The Hominin Transition 2

Question 1

In terms of our skeletal anatomy what makes us humans?

Answer 1

1. We walk upright

2. Our brains are significantly larger (relative to the size of our bodies)

Question 2

The first definite hominins

Answer 2

The first hominis was discovered by Raymond Dart in 1925

Question 3

The Piltdown man hoax

Answer 3

Charles Dawson faked finding human remains

Question 4

Rift valley

Answer 4

1. Is a long valley in east africa where the earth is “pulling apart”
2. Cradle of humanity & contains many fossils

Question 5

Olduvai Gorge

Answer 5

Located in western tanzania, is a cleft in the rift valley & is where the leakey family found many remains

Question 6

The Leakey family

Answer 6

Argued against Asian evolution & found majority of hominin fossils

Question 7

Describe the development of distinct hominin traits?

Answer 7

1. Didnt evolve together
2. 4mya had a bipedal locomotion
3. 2mya had brain expansion, pelvic modify, and reduction in face, teeth, and jaws

Question 8

What are bipedalism characteristics?

Answer 8

1. More gracile musculature
2. Skull morphology
3. Bowl-shaped pelvis
4. Lumbar spinal curve
5. Straighter limbs
6. Angles knees
7. Arched feet that are not prehensile

Question 9

Describe the two roles of the pelvis

Answer 9

1. Wide pelvic inlet for big brained babies

2. Modified pelvis for bipedalism

Question 10

What are some theories of evolution of bipedalism (why we turn into bipedalism)

Answer 10

1. Use our hands
2. Adaption to savannas
3. Body temperature regulation
4. Long distance travel
5. Mating

Question 11

Theories for evolution of bipedalism (Use of hands)

Answer 11

Believed use our hands to carry & create things only problem with that theory is no archaeological record support it (But its current hominoid practice)

Question 12

Theories of evolution of bipedalism (Adaptation to savannas)

Answer 12

Believed that was able to see over tall grasses in the savanna but issue with the theory is that other predator’s can see you, & other hominoids in the area)

Question 13

Theories for evolution of bipedalism (body thermal regulation)

Answer 13

1. Humans experience cooler temperatures & breezes
2. 60% less sun exposure than knuckle walker at noon
3. Less water required to stay hydrated

Question 14

Theories for evolution of bipedalism (Long distance travel)

Answer 14

1. Energy conservation

2. Travel longer distance without getting tired (“Endurance hunters”)

Question 15

Theories for evolution of bipedalism (mating)

Answer 15

1. Natural selection (collect food, make tools, travel further, protection, etc)
2. Create social cohesiveness

Question 16

Disadvantages of bipedalism

Answer 16

1. Blood circulation
2. Body weight stress
3. Body distribution & balance
4. Injury prone
5. Birth

Question 17

What were the first possible bipedalists on the fossil record?

Answer 17

1. Sahelanthropus tchadensis (7mya)
2. Orrorin tugenensis (5.8-6mya)
3. Ardipithecus (4.4-5.8mya)

Question 18

What were the actual first definite bipedalist?

Answer 18

1. Australopithecus (8 species possibly direct human ancestor)
2. Paranthropus (3 species, unlikely to be human ancestor)

Question 19

Australopithecus afarensis

Answer 19

1. Most well-represented australopithecus in fossil record
2. Lucy (40% complete, bipedal but thick & had large teeth)
3. Laetoli

Question 20

Laetoli footprints

Answer 20

1. Preserved footprints in volcanic ash
2. 3.6mya
3. Two bipedalist (Near A. afarensis fossil)
4. Measure stride , height , etc

Question 21

Paranthropus (“robust australopithecines”)

Answer 21

1. 3 species (no direction human ancestor)
2. 2.7 - 1 mya
3. Lived in east & southern africa
4. Traits: - Thick dentition & broad face
   - Sagittal crest
   - Slightly larger brain than Australopithecus

Question 22

Paranthropus aethiopicus

Answer 22

1. Lived 2.7-2.3 mya in eastern africa

2. Had “black skull” fossil & sagittal crest