Hominin Evolution and Tool Use Quiz

Hominin Evolution

• Hominins are humans and their extinct ancestors
• Hominins differ from other apes in structure and behavior, including: bipedal locomotion with a striding gait and erect posture
• Learning Outcomes: determining relatedness and possible evolutionary pathways for hominins using fossil evidence from comparisons of modern humans and great apes with fossils of: Australopithecus afarensis, Australopithecus africanus, Paranthropus robustus, Homo habilis, Homo erectus, Homo neanderthalensis, and Homo sapiens.
• Learning Outcomes: tool use is seen in a number of hominin species; examining these tools provides insight into human cognitive abilities and lifestyle trends, specifically seen in manufacturing techniques and materials observed in those species tool cultures; focusing on Homo habilis, Homo erectus, Homo neanderthalensis, and Homo sapiens.

Pre-Requisite Knowledge

• Chapter 12.1: Primate evolution
• Chapter 12.2: Evolutionary trends in hominids

Contents

• Introduction
• Australopithecus sp.
• Homo habilis
• Homo erectus
• Homo neanderthalensis
• Homo sapiens

Introduction

• Classify humans as hominins, belonging to the Hominini tribe
• Hominins differ from other apes in structure and behavior
• Bipedal locomotion with a striding gait
• Erect posture

Figure 13.2

• Includes a phylogenetic tree showing the evolutionary relationships among hominin species.
• Shows the time in millions of years ago each species existed.

Culture

• Activities like making stone tools, hunting techniques, food preparation, using language, and art
• Cultural evolution observed in tools, such as gradual improvement, better methods of obtaining food, and increased sophistication of language

Anatomical trends in hominin evolution

• Characteristics of ape-like (primitive) hominins and human-like (modern) hominins.
• Compares features like skull, mandible and teeth, torso, upper limbs, and lower limbs.
• Key anatomical features, such as forehead, brow ridges, and jaw structure, tooth size, pelvis shape, limb length, and proportions, are described as more ape-like or human-like.
• Data on cranial capacity is discussed.

Figure 13.3

• Illustration of the cranial capacities of hominin skulls over time.
• Shows the increased cranial capacity and reduced prognathism in hominins from the early australopithecines to modern humans.

Australopithecus sp.

• Raymond Dart discovered the first fossil of Australopithecus africanus—southern ape of Africa.
• Bipedal with human-like hands and feet but smaller brains (~one-third of modern human brains).
• Lived between 3.9-2.8 million years ago
• Other fossils (e.g., Australopithecus africanus, Paranthropus robustus) found; differentiated from other species (e.g., by variation in teeth shape and size)

Second fossil

• Robert Broom found a second Australopithecine fossil in the Transvaal, South Africa ~10 years later
• Other fossils found nearby, such as those from Sterkfontein, helped classify a new hominin species (Paranthropus robustus).

Recent fossils of Ethiopia (Hadar)

• Includes many fossil fragments including "Lucy" (female skeleton, ~40% complete)
• Classified as Australopithecus afarensis
• Features like size of canines, and cheek tooth prominence were observed and inter-related.
• Existed between 3.9-2.8 million years ago

ii. Laetoli

• 23-metre trail of footprints found in volcanic ash
• Potassium-argon dating and stratigraphy indicate footprints were 3.6 million years old
• Features of footprints indicate bipedal locomotion including a deep impression from where the heel struck the ground.
• Evidence suggests Australopithecus afarensis individuals leaving the trail.

Homo habilis, "handy human"

• Adept at tool making—Oldowan.
• Larger brain and smaller teeth compared to australopithecines
• Upright, bipedal walkers with more robust hands than modern humans
• Brains significantly larger compared to gracile or robust australopithecines.

Culture of Homo habilis

• Oldowan tool culture (simple and unspecialized tools) for cutting wood, scraping hides, and digging up edible roots and plants
• Homo habilis consume meat (animal bones found at sites)
• Adult males were likely the primary hunters, leaving females and others to gather plants.

How to create stone tools

• Use of a hammerstone to strike a core stone to remove flakes, resulting in Oldowan tools
• Flake removal, resulting in a functional tool.
• Cobble (core stone) from which flakes are removed.

Sharing of Food

• Food exchange within a group increases the sense of interdependence between individuals
• Development of spoken language correlates with an increased speech-producing area in the brain.
• The larynx might not be capable of producing complex sounds yet.

Homo erectus

• Teeth generally smaller than earlier members of the species.
• Larger cranial capacity compared to Homo habilis.
• "Peking Man" found in Beijing, China.
• Footprints found at Ileret in Kenya (2009), with parallel big toe to other toes, and short toes, similar to modern humans, were made by Homo ergaster.

Culture of Homo erectus

• Modifying the environment to suit one's needs; building shelters.
• Use of fire—its effects: warmth, cooking, deterrents, and providing light for extended social interaction. Acheulian tool culture

Acheulian tool culture

• Flaked all around the edges, first in one direction and then in another.
• Two-faced lumps/bifacial, approximately teardrop in shape.
• Tools used as choppers, scrapers, etc.

Transition to modern humans

• Homo heidelbergensis—seen by many as a common ancestor of modern humans and Neanderthals
• Homo antecessor—another hypothesis that the species evolved into Homo heidelbergensis (or Neanderthals in Europe and Homo sapiens in Africa)

Homo neanderthalensis (Neanderthals)

• Existed in Europe during the last of the ice ages
• Adapted to the cold environment
• Large faces, low skulls, and heavy brow ridges
• Brains slightly larger than modern humans
• Occipital bun—skull drawn out in a "bun" shape.
• More prognathism—projecting jaw.
• Evidence of nasal bone forward projection, short stature, short limbs with heavily jointed, powerful muscles, and barrel-shaped chests

Neanderthal culture

• Production of stone flakes (which were trimmed into tools for cutting, scraping, etc.)—Mousterian industry
• Ability to make clothes.
• Buried their dead—evidence of spiritual belief
• Evidence of ritual burial with objects like wild goat horns

Homo sapiens (Cro-Magnon people)

• Features more modern than Neanderthals (e.g., shorter/wider skulls front to back with rounder back; less prominent brow ridges, reduced prognathism, smaller jaws, larger brains ~1350 cubic centimeters, and a chin).

Modern human tool culture

• Finer blades, projectile weapons.
• Aurignacian tools (e.g., beautifully made willow-leaf and laurel-leaf points).
• Solutrean culture
• Dominance of bone and antler tools over flint and stone tools (tools were fashioned with burins).

The Denisovans

• Fossilized little finger bone discovered in Denisova Cave in Siberia
• mtDNA – neither Neanderthal nor a modern human
• Denisovan hominin was more closely related to Neanderthals than modern humans
• Denisovan genes found in present-day Melanesians

Indigenous people of Australia

• Exhibit Denisovan ancestry
• Evidence includes a second bone and a molar tooth, which are larger than those found Neanderthals and early modern humans.

The Red Deer Cave people

• Thick bones, prominent brow ridges, short and flat face, but lacked a human-like chin
• Unusual combination of features—11,500 years old.
• Evidence indicates these people cooked large deer
• Suggested that they are the product of mating of Denisovans and our ancestors from East Asia

The beginnings of Agriculture

• Neolithic Revolution: domestication of plants and animals, construction of villages.
• First took place in Southwest Asia (e.g.,Natufian communities of Palestine)
• Hybrids created—e.g., emmer wheat created from a cross of wild goat grass and wild wheat
• Other forms of plant domestication were found throughout the world.

Large grains and Animals

• Grains ground into flour and used as damper.
• Domestication of animals like sheep, pigs, goats, and cattle in Southwest Asia (~11 000-8000 years ago).
• Early agricultural settlements around the eastern shores of the Mediterranean.

Causes and Effects of the Neolithic Revolution

Causes: scattered seeds, growth of new crops, scarce game animals, and climate change Effects: abandonment of nomadic lifestyles, permanent settlements, increased populations, animal domestication, specialization of labor, tool development, culture

Common Mistakes:

• Mistaking common names (e.g., "Australopithecine") as species names.
• Improperly formatting species names (first letter of the genus capitalized, species name underlined).