New research exposes humans’ early ecological versatility | University of Helsinki
Most of the abilities that enabled humans to spread across the world and occupy so many different habitats, from grasslands, forests, Arctic tundra and the icy wastes of Greenland, Northern Canada and Alaska are the result of our evolution on the savannah of East Africa in that long period of history before the mythical 'Creation Week' when creationists think the universe was created. In this case, 1-2 million years before humans and Earth were created according to the creation myths of the Abrahamic religions.
And, because we evolved as a savannah species, it has been assumed that the earliest humans to migrate out of Africa would have migrated along grassland corridors and eventually up into the steppes of Central Asia. But new research by anthropologists at Helsinki University, Finland, led by Tegan I. F. Foister, is casting doubt on that assumption. They argue that human cultural plasticity enabled us to exploit and expand different ecological niches. In effect, we were 'generalist-specialists', which means we could adapt to a new environment, and then quickly become specialist at living in it.
The team have published their findings in the journal Evolutionary Anthropology and explain their work on a news release from Helsinki University:
The origins of human genus have long been associated with savannah and grassland environments of Africa. Due to this association, it was thought that the first human dispersal into Eurasia followed grassy corridors leading from Africa to Asia and to Europe. This link between humans and savannah-grasslands has been considered so strong that it delayed the appearance of early humans in Europe compared to Asia, as open grassy environments appeared in Europe later than in Asia. According to this view, early humans were ecologically clearly less versatile than our own species, Homo sapiens, as we have colonized almost all terrestrial environments on the planet.More technical detail is provided in the Abstract and Introduction to the team's open access paper in Evolutionary Anthropology:
“But that’s clearly not the whole story” says the lead author Tegan Foister, a doctoral researcher in the Hominin Ecology group at the University of Helsinki. “Because we knew of some studies suggesting that early humans were living in environments other than savannah-grassland, we thought that it would be interesting to do a more systematic investigation on the environments humans are known to have occupied during this crucial time period”.
The research published in Evolutionary Anthropology is a systematic review of 121 previously published reconstructions of early human habitats and it revealed that humans, when dispersing out of Africa for the first time, started to occupy a diverse set of environments from grasslands to forests.
“We have long associated early humans with savannah-like environments outside of the African continent. However, when the research published over the past two decades is considered together, it shows humans inhabiting diverse environments early in the evolution of the genus Homo. Already one million years ago humans in Europe were occupying fully forested environments”. Foister continues.
Although the analysis shows that grasslands and savannahs were important components of early human habitats, it places humans into a wide spectrum of environments, and in many cases environments with varied vegetation composition. This suggests that commonly held beliefs about early humans are not entirely correct: Humans did not have that strict requirements for their habitats and they seem to have been ecologically more versatile than previously assumed.
The study also indicated regional differences in human habitat characteristics. The grasslands and savannahs show the highest prevalence among African habitats, whereas forested habitats were more prominent in Eurasia making the range of different habitats wider in Eurasia. This suggests a possibility that the first human range expansion into Eurasia was accompanied and potentially even enabled by the expansion of human ecological niche.
The research is part of University of Helsinki and Kone Foundation funded project that investigates the evolution of the human niche over the past 2 million years. Although the present study focuses on the early humans, its findings are important also to the understanding of the origins of uniquely wide niche of our own species Homo sapiens.
Co-author Miikka Tallavaara, leader of the project and the Hominin Ecology group, says: “The ability of Homo sapiens to occupy most of the terrestrial ecosystems has enabled our ecological dominance and triggered the current biodiversity crisis. Our finding that human species in the Early Pleistocene were also able to thrive in multiple environment types provides an exciting target for future research into the evolutionary origins of the human plasticity and ecological success.”
AbstractCreationists will tie themselves into knots to explain these finding, invoking 'flawed' dating, 'changing radioactive decay rates', Satanic conspiracy theories and forged fossil evidence, but the fact will remain that 99.97% of Earth's history, and several million years of hominin history such as this paper reveals, occurred in that vast expanse of time before they think the Universe was created.
To understand the ecological dominance of Homo sapiens, we need to investigate the origins of the plasticity that has enabled our colonization of the planet. We can approach this by exploring the variability of habitats to which different hominin populations have adapted over time. In this article, we draw upon and synthesize the current research on habitats of genus Homo during the early Pleistocene. We examined 121 published environmental reconstructions from 74 early Pleistocene sites or site phases to assess the balance of arguments in the research community. We found that, while grasslands and savannahs were prominent features of Homo habitats in the early Pleistocene, current research does not place early Pleistocene Homo, in any single environmental type, but in a wide variety of environments, ranging from open grasslands to forests. Our analysis also suggests that the first known dispersal of Homo out of Africa was accompanied by niche expansion.
1 INTRODUCTION
Our own species, Homo sapiens, has expanded globally to dominate an exceptionally diverse range of ecological settings. This has often happened at the cost of other species, leading to the present biodiversity crisis.1, 2 To understand the long-term causes of this, it is necessary to investigate the trait thought to have enabled this rapid expansion—plasticity.3 The degree to which the ecological plasticity displayed by H. sapiens is unique compared to other species of the genus Homo is increasingly studied.4, 5, 6 An emerging concept in this research is the generalist-specialist niche.4, 7 This term refers to the specific plasticity of H. sapiens and how it allowed the development of highly specialized adaptations to exploit resources across a wide range of different ecosystems.6 Evidence on the range of suitable habitats earlier H. species occupied8, 9, 10 may provide important insights into the origins of the plasticity which has enabled H. sapiens to adopt its generalist-specialist strategy and colonize almost all environments on the planet.
Here we apply a novel approach to review and synthesize published reconstructions of the environmental context of early Pleistocene humans to explore the current state of the research regarding the variability in suitable environmental conditions. We focus on sites dated to between ∼2.0 and 0.8 Ma. When using the term human, we are referring to any member of the genus Homo. In many cases, human presence is indicated just by archaeological remains, making species identification impossible. However, in this period the human species occupying this site can often be treated as Homo erectus sensu lato. We nevertheless remain agnostic about the taxonomy of Homo in the early Pleistocene and operate at the genus level.
Foister, T. I. F., Žliobaitė, I., Wilson, O. E., Fortelius, M., Tallavaara, M.
Homo heterogenus: variability in early Pleistocene Homo environments.
Evolutionary Anthropology. 2023; 1-13. https://doi.org/10.1002/evan.22005
Copyright: © 2023 The authors.
Published by John Wiley & Sons, Inc. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)