The Various Humans of the World
As our species (Homo sapiens) developed and spread around the world, they lived at the same time as numerous other hominins. These include the well-known Neanderthals, as well as Denisovans, Homo floresiensis (mostly in Indonesia), Homo luzonensis (discovered in the Philippines), and Homo naledi (known from South Africa).
Looking down from our position of power, it's easy to believe that we have always ruled this planet, controlling animals and shaping the environment as we see fit — and that we were the sole travelers on this journey. Not quite. It's amazing that not just one, but at least five other human species were at some point coexisting on this small blue planet of ours.
These humans didn't appear out of nowhere. We all stem from a common ancestor that emerged around approximately six million years ago. Scientists have identified about 20 hominin species in total — but there are likely many more. Half of these species have been found in the last 30 years alone, and more will probably be discovered in the future with time (and funding).
How did all these humans evolve? Why did some lineages thrive while others faded and eventually became extinct?
A Change in Evolutionary Patterns
The general agreement among paleontologists is that climate change is the main factor shaping the emergence and extinction of hominin species. However, a recent study from the University of Cambridge has revealed an unusually different pattern in human evolution. Researchers discovered that the rate of new species emerging in our lineage is unmatched among vertebrates — and it is all linked to interspecies competition.
The study revealed that unlike other vertebrates, where competition typically inhibits speciation after ecological niches are filled, the Homo lineage demonstrates an uncommon trend where heightened competition coincides with an increase in the formation of new species.
“We have been overlooking the way competition between species has influenced our own evolutionary tree,” stated lead author Dr. Laura van Holstein, a biological anthropologist at the University of Cambridge.
“The impact of climate on hominin species is just part of the picture.”
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