Human Origins: Bipedalism and Beyond

Human Origins: Bipedalism and Beyond

Exploring the evolution of walking upright Understanding why humans lost body hair Examining fossil evidence from Laetoli Year 13 Science - NZ Curriculum

Learning Objectives

Explain the significance of bipedalism in human evolution Analyse theories about why humans lost body hair Evaluate the importance of Laetoli footprints as fossil evidence Connect these adaptations to early human survival strategies

Starter Question

What advantages might walking upright give to our early ancestors? Think about: energy efficiency, tool use, predator detection, heat regulation

What is Bipedalism?

Bipedalism = walking upright on two legs Humans are the only fully bipedal primates Evolved approximately 6-7 million years ago Required major anatomical changes to skeleton and muscles Distinguishes our lineage from other great apes

Why Did Bipedalism Evolve?

{"left":"Energy efficiency - less energy to walk long distances\nTool use - freed hands for carrying and making tools\nThermoregulation - less body surface exposed to sun","right":"Predator detection - better view over tall grass\nFood gathering - reach higher fruits and see resources\nSocial signalling - height advantage in group interactions"}

The Mystery of Human Nakedness

Humans are the 'naked ape' - lost most body hair Occurred sometime after bipedalism evolved Unique among primates and most mammals Must have provided significant evolutionary advantages Several competing scientific theories exist

Theories for Hair Loss - Research Task

Research these theories and find evidence for each: 1. Thermoregulation theory - cooling in hot climates 2. Aquatic ape theory - adaptation to water environments 3. Parasite reduction theory - fewer places for parasites to hide 4. Sexual selection theory - attraction and mate choice Create a summary table comparing evidence for each theory

The Laetoli Footprints Discovery

What the Laetoli Footprints Tell Us

Direct evidence of bipedalism 3.6 million years ago Three individuals walked together - social behavior Footprints preserved in volcanic ash Show fully upright gait, not knuckle-walking Prove bipedalism evolved before large brain size Demonstrate family group cooperation

Connecting the Evidence

"The Laetoli footprints, bipedalism, and hair loss all tell the story of human adaptation to changing environments. These weren't isolated changes, but interconnected evolutionary responses to new challenges and opportunities."

Synthesis Task: Create Your Infographic

Create an infographic or detailed paragraph explaining: How bipedalism, nakedness, and the Laetoli footprints connect Why these adaptations were critical for human survival What evidence supports each evolutionary change Include: scientific vocabulary, logical flow, visual elements (if infographic) Submit via your online platform