Topic 35: Primates and Humans Flashcards
Order Primates
Lemurs, monkeys, and apes. Evolved from mammals that inhabited trees.
Traits of Primates
Grasping hands/feet with opposable thumbs.
Flexible limbs and shoulder joints.
Forward facing eyes (judges distance)
Larger brain (better learning)
Basal Primates
Lemurs
Anthropoids
Monkeys and Apes.
Apes
Lack tails and have larger brains.
Humans Related to Monkeys
Descendants of the great ape lineage w/ bipedal locomotion. Though we are closest to chumps and bonobos.
Hominins
Include chimps, bonobos, and humans w/ extinct relatives.
Shared Derived Traits of Humans
Obligate bipedalism
Larger brains (complex language)
Reduced jaw and facial structure
Extended childhood and learning.
Why did bipedalism occur
In response to larger predators and change in habitat that created more open grasslands and woodlands.
Skeletal Adaptation for Bipedalism
Skull repositioning for head balance
S-shaped spine
Pelvis is shorted and broadened
Leg lengthening
No opposable big toe.
Ardipithecus
Early hominins that had increased bipedalism but retained small brain
Australopiths
Fully bipedal
Short
Sexual dimorphism
Small brains
Tool use
Homo Ergaster and Homo Erectus
Fully bipedal AND large brained hominins.
Reduced sexual dimorphism
First species to migrate out of Africa.
Homo Heidelbergensis
Evolved from erectus, and lead to Neanderthals and Denisovans.
Neandethals
Cold-adapted, evidence of interbreeding w/ humans.
Denisovans
Shared common ancestor w/ Neanderthals, but taxonomic status is pending.
Humans (Homo sapiens)
Originated in Africa, likely descending from Homo heidelbergensis. Evolutionarily very young <200kya. Little genetic variation.
