evidence for evolution

• Fossils that provided evidence for human evolution

  • 'Ardi' - 4.4 million years old
  • 'Lucy' - 3.2 million years old
  • Leakey discovered 1.6 million year old fossils
• 'Ardi' fossil


  • Female hominid fossil. She shows phenotypic traits which encompass characteristics of both humans and apes:
  • Ape-like characteristics e.g. long arms, large big toes
  • Human-like characteristics e.g. the structure of her bones suggests that she walked upright
• 'Lucy' fossil


  • Female hominid fossil. She shows phenotypic traits which are more human-like than that of 'Ardi':
  • The structure of bones in her legs and feet are more adapted to walking than climbing
  • However, her brain size is closer to that of an ape's
• Leakey's findings

  • He discovered many hominid fossils.
  • The 1.6 million year old fossil 'Turkana Boy' showed traits comparable to that of modern-day humans e.g. similar brain size.
• Development of stone tools as evidence for evolution

  • Correlation between the development of more complex tools and an increase in brain size
  • Primitive tools are older than more complex tools. Brain size has increased over time ∴ as brain size increased, advancements in tool use were made.
• Methods used by scientists to date tools

  1. Carbon-14 dating - estimating the age of carbon-containing material that is found in tools (e.g. wooden handles) or alongside tools (e.g. fur)

  2. Stratigraphy - using the age of the layers of sediment surrounding the tool as an indication of the age of the tool
• Pentadactyl limb


  A limb with five digits present in animals, bird, reptiles and amphibians
• Pentadactyl limb as evidence for evolution


  • The presence of the pentadactyl limb suggests that all species which possess it have descended from a common ancestor.