lecture 18

Question 1

The recent ancestry of Humans

Answer 1

evolution since the last common ancestor with chimps and bonobos (8 mya).

Question 2

hominin

Answer 2

any species more closely related to humans than to chumps and bonobos.

Question 3

Sahelanthropus tehadensis

Answer 3

early hominin; close to time of human-chimp divergence. chimp-ish braincase, humanish face.

Question 4

archaic hominins

Answer 4

2-4 million years ago. level of structural variation among these fossils is similar to variation within humans, chimps, and bonobos.

Question 5

megadont archaic humans

Answer 5

large faces, small braincase, enormous cheek teeth, robust jaws, and powerful chewing.

Question 6

transitional hominins

Answer 6

first “humans”? sympatric species? found with stone tools.

Question 7

premodern humans

Answer 7

outside of africa, undisputed “humans,” large braincase, smaller flat face, smaller teeth and jaws, taller, longer legs, and less sexual size dimorphism.

• H. neanderthalensis (europe)
• H. heidelbergensis (africa)
• H. erectus (asian)
• H. ergaster (africa)
• • the last two the two species in which modern humans descended from.

Question 8

anatomically modern human

Answer 8

anatomically modern H. sapiens 100,000 years ago in Africa. large braincase, high steep forehead, short flat face, and prominent nose.

• found in prepared grave with others (men, women, infant).
• buried with animal bones, jewelry, and tools.

Question 9

homo sapiens are the

Answer 9

sole survivors of an otherwise extinct radiation of bipedal african hominins.

Question 10

perhaps up to

Answer 10

5 hominin species coexisting in africa.

Question 11

out of africa model (origins of homo sapiens)

Answer 11

modern humans evolved current geographic variation within the last 100,000-200,000 years after migration out of africa.

Question 12

hybridization/assimilation model (origins of homo sapiens)

Answer 12

some modern humans have genes from archaic homo species that are now extinct.

Question 13

multiregional evolution model (origins of homo sapiens)

Answer 13

geographic variation may be derived from variation in ancestral H. erectus 1.5 to 2 million years ago.

Question 14

Genetic variation in Homo sapiens

Answer 14

2,004 individuals, 26 populations, and 84.7 million SNPs.

Question 15

chimps from the same social group are

Answer 15

more genetically different than any two humans from anywhere in the world.

Question 16

most genetic diversity in humans occurs as

Answer 16

differences among individuals, within populations, not differences between populations.

Question 17

human phylogenetic relationships:

Answer 17

• evidence from full genomes:
  > gene flow with Neandertal.
  > gene flow with Denisovan.
  > extinct lineages?

Question 18

phylogeography - Africa

Answer 18

2,500+ individuals, 185 populations, 1,327 microsatellites.
- mixed ancestry, migration across the continent, african-americans (71% niger-kordofanian, 13% european, and 8% african).

Question 19

phylogeography - europe

Answer 19

3,000 europeans, 500,000+ SNPs. strong correlation between genetic/geographic distances, genotype predicts origin, and disease mapping problem.

Question 20

phylogeography - bering land bridge

Answer 20

biotic exchange and glacial cycles.

• divergence siberians/proto-native americans: 24.9 ka.
• native american founder lineages: 18.4 ka.
• population expansion: 16 ka.
• plesitocene extinction: 1) overkill 2) climate change

Question 21

phylogeography - post-colonial usa

Answer 21

770,000 individuals, 20 million genalogical records, 500 million genetic connections, ~1 million SNPs.