T34 - Humans

Question 1

T/F: Humans (Homo sapiens) and Denisovans are the only homo groups that exist today.

Answer 1

FALSE. humans are the only homo groups that exist today.

Question 2

Which two species are the closest living relative to humans? How long ago did our shared ancestor exist?

Answer 2

chimpanzees and bonobos

the shared ancestor existed 6-8 mya

Question 3

Fill in the following shared, derived traits of humans:
1. _ _ _ _ _ posture and _ _ _ _ _ _ _
2. _ _ _ _ _ brains
3. _ _ _ _ _ _ jawbone and jaw muscles
4. _ _ _ _ digestive tract

Answer 3

1. upright posture and bipedal locomotion
2. larger brains
3. reduced jawbone and jaw muscles
4. shorter digestive tract

Question 4

T/F: the evolution of humans is a linear progression

Answer 4

FALSE

Question 5

At which point did bipedalism increase in hominins? Did the onset of bipedalism immediately result in the progression of other eventual human traits?

Answer 5

early homonins

NO, they still retained the unimproved small brains and maintained the arboreal skeleton

Question 6

At which point did brain expansion and brain capacity increase in hominins?

Answer 6

later homonins, closer to humans

Question 7

Name 3 more examples of trends in hominin evolution
- e.g. reduction in jaws, infant/child dependency

Answer 7

• pelvis modification
• reduction of teeth, face, jaws
• hairlessness
• reliance on meat
• tool use

Question 8

what were the advantages of bipedalism

Answer 8

• ability to see predators and prey
• energy-efficient locomotion, good for long travel
• better thermoregulation
• free hands for infant care and tool use

Question 9

what are the disadvantages fo bipedalism?

Answer 9

• injuring one foot is 1/2 of the locomotive system gone
• strain on hips, backs, knees, ankles

Question 10

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

Answer 10

1. foremen magnum is on top of the vertebral column
2. spine is s-shaped
3. pelvis is reconfigured for the upright position, internal organs are supported over it
4. legs are longer to support locomotion, knee joints support body weight
5. foot has a large heel, large big toe, narrow

Question 11

which hominin is the predecessor of the homo evolution?

Answer 11

australopiths

Question 12

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?

Answer 12

1. yes
2. no, they were short
3. small brains
4. size. males could be up to 50% larger

Question 13

which homo species is the earliest?

Answer 13

homo habilis

Question 14

What were some evolved traits homo habilis had in comparison to australopiths?

Answer 14

larger brain, short jaw

Question 15

What were some evolved traits homo ergaster had in comparison to homo habilis?

Answer 15

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

Question 16

What were some evolved traits homo erectus had in comparison to homo ergaster?

Answer 16

first to leave africa, larger brain, societies and fire

Question 17

What were some evolved traits homo heidelbergensis had in comparison to homo erectus?

Answer 17

more similar body plan, dental adaptations, and cognitive ability to homo sapiens

sophisticated tools

Question 18

who is the predecessor for both neanderthals and homo sapiens?

Answer 18

homo heidelbergensis

Question 19

What were some evolved traits neanderthals had in comparison to homo heidenbergensis?

Answer 19

europe

interbred with homo sapiens and denisovans

Question 20

who were the denisovans

Answer 20

existed at around the same time as neanderthals, but were genetically distinct

interbred with both humans and neanderthals

Question 21

What were some evolved traits homo sapiens had in comparison to homo heidenbergensis?

Answer 21

• larger brains
• migration out of africa all over the world
• little genetic variation due to young evolutionary history

Question 22

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

Answer 22

1. australopiths
2. homo habilis
3. homo ergaster
4. homo erectus
5. homo heidenbergensis
6. neanderthals
7. denisovans
8. homo erectus