A Five Million Year Odyssey reveals how migration has shaped humanity

The five million odyssey
Peter Bellwood
Princeton University, $29.95

Archaeologist Peter Bellwood’s academic odyssey took him from England to teaching positions halfway around the world, first in New Zealand and then in Australia. For more than 50 years, he has studied how people settled islands from Southeast Asia to Polynesia.

So it’s fitting that his new book, a plain-English summary of what’s known and what’s not about the evolution of humans and our ancestors, emphasizes movement. in The A Five Million Year OdysseyBellwood examines a number of species in the human evolutionary family—he collectively calls them hominins, while some others (incl. Scientific news) use the term hominids (SN: 9/15/21) — and tracks their migrations by land and sea. He collects evidence showing that hominids on the move constantly changed the direction of biological and cultural evolution.

During his tour, Bellwood presents his own take on controversial topics. But when the available evidence leaves the debate unresolved, he says so. Consider the earliest hominids. Species from at least 4.4 million years ago or older whose hominid status is disputed, such as Ardipithecus ramidus, get a brief mention. Bellwood did not pass judgment on whether these finds came from early hominids or from ancient apes. Instead, he focuses on the African australopithecines, a set of upright but partly ape-like species that are thought to have comprised populations that evolved into members of our own genus, Homo, about 2.5 million to 3 million years ago. Bellwood puts forward the idea that the production of stone tools by the last Australopithecines, the first Homo groups or both contributed to the evolution of larger brains in our ancestors.

The action is accelerated when A straight man became the first known hominid to leave Africa about 2 million years ago. Questions remain, Bellwood writes, about how many such migrations occurred and whether this human-like species reached distant islands like Flores in Indonesia, perhaps giving rise to small hominids called hobbits, or Homo floresiensis (SN: 03/30/16). It is clear that H. elevated groups travel across mainland Asia and at least as far as the Indonesian island of Java.

Intercontinental migrations flourished thereafter Wise man debuted about 300,000 years ago in Africa. Bellwood greeted H. wise, Neanderthals and Denisovans as separate species that interbred in certain parts of Asia and Europe. He suggests that Neanderthals became extinct around 40,000 years ago as they interbred with representatives of more numerous H. wise populations, leaving a genetic legacy in humans today. But he does not consider such a different counterargument Homo populations at the time, including Neanderthals, were too closely related to be separate species, and that periodic mating between these mobile groups drove the evolution of modern humans (SN: 6/5/21).

Bellwood devotes considerable attention to the rise of food production and domestication in Europe and Asia after about 9,000 years. It builds on an argument drawn from his 2004 book First farmers, that expanding populations of early cultivators migrated to new lands in such large numbers that they spread the major language families with them. For example, farmers in present-day Turkey spread Indo-European languages ​​across much of Europe about 8,000 years ago, Bellwood said.

He rejects a recent alternative proposal, based on ancient DNA evidence, that horse herders of the Yamnaya culture in Central Asia brought their traditions and Indo-European languages ​​to Europe about 5,000 years ago (SN: 11/15/17). Too few Yamnaya immigrated to impose a new language on European communities, Bellwood says. Likewise, he argues, ancient Eurasian conquerors, from Alexander the Great to the Roman emperors, could not make speakers of regional languages ​​adopt new ones spoken by their outnumbered military lords.

Bellwood concludes his evolutionary odyssey with a reconstruction of how early agricultural populations expanded through East Asia and beyond, to Australia, a series of Pacific islands, and the Americas. Between about 4000 and 750 years ago, for example, marine farmers spread Austronesian languages ​​from southern China and Taiwan to Madagascar in the west and Polynesia in the east. How exactly they accomplished this remarkable feat remains a puzzle.

Disappointingly, Bellwood does not weigh in on the recent archaeological argument that ancient societies were more flexible and complex than long assumed (SN: 11/9/21). On the plus side, its evolutionary odyssey moves at a rapid pace and, like our ancestors, covers a lot of ground.

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