ANTHROP 1AA3 Lecture 9: Lecture 9 – Earliest Humans
27 Jun 2018
School
Department
Course
Professor
Lecture 9 – Earliest Humans
Paleonanthropology
• The study of fossil humans
When and Where did the first humans appear?
• Hominid – humans and their direct ancestors
• Multidisciplinary – physical sciences (e.g., geology); biological
sciences; and social sciences
What are Fossils?
• Organic material (e.g., bone) is replaced by minerals from
surrounding soil – petrifaction
Where are the earliest fossils found?
• In east and south Africa
Rising Star Expedition
•
Arpidithecus ramidus
• 4.4 mya
• 35 individuals
• Have ape like skeleton
• Same number of teeth as humans, same dental
• Big toe is more like chimpanzee but not a flexibility like it. Not good
for grasping, transition to walking kind of arrangement. Not certain
they were bipedal
• Lived in a forest environment
• Maybe it evolved in a woodland setting VS what is thought which
is on grassland
• Early signs of bipedalism in a woodland setting
What does a hominid look like?
• Small front teeth & large molars
• Bipedalism & associated anatomical adaptations
• ↑ manual dexterity
Autralopithecus afarensis
• 4-3 mya
• Lucy reconstruction – Most compelte example, 40% of preserve,
lower limb bones like pelvis, femeur and Tibia, legs. Bones
important for study of how bipedalism developed. Consistnat
features with bipedalism, but looks like an ape like structure,
• Laetoli footprings – found in Tanzania. Early hominin anatomy,
evidence supports bipedalism.
Major features of bipedalism
• Position of foramen magnum – in hominins, its migrated towards
front of skull. Chimp is geared at back because their skull is
forward. We are balancing.
• Hominid spine has two distinctive curves – lumbar and thoaric.
Weight distribution on truck
• S-shaped
• Shape of the pelvis – broad and low. Blades are wider for us and
not very tall vertical, shorter and broarder. Means that points
where legs and femeurs are attacted are further apart, helps us
stable.
• Length of lower limbs – elongated, us is 20% weight, and gorilla is
11%. Dominance of legs is increased in walking.
• Structure of femur and knee. Femur goes straight down, in
humans it bends inwards
• Shape and structure of the foot (arch). Our is brought inline with
other toes as we shift our weight forward.
Why did bipedalism develop?
• Tool use? No – earliest tool date to 2.5 mya. Bipedalism evolved
4.4 mya or more.
• Efficient scavenging? Cope more territory or look out for predator?
• Long distance travel? Oxygen use for travelling is much less for
humans compared to chimpanzees walking Quadraply. Walking
for us is more efficient
• Predator avoidance? Helps us look out for threats, or look for
herbs we want to scavenge.
Why bipedalism
• Bipedalism came before change in brain
• Man as hunter
• 2-Parent family & sexual division of labor
• Food-sharing and carrying
• Carrying offspring
• Enhanced heat loss – move around when its very hot, and
predators are resting in the heat. Less exposure to sun, balancing
temperature.
• Threaten other organisms
• Communication – hand gestures
The Australopithecines (~4 – 2 mya)
Document Summary
When and where did the first humans appear: hominid humans and their direct ancestors, multidisciplinary physical sciences (e. g. , geology); biological sciences; and social sciences. What are fossils: organic material (e. g. , bone) is replaced by minerals from surrounding soil petrifaction. Where are the earliest fossils found: in east and south africa. Arpidithecus ramidus: 4. 4 mya, 35 individuals, have ape like skeleton, same number of teeth as humans, same dental, big toe is more like chimpanzee but not a flexibility like it. Not good for grasping, transition to walking kind of arrangement. Not certain they were bipedal: lived in a forest environment, maybe it evolved in a woodland setting vs what is thought which is on grassland, early signs of bipedalism in a woodland setting. What does a hominid look like: small front teeth & large molars, bipedalism & associated anatomical adaptations, manual dexterity.
