Lecture 22

Question 1

Primates

Answer 1

• Arboreal ancestor
• Grasping limbs with opposable thumbs
• forward- facing eyes (Depth perception, overlap btwn eyes is what causes 3D sight)
• Big cerebrum (encodes memory, higher functioning)
• Highly social (reduced brood size and extended parental care)
• Two major groups: (prosimians, anthropoids)

Question 2

Prosimians

Answer 2

• ex. lemurs, loris
• Not monkeys although they are primates
• mostly arboreal and nocturnal
• Once found on all continents, but now just Madagascar, SE Asia (no lemurs are found in Africa but some lorises are)
• Lemurs in Madagascar have radiated, not all found in trees and some are diurnal (Diurnal: awake during the day, opposite to nocturnal)
• Many species are threatened or endangered

Question 3

Anthropoids “the rest”

Answer 3

• Ex. Tarsier

among the smallest primates, only entirely carnivorous primate, large eyes that are heavier than their brain

Question 4

New World vs. Old World Monkeys

Answer 4

• New World: North and South America
• Old World: Africa and Asia
• Prehensile tail = tail used to grasp/hold objects (not present in Old World monkeys)
• New World monkeys also have flat noses and tend to be arboreal

Question 5

Gibbons, Orangutans and African Apes

Answer 5

• Lack tails
• Gibbons: smaller than other apes, mostly arboreal
• Orangutans: too large to cross from one tree to another by branches and mist go down to the ground and walk between them
• African apes (includes

Question 6

Old World Monkeys

Answer 6

long tailed macaques [Indonesia], baboon[South Africa], vervet [South Africa])

Question 7

New World Monkeys

Answer 7

(White-faced Capuchin, spider monkey, Howler monkey, vervet [introduced from the old world to the new world]

Question 8

Hominids

Answer 8

• Ardipithecus

- Australopithecus

Question 9

Ardipithecus

Answer 9

• In 2009, fossils of Ardipithicine ancestor uncovered dating back 4.4 million years ago (oldest)
• Fossils suggest it walked upright and didn’t use its arms for walking, as chimps do, yet it retains a primitive big toe that could grasp a tree like an ape

Question 10

Australopithecus

Answer 10

• Brains approx. 35% size of modern human brain
• Australopithecus afarensis
• Fully Bipedal
• “Lucy” 3.5 MYA from Ethiopia, most complete skeleton
• Provided evidence that bipedalism evolved before brains fully evolved

Question 11

Bipedalism

Answer 11

• walking on two legs

- Australopithecus

Question 12

Early Homo species

Answer 12

• Homo habilis “handy/skillful” (In Africa, 2.5-1.5 MYA, first tool use 2 MYA, shorter jaw, bigger brain)
• Homo erectus “standing” (Believe to be first hominid to leave Africa) (Spread to Eurasia) (1.6 MYA to 250,000 years ago, first fire use, as large as modern humans, but smaller brains, thick skull)

Question 13

Recent Homo species

Answer 13

Homo neanderthalensis

• discovered in Neander valley, Germany
• Coexisted with H. sapiens
• Disappeared approx. 30,000 years ago [possible due to extermination by H. sapiens]
• Short, stalky but powerful build
• brains larger than H. Sapiens

Question 14

Did H. Sapiens interbreed with Neanderthals?

Answer 14

• 1.5-2.1% DNA in non-Africans is estimated to be from Neanderthals
  (0% in mitochondrion, found interbreed in nucleus)

Question 15

Did we interbreed with anyone else other than Neanderthals?

Answer 15

• 4-6% DNA in Melanesians is estimated to be from Denisovans
• Denisovans DNA is found only really in Melanesia and in Tibet where the genes were selected for because of high altitude living conditions (good to mate with neanderthals)

Question 16

Homo Floreisensis

Answer 16

• Found in Flores, Indonesia
• survived until 17,000 years ago
• Volcanic eruption likely caused its extinction
• Much smaller than present-day H. sapiens

Question 17

Homo Sapiens

Answer 17

• 0.2 MYA also arose in Africa
• spread out of Africa across Eurasia and to rest of world
• Larger brains than earlier Homo species, favoring increasingly complex social life
  Neanderthals are very closed to us

Question 18

Mammalian Nervous System

Answer 18

• CNS
• PNS
• The brain

Question 19

Central Nervous System (CNS)

Answer 19

• brain and spinal cord
• Dorsal, hollow tube of nervous tissue (large cephalic ganglion [brain], long tube inferior to it [spinal cord], both brain and spinal cord protected by bone)

Question 20

Peripheral nervous system (PNS)

Answer 20

• System of lateral nerves

cranial nerved from brain, spinal nerves from the spinal cord

Question 21

Brain (4)

Answer 21

• Contains four distinct structures (cerebrum, cerebellum, diencephalon, brain stem)

Question 22

Cerebrum

Answer 22

• enlarged in primates (intellect, learning, memory, language, consciousness)
• divided into 2 hemispheres
• Top layer = cerebral cortex, rich in cell bodies (grooves and ridges, increasing surface area)

Question 23

Cortex

Answer 23

• Motor & sensory cortex
• amount of cortex devoted in various parts of the body
• Notes: lots of cortex devoted to mouth (talking, eating) and hands (tool use, fighting)

Question 24

Frontal lobe

Answer 24

• Phineas Gage - was stabbed through the brain by a rod when setting up dynamite (he survived but his personality changed)

Question 25

Temporal Lobe

Answer 25

• Facial recognition

- Tested monkey by showing him pictures of other monkeys to see if they could recognize it

Question 26

Limbic System

Answer 26

• include amygdala, Hippocampus & nucleus accumbens
• Responsible for basic physiological drives like hunger, thirst, emotions, long-term memory
• “pleasure and pain centres” located here

Question 27

Hippocampus

Answer 27

• spatial memory
• tested the brains of london taxi drivers vs. bus drivers (found taxi drivers had greater gray matter volume in the mid-posterior hippocampi (where spatial memory is stored) and less in the anterior hippocampi

Question 28

Amygdala

Answer 28

• “annoyance” of a sound is encoded in this part of the brain