WE'RE THE LAST OF AT LEAST 23 SPECIES OF HUMANS.
WE'RE THE LAST OF AT LEAST 23 SPECIES OF HUMANS.
The Smithsonian Museum of Natural History lists 21 species that they claim are recognized by most scientists. Evolutionary paleoecologist John Stewart thinks the list is likely to keep growing and is already at least 23, with new additions like Denisovans and Homo luzonensis. The exact numbers accepted by individual scientists vary widely mainly based on two definitions: What defines a human, and what defines a species. It used to be accepted that if two individuals could produce fertile offspring, they were the same species. But the lines have blurred as researchers struggle with many gray areas such as asexual reproduction or hybrids like ligers, which come from lion-tiger combinations. Many, perhaps most, scientists think we need a more expansive definition of species. And what defines humanity is an even thornier question. If you accept the 23-and-growing number of human species (and that's likely to depend on whether you're a lumper or a splitter), it's astonishing that more than a third of these overlapped in time with us - Homo sapiens. At least eight other human species lived alongside us, and we interbred with several of these and today carry their genes. However, except for a few genetic traces, they're all gone now, and I find myself deeply saddened by that. We often look up at the stars and wonder if there is, or ever was, other intelligent life out there. It turns out there WAS - right here on Earth. But no longer.
The Smithsonian Museum of Natural History lists 21 species that they claim are recognized by most scientists. Evolutionary paleoecologist John Stewart thinks the list is likely to keep growing and is already at least 23, with new additions like Denisovans and Homo luzonensis. The exact numbers accepted by individual scientists vary widely mainly based on two definitions: What defines a human, and what defines a species. It used to be accepted that if two individuals could produce fertile offspring, they were the same species. But the lines have blurred as researchers struggle with many gray areas such as asexual reproduction or hybrids like ligers, which come from lion-tiger combinations. Many, perhaps most, scientists think we need a more expansive definition of species. And what defines humanity is an even thornier question. If you accept the 23-and-growing number of human species (and that's likely to depend on whether you're a lumper or a splitter), it's astonishing that more than a third of these overlapped in time with us - Homo sapiens. At least eight other human species lived alongside us, and we interbred with several of these and today carry their genes. However, except for a few genetic traces, they're all gone now, and I find myself deeply saddened by that. We often look up at the stars and wonder if there is, or ever was, other intelligent life out there. It turns out there WAS - right here on Earth. But no longer.
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