Human Evolution

Review of knowledge

Finding the evidence for evolution

• Right conditions = few examples. Once have them need to date them, potassium-argon dating, C14, relative dating all used.

Human evolution is divided into two strands:

• Biological evolution: the transmission of factors by genes, what is inherited.

• Cultural evolution: transmission of ideas, beliefs, what is learned.

• KPCOFGS– Animalia– Chordata– Mammalia– Primates– Hominidae– Homo– sapiens sapiens

Humans are Mammals:• Hairy and sweat glands• animals that suckle young on secreted milk.• viviparous• Are homeothermic (maintain a constant body

temperature)• Give birth to live young• External ear• Four chambered heart• Diaphragm• Differentiated teeth• Higher intelligence

Humans are primates:

• Primate classification

Divided into two main suborders:

• Suborder Prosimii: tarsiers, lemurs, lorises

• Suborder Anthropoidea: monkeys, apes, humans

• Primates developed in the three dimensional world of trees. Ancestors probably had a good sense of smell but lost it as not a good way to communicate in the trees. Sight and colour vision developed as the dominant sense. Characteristics are related to being in an arboreal environment.

Characteristics of primates• Prehensile grasping hands (and tails)• Nails not claws, sensitive finger pads• 5 functional digits on feet• Retention of collar-bone• Binocular, stereoscopic vision and improved retina• Good eye hand coordination• Oestrus cycle• Bony eye ridges• Mobile arm joints• One young per pregnancy (usually)• Strong social groupings

Primate Locomotion -Some are arboreal and some adapted to ground

ABOREAL

• Quadrupedalism– Walking on four limbs. Arms and legs are of

more or less equal length and importance. Most primitive form lived in trees (lemurs)

• Modifield quadrapedilism– Leaping and clinging. Torso is vertical after

each leap and in resting position. When on ground hop on back legs. (some prosimians)

• Brachiation– Involves use of the arms, which become

longer and are used to suspend body during feeding and to move by swinging. Can be full (gibbons) or semi (spider monkeys).

GROUND Quadrapedilism – baboons Knuckle walking – chimps and gorillas.

Walking on the backs of the middle parts of fingers. Fingers hands and wrists are adapted to this from of locomotion.

Bipedalism (habitual) – hominin (humans). This involves major changes to the pelvis, backbone and foot.