The evolving three-dimensional landscape of human adaptation.

Area of Science:

• Paleoanthropology
• Human Ecology
• Evolutionary Biology

Background:

• Humanity's ecological niche has expanded over 3 million years, adapting to diverse environments.
• The temporal dynamics and drivers of this niche expansion are not well understood.

Purpose of the Study:

• To investigate the evolution of human habitat preferences over the past 3 million years.
• To identify environmental and climatic factors influencing human niche expansion and contraction.

Main Methods:

• Combined archaeological data with landscape topography, climate, and biome simulations.
• Analyzed spatial clustering of human sites in relation to terrain roughness and biodiversity.
• Utilized statistical analysis to track changes in habitat preferences over time.

Main Results:

• Human sites initially clustered in rough, biodiverse areas, peaking around 1.1 million years ago (Ma).
• A niche contraction occurred from 1.1 Ma to 0.8 Ma, coinciding with the Mid-Pleistocene Transition and population bottlenecks.
• Post-0.8 Ma, human species (e.g., Homo heidelbergensis, Homo neanderthalensis, Homo sapiens) adapted to rougher terrains, colder/drier conditions, and increased ecological diversity.

Conclusions:

• Human niche expansion is characterized by dynamic shifts in habitat preference, influenced by environmental changes.
• The Mid-Pleistocene Transition marked a significant period of ecological niche contraction and subsequent adaptation.
• Later human species demonstrated remarkable adaptability to challenging environments, expanding into diverse ecological zones.