Mosaic landscapes are made up of a variety of habitat types, including forests, grasslands, rivers, and open savannas. Such landscapes may have appealed to early humans because they provided a variety of resources, such as a variety of plant foods, hunting opportunities for various animal species, and access to water sources. This variety of resources would have improved their chances of survival and success in locating food and shelter.
An international team of researchers discovered that early human species adapted to mosaic landscapes and diverse food resources, which would have increased our ancestors’ resilience to past climate shifts.
Over the last 3 million years, our genus Homo has evolved in response to increasing warm/cold climate fluctuations. It is unclear how early human species adapted to the intensification of climate extremes, ice ages, and large-scale shifts in landscapes and vegetation. Did our forefathers adapt to local environmental changes over time, or did they seek out more stable environments with a diverse range of food resources? Was it the temporal changes in climate that influenced our human evolution, or the spatial character of the environment?
To quantitatively test these fundamental hypotheses about human evolution and adaptation, the researchers used a collection of over three thousand well-dated human fossil specimens and archaeological sites representing six different human species, along with realistic climate and vegetation model simulations spanning the last three million years. The researchers focused on biomes, which are geographical regions with similar climates, plants, and animal communities (for example, savannah, rainforest, or tundra).
For the archeological and anthropological sites and corresponding ages, we extracted the local biome types from our climate-driven vegetation model. This revealed which biomes were favored by the extinct hominin species H. ergaster, H. habilis, H. erectus, H. heidelbergensis, and H. neanderthalensis andbyour direct ancestors – H. sapiens.
Elke Zeller
“For the archeological and anthropological sites and corresponding ages, we extracted the local biome types from our climate-driven vegetation model. This revealed which biomes were favored by the extinct hominin species H. ergaster, H. habilis, H. erectus, H. heidelbergensis, and H. neanderthalensis andbyour direct ancestors – H. sapiens.,” said Elke Zeller, a Ph.D. student from the IBS Center for Climate Physics at Pusan National University, South Korea, and lead author of the study.
According to their findings, earlier African groups preferred to live in open environments such as grassland and dry shrubland. Hominins, such as H. erectus and later H. heidelbergensis and H. neanderthalensis, migrated into Eurasia around 1.8 million years ago and developed higher tolerances to other biomes over time, including temperate and boreal forests.
“To survive as forest dwellers, these groups developed more advanced stone tools and, most likely, social skills,” said co-author Prof. Pasquale Raia of the Università di Napoli Federico II in Italy. H. sapiens eventually emerged in Africa around 200,000 years ago, quickly becoming the master of all trades. Our direct ancestors, unlike any other species before them, were mobile, adaptable, and competitive, allowing them to survive in harsh environments such as deserts and tundra.
The scientists discovered a significant clustering of early human occupation sites in regions with increased biome diversity when they looked further into the preferred landscape characteristics. “What this means is that our ancestors preferred mosaic landscapes with a wide variety of plant and animal resources nearby,” said Prof. Axel Timmermann, co-author of the study and Director of South Korea’s IBS Centre for Climate Physics. According to the findings, ecosystem diversity played an important role in human evolution.
The authors demonstrated this preference for mosaic landscapes on continental scales for the first time and propose a new Diversity Selection Hypothesis: Homo species, particularly H. sapiens, were uniquely equipped to exploit heterogeneous biomes. “Our analysis demonstrates the critical importance of landscape and plant diversity as a selective element for humans and a potential driver of socio-cultural developments,” Elke Zeller adds. The new Science study provides an unprecedented look into human prehistory and survival strategies by elucidating how vegetation shifts have shaped human sustenance.
The climate and vegetation model simulations, which cover the Earth’s history of the past 3 million years, were conducted on one of South Korea’s fastest science supercomputers named Aleph. “Supercomputing is now emerging as a key tool in evolutionary biology and anthropology,” said Axel Timmermann.
