Lecture 17

Question 1

Uniquely Human Features

Answer 1

• large brains
• bipedal walking
• verbal symbolic speech
• music
• domestication of wolves and other animals

Question 2

Human Features Shared With Chimps

Answer 2

• self awareness
• use of tools
• making tools
• making weapons for hunting
• warfare
• complex social structures

Question 3

Ape–>Human size/proportion

Answer 3

• hips changed first, then foot then rib cage and skull
• variety of different things changing under variety of selective pressures at different times
• didn’t evolve because of our smarts, those came later
• upright walking came when we started to move away from forests, forests retreating and much of the ground is being replaced by dryer land ecosystems

Question 4

A. afarensis

Answer 4

• foragmen magnum that’s now in the base of the skull like ours because of how they walked (upright now)
• shows a lot of changes in anatomy
• pelvis and links to legs changes so they can walk upright (pelvis has to support vertical being)
• number of vertebrae changes as well as number of ribs

Question 5

Human vs. Ape Hip Girdle

Answer 5

• apes is longer and sticks out backward to support their locomotion
• humans is smaller and oriented so the human can walk upright

Question 6

Chimps vs. Humans

Answer 6

• femur is a straight line from hip articulation down to inside of kneecap
• human femur goes from inside hip articulation down to outside of kneecap (so it crosses over)
• chimps birth canal is smaller than humans because we have bigger brains to fit through
• human butt helps you stand upright-gives you stability; gut is upright and has to be supported by the pelvis so the butt helps with holding all this vertically
• humans developed to be able to run for a long

Question 7

Humans vs. Gorillas

Answer 7

• humans are the only primate with a chin

- humans teeth shaped in a parabola while gorillas shaped in a larger U

Question 8

Mosaic Evolution

Answer 8

-in bits that aren’t at the same time/place

Question 9

Piltdown Man

Answer 9

• made skull with human and ancient orangutan jaw

- fooled lots of people into thinking this was the most likely ancestor

Question 10

First Skull of A. africanus

Answer 10

• has endo cast of brain
• child skull
• fairly large brain
• teeth like ours

Question 11

H. ergaster (1)

Answer 11

-when this was discovered so are stone tools in the same strata

Question 12

H. erectus (1)

Answer 12

• individuals leave Africa and survive for a very long time
• last one died around 20,000 years ago in East Asia
• split with Neanderthals around 500,000 years ago (sister species)
• Neanderthals took care of each other and injuries had a culture
• at least two hybridization events that take place with these two ancient humans

Question 13

How many kinds humans living on earth at one time?

Answer 13

• 5
• Denisovians (only known via genome sequence from 43 kyr finger bone found in Denisova cave-Russia)
• H. neanderthalensis (genome also sequenced by Paabo lab)
• H. floriensis (possibly dwarfed H. erectus or older hominid-no DNA available) “Hobbits”
• H. erectus (slight chance that they survived this late in S. Asia)
• H. sapiens (rapidly leaving Africa at this time and meeting up with other hominids)

Question 14

What makes a human a human?

Answer 14

• speech

- gene required for human speech is FOXP2

Question 15

Weirdest Discovery Ever Made

Answer 15

• H. floresiensis
• called hobbits, didn’t ever get much bigger than a couple feet
• is it an australopithecine?
• a lot of species developed miniature variations of many that’s what this little guy is

Question 16

Body Size on Islands

Answer 16

-big animals get smaller and small animals get bigger

Question 17

Ardipithecus ramidus

Answer 17

• now our oldest well known ancestor
• likely split of humans and chimps 6-7 million years ago
• ape like skull
• brain ape sized
• teeth intermediate between ape and human
• walked upright-hip
• could climb well-foot still hand like

Question 18

H. hablils

Answer 18

• many features still similar to Australopithecus
• dates about 1-1.8 mya
• somewhat larger brain than Australopithecus
• small in stature
• post cranial skeleton not well known

Question 19

H. ergaster (2)

Answer 19

• early Homo
• post cranial skeleton much more like ours, larger skull than earlier hominids
• probable maker of first stone tools, 2.5 mya, and probable ancestor of H. erectus

Question 20

H. erectus (lots of info)

Answer 20

• appeared 1.8-1.7 mya
• closely related descendant of H. ergaster, but migrated from Africa into Eurasia as early as 1.8 mya-first hominid to adapt to cold conditions
• by about 700 kya gave rise to H. heidelbergensis, the ancestor to H. neanderthalensis and H. sapiens
• remarkably stable in morphology and apparently behavior for about 1 mya, although brain size increased
• brain size 800-900 cc earlier members and 1100 cc in latest
• pronounced supraorbital torus and prognathism
• dentition human, postcranium similar to humans, similar in size
• first human nose
• moderately arched basicranium-some ability to speak?
• stone tools limited and conservative use of fire (China)
• processed meat, likely hunter
• persisted in Asia to somewhere between 100 kya 20 kya

Question 21

Tools Australopithecus

Answer 21

• no trace oldest ca 2.5 million years oldowan tradition possible copper associated with H. habilis
• by ca 1.5 million years have much more sophisticated acheulean industry

Question 22

H. neanderthalensis

Answer 22

• middle East, western Asia, Europe-an ice age phenomenon (with a bad name in pop culture)
• brains size larger than ours (1200 to over 2000 cc)
• powerful skeletons-injuries like modern extreme athletes
• mid facial prognathism, an adaptation to serve cold
• very large supraorbital torus
• peculiar wear on incisors-behavioral indication
• brain asymmetry as in H. sapiens
• some interbreeding with humans indicated by genomic studies
• appear in Europe 130,000 years ago
• became extinct within a few thousand years from time of entry of H. sapiens into Europe

Question 23

Some indications of culture in Neanderthals

Answer 23

• buried dead

- no art of personal adornment as in modern humans, made clothing, spears and sophisticated stone tools

Question 24

Homo Sapiens

Answer 24

• Europeans and Asians-a bizarre evolutionary history revealed by genome sequencing of us, Neanderthals, and Denisovans
• H. sapiens expanding out of Africa and into Europe asia and southern asia and pacific
• meet and mate with neanderthals in europe

Question 25

Interbreeding

Answer 25

- all out of africa - H.s. and Denisovans-in south Asia - also traced in western pacific - H.s. and H.n. intermingling occurred just out of Africa

Question 26

Genome Sequencing of Extinct Humans

Answer 26

- methods developed by Svante Paabo in Germany - DNA isolated from bones in caves or other cool dry sites. - DNA survives up to 100,000 years - Fragments sequenced and aligned and compared to modern human genome - they have nearly complete genomes of Neanderthals and Denisovans (from a single finger from Denisova Cave)

Question 27

Modern Humans-Record of Hybridization

Answer 27

- Africans-no Denisovan and no Neanderthal genes--highest diversity of modern humans - Europeans and north Asians-4-6% neanderthal genes in their DNA, but not Denisovan - Australian and New Guinea people--a few percent Denisovan genes in their DNA, as well as some Neanderthal genes - molecular clock says Denisovans 1 myr diverged from us

Question 28

FOP2 Gene

Answer 28

- required for human speech - differs in two bases from all apes - these two bases are shared between modern humans and neanderthals

Question 29

An enhancer of the FZD9 gene in neocortex growth

Answer 29

- human version increases neocortex growth when expressed in mouse embryos - the enhancer from chimp does not

Question 30

Unexpected Discoveries Still Happen

Answer 30

- H. floresiensis complete skull and skeleton of recent, tiny and primitive looking hominid - possible explanations: Australopithecus, island miniaturized H. erectus, pathological H. sapiens - DNA not preserved in hot wet environment - hope for more fossils