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EVOLUTION > Human Evolution (10) > Flashcards

Human Evolution (10) Flashcards

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1
Q

Evolutionary trends?

A

= persistent, directional change in a character that results in significant change through time.

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2
Q

Primate lineage?

A

From Miocene until present day.

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3
Q

Hominoid?

A

= extinct & extant apes and humans.

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4
Q

Hominid?

A

= extinct & extant great apes and humans.

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5
Q

Hominin?

A

= extinct & extant humans (human lineage only).

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6
Q

Hominin lineage initially vs reality?

A

● Initially
= Linear model.

● Reality
= Bush model.

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7
Q

How do we know which taxa to include in the hominin lineage?

A

We use traits to identify & classify taxa as hominins.

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8
Q

Main traits that group hominins & exclude other great apes? (3)

A

• Bipedalism.
• Dentition (Canine reductio.
• Increased brain size.

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9
Q

Bipedalism forms? (3)

A

• Facultative.
• Habitual.
• Obligate.

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10
Q

Facultative bipedalism?

A

= assumed for particular action.

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11
Q

Habitual bipedalism?

A

= regular form of locomotion.

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12
Q

Obligate bipedalism?

A

= only form of locomotion.

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13
Q

Trait changes to allow for bipedalism? (6)

A

• Foramen magnum.
• Spine shape.
• Pelvis shape.
• Rib cage shape.
• Angled knee.
• Foot.

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14
Q

Canine reduction attributes? (3)

A

• Loss of canine honing.
• Enamel thinning.
• Diminished sexual dimorphism.

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15
Q

Results of canine reduction? (2)

A

• Enamel thinning.
• Diminished sexual dimorphism.

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16
Q

Diminished sexual dimorphism?

A

= no differences in female teeth & male teeth.

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17
Q

Increased brain size attributes? (3)

A

• Frontal lobe increases over time.
• Enabled cognition.
• Potentially facilitated tool use & other cognitive abilities.

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18
Q

Results of frontal lobe change? (2)

A

• Enabled cognition.
• Potent tool use & other cognitive function.

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19
Q

How do we compare these 3 traits across taxa?

A

Look for apomorphies, especially synapomorphies.

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20
Q

What can we use these comparisons across taxa for?

A

Used to find evolutionary trends.

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21
Q

Outline the hominin lineage? (3)

A

• Pre-Australopithecines.
• Australopithecines.
• Homo species.

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22
Q

List the Pre-Australopithecines? (3)

A

• Sahelanthropus tchadenis.
• Orrorin tugensis.
• Ardipithecus ramidus.

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23
Q

Sahelanthropus tchadenis year?

A

7Ma.

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24
Q

Sahelanthropus tchadenis attributes? (5)

Study These Flashcards
A

• Bipedalism (facultative?).
• Reduced canines.
• Smaller chimpanzees.
• Thick molar enamel.
• Cranial size (380cm²).

25
Orrorin tugensis year?
6Ma.
26
Orrorin tugensis attributes? (5)
• Bipedalism (facultative?). • Reduced canines. • Ape-like • Thick enamels. • Kenya.
27
Ardipithecus ramidus year?
4.4Ma.
28
Ardipithecus ramidus attributes? (6)
• Bipedalism (facultative/obligate?). • Arboreal. • Opposable big toe. • Pelvis broad?. • Thin enamel. • Little canine sexual dimorphism.
29
List of Austalopithecines? (2)
• A. anamensis. • A. afarensis.
30
A. anamensis year?
4.2Ma - 3.9Ma.
31
A. anamensis attributes? (8)
• Bipedalism (habitual?). • No canine honing. • Thick enamel. • Large canine root size. • Similar to extant apes. • Kenya. • Arboreal? • Sexual dimorphism?
32
A. afarensis year?
4Ma - 3Ma.
33
A. afarensis attributes? (6)
• Bipedalism (habitual/obligate?). • Forelimbs indicate access to arboreal resources. • Smaller canines than apes. • Sexual dimorphism similar to humans. • Some honing mechanism. • Ethiopa.
34
List of Homo species? (5)
• H. ergaster. • H. habilis. • H. erectus. • H. heidelbergensis. • H. sapiens.
35
H. ergaster year?
2Ma - 0.9Ma.
36
H. ergaster attributes? (6)
• Obligate biped. • Reduced jaw. • Post canine reduced as brain size increases. • Dietary changes. • Increased sociability, group size & home range. • East Africa (mandible) & SA (cranium).
37
Variability selection hypothesis?
= hypothesis that explains changes in hominin traits & gives us an idea of the selection pressures that may have changed hominin traits (anatomy & morphology).
38
Selection pressure on brain size?
Climate variability.
39
Selection pressure on morphology?
Resource availability.
40
Results of climate variability? (4)
Changes in resources/food. | Changes in diet. | Adaptations to dietary changes. | Changes in anatomy & morphology.
41
Homo habilis?
First tool maker.
42
Homo erectus year?
2Ma.
43
Homo erectus attributes? (4)
• 1st hominin to migrate out of Africa. • Large brain. • Dexterous fingers. • Long legs.
44
Homo heidelbergensis?
= homo species that arose in time of fire control.
45
Human-Chimpanzee divergence attributes? (2)
• Divergence occurred about 8-10mya. • Supported by fossil & DNA evidence.
46
Evolutionary trends of morphological traits? (6)
• Small to large brain size. • Quadripedal to Bipedal. • Canine reduction & enamel thinning. • Arboreal to terrestrial. • Change in spine attachment & dentition. • Change in skull shape.
47
What do we mean by change in spine attachment?
We mean change from back of spine (towards the back) to directly under the spine.
48
How did pelvis change?
From narrow (apes) to wide (humans).
49
How did the knee angle change?
From knees angle outwards (apes) to knees angle inwards (humans).
50
How did the foot change?
From opposable thumbs on foot (apes/chimpanzees) to non-opposable thumbs on foot (humans).
51
Differences between Pre-Australopithecines & Australopithecines? (2)
• Skull shapes. • Bipedality.
52
A. afarensis is AKA?
Lucy.
53
H. ergaster is AKA?
Homo erectus in Africa.
54
What accounts for dietary changes seen in H. ergaster?
New selective pressures on brain size.
55
How do we about increased sociability, group size & home range observed in H. ergaster?
Fossils were found together.
56
What kind of selection type trait is brain size?
A directional selection trait.
57
Main differences/traits that distinguish Australopithecines from Homo species? (3)
• Brain size. • Canine reduction. • Bipedalism.
58
Selection pressures on Homo species? (2)
• Climate variability. • Resource availability.

EVOLUTION (12 decks)

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