Lecture 16 Flashcards
What do all order Primates, including Prosimians have?
- nails instead of claws
- binocular vision
- grasping hands (arboreal adaptation)
What are the 5 (6) great ape species what are hominids (“man-like”)
- orangutan
- gorilla (2 species?)
- chimpanzee
- bonobo
- humans
explain hominid DNA and fossil phylogeny of humans and chimps
- last shared a common ancestor ~5-7 mya
- chimps/bonobos are our closest living relatives genetically, but are not in the human lineage
PHYLOGENY:
outgroup : old world monkey
then gibbon
then orangutan
then gorilla
then chimpanzee
then humans
what are hominins?
- a monophyletic group that includes Homo sapiens and all our extinct bipedal non-ape relatives
What is are the arboreal traits?
- long arms
- curved long fingers
what is the key derived hominin trait and what are the clues to modes of locomotion?
- key derived hominin trait: bipedalism
- clues (kinesiology): arm length, knee joints, finger length, attachment of skull to vertebrae, pelvis
what is a key evidence of Genus Australopithecus (southern “ape”) and review the rest
- evidence from skeleton and footprints: they also walked upright (~bipedal) unlike any living apes
- all from south or east africa (4-2 mya)
- early fossils are small and have very ape-like skills (small brains)
review and memorize Australopithecus afarensis
- famous ‘Lucy’ fossil
- found in ethiopia, 3.2mya, 40% complete skeleton
- ape-like physical characterisitcs (long arms, curved fingers; partly arboreal adaptations)
- small brain
- bipedal!
- footprings in volcanic ash (no knuckle marks)
What is the Human (hominin) lineage
- not a ‘ladder of progress’ but a ‘bush’ of many fossil species (~4-5 coexisting fossil species at ~1.8 mya)
did climate change promote bipedalism?
- droughts increased the area of savannah (open grassland, few trees) in Africa around the time of hominin evolution, driving adaptations to open areas
- upright stance (bipedalism) frees the hands for tool manufacture and use, carrying large loads, as well as running, seeing over longer distances, and other developments
What MAY have increased brain size?
- social evolution and speech
What group was an example of a successful hominin and describe them
- Neanderthals
- Europe ~200000 to 28000 years ago
- stocky, strong and thick-boned with a large brain (larger than modern humans)
- buried their dead and made hunting tools
- lighter skin with blue eyes and red hair
What did the Genographic project : RM’s DNA do?
- used thousands of genetic markers (mutations) to trace development of DNA
What are the 2 predictions on why the Neanderthals went extinct by ~28000 year?
- last “ice age”, altered climate, vegetation and animal distributions? (but they were well adapted to cold environments)
- competition from modern humans who left Africa around 60000 years ago?
Where has the highest genetic diversity of humans?
- africa
