The Hominin Transition

Question 1

What makes humans humans?

Answer 1

We walk upright & our brains are significantly larger

Question 2

When was the first definite hominins discovered?

Answer 2

The first hominins discovered by raymond dart in 1925

Question 3

Rift Valleys

Answer 3

Long valley in east africa where earth is pulling apart & many fossils are found

Question 4

Oldvvai Gorge

Answer 4

Leaky Fmaily found many fossils remains there

Question 5

The leaky family

Answer 5

Louis leakey

• Patriarch of the “dynasty”
• East African Childhood
• Church of god missionaries
• Raised among kikuyu

Question 6

Skeletal Adaptation & fossil discoveries

Answer 6

Development of distinct hominin traits:

• Didnt evolve together
• 4mya (Bipedal locomotion)
• 2 mya (Brain expanison, pelvic modifications, reduction of face, teeth, & jaws)

Question 7

Bipedalism Characteristic

Answer 7

• More gracile musculature
• Skull morphology
• Bowl- shapped pelvis
• Lumberspinal curve
• Straighter limbs
• Angled knees
• Arches feet that are not prehensile

Question 8

Adaptations to savannas

Answer 8

Pros: See over tall grass

Issues: - Can’t see over tall grass if your short

• Predators can see you if your tallers than the grass or if they are taller than the grass
• Other hominoids may be in the area

Question 9

Body Thermal Regulation

Answer 9

Pros: -Cooler temp & breezes

• 60% less sun exposure than knuckle walkers at noon
• Less water required to stay hydrated

Question 10

Long distancee travel

Answer 10

Pros: -Energy conservation

• Traveled longer distance without getting tired
• “Endurance hunters”

Question 11

What are the pros of natural selection?

Answer 11

Social Cohesiveness

Question 12

Disadvantages of Bipedalism

Answer 12

• Blood circulation
• Body weight stress
• Body distribution & balance
• Injury prone
• Birth

Question 13

Australopithecines (Southern Apes)

Answer 13

• 8 species
• 4-2mya
• East & Southern africa

Traits:

• Brain 1/3 size of normal humans
• Height (stature) 3.5-5ft
• Smaller dentition & lighter face musculature

Question 14

___________ is the most well-represented australlopithecus in fossil record

Answer 14

Lucy

Question 15

Laetoli Footprints

Answer 15

• Preserved footprints in volcamic ash
• 3.6 mya
• Two bipedalist
• Near A. Afarensis fossil
• Used to measure stride, stature, etc

Question 16

Paranthropus (“Rohust australopithecines”)

Answer 16

• 3 species
• 2.7mya
• East & Southern Asia

Traits:

• Thick dentition & broad face
• Sigittal crest
• Slightly larger brain than australopihecuw

Question 17

Paranthropus Aethropicus

Answer 17

• 2.7 - 2.3 mya
• Lived in eastern Africa
• “Black Skull”