ANTH3100: Chapter 6 - Anchient Human Forms

What is Taphonomy?

The study of what happens to an organism's remains after death

What is Petrification?

Skeletal remains absorb surrounding minerals that eventually replace the organism's inorganic tissues

What is Radiocarbon Dating?

Primary technique for estimating antiquity from Pleistocene through the present

What are the 4 Dating Techniques? How do they work?

1) Tephrostratigraphy

- Dating of Pyroclastic Layers of Volcanic Ash

2) Biostatigraphy

- Relative Age Based on Fossil Location/Assemblages

3) Paleomagnetism

- Using Rocks to Determine Direction and Intensity of Earth's Mangetic Field

4) Obsidian Hydration

- Measuring Water in Obsidian Tools for Abs Dating

What Caused the O-S Extinction Event (445MYA)?

Global Warming Related to Volcanism and Anoxia

What Caused the Late Devonian Extinction Event (372-359MYA)?

Kellwasser Event (372) - Destroyed Coral Reefs and Marine Life

Hangenberg Event (359) - Wiped Out Most Other Fish and Ammonoids

What Caused the P-T Extinction Event (252MYA)?

Volcanoes and Excess CO2 in the Atmosphere

What Caused the K-T Extinction Event (66MYA)?

Asteroid and Global Heating

What Early Mammals Survived After the K-T Extinction Event?

1) Carsioptchus

2) Eoconodon

3) Purgatorius (66-63mya)

What changes occurred in the Paleocene related to the Origin of the Primates?

- Small Brains

- Prognathic Face

- No Postorbital Bar

- Diastema (Tooth Spacing

First True Primates:

Adapoids and Omomyoids

Strepsirrhine Ancestors

- Small to Medium-Sized

- 3.5 oz to 15 lbs

- Slow-Moving Arboreal Quadrupeds

- Diurnal

- Diet of Fruit and Leaves

Haplorrhine Ancestors

- 1 oz to 5 lbs

- Diets of Insects and Fruit

- Nocturnal (Large Eye Orbits)

- Arboreal Quadrupeds

What Favored the Origin of Anthropoids?

- Eye Orbit and Mandible Changes Allowed for Chewing Tougher Foods and Better Eye Protection

- Increase in Body Size due to Better Diets

- Stereoscopic Vision

- More Leaf-Based Diets

What is something all early apes possessed?

Y-5 molar patterns

Earliest Apes: Early Miocene: Proconsul

- 21 to 14 mya

- Arboreal Quadraped

- Lacking Tail

- Larger Brain to Body Size

Earliest Apes: Early Miocene: Dryopithecus

- 12.5 mya to 11.1 mya

- Primative Anatomy like Proconsul and Gibbons

- 100 lbs

- Europe

- Some suspensory, also some quadraped

Earliest Apes: Early Miocene: Sivapithecus

- 12.2 mya

- Found in India and Nepal

- Similar in Size to Modern Orangutan

- Spent a lot of time on the ground foraging for seeds, not just living in trees

Earliest Apes: Early Miocene: Oreopithecus

- Found in Italy

- Measurements of the semicircular ear canals suggest that the size falls in the range of great apes

Earliest Apes: Early Miocene: Gigantopithecus

- Largest primate that ever lived

- 400 to 700 lbs

Bipedal Hypotheses: Schlepp

Food Transportationm Carrying of Offspring

Bipedal Hypotheses: Peek A Boo

Standing Up Over Savannah's Grasses

Bipedal Hypotheses: Trench Coat

Phalic Exhibition in Males to Attract Females

Bipedal Hypotheses: Hot to Trot

A Way to Lose Heat When Exposed in the Open Savannah

Heterodont

Tooth array in which different teeth have different forms and functions

- HOMININ CHARACTERISTIC

Homodont

Having teeth that are uniform in form, shape, and function.

- HOMININ CHARACTERISTIC

Prognathism

Lower Jaw Protrusion

- HOMININ CHARACTERISTIC

CP3 Honing Complex

Combination of canine and first premolar teeth that form a self-sharpening apparatus

Features of Sahelanthropus Tchadensis (7.0-6.0 MYA)

- Less Prognathic Face

- Smaller Canines

- Thin Enamel

- Anterior Formane Magnum

Why is Sahelanthropus Tchadensis (7.0-6.0 MYA) so hotly debated?

The skull of Sahelanthropus Tchadensis is argued to be the earliest of the hominins and one of only two known species from Western Africa.

Features of Orrorin Tugenensis (6.0 MYA)

- Thick Enamel

- Small Teeth

- Large Upper Canines

- MAY BE OLDEST OF HOMININS

What did Selection Pressures and the Divergence of Monkeys and Apes cause?

- Evolution of Branchiation

- Knuckle-walking developed in African Apes

- Dental Evidence: A Dietary Shift with Apes Eating More Fruits

T or F. Walking Upright was Extremely RARE

True

Anatomical Changes in Vertebral Column and Skull Include:

1) Vertebrae: S-Shaped Spine, Rather Than C-Shaped Spine of Quadrupeds

2) Foramen Magnum

3) Nuchal Plane: Horizontal Flat Region on Back of Skull

Bipedal Hypotheses: Tag Along

Following Herds of Herbivores During Migration

Bipedal Hypotheses: Two Feet Are Better Than Four

Bipedalism is Favorable Energetically for Long Treks

What region did Australopithecus anamensis (4.2-3.9 MYA) live in?

Lived in forested region

- ALSO HAD PRIMITIVE DENTITION

Features of Australopithecus affarensis (3.9-2.9 MYA)

- Short, broad pelvis

- Tilted femurs

- Sagittal Crest

- Likely lived in groups

Features of Australopithecus deyiremeda (3.5-3.3 MYA)

- A dextrous big toe

- Prognathic jaw

THINK: "Medias"

Features of Australopithecus Africanus (3.5-<2.0 MYA)

- Slight brain increase

- Rounded vault

- No crests

Features of Australopithecus garhi (2.5 MYA)

- Small brain, Prognathic face

Still learning (36)

You've started learning these terms. Keep it up!