anthro exam 2

How is evolution assessed in fossil studies?

Indirectly via morphological change, especially bones and teeth; infer genotypic change from phenotype.

Why must bias be avoided in paleoanthropology?

Bias can mislead interpretations (e.g., Piltdown Man hoax).

What does similarity in morphology across fossils suggest?

Common ancestry with subsequent divergence.

Sagittal plane

Divides body into left and right.

Coronal (frontal) plane

Divides body into front (anterior) and back (posterior).

Transverse plane

Divides body into top (superior) and bottom (inferior).

Anterior vs Posterior

Anterior = front of body; Posterior = back of body.

Medial vs Lateral

Medial = toward midline; Lateral = away from midline.

Superior vs Inferior

Superior = above; Inferior = below.

Proximal vs Distal

Proximal = toward trunk; Distal = away from trunk.

Axial skeleton

Skull, vertebrae, ribs.

Appendicular skeleton

Limbs and hips.

Is bone living tissue?

Yes—dynamic, remodels, records life history & behaviors.

Functions of bone (list 5)

Support/protection, muscle anchoring, movement, RBC production, fat & calcium storage.

What can bone reveal?

Sex, age, body size, locomotion, diet, health, population affinity, activity, geography, brain, behavior.

Long bone regions

Epiphyses (ends), diaphysis (shaft), metaphysis (between).

Short/Flat/Irregular bones

Short = cube-like; Flat = thin (e.g., skull); Irregular = complex shapes (e.g., vertebrae).

Synovial joint

Highly movable; hyaline cartilage & synovial fluid.

Cartilaginous joint

Little/immovable, joined by cartilage.

Fibrous joint

Interlocking; essentially immobile.

Paired cranial bones

Parietal, temporal, zygomatic, nasal, maxilla.

Single cranial bones

Frontal, occipital, sphenoid, mandible.

Which skull bone with teeth?

Maxilla (upper) and mandible (lower).

Sternum parts

Manubrium and body.

Vertebral column counts

7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused), 1 coccyx.

Forelimb bones

Scapula, clavicle, humerus, radius, ulna; hand = carpals, metacarpals, phalanges.

Hand bone counts

8 carpals, 5 metacarpals, 14 phalanges (per hand).

Os coxae composition

Ilium, ischium, pubis (fused pelvis).

Leg bones

Femur, tibia, fibula, patella.

Foot bone counts

7 tarsals (incl. talus & calcaneus), 5 metatarsals, 14 phalanges (per foot).

Eras with major life forms

Paleozoic (fish/amphibians/reptiles), Mesozoic (dinosaurs, mammals), Cenozoic (mammals).

What is taphonomy?

Study of processes affecting remains from death to discovery.

Key fossilization conditions (2)

Rapid burial and oxygen-poor environment.

Relative vs Absolute dating

Relative = order (e.g., stratigraphy, fluorine); Absolute = numeric ages (radiometric, dendro).

K/Ar dating basics

Dates volcanic rock matrix; half-life ~1.25 billion years.

Carbon-14 dating basics

Dates organic material; half-life ~5,700 years.

Dendrochronology

Dating based on annual tree rings.

Stratigraphic correlation

Matching layers across sites to order events.

Infraspecific vs Interspecific variation

Within species (age, sex, individuals) vs between species differences.

Lumpers vs Splitters

Lumpers group variation into fewer species; splitters designate more species.

Homology

Shared-derived trait due to common ancestry (synapomorphy).

Analogy (homoplasy)

Similar function/appearance without close ancestry; convergent or parallel evolution.

Speciation assessment factors

Separation time, adaptation differences, reproductive isolation sufficiency.

Core mammalian traits (6)

Lactation; hair/fur; single jawbone; 3 middle ear bones; diaphragm; single main artery exits left.

Mammal brain trend

Cerebrum enlargement → motor control, perception, intelligence.

Heterodont dentition

Different tooth types; ancestral mammal formula 2.1.4.3.

Primate hallmark traits (5)

Opposable hallux; nails not claws; forward-facing eyes; post-orbital bar; petrosal auditory bulla.

K-selection vs r-selection

K: few, big, long-lived, high care (humans). r: many, small, short-lived, low care (insects).

Precision vs Power grip

Precision: fingertips & thumb for fine control; Power: fist-like grip with wrapped fingers & thumb.

Arboreal quadrupedalism features

Long tail; curved digits; abducted limbs for balance above branches.

Terrestrial quadrupedalism features

Long limbs; short tail; short digits; adducted limbs for speed/agility.

Vertical clinging and leaping

Longer legs vs arms; propulsion from hindlimbs; long curved toes/fingers.

Plesiadapiforms (Paleocene)

Primate-like but not true primates; lateral eyes, no post-orbital bar; some grasping features.

Adapids vs Omomyids

Adapids → strepsirhine-like; Omomyids → haplorhine-like (large eyes, short snout).

Why primates evolved: 3 hypotheses

Arboreal; Visual predation; Angiosperm radiation.

Strepsirhine sensory traits

Tapetum lucidum (eye-shine), rhinarium (wet nose), large olfactory structures.

Tooth comb & grooming claw

Present in strepsirhines for grooming/feeding; absent in most haplorhines.

Galagos (bushbabies) traits

Nocturnal, solitary; arboreal quadrupeds & leapers; male-dominant; infant parking. Special behavior: leaping and infant parking.

Lorises traits

Nocturnal, solitary; slow arboreal quadrupeds; infant parking; toxic saliva. Special behavior: slow movement and toxin defense.

Lemur radiation in Madagascar

Arrived via rafting; few competitors → adaptive radiation into many niches.

Ring-tailed lemur highlight

Female-dominant, crepuscular; stink fighting behavior. Special behavior: stink fighting.

Indri & sifakas locomotion

Vertical clinging and leaping; some monogamous sociality. Special behavior: family-based calls (Zoboomafoo).

Aye-aye specializations

Percussive foraging; continuously growing incisors; elongated third digit; large brain for strepsirhines. Special behavior: tapping to locate larvae.

Key haplorhine features

No tapetum lucidum, no rhinarium; post-orbital closure; larger brains; reduced olfaction.

Tarsier classification puzzle

Haplorhine with some strepsirhine-like traits (grooming claw); vertical clinger/leaper; insectivorous/carnivorous. Special behavior: entirely carnivorous primate.

Fayum fossils (Oligocene)

Parapithecids (3 premolars—platyrrhine-like) & Propliopithecids (2 premolars—catarrhine-like).

New World monkey hallmarks

2.1.3.3 dentition; mostly arboreal; some prehensile tails; three premolars.

Marmosets & tamarins social system

Tendency toward twins; polyandry with core breeding female and 1–2 males. Special behavior: cooperative parenting.

Capuchin uniqueness

High brain/body ratio; cultural tool use (nut cracking, leaf sponges). Special behavior: tool use and problem solving.

Howler vs spider monkeys

True prehensile tails; frugivory vs more folivory; suspension & arboreal quadrupedalism. Special behavior: howling calls and brachiation.

Frugivore dental traits

Large spatulate incisors; low-cusped molars for soft fruit.

Folivore dental traits

Small incisors; high-cusped, shearing molars for fibrous leaves.

Catarrhine dental traits

2.1.2.3; two premolars; CP3 honing complex (in many).

Aegyptopithecus significance

Early catarrhine; 2.1.2.3; Y-5 molars; Fayum; frugivore; sexually dimorphic; quadruped/climber.

Cercopithecoid molars

Bilophodont molars—derived for folivory in many OW monkeys.

Langur social behavior

Polygyny; infanticide linked to male takeovers (evolutionary strategy). Special behavior: infanticide after male dominance change.

Macaques/baboons/mandrills sociality

Large polygamous troops; hierarchies; marked sexual dimorphism. Special behavior: social grooming and hierarchy display.

Dominance hierarchy functions

Reduce violence; structure competition; reinforced by grooming and alliances.

Sexual selection effects

Male–male competition & female choice → dimorphism, bright colors as fitness signals.

Hominoid dental trait

Y-5 molars (ancestral ape trait).

Hominoid key traits

No tail; larger brain; robust hallux; suspensory potential.

Miocene epoch nickname

“Age of the Apes” (5–29 mya) with widespread ape radiation.

Proconsul overview

Early ape; tailless quadruped; Y-5 molars; sexually dimorphic; East Africa. Special behavior: climbing and quadrupedal movement.

Dryopithecus overview

European ape; mid–late Miocene; thinner enamel; suspensory adaptations. Special behavior: fruit-eating suspensory locomotion.

Sivapithecus link

Asian ape with many traits shared with orangutans—probable ancestor. Special behavior: tree climbing and arboreal foraging.

Gigantopithecus

Massive Asian ape; likely bamboo-eating (folivore). Special behavior: ground dwelling giant herbivore.

Gibbons & siamangs

Lesser apes; SE Asia; brachiators; socially monogamous; duet vocalizations. Special behavior: vocal duetting and pair bonding.

Orangutan behavior

Solitary frugivores with cultural tool use; pronounced sexual dimorphism. Special behavior: nest building, tool use, and leaf umbrellas.

Parapatric speciation

Adjacent populations diverge with a hybrid zone (e.g., Sulawesi hybrid zones).

Sympatric speciation

Divergence within the same area via niche/behavior differences (e.g., bamboo lemurs).

Japanese macaque culture

Hot-spring bathing; sweet potato washing; cultural transmission. Special behavior: learned behaviors passed through group.

Rock stacking (macaques)

Example of playful cultural behavior observed in some groups.

Alloparenting

Non-maternal individuals help care for infants (e.g., colobus/langurs).

Ancestral mammal dental formula

2.1.4.3 (incisors.canines.premolars.molars).

New World monkey dental formula

2.1.3.3.

Old World monkey/ape/human dental formula

2.1.2.3.

Ring-tailed lemur test fact

Known for “stink fighting.”

Tapetum lucidum function

Reflective eye layer aiding low-light vision (strepsirhines).

Rhinarium function

Wet nose that traps odor particles; enhanced olfaction.

Jacobson’s (vomeronasal) organ

Accessory olfactory organ; larger with longer snout.