5 Human Evolution

Question 1

• Opposable thumbs
• Frontally directed eyes
  with binocular vision
• Large and convoluted
  brains
• Complex social
  behavior
• Earliest primate (prosimian)
  arose 65 MYA when
  dinosaurs became extinct

Answer 1

The primates (Class Mammalia, Sublass Eutheria, Order Primates)

Question 2

Suborders of Order Primates:

• Known as Prosimians
• Found in tropical rain forests in Madagascar, Africa and Southeast Asia
• May be polyphyletic, with the tarsiers being a separate group
• Skull has large orbits, reduced brain case, elongated snout, and well
  developed olfactory and auditory regions

Answer 2

Suborder Prosimii

Question 3

Suborders of Order Primates:

• Monkeys and apes (including humans)
• Rely more on sight and less on sense of smell as in prosimians
• Larger brain relative to body size

Answer 3

Suborder Anthropoidea

Question 4

• Africa and Asia
• Tails are NOT prehensile
• Nostrils face downwards
• Arboreal and ground-

Answer 4

Old World Monkeys

Question 5

• Central and South America
• Tails are prehensile
• Nostrils face sideways and are wide apart
• All are arboreal
  dwelling

Answer 5

New World Monkeys

Question 6

Apes are capable of ___________
(arm swinging) but not monkeys

Answer 6

BRACHIATION

Question 7

These primates lack tails
and have forelimbs
longer than their hind
limbs (except humans)

Answer 7

The Great Apes

Question 8

• Oldest known hominid found (Ethiopia)
• Lived around 4.4 million years ago
• weighed about 110 pounds, had very
  long arms and fingers, and possessed
  an opposable big toe that would have
  helped her grasp branches while
  moving through trees

Answer 8

Ardipithecus ramidus (“Ardi”)

Question 9

Two hypothesis on the origin of humans

Answer 9

Multiregional hypothesis, recent single origin hypothesis

Question 10

Key Trends in Human Evolution

Answer 10

1. Terrestriality
   - Coming down from trees
2. Bipedalism
   - Obligately having to walk on two feet
3. Encephalization
   - Increase in brain size relative to body
   - Development of language
4. Civilization
   - Complex technology, moral systems, society
5. Behavior
   - Increasingly complex with some key ingredients

Question 11

Four ingredients of human behaviour

Answer 11

1. Abstract thinking
   - Concepts free from specific examples
2. Planning
   - Taking steps to achieve a farther goal
3. Innovation
   - Finding alternative solutions
4. Symbolic behavior
   - Making use of images and rituals

Question 12

High Altitude Genes (EPAS1):

Lowlander Response

Answer 12

– Produce more red blood cells
– Help transport oxygen more efficiently

Question 13

High Altitude Genes (EPAS1):

• Tibetan highlander response

Answer 13

– Produce less red blood cells
– too many red blood cells = blood too thick
(particularly dangerous for pregnancy)

Question 14

High Altitude Genes (EPAS1):

When genome was compared to Han Chinese

Answer 14

Region EPAS1 different

Question 15

High Altitude Genes (EPAS1):

• Split between Tibetans and Han Chinese

Answer 15

– Estimated to be less than 3,000 years ago
– Pretty fast evolution (~100 generations)

Question 16

• Found in 10% of Americans, 10% of
  Africa’s, Tutsi tribe, 50% of Spanish and
  French people, and 99% of Chinese
• Lactose cannot be digested (lacks lactase)
• Gene that makes lactase is shut down
  after weaning

Answer 16

Lactose Intolerance

Question 17

• Lactose tolerance advantageous in people who have access to
  animal milk
• Drink milk directly rather than process (e.g. Cheese)
• Provide additional sustenance and, during droughts, a source of
  water
• Parallel evolution: Europe and Africa

Answer 17

Lactose Tolerance

Question 18

Wisdom Teeth:

– Advantageous for diet (leaves, roots, raw meat), large jaws that accommodate all 32 teeth

Answer 18

Quadruped

Question 19

Wisdom Teeth:

– Hands can be used to obtain food; jaws became smaller

Answer 19

Biped

Question 20

Wisdom Teeth:

– Cook and process food; reliance on third molar decreased

Answer 20

Increased intelligence

Question 21

Mutation in MYH16 gene produces ___________

Answer 21

smaller jaws

Question 22

______________ are the consequence of [formation of boundaries between human communities], and boundary formation is perhaps the central and most important element of the evolutionary ecology of culture.

Answer 22

cultures

Question 23

What leads to diversification of cultures?

Answer 23

• Resources, ecology and environment
• Kinship and reproduction

Question 24

Outcomes of Forming Cultures

Answer 24

• Biologically-related individuals likely share a culture
  – Culture constrains biology (choice of mate and gene transfer)
• Regional Diversity
  – High levels of geographic isolation
  – High gradient in resource availability
• Extinction