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human genetics and evolution > Key steps in human evolution > Flashcards

Key steps in human evolution Flashcards

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Biology 101 flashcards
1
Q

when did chimps and human diverge

A

5-6mya

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2
Q

what has occured to climate in homo evolution

A

6-4.5mya - stable and slightly warmer than today

4.5-1mya - increasingly unstable and fluctuations

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3
Q

when did the current ice age begin and the last glacial maximum

A
  1. 58mya

11. 7kya

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4
Q

what are the period called before and after the last glacial maximum

A

before - Pleistocene

after- holocene

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5
Q

what are hominids

A

member of hominidae (great apes)

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6
Q

what are hominins

A

bipedal hominids

the lineage that leaads to homo sapiens

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7
Q

when did anatomically modern homo sap arise

A

200kya

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8
Q

what are premodern homo

A

pleistocene homo that lack modern human cranium and post cranial skeleton
inc N
H.heidelbergensis

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9
Q

what is the transitional homo

A

H.habilis (fingers could grasp)

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10
Q

what are the archaic Homo and when were they pressent

A 
Australopithecus africanus (3-2.4mya)
Australopithecus afarensis (3.7-3mya )
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11
Q

what is some of the main difficulties in the field

A

rarity of fossils
what are en route to H.sap
homoplasy

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12
Q

why is there a rarity of fossils

A

up until 2mya on African plane - scavenged

low population and frequent bottlenecks

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13
Q

what is homoplasy

A

shared characteristics that aren’t inherited from LCA

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14
Q

what is unusual about earth now

A

only one hominin

up until 13kya always at least two

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15
Q

what hominins were present 60kya

A

N
D
H.floresiensis

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16
Q

what is the earliest bipedal hominin

A

Ardipithecus ramidus

  1. 2m heght
  2. 4.mya
17
Q

what interesting about A.ramidus fossil

A

opposoble thumbs - like Chimp - evidence spent time in trees

suggets transitional phase

18
Q

what do A.afarensis fossils show about bipedalism

A

lucy - 3.6mya
same height as A.ramidus nut pelvis and muscle =
modern features = walk as we do
Laetoli footprint - suggets a gait and speed of walk sim
modern human

19
Q

what are some eamples of theories for the evolution of bipedalism

A

hands free -but this not sel pressure
thermoreg on savanna - but A.ramidus in forest
incr energy efficiency - especially over long distance/pot competitive adv over other hominins
aquatic ape theory

20
Q

what were the firt hominins to use tools

A

H. habilis

2.2mya

21
Q

what is the first tool culture

A

olduwan

split flakes from surface of pebbles - scavenging meat not hunting

22
Q

how is hommo tool use different from other animals

A

ability to improve/modify

23
Q

what are the tools used by H.erectus

A 
Achuelean tools 
1.6mya -150kya little change
well balanced 
some shaped for hand axes
for hunting
more sophisticated
24
Q

what is speech and what does it require

A

ability for sound

anatomy inc low larynx/distorted tongue/large windpipe

25
Q

what is language

A

system for communication

26
Q

what do fossils of H.erectus show us about their ability for speech

A

similar windpipe to h.sap

threfore speech probs ev

27
Q

what do N fossils suggest about their ability for speech

A

probs lacked lower larynx- less ability/limits no of sounds

28
Q

what does cranial capactiy of hominins suggets about the evolution of language

A

in A.afarensis - 375-550cm^3
in H.habilis 650cm^3 and evidence of Broca area
after this all more than 1000cm^3

29
Q

what is the problem with looking at brocas area on fossils

A

not human specific

not solely language role

30
Q

what gene has genetics studied for the ev of language

A

FOXP2

assoc with diseases in which language affected

31
Q

what subsitutions present in H.sap of FOXP2 and what hominins present in

A

T303N
N325S
both in N and some studies suggest in Erectus

32
Q

what the effect of incr FOXP2 in zebra finch

A

incr dev of song = pot inv in reg song syst

33
Q

what the phenotype shown by mouse with the FOXP2 homo subs

A

incr neuron growth in forebrain
altered patterns of ultrasonic vocalisations
incr dendrite length and synaptic plastcity
decr in dopamine conc

34
Q

comparison of genes in human and chimp

A

incr nerual gene in homo

35
Q

what evidence does tool use suggest about language

A

oldowan - tech stasis inconsitent with presence of language

pot a coev relationship would expect

36
Q

what have studies on the social transmission of tool use shown

A

imporve when laguage to teach
not by imitation
suggest pot a sel for language

human genetics and evolution (12 decks)

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