Trends in Human Evolution

Biological Evolution

Changes in features coded for by DNA, passed down through generations

Cultural Evolution

Transmission of knowledge, through learning, quickly, teach many, H. habilis

Bipedalism

Habitual upright walking on two limbs, energy efficient method that favours low speed, long distance walking

Foramen magnum

hole where spinal cord enters skull, central gravity, less neck muscle

Advantages and disadvantages of BIPEDALISM

Free hands, thermoregulation, less energy for long distances, see further / back ache, larger headed baby

Dentition

Number, size, arrangement of teeth

Broca’s region

creation of speech, controls muscles = lips, jaw, tongue, soft palate, vocal chords

Bowl shaped hip girdle

Reduce stress on hip that transmits body weight / bone support abdominal organs

Thermoregulation

Keep stable internal temperature

Valgus angle femur

Stronger, longer, angled inwards from the hip, shifts knees under hips = balance, no swagger

Wernicke’s area

comprehension of spoken words, listening

Opposable / Aligned big toe

Linear motion, shock absorption

Flat foot / Arched foot

Linear motion, shock absorption

Curved spine / S shaped spine

Linear motion, shock absorption

Large jaw, bigger teeth / small jaw, smaller teeth

More refined diet, no need for strong chewing muscles

Nuchal crest

keeps balanced above first vertebrate, ridge where neck muscles attach, quad = drooping heads

Long arm : leg ratio / shorter arms

Not needed for brachiating

Curved, less mobile = power grip / shorter, straighter fingers = precision grip

precision grip, no branches, tool making

Cranial capacity APE

approx 450cc

Cranial capacity HUMAN

approx 1450cc, increased development

Oldowan Tools

H. Habilis, 5 blows simple multi use, sharp end and flakes, 2.6 to 1.7 mya

Acheulean Tools

H. erectus, 50 blows, planning and time, processing meat = improved access, 1.7 to 200 kya

Mousterian Tools

H. Nea, 150 blows, specialised, hunt and make clothes, 300 to 400 kya

Upper Palaeolithic Tools

H. sapiens, 250 blows, finely worked and composite, high skill and creativity, variety of uses, 50-12

Who first used fire?

Homo erectus, controlled by Homo sapiens

WHY fire?

Protection, light, warmth, time, tools, cook, home base

Precision Grip

Intermediate hand, fingertips press, low power

Power Grip

high power, force generation

Multiregional Theory

H. Erectus dispersed from Africa and evolved over time with continual gene flow = H. Sapiens evolving in all regions = require gene flow across continents = unlikely

Out of Africa Theory

H. Erectus evolved into H. Sapiens in Africa, limited gene flow occurred between species, H. Sapiens left Africa replacing other hominins = fossil evidence, mtDNA, genetic similarities across races

Assimilation Theory

Modern humans evolved in Africa, spread across world, interbreeding with other hominins that left Africa earlier

nDNA

not subjected to selection pressure and therefore accumulates mutations at a constant rate

mtDNA

inherited from mother, trace maternal linkage due to slow mutation rates = compare sequences, trace to one woman 200,000 ya