Chapter 8 Flashcards
Transition to Modern Homo sapiens
lumping vs splitting taxonomy of modern homo sapiens
Wood and Lonergan’s:
Lumpers:
homo sapiens
Splitters:
homo antecessor
H. cerparendis
H. nethandrathalists
H. sapiens
Anatomically Modern Humans (AMH)
Humans who you wouldn’t’ recognize as being different.
Behaviourally Modern Humans (BMH)
humans engaged in symbolic behaviour (e.g.
drawing, showing clear signs of belief in an afterlife, deliberate
burial of the dead, or taking part in other ‘typically human’ activities
Mosaic evolution
major evolutionary change in a species takes place in stages, with one aspect of the species changing independently of the others
Origin Theory 1:
Out of Africa
modern homo sapiens developed antigenically from and earlier species in Africa.
Non recombinant genes
genes passed down from only one parent
mitochondrial DNA (mtDNA) 1
tracks evolutionary lines
(haplogroups) based on the fact that the mother is the sole provider of genetic content
What does mtDNA show?
Everyone who possesses a particular suite of mutations will be
related
mitochondrial DNA (mtDNA) 2
mtDNA code is not
involved in construction; therefore, mutants will not die off because they cannot harm the physical form
mitochondrial DNA (mtDNA) 3
track change over relatively shorter
periods of time because mtDNA mutates faster than nuclear DNA, only 16,500 base pairs
Mitochondrial Eve
hypothetical woman who first bore the mtDNA pattern that all currently living humans share, i.e. our most recent common ancestor (MRCA)
Mitochondrial Eve study methods and findings
initial study sampled people from five geographical areas
Two primary branches of descent emerged:
entirely African and one that had all five geographical groups
mutations occurred at different rates with different parts of the
mtDNA
common
ancestor date
171,500 ± 50,000
Y chromosomes
evidence for Out of Africa hypothesis, y chromosome found dating about 60,000 to 90,000 ya
2nd theory of origin: Multiregionalism
sees modern H. sapiens as having developed at roughly the same time in a number of different parts of the world, most notably Africa, China, and Indonesia
Evidence of Multiregionalism
traditional ‘stones and
bones’, and an emphasis on the continuity of features in different regions eg. shovel-
shaped incisors of H. erectus with the same feature found in East Asians and the Aboriginal peoples of the Americas.
3rd origin theory:
Clinal Replacement
geographically defined
populations with different gene frequencies (and physical traits) that
intergrade at the edge. Waves of cline movement over time.