Theme 6 Flashcards

1
Q

What are the 3 periods that characterize the early study of primate evolution?

A

Linneus’ Systema Naturae, discovery of 1st primate fossils in Europe, Darwin’s Origin of Species

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2
Q

Dating Methods

A

Provenance, original context, relative vs absolute (or chronometric), nature of material, geological context.

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3
Q

What is the crown group and stem group in primate classification?

A

Crown-everything present now.

Stem-Everything that occured before common ancestor.

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4
Q

Classification: Dietary Reconstruction

A

Body mass estimates, dental microwear, dental texture, molar tooth shape, molar cusp shape, enamel thickness.

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5
Q

Classification: social behaviours

A

Based on observations of extant (currently living) primates: Sexual dimorphism

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6
Q

Palaeocene Epoch

A

First primates, 66 million years ago. North America and Europe were subtropical.

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7
Q

Plesiadapiformes

A

North America, Europe, Asia. 53 genera, 140 species. Dental numbers: 3143. Procumbent central incisors, long snout, lateral orbits, claws, no postorbital bar. Included purgatorius, plesiadapis, and carpolestes.

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8
Q

Eocene Epoch

A

North America connected to Europe. Omomyidae (tarsiers), and Adapidae (lemurs)-first higher primates, first anthropoids.

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9
Q

Oligocene Epoch

A

Global temperature decline, reduction in forests. Fayum Desert, Egypt (17+ genera, warm tropical environment). Included Oligopithecidae, Parapithecidae, Propiliopithecidea, and Aegyptopithecus (first fossil similar to hominids).

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10
Q

New World Monkeys

A

Africa and South America Separate. Originated in Afrca, Lower sea levels and floating vegetation islands.

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11
Q

Miocene Epoch

A

20-5 million years ago. Origin of old world monkeys rare during early miocene (23-16 million years ago). Egypt, Libya, Kenya. Bilophodont molar. Included Victoriapithecidae, and Mesopithecus. Age of hominids, geological, climatic, and environmental changes. Land bridge between Asia and Africa. Increased temps, more tropical forests.

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12
Q

Early Miocene Epoch

A

23-16 million years ago, African Forests, woodlands. Proconsul: Y-S pattern, cingulum, no tail. (Afropithecus, Heliopithecus).

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13
Q

Mid Miocene

A

16-12 million years ago, cooler climate, reduced sea levels, land bridge between Africa and Eurasia

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14
Q

Late Miocene

A

12-5.3 million years ago. Cold, dry climates, increased open grasslands. Knuckle walking primates. Possible ancestors of chimps, gorillas, and orangutans. Sivapithecus and Gigantopithecus.

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15
Q

Molecular Systematics

A

Molecular data used to reconstruct phylogeny. Assumes that species who share molecular similarities are likely to share a common ancestor.

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16
Q

What did Sarich and Wilson find out?

A

Compared serum proteins in humans and great apes, found that African great apes and humans shared a common ancestor 5 million years ago.

17
Q

Hominin Traits

A

Bipedalism, small generalized teeth, large brains, hairless.

18
Q

Mosaic Evolution

A

Traits did not develop at the same time

19
Q

Foramen Magnum in panins and hominins

A

Located more anteriorly in hominins, skull is in line with body.

20
Q

Pelvis shape in panins and hominins

A

Hominins have a short, broad pelvis for walking upright. (bowl shaped).

21
Q

Spine in panins and hominins

A

Hominins have an S shaped spine compared to the C shaped one in panins.

22
Q

Valgus knee in panins and hominins

A

Hominins thigh bones are angled inwards for upright walking.

23
Q

Feet in panins and hominins

A

Panins have opposable big toe for climbing. Hominins have a bipedal foot for walking, with transverse and longitudinal arches.

24
Q

Human Gait

A

Has a stance phase and a swing phase

25
Q

Why don’t we just fall over?

A

Large blade-like ilium shorter, ilium directed to side and not back, gluteal muscles used for propulsion, stability and balance.

26
Q

Why did we become bipedal?

A

Most likely due to accessing food. Other theories include hunting, surveillance, thermoregulation, endurance running, walking in water etc.

27
Q

Costs of Bipedalism: Gravity and Circulation

A

Greater risk of heart attack and stroke.

28
Q

Costs of Bipedalism: Musculoskeletal Problems

A

“Fallen Arches,” prolapse of intervertebral disks, patello-femoral syndrome.

29
Q

Costs of Bipedalism: Childbirth

A

Obstetric dilemma-narrow birth canal+large brain= incredibly difficult birth and labour.

30
Q

Adaptations to the childbirth dilemma

A

Early birth, skull plates are unfused, flexible pelvis, obligate midwifery, wedge shaped lumbar vertebrae.

31
Q

Facultative vs Obligate Bipedalism

A

Facultative- can be bipedal under extreme cirumstances

Obligate-Bipedal like us

32
Q

Terrestrial vs Arboreal Bipedalism

A

Terrestrial-Protograde knuckle-walking, chimps and LCA.

Arboreal-Orthograde clamber, orangutans, using hands and feet

33
Q

Human Brains

A

Larger, structure reorganized, encephalization, expensive tissue hypothesis, burns approximately 4.2KJ/min, significant dietary change-high quality diets+short digestive tracts makes for greater brain size.

34
Q

Isometric vs Allometric Scaling

A

Isometric-body parts increase in size at the same pace

Allometric-body parts increase in size at different paces.