2.1 Early Human Evolution and Migration

Human evolution is a fascinating journey spanning millions of years. From early hominids like Ardipithecus to modern Homo sapiens, each stage brought significant advancements in physical traits, cognitive abilities, and tool use.

Paleolithic migration was driven by various factors, including climate change and population pressure. As humans spread across the globe, they developed increasingly sophisticated tools and harnessed fire, which had profound impacts on their survival and development.

Early Human Evolution

Stages of human evolution

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• Ardipithecus ramidus (4.4 million years ago)
  • Earliest known hominid species
  • Exhibited bipedal locomotion, walking upright on two legs
• Australopithecus afarensis (3.9-2.9 million years ago)
  • Displayed more advanced bipedalism compared to earlier hominids
  • Had a larger brain size relative to previous species (Ardipithecus)
• Homo habilis (2.3-1.4 million years ago)
  • First species classified in the genus Homo, marking a significant evolutionary step
  • Developed simple stone tools known as Oldowan tools
• Homo erectus (1.9 million-143,000 years ago)
  • Possessed a larger brain and body size compared to earlier hominids
  • Created more advanced stone tools called Acheulean tools
  • First hominid species to leave Africa and migrate to other continents (Asia, Europe)
• Homo sapiens (300,000 years ago-present)
  • Modern human species that emerged in Africa
  • Developed complex language abilities and symbolic thought
  • Created advanced tools, art, and cultural practices (cave paintings, jewelry)

Factors in Paleolithic migration

• Climate change
  • Glacial and interglacial periods caused shifts in temperature and precipitation
  • Changing sea levels created land bridges that facilitated migration (Bering Strait between Asia and North America)
• Following animal migrations for food sources
  • Paleolithic humans relied on hunting megafauna (mammoths, giant sloths) for sustenance
  • As animal populations moved to new areas, human groups followed their prey
• Population pressure
  • Growing human populations led to increased competition for resources
  • Migration to new territories helped alleviate pressure and ensure access to food and shelter
• Curiosity and exploration
  • Innate human desire to explore and discover new environments
  • Venturing into unfamiliar landscapes led to the spread of human populations
• Technological advancements
  • Improved tools (spears, bows) and hunting techniques allowed for more efficient food acquisition
  • Enhanced ability to travel further distances and adapt to new environments
• Out of Africa theory
  • Proposes that modern humans originated in Africa and migrated to other continents
  • Supported by genetic and fossil evidence

Paleolithic Tools and Fire

Impact of tools and fire

• Stone tools
  • Oldowan tools (2.6 million years ago)
    • Simple stone flakes and choppers used for scavenging and processing animal carcasses
    • Allowed early hominids to access meat and marrow, providing a high-energy food source
  • Acheulean tools (1.7 million years ago)
    • More complex handaxes and cleavers used for hunting and butchering
    • Improved efficiency in acquiring and processing food, leading to increased survival rates
  • Access to new food sources and nutrients facilitated brain development and growth
  • Tool-making skills fostered cognitive abilities and social learning
• Fire (controlled use by 1 million years ago)
  • Provided warmth and protection from predators, increasing safety and survival
  • Allowed for cooking meat and vegetables, improving food digestibility and nutrient absorption
  • Extended activity hours, enabling more time for social interaction and knowledge sharing
  • Enabled migration into colder climates by providing a means to stay warm
  • Used for hardening wooden tools (spears) and creating adhesives for attaching stone tools to handles

Evolutionary Mechanisms and Early Human Societies

• Natural selection
  • Process by which advantageous traits become more common in successive generations
  • Played a crucial role in shaping human physical and cognitive abilities
• Bipedalism
  • Allowed for more efficient locomotion and freed hands for tool use
  • Contributed to changes in skeletal structure and energy efficiency
• Tool use
  • Enabled access to new food sources and improved survival capabilities
  • Drove cognitive development and social learning
• Genetic mutation
  • Source of variation in populations, providing raw material for natural selection
  • Contributed to the emergence of new traits and adaptations in human evolution
• Hunter-gatherer societies
  • Early human social organization based on foraging and hunting for subsistence
  • Shaped human social structures, division of labor, and cultural practices
• Adaptive radiation
  • Diversification of species to fill different ecological niches
  • Contributed to the spread of early humans across diverse environments