foot
Arboreal primate’s skeletons reveal that they have a lot more stored energy for travelling across canopy.
What are the anatomical adaptations of a terrestrial quadruped?
- reduced tail
- narrow thorax
- restricted shoulder movement
- Posteriorly extended olceration process
- robust radius
- short digits
- long, similar-length forelimb and hindlimb
What can be determined by studying the skull and mandible of a primate?
Can discover a wide range of diets; -herbivores (including folivores and gumnivores)
- omnivores
- obligate carnivores
molars are relatively unspecialized
Visual sense is highly developed. Eyes are large and forward facing, permitting stereoscopic vision.
Post-orbital bar (strepsirrhines) Enclosed orbits (haplorhines)
Unspecialised olfactory apparatus (greatly reduced in diurnal species)
Brain large compared with brains of similar sized mammals.
What are the main mating units for primates and give examples of species that use the mating strategy.
Promiscuity (many:many)
e.g; chimpanzees
Polygamy (one:many)
- Polygyny (1 male:many females) e.g; baboons, langurs, howler monkeys, gorillas.
- Polyandry (1 female:many males) e.g; small new world primates like the marmosets and tamarins.
Monogomy (one:one)
e.g; gibbons, titi monkeys, indris.
What is a Hominoid?
Anything in the homo genus. Any species that contributed to human evolution.
List the differences between apes and monkeys
Monkeys:
-climb on tops of branches using hands and feet to grip, tail to balance.
- long trunks
- arms and legs similar length
Apes:
-swing from branch to branch often hang whilst feeding, no tail.
- short trunks
- long arms
- flexible shoulder joints.
Describe the features of a hominoid skeleton
- ‘braincase’ - frontal, temporal, parital, occipital
- ‘face’ - frontal, maxilla, nasal, zygomatic (jugal and squamosal)
- ‘jaws’-maxilla, mandible, dentition
- ‘skull base’-basicranial bones
(Male gorilla has big sagittal crest for jaw muscle attachment. )
(Humans have no sexual dimorphism in the skull.)
Describe the features of an appendicular hominoid skeleton
Pectoral girdle - clavicle, scapula
‘upper arm’ - humerus
‘lower arm’ - radius, ulna
hand - manus; carpals, metacarpals, phalanges
Pelvic girdle - innominate - ischium, ilium, pubis
‘upper leg’ - femur
‘lower leg’ - tibia, fibula
foot - tarsus; tarsals, metatarsals, phalanges
Name the 4 anatomical planes
median
sagittal
coronal
transverse
What factors are related to hominoid morphological variation?
body size
brain size (encephalisation)
locomotion
ecological niche
Where are the main cranial differences found in hominoids?
- cranial height
- nuchal crest
- sagittal crest
- supraorbital torus
- prognathism (Humans have no prognathism at all. We are perfectly balanced for bipedalism. )
- Orthognathism (having a face that lies beneath the anterior cranial fossa
