Lecture 36 Amniotes - Humans Flashcards
what is the superfamily of apes?
hominoidea – hominiods
what are hominoids?
lack tails, relatively large brains, includes gibbons (lesser apes), hominid great apes (orang, gor, chimp, bonobos humans)
- monophyletic group
what are hominids?
hominidae - great apes – orang, goril, chimps, humans
what are hominines?
homininae - goril, chimps, humans
what are hominins?
hominini - modern humans and extinct relatives
what are the closest living relatives to Homo?
chimpanzees and bonobos
- extinct hominins are more closely related to humans than to chimps
what are the derived characteristics of humans?
- upright posture and bipedal locomotion
- larger brains
- reduced jawbones and jaw muscles
- shorter digestive tract (omnivore instead of herbivore)
where did hominins originate?
africa 6-7MYA
what are trends in hominin evolution?
- bipedalism
- expansion of brain and increase in brain complexity (later)
- modification in female pelvis
- reduction of teeth, face, jaws
- extended period of infant and child dependence
- hairlessness
- increased reliance on meat
- emergence of tool use
what changes occurred with bipedalism?
- changes in knee, foot (big toe), pelvis, spine curvature, skull attatchment
what is the best hypothesis of bipedalism?
- energy efficiency
- thermoregulation
what are australopiths
paraphyletic assemblage of early hominins
- bipedal: bowl shaped pelvis
- diminutive
- large degree of sexual dimorphism
- small brain
- relatively large and jutting jaw
- 44yr life expectancy
- robust paranthropus – sturdy skulls and powerful jaws
- gracile – more slender, lighter jaws: ancestors of modern humans
what are trends in hominin evolution?
- bipedalism
- expansion of brain and increase in brain complexity (later)
- modification in female pelvis
- reduction of teeth, face, jaws
- extended period of infant and child dependence
- hairlessness
- increased reliance on meat
- emergence of tool use
- increased cranial capacity
- tool use
what are australopiths
paraphyletic assemblage of early hominins
- bipedal: bowl shaped pelvis
- diminutive
- large degree of sexual dimorphism
- small brain
- relatively large and jutting jaw
- 44yr life expectancy
- robust paranthropus – sturdy skulls and powerful jaws
- gracile – more slender, lighter jaws: ancestors of modern humans
what is the earliest homo species?
- H. habilis – handy man, had shorter jaws, larger brain capacity, less diminutive
what was homo ergaster?
first fully bipedal, large brained hominin
- larger brain than habilis
- long slender legs, hip joints suited to long distance walking
- smaller teeth (ate more meat, less grinding of plants)
- more sophisticated tool use
- significant decrease in sexual dimorphism (pair bonding?)
what was homo erectus?
- first hominin to leave africa
- likely first to live in hunter gatherer society gave rise to Homo heidelbergensis – led to Neanderthals and H. sapiens
what were neanderthals?
H. neanderthalensis
- cold adapted hominins with stout physiques, complex behaviours (buried dead, hunting tools), brains similar in size to humans
- lived alongside H. sapiens
where did all living humans descend from?
african ancestors (H. heidelbergensis)
what hypothesis does this course support?
out of africa hypothesis
-supported by mtDNA
