East Africa contains the world’s most complete record of human evolution, yet scientists know little about how long-term biogeographic dynamics in the region have influenced human diversity and distribution.
An artist’s depiction of early human habitation in Tanzania 1.8 million years ago. Image courtesy of M. Lopez-Herrera / Enrique Baquedano / Olduvai Paleoanthropology and Paleoecology Project.
In the new study, Dr. Ignacio Razaga-Baster from the National Center for Research on Human Evolution (CENIEH) and his colleagues focused on the mammal fossil record of the East African Rift Valley.
“The Late Cenozoic fossil beds of the East African Rift Valley provide the world’s richest, longest and most continuous record of human evolution and its environmental context,” the authors explained.
“As such, the human and faunal records of East Africa have been central to understanding the factors that shaped human evolutionary history.”
“Our study provides a new perspective on how climatic and environmental changes over the past six million years have influenced mammal and human evolution,” Dr Razaghabastar said.
“This study particularly highlights how biotic homogenization – the process by which the faunas of different regions become more similar in composition – has been an important factor in the evolution of ecosystems and the species that live in them.”
“Beta diversity analysis, which shows the relationships between regional and local biodiversity, allows us to trace how changes in vegetation and climate have driven patterns of dispersal and extinction over time.”
The team found that faunas from the Late Miocene and Pliocene (approximately 3 million to 6 million years ago) were primarily made up of endemic species.
The shift towards biotic homogenization, or faunal homogenization, began around 3 million years ago with the loss of endemic species within functional groups and an increase in the number of grazing species shared between regions.
This important biogeographic transition coincides closely with the regional expansion of ecosystems dominated by grasses and C4 grasslands that thrive better in warmer, drier climates.
These environmental changes directly affected the feeding and migration patterns of humans and animals that shared the habitat.
“We are certain that hominoids, like other East African mammals, were influenced by many factors. This study offers a new perspective on the link between environmental and human evolutionary change and, through an integrated approach, provides a framework for future research and to test the hypothesis that hominoids adapted to their environment,” Dr Razaghabastar said.
of study Published in the journal on July 15, 2024 Natural Ecology and Evolution.
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J. Rowan othersLong-term biotic homogenization in the East African Rift Valley during the past 6 million years of human evolution. Nat Ecol EvolPublished online July 15, 2024; doi: 10.1038/s41559-024-02462-0
Source: www.sci.news
