T34 - Humans Flashcards
T/F: Humans (Homo sapiens) and Denisovans are the only homo groups that exist today.
FALSE. humans are the only homo groups that exist today.
Which two species are the closest living relative to humans? How long ago did our shared ancestor exist?
chimpanzees and bonobos
the shared ancestor existed 6-8 mya
Fill in the following shared, derived traits of humans:
1. _ _ _ _ _ posture and _ _ _ _ _ _ _
2. _ _ _ _ _ brains
3. _ _ _ _ _ _ jawbone and jaw muscles
4. _ _ _ _ digestive tract
- upright posture and bipedal locomotion
- larger brains
- reduced jawbone and jaw muscles
- shorter digestive tract
T/F: the evolution of humans is a linear progression
FALSE
At which point did bipedalism increase in hominins? Did the onset of bipedalism immediately result in the progression of other eventual human traits?
early homonins
NO, they still retained the unimproved small brains and maintained the arboreal skeleton
At which point did brain expansion and brain capacity increase in hominins?
later homonins, closer to humans
Name 3 more examples of trends in hominin evolution
- e.g. reduction in jaws, infant/child dependency
- pelvis modification
- reduction of teeth, face, jaws
- hairlessness
- reliance on meat
- tool use
what were the advantages of bipedalism
- ability to see predators and prey
- energy-efficient locomotion, good for long travel
- better thermoregulation
- free hands for infant care and tool use
what are the disadvantages fo bipedalism?
- injuring one foot is 1/2 of the locomotive system gone
- strain on hips, backs, knees, ankles
Explain how the restructuring of these parts of skeletal anatomy aided in bipedalism:
1. skull attachement
2. spinal curvature
3. pelvis
4. legs
5. foot
- foremen magnum is on top of the vertebral column
- spine is s-shaped
- pelvis is reconfigured for the upright position, internal organs are supported over it
- legs are longer to support locomotion, knee joints support body weight
- foot has a large heel, large big toe, narrow
which hominin is the predecessor of the homo evolution?
australopiths
answer the following questions about australopiths
1. were they fully bipedal?
2. were they tall when upright?
3. did they have larger or equal brains when compared to other hominins?
4. what is the distinguishing feature between males and females?
- yes
- no, they were short
- small brains
- size. males could be up to 50% larger
which homo species is the earliest?
homo habilis
What were some evolved traits homo habilis had in comparison to australopiths?
larger brain, short jaw
What were some evolved traits homo ergaster had in comparison to homo habilis?
the main difference is that they were the first bipedal and large-brained hominin
- large brain, skeleton for walking
- smaller teeth
- sophisticated tools
- decreased sexual dimorphism
What were some evolved traits homo erectus had in comparison to homo ergaster?
first to leave africa, larger brain, societies and fire
What were some evolved traits homo heidelbergensis had in comparison to homo erectus?
more similar body plan, dental adaptations, and cognitive ability to homo sapiens
sophisticated tools
who is the predecessor for both neanderthals and homo sapiens?
homo heidelbergensis
What were some evolved traits neanderthals had in comparison to homo heidenbergensis?
europe
interbred with homo sapiens and denisovans
who were the denisovans
existed at around the same time as neanderthals, but were genetically distinct
interbred with both humans and neanderthals
What were some evolved traits homo sapiens had in comparison to homo heidenbergensis?
- larger brains
- migration out of africa all over the world
- little genetic variation due to young evolutionary history
arrange the following homo species in order of first appearance in history:
- neanderthals
- homo ergaster
- denisovans
- homo habilis
- homo sapiens
- homo heidenbergensis
- australopiths
- homo erectus
- australopiths
- homo habilis
- homo ergaster
- homo erectus
- homo heidenbergensis
- neanderthals
- denisovans
- homo erectus
