CH. 8 + 9 (What about Us?)

Question 1

Raymond Dart

Answer 1

Anthropologist who was handed part of “the missing link” ‘s fossilized remains.

Question 2

Australopithecus Africanus

Answer 2

Southern Ape Man (species name coined by Raymond Dart)

Question 3

Taungs child

Answer 3

Specimen of “Southern ape-man” species found in Taung South Africa. Mix of human and ape like characteristics. Written about by Raymond Dart. Provided some of the first fossil evidence to back up Darwin’s claims that man evolved from Africa.

Question 4

Human’s closest relative?

Answer 4

Chimps and Bonobos equally. We are not descended from chimps!! We simply had a common ancestor several million years ago which split

Question 5

Did Darwin suggest we evolved from other species in “The Origin of Species”?

Answer 5

No, he knew the controversial firestorm that would ignite if he did. He definitively stated this later on in The Descent of Man ten years later. A.R. Wallace and Charles Lyell did not agree with Darwin on this point (natural selection couldn’t have produced something so smart as humans).

Question 6

Human features that identify us as primates?

Answer 6

forward-facing eyes, fingernails, colour vision, opposable thumbs (includes monkeys, apes, lemurs)

Question 7

Hominoidea

Answer 7

smaller superfamily that includes lesser apes (gibbons) and great apes (chimps, gorillas, orangutans, and ourselves)

Question 8

Hominidae

Answer 8

great apes. flattened fingernails, 32 teeth, enlarged ovaries, prolonged parental care.

Question 9

Missing Link

Answer 9

Single ancestral species that gave rise to both modern humans and chimps. Likely that it looks closer to chimps than humans. Has not been discovered and is not reasonable to expect such a discovery because we would need complete human and chimp fossil record.

Question 10

How can we tell we have changed more than modern apes?

Answer 10

Humans have many divergent features while chimps, gorillas, and orangutans are similar.

Question 11

Do we have a continuous fossil record of human ancestry?

Answer 11

No. We have a mosaic of fossils and we are not sure if they are evolutionary dead ends or part of the single thread that became modern humans. Possible that as many as four human-like species lived in Africa at same time.

Question 12

Hominin

Answer 12

All species on human side of split of our common ancestor with chimps

Question 13

Sahelanthropus tchadensis

Answer 13

Possibly an older hominin, discovered in 2002 by Michael Brunet between 6-7 mil years old (close to split). Maybe earliest human ancestor!

Question 14

Orrorin Tugensis

Answer 14

6 mil year old species we found some bone fragments of

Question 15

AL 288-1 or “Lucy”

Answer 15

Specimen of Australopithecus afarensis. Showed that bipedalism evolved before larger brains (femur angles inwards).

Question 16

Laetoli footprints

Answer 16

Fossilized footprints found in Tanzania confirming bipedality of A. afarensis (only hominin on record from 3.6 mil YA). Fossilized human behaviour.

Question 17

Difference between genus Homo and Australopithecus?

Answer 17

They’re sort of borderline, but genus homo generally has larger brain (arbitrary cut off size though of arouns 600 cubic cm)

Question 18

Homo Habilis

Answer 18

2.5 mil years old, first tool using human

Question 19

What species are in the genus Paranthropus?

Answer 19

Bosei, robustus, and aethiopicus (robust hominins) all three of which went extinct leaving no descendants

Question 20

Homo erectus

Answer 20

first hominin to Leave Africa (remains have been found in China (peking man), Indonesia (Java man, bones that Dubois hid under his house), Europe and Middle East)

Question 21

How successful was H. erectus?

Answer 21

Very—large pop and was around for 1.5 mil years ish. Went extinct 300 000 years ago but may have left descendants — H. heidelbergensis and H. neanderthalensis.

Question 22

Why do neanderthal fossils disappear around 28 000 YA?

Answer 22

Trick question, we don’t know. Seems like homo sapiens outcompeted every other species.

Question 23

“Multi-regional” theory

Answer 23

Theory that explains why neanderthals and H. erectus disappeared. Evolutionary replacement: H. erectus (and perhaps neanderthals) evolved into H. sapiens independently in several areas. Doesn’t make much sense however because it would imply a much greater genetic difference than what exists currently between populations.

Question 24

“Out of Africa” Theory

Answer 24

Modern H. sapiens originated in Africa and spread, physically replacing H. erectus and Neanderthals. Outcompeted them.

Question 25

Homo floresiensis

Answer 25

Hobbit species (fossils from 18 000 YA) that are in homo genus but are not sapiens. Their brains are too small. They were possibly an isolated population of H. erectus that colonized Flores and were bypassed when modern H. sapiens spread.

Question 26

Where and when did our divergence from ancestor of chimps occur?

Answer 26

East or Central Africa about 7 million years ago.

Question 27

Why do we think the evolution that produced humans occurred?

Answer 27

Between 10 and 3 million years ago was huge drought, which was followed by periods of drought and rainfall. During dry periods, rainforests gave way to more open habitat (savanna, grassland, open forest, desert scrub)—freed our hands to carry foods that were newly available, moved body off ground reducing exposed SA to sun.

Question 28

Difference between us and chimps

Answer 28

genetic divergence: changes in the proteins produced by genes, presence/absence of genes (6% of our genes aren’t found in any chimp), number of gene copies, when and where genes are expressed during development.

Question 29

amylase

Answer 29

Salivary enzyme helps break down starch into digestible sugar. Chimps have a single copy, humans have between two to sixteen copies (average of six).

Question 30

Can we tell which genes make us human?

Answer 30

No, not really. We can’t zero in on single gene to demonstrate mutation made it human vs chimp. We can pick out classes of genes that have evolved rapidly on the human branch. Include genes involved in immune system, gamete formation, cell death, and sensory perception and nerve formation.

Question 31

FOXP2

Answer 31

gene that might have been involved in appearance of human speech.

Question 32

How can we conclusively prove that a given gene causes human/chimp differences?

Answer 32

moving the gene from one species to another. WE REALLY DONT WANT TO DO THIS.

Question 33

Does genetic evidence back the existence of races?

Answer 33

No, not in the way we identify ‘race’. Only about 10-15% of all genetic variation in humans is represented by differences in physical appearance. Remainer of genetic variation (85-90% occurs among individuals within races).

Question 34

Sickle-cell anemia and Tay-Sachs disease

Answer 34

• Most common in blacks whose ancestors came from equatorial Africa because the mutation also provided some resistance to malaria
• fatal genetic disorder common among Ashkenazi Jews and Cajuns of Louisiana (genetic drift in ancestral populations)

Question 35

How is knowing ethnicity and differences in allele frequency important?

Answer 35

Important to know because it can be helpful to diagnose certain genetic diseases, also successful organ donation requires a match between several genes.

Question 36

Why is there greater variation between races in genes that affect physical appearance?

Answer 36

Sexual selection. Gene-culture coevolution.

Question 37

Lactase-persistence

Answer 37

Exists in pastorlist populations (some African, Middle Eastern and European) who raise cows.

Question 38

CCR5-delta32

Answer 38

Provides strong resistance against infection with AIDS virus.

Question 39

Some evolutionary questions we still don’t know

Answer 39

• how exactly does sexual selection work
• do females select males with good genes
• how much of a role does genetic drift as opposed to natural or sexual selection play in evolution of DNA sequences or features
• which fossil hominins are on the direct line of H. sapiens.
• what caused Cambrian explosion of life