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ANT-Human Evolution > Midterm > Flashcards

Midterm Flashcards

1
Q

What is paleoanthropology?

A

The study of human fossils

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2
Q

a. Two main concepts in biological anthropology

A

1) All humans are a product of their evolutionary history

2) all humans are a product of their individual life history

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3
Q

What’s evolution?

A

“Evolution is a change in the frequency of alleles within a population from one generation to the next”

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4
Q

John Ray

A

Identified the existence of biological species “natural theology: the creation of life”

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5
Q

Carl Linnaeus

A

Created binomial nomenclature and taxonomy

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6
Q

James Hutton

A
  • Father of modern geology
  • Understand Earth’s history through natural forces
    -Uniformitarianism: The formation of the Earth is a long slow process
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7
Q

iv. George Cuvier

A

Established extinction was a fact

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8
Q

v. Jean-Baptiste Lamarck

A
  • Recognized that evolution could occur in contrast to Cuvier
  • Believed species change over time in response to the environment and changes are inherited by offspring
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9
Q

Charles Lyell

A
  • Principles of geology
  • Uniformitarianism: the belief that geological processes shaped our world
  • Deep time: geological processes are very slow, so the earth must be very old
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10
Q

Thomas Malthus

A

-Highly influential to Darwin
- Wrote “An Essay on the Principle of Population”
1) food is necessary for human existence
2) humans populations can grow geometrically while resources grow (next additively
3) since humans don’t voluntarily choose not to reproduce famines, diseases, poverty, and war will result

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11
Q

Charles Darwin

A
  • Voyage of the Beagle (1831-1836): intended 3-year trip to chart S. American waters for the UK
  • He returned from the voyage with the idea of evolution!
  • He understood that species can diversify in descendent species
  • Species can change and adapt to their environment, but he initially lacked a mechanism for this
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12
Q

Importance of Galapagos Islands

A
  • The islands were very isolated, so there were animals that had some resemblance to mainland species
  • Lacked whole groups of animals, so the island animals filled these open niches (adaptive radiation)
  • Different environments make certain features more advantageous; the animals were oddly approachable, making them easy to study
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13
Q

Adaptive Radiation

A

New species evolve to fill voids left by other animals’ absences

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14
Q

What were Darwin’s observations?

A

1) organisms vary in several traits (ex. Color, shape, and size)

2) much of this variation is heritable

3) more individuals are produced than can be supported by available resources. Therefore, there must be a fierce struggle for existence among individuals of a population

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15
Q

What is Natural selection?

A

The gradual process by which heritable biological traits become either more or less common in a population because of the effect of inherited traits on the reproductive success of different organisms interacting within their environment.

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16
Q

What are the 3 principles of Natural selection?

A

1) physical characteristics inherited from parents

2) individuals within a species vary

3) great fertility or organisms relative to support from the environment results in competition

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17
Q

Darwin and Wallace’s Significance

A
  • They independently came up with the idea of Natural Selection
  • Darwin had been sitting on the idea for 25 years
  • Wallace’s 1858 letter prompted Darwin to publish
  • They presented the idea to the Linnean Society together in 1858 (although Wallace wasn’t there)
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18
Q

a. Survival of the Fittest?

A
  • Herbert Spencer
  • It’s actually “Survival of the Fitter”: heritable traits of the more successful reproducers passed on at higher frequency
    -Organisms with higher reproductive success pass on their genes (survival will help produce viable offspring)
  • Natural selection produces fit but not necessarily optimal phenotypes
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19
Q

Gregor Mendel

A
  • Father of genetics
  • Cross pollinated true-bred strains of pea plants
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20
Q

Phenotype

A

The observable appearance of an organism

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21
Q

Genotype

A

The genetic components (alleles or variants) that an individual has for a particular gene

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22
Q

Homozygous Alleles

A

Alleles are the same
- Homozygous dominant: AA
- Homozygous recessive: aa

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23
Q

Heterozygous Alleles

A

Alleles are different (Aa)

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24
Q

Dominant allele (A)

A

Only one copy of allele needed to produce phenotype

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25
Q

Recessive allele (a)

A

Both copies of allele needed to produce phenotype

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26
Q

Natural selection acts on _________

A

individuals

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27
Q

Evolution acts on __________

A

populations

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28
Q

Modern Evolutionary Synthesis

A

Combination of natural selection (mechanism of evolution) and genetics (mechanism of inheritance)

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29
Q

4 Forces of Evolution

A

(1) mutation: the spontaneous generation of new alleles
(2) migration: movement between two reproductively isolated populations
(3) genetic drift: random change in allele frequency (4) natural selection: differential reproduction based on adaptation

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30
Q

Mutation

A

Spontaneous error that occurs during the replication of DNA; the only source of new genetic variation or alleles

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31
Q

Basic DNA structure

A

Phosphate, diribose sugar, nucleotide

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32
Q

SNPs

A

Single nucleotide polymorphism, basically a point mutation

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33
Q

d. Point mutations

A

alteration of a single base pair in the DNA sequence

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34
Q

Missense

A

A single nucleotide change that results in a different amio acid being coded

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35
Q

Nonsense

A

A single nucleotide change that results in a stop condon. This causes that protein to stop translating early

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36
Q

Frameshift

A

Insertion or deletion of nucleotide bases in numbers other than 3

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37
Q

Silent mutations and codons

A

Silent mutations occur when a base is switched with another nucleotide, but the codon (3 nucleotides) still codes for the same amino acid

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38
Q

Large Scale mutations

A

Rearrangements that occur in lager sections of the chromosome

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39
Q

Examples of large scale mutations

A
  • Melanocortin 1 receptor: redheads
  • Sickle Cell Mutation: homozygous SS can lead to sickle-cell disease
  • Sickle-Cell Anemia and malaria
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40
Q

Balanced polymorphism

A

Situation where selection maintains two or more alleles for a specific gene in a population

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41
Q

Migration/gene flow

A

Immigration from other populations can introduce new alleles; alleles can be selected for in one population and migrate into another

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42
Q

Genetic Drift

A

Drift changes in allele frequencies resulting from random chance (ex. Bottleneck)

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43
Q

Natural Selection simplified

A

Differential survival of individuals due to differences in phenotype

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44
Q

What are the types of natural selection?

A
  • Directional selection
  • Stabilizing selection
  • Disruptive selection (know the graphs)
  • Positive selection: fixes beneficial variation
    -Purifying selection: removes deleterious variation
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45
Q

List out the taxonomy order

A

Life > Kingdom > phylum > class > order > family > genus > species

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46
Q

Ancestral traits

A

Old traits shared with a distant ancestor (primitive)

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47
Q

Derived traits

A

Newer more recently evolved traits inherited from a more recent common ancestor

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48
Q

Cladogram

A

Depicts the evolutionary relationships of species; each node is a speciation event, indicates a last common ancestor for a group of descendent species; more closely related species are linked by shared derived or more recently evolved character

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49
Q

What is a primate?

A

A very diverse group of mammals (~230-270 species)

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50
Q

General characteristics

A

Well adapted for a variety of ecological niches; anatomy more similar to earlier forms; well suited for changing environments (ex. Primates and black bears)

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51
Q

Specialist characteristics

A

Well adapted for stable environments with specific traits for that environment (ex. Pandas are well adapted for bamboo forests)

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52
Q

Postcranial traits in primates

A
  • Grasping hands and feet; nails instead of claws
  • Forearm mobility
  • Clavicle: forelimb flexibility
  • Unique quadrupedal gait
  • Upright postures
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53
Q

Locomotion in primates

A
  • Quadrupedalism
  • Vertical clinging and leaping
  • Slow or cautious climbing
  • Brachiation
  • Knuckle-walking
  • Bipedalism
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54
Q

Cranial traits in primates

A
  • Decreased reliance on olfaction
    -Orbital frontation and convergence
  • Postorbital bar
  • Generalized dentition
  • Encephalization
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55
Q

Behavior and life history in primates

A
  • Life history
  • Complex social systems
  • Behavioral complexity and flexibility
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56
Q

Persymines

A

lemurs and tarsiers

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57
Q

Haplorhines

A

lemurs, lorries, galagoes

58
Q

Strepsirrhines

A

anthropoids and tarsiers

59
Q

Anthropoids

A

all haplorhines, except for tarsiers

60
Q

Catarrhines

A

old world monkeys

61
Q

Platyrrhines

A

new-world monkeys

62
Q

Cercopithecoids

A

Old-world monkeys

63
Q

Hominoids

A

apes and humans

64
Q

Hominins

A

human lineage (genus Homo)

65
Q

How unique are humans? What makes them so unique?

A

Very.

  • Encephalization
  • Life history
  • Behavioral and dietary flexibility
  • Phenotypically plastic/adaptable
  • Tool use/culture, language
  • Prosociality
  • Socially transmitted knowledge – teaching
66
Q

How can we reconstruct human behavior?

A

Questions of hominin origins and evolution must be posed within the context of primate biology (body size, diet, life history; dental morphology; canine size and social structure; brain size and complex behavior; limb proportions and locomotion)

67
Q

William “Strata” Smith

A
  • He discovered the Principle of Faunal Succession: more ancient fossils tend to reside in the lower strata.
  • He created the first large-scale geological map
68
Q

James Hutton and Charles Lyell

A
  • The Fathers of modern geology
  • Helped us understand Earth’s history through natural forces
  • Erosion from wind and rain provides material for new geological layers or strata
69
Q

What are the different kinds of fossils?

A

Coprolite (poop); burrows; footprints

70
Q

Fossilization process

A

1) Die
2) Buried quickly (not too acidic to dissolve bone (Few micro-organisms; dry good, damp bad; sedimentation)
3) Mineralized into rock (groundwater replacement; leeching of minerals)
4) Be found!

71
Q

Geologic Time

A
  • Precambrian (4.6 billion – 540 mya)
  • Paleozoic – Early Life (570 mya – 230 mya)
  • Mesozoic – middle life (230 mya – 66 mya) Age of dinosaurs
  • Cenozoic – new life (66 mya -present) age of mammals
72
Q

Epochs of the Cenozoic and major radiations that occurred

A
  • Paleocene (66 mya) Origin of primates; radiation of primate-like mammals
  • Eocene (56 mya) Adaptive radiation of true primates and prosimians
  • Oligocene (34 mya) adaptive radiation of anthropoids
  • Miocene (23 mya) adaptive radiation of apes
  • Pliocene (5 mya) adaptive radiation of biped hominids
  • Pleistocene (2.6 mya) evolution of genus Homo
  • Holocene (10 ka) development of agriculture
73
Q

What was the K-T boundary?

A

marks the extinction of dinosaurs. The rise of primate-like mammals

74
Q

Plesiomorphy

A

Primitive trait

75
Q

Symplesiomorphy

A

Shared primitive trait

76
Q

Apomorphy

A

Derived traits

77
Q

Synapomorphy

A

Shared derived trait

78
Q

Homoplasy

A

Non-homologous similarity

79
Q

Autapomorphy

A

Derived trait unique to a single taxonomy

80
Q

Parsimony

A

The idea that the slimiest explanation is most likely to be true

81
Q

Monophyletic

A
82
Q

Paraphyletic

A

Group that shares apomorphy (derived traits)

83
Q

Clade

A

A grouping that includes a common ancestor and all the descendants, living and dead

83
Q

Polyphyletic

A

Taxa have different ancestors

84
Q

Grades

A

A group of organisms that are united by a level of physiological or morphological complexity

85
Q

Crown

A

All living representatives together with their ancestors back to common ancestor

86
Q

Stem

A

Taxa closely related to crown group but lacking derived characters of crown group. Extinct.

87
Q

What is a model of primate origins? What evidence if there? What is the problem with it?

A

The Arboreal Model
- Adapted to climbing and foraging in the trees because of their…

  • Grasping hands and feet
  • Tactile finger and toe pads
  • Increase reliance on binocular vision and reduced olfaction
  • Increased intelligence for mapping complex 3D environment

Problem: It doesn’t explain generalized anatomy and care dedicated to single young

88
Q

Proconsul

A
  • Early Miocene of east Africa (22-17 mya)
  • 4 species recognized, ranging from 17-50kg
  • Dental characteristics linking to earlier
  • Larger brain, no tail, longer limbs, some increased forelimb mobility
  • Some old money-like features: IMI of 100, long flexible spine, deep chest, scapula on the side of the thorax
  • Above branch quadruped
89
Q

Ape demographic dilemma

A
  • Apes have very low reproductive rates
  • Typically 5-7 year interbirth intervals
  • Monkeys have 2-3 year interbirth intervals
  • You would think that monkeys would over take the apes from the Miocene to present time
90
Q

Transition from apes to humans

A
  • There is a break in the late Miocene fossil record in Africa form 13-15 mya
  • Can’t directly trace Proconsul to modern apes or the human lineage
  • Apes in Eurasia are more “modern” since they showed signs of partial suspension
91
Q

Hominin phylogeny (oldest to newest)

A

P. aethiopicus > P. boisei >

92
Q

Challenges in paleoanthropology

A
  • Only have bones and teeth
  • Don’t know the taxomomy
  • Difficult to know whether a fossil should be assigned to a new species
  • Limits to analyses and what we can know
  • Confirmation bias
93
Q

Major adaptive suites

A

1) Brain and behavior
- Ape: Small brain (<400 cc)
- Human: Large brain (~1300 cc)
2) Skeleton and bipedalism
- Ape: arboreal, suspensory
- Human: terrestrial, bipedal
3) Diet
- Ape: thin enamel, large canine dimorphism
- Human: thick enamel, small canine
4) Reproduction
- Ape: range in body size
-Human: moderate size

94
Q

What makes a hominin?

A
  • Reduced canine size and dimorphism
  • Bipedalism
  • Brain size
  • Tool use
95
Q

Late Miocene climatic change

A
  • Increased seasonality
  • Contraction of forest habitats
  • Messinian Salinity Crisis
  • Development of Asian monsoons
  • Desertification of North Africa
96
Q

Hominid vs. hominin

A
  • Hominid: includes all apes and humans
  • Hominin: includes the genus Homo and all bipedal, upright walkers
97
Q

Sahelanthropus tchadensis

A
  • Chad
  • 6-7 mya
  • Robust brow
  • Intermediately thick enamel
  • Small canine
    Forwardly placed foramen magnum
  • 360-370 cc
98
Q

Orrorin tugenensis

A
  • Kenya
  • 6 mya
  • Intermediately thick enamel
  • Small canines
  • Bipedal adaptations
99
Q

Ardipithecus kadabba

A
  • Ethiopia
  • 5.8-5.2 mya
  • Possibly some C/P3 honing (rubbing of canine on other teeth to sharpen them)
100
Q

Ardipithecus ramidus

A
  • “Ardi”
  • Ethiopia
  • 4.4 mya
  • “Best known early hominin”
  • ~300 cc
  • Reduced canine dimorphism
  • Intermediate enamel thickness
  • Relatively low body size dimorphism
  • Primative skeleton had… grasping toe, quadruped like limb proportions, hand adapted for palmigrady
  • Not habitually bipedal
101
Q

The Ardipithecines

A
  • Lineage dating back to near 7 mya
  • Canine reduction and bipedalosm are earliest hominin traits (they still had small brains)
  • Wide geographic range from Central to Eastern Africa
  • Lived in forested and woodland environments (not open grasslands)
  • May be a common lineage
102
Q

African hominin sites (generally)

A
  • South Africa
  • East Africa
  • Chad
103
Q

Lumpers vs. splitters

A
  • Lumpers: lump fossils together into larger more diverse species
  • Splitters: decided that fewer specimens get assigned to each species resulting in a more speciose phylogeny
104
Q

Bipedalism in Au. afarensis

A
  • Forelimb more primitive and ape-like
  • Retained functional climbing features?
  • Retained ancestral features because of the lack of selection to change them?
  • Hind limb more derived and human-like
  • Pelvis
  • Bicondylar (pelvic angle)
  • Non-grasping foot
  • Clear evidence of adaptation to bipedal walking and running
  • Legs intermediate between Ardi and humans: getting longer
  • 5-6 lumbar vertebrae: similar to humans: can produce lorosis
105
Q

Laetoli footprints

A
  • Tanzania, 3.6 ma
  • 3 individuals’ footprints
  • Big toe in line with rest of the foot
  • Rounded heel
  • Arch of the foot
  • Fully bipedal
106
Q

The Burtele foot

A
  • 3.4 ma
  • Ethiopia
  • Retained Ardipithecus like divergent hallux
  • Indicates locomotor diversity was around for longer than previously thought
  • Not currently assigned to a specific species
  • There isn’t one way to walk bipedally
107
Q

Au. afarensis

A
  • Hadar, Ethiopia and Laetoli, Tanzania
  • 3.6-3 ma
  • “Lucy”
  • “First Family”: one site had more than 200 fossils, at least 13 individuals, infants to adults
108
Q

Robust Australopiths (Paranthropus)

A
109
Q

Au. garhi and stone tools

A
110
Q

Australopithecine patterns

A
111
Q

The oldest stone tools

A
  • 3.3 mya, found in Kenya at Lomekwi
  • Not associated with a particular hominin
  • Date suggests stone tools were being used before the evolution of the genus Homo
112
Q

Australopithecus anamensis

A
  • 4.2-3.8 ma
  • Kenya
  • Mosaic of primitive and derived traits
  • Parallel dentral rows
  • Sexually dimorphic canines
  • thick enamel, like afarensis
  • Tibia indicates bipedalism, but some primitive features in upper limb
  • ~50kg
113
Q

Australopithecus afarensis environments

A
  • Hadar, Ethiopia: open woodland
  • Laetoli, Tanzania: grassland
  • Invading new habitats
114
Q

Little Foot

A
  • 3.3 ma
  • Australopithecus unidentified
  • Prominent nuchal crest
  • Posterior saggital crest
  • Hand proportions like humans
  • Curved phalanges
  • Slightly divergent large toe
  • Arm length = leg length
115
Q

Australopithecus africanus

A
  • “Taung Child” and “Mrs. Ples”
  • 3.3-2.1 mya
  • South Africa
  • Fully bipedal
  • Large molars
  • Rounder slightly larger skull than afarensis (400-500 cc)
116
Q

E. African Robusts (Australopithecus aethiopicus)

A
  • “The Black Skull”
  • 2.6-2.3 mya, Kenya and Ethiopia
  • Prognathic face like Au. aferensis
  • Enormous molar teeth (postcanine megadontia)
117
Q

E. African Robusts (Australopithecus boisei)

A
  • “Nutcracker Man”
  • 2.3-1.2 mya
  • Ethiopia, Kenya, Tanzania, Malawi
  • Ginormous premolars and postcanine megadontia
  • Flatter face
  • Brain ~ 500 cc
118
Q

Australopithecus garhi

A
  • 2.5 mya, Ethiopia
  • Brain 450 cc
  • Larger molars than Au. afarensis
  • Large incisors too
  • Human like leg length
  • Found with oldest stone tools at 2.6 ma
  • Animal bones showing evidence of butchery
119
Q

Australopithecus sediba

A
  • 1.97 mya
  • Malapa (cave), South Africa
  • Distinct from E. Africa australopiths
  • Biped, but retained primitive traits in the upper limb and torso
  • Quite a few fossils, but 2 main partial skeletons
120
Q

Australopithecus robustus

A
  • 2-1.5 mya
  • Kramdraai and Swaethkrans
  • 530 cc
  • Large molars and premolars
  • Sagittal crest and zygomatic arch for chewing muscles
  • Associated with more open habitats
  • Ate more C4 plants
  • Bulbs and tubers a possibility
121
Q

Australopithecines

A

1) Obligate bipedalism: very human, maybe better

2) Enlarged molars and premolars: thick enamel

3) Multiple lineages

4) Initial use of stone tools

5) Expanding habitats and territory: continent-wide distribution

122
Q

Bipedal stance

A
  • Must place base of support under your COM
  • Human COM in pelvis anterior to sacral vertebrae
  • Feet form a supporting quadrangle
  • Quadrupeds have a large supporting quadrangle and a relatively low COM
  • Bipeds have a small supporting quadrangle and a relatively high COM
  • Bipedalism is generally less stable than quadrupedal stance
123
Q

Human gait

A
  • Gait refers to a particular sequence of lifting and placing feet during legged locomotion
    - Affected by speed, number of legs, terrain
    - Human bipedal walking and running are two types of gait
  • Gait cycle is the repetition of the sequence of leg movement
    - In one gait cycle each leg goes through one complete step cycle
124
Q

How does walking require little muscular work?

A
  • Humans walk with extended limbs so relatively little muscular activity is needed support COM and resist ground reaction force
125
Q

How is walking similar to an inverted pendulum?

A
  • The COM oscillates up and down during gait
  • Much of the energy for forward motion results from converting potential energy into kinetic energy
  • Each stride relocates the pivot point anteriorly
  • Most work goes into pushing the COM upward
126
Q

Quadruped vs. biped

A

Quadrapeds:
- Wide base of support
- Low center of mass
- Forelimbs: shock absorbers
- Hind limbs: engine

Bipeds:
- Narrow base of support
- High center of mass
- Hind limbs: shock absorbers and engine

127
Q

Foramen magnum position in quadrupedal and bipeds

A
  • Quadrupedal posture places head in front of spinal chord
  • Foramen magnum faces backward in quadrupeds
  • For bipeds, their upright posture places the head on top of the spinal chord
  • Foramen magnum points down
128
Q

The curvature of the spine/lumbar lordosis

A
  • Lordosis: the backward curvature of the spine
  • Need longer back and lordosis to place trunk over pelvis and legs
129
Q

Bent hip bent knee gait in chimps and monkeys

A
  • Chimps must bend at the hip to place their center of mass over their feet
  • Longer backs of monkeys enable them to become competent bipeds
130
Q

Pelvis shape from ape to human pelvis

A
  • Shorter and wider
  • Shorter iliac blades
  • Iliac blades flared to side
  • Shorter ischium with curved attachment for hamstring muscles
131
Q

Difference in lesser gluteal muscles

A
  • In apes, they pull the top of the thigh forward which pushes the leg backward (propulsion)
  • In humans they keep the pelvis from dipping toward the swinging leg with each step (stabilization)
132
Q

Body proportions of apes and humans

A
  • Apes have Long arms and short legs , with an IMI of >100
  • Humans have short arms and long legs, with an IMI of <100
133
Q

Lateral lip of the patellar surface

A
  • Helps keep the patella from dislocating during bipedal movement
  • Sexually dimorphic: females have more pronounced lateral lips than males
134
Q

Loss of grasping feet

A
  • Humans are the only primates to lose their grasping big toe
  • It permits the formation of an arch
  • The big toe (hallux) is now aligned with the rest of our foot and toes, which helps with fluid bipedal walking, rather than grasping for branches
135
Q

Arch of the foot

A

Arch supported by ligaments and muscles; body weight placed on the foot stretches the muscles which absorb energy (like a rubber band); keeps shocks from going into bones and joints, reducing injuries

136
Q

Calcaneal Tuberosity

A

Tuberosity the heel is mostly trabecular bone and less cortical bone, which helps with absorbing force when we heel strike

137
Q

Femoral angle or Bicondylar Angle

A
  • Human thigh bone (femur) slants inward from the hip joint to knee joint
  • This only forms when an individual walks bipedally during their lifetime
  • Allows foot and knee to be placed under the center of mass while walking
138
Q

Australopithecus deyirmeda

A
  • 3.3 -3.5 ma
  • Ethiopia
  • Found very close in time and space to Au. afarensis, indicates potential diversity of species living at the same time
139
Q

Kenyanthropus platyops

A
  • 3.5-3.2 ma
  • Very flat face and unique dentition indicates morphological diversity at the time afarensis was alive
140
Q

Australopithecus bahrelghazali

A
  • 3-3.5 ma
  • Evidence of Australopiths in central Africa (wide home range)
141
Q

Au. afarensis dentition

A
  • Small canines, but with small retained diastema
  • Larger molars with thick enamel
  • Low rounded cusps
  • Likely a forest omnivore: tubers, fruit, vegetation., invertebrates, small animals
  • Resist wear –> longevity

ANT-Human Evolution (1 decks)

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