origin of humans; Neanderthal definitely different species (Origins)

by David Turell , Sunday, December 08, 2024, 20:46 (14 days ago) @ David Turell

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https://phys.org/news/2024-12-neanderthals-modern-humans-classed-species.html

"A new study published by researchers at London's Natural History Museum and Institute of Philosophy, KU Leuven has reinforced the claim that Neanderthals and modern-day humans (Homo sapiens) must be classed as separate species in order to best track our evolutionary history.

"Different researchers have different definitions as to what classifies as a species. It is undisputed that H. sapiens and Neanderthals originate from the same parental species, however studies into Neanderthal genetics and evolution have reignited the debate over whether they should be classed as separate from H. sapiens or rather a subspecies (H. sapiens neanderthalensis).

"Advocating the former, Chris Stringer (Natural History Museum, London) and Andra Meneganzin (Institute of Philosophy, KU Leuven, Belgium) state that despite the inherent limitations of the fossil record, there is enough morphological, ecological, genetic and temporal evidence to justify this categorization, and claim that this evidence reflects the complexity of the speciation process, in which populations from one parent species progressively diverge to become different descendant species.

"Taxonomic disagreement, they claim, is best explained by how the speciation process is modeled in the record, rather than conflicts between evidence types.

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"Professor Stringer, Research Leader at the Natural History Museum and joint author of the paper, says, "In the context of Neanderthals and Homo sapiens, we need to regard speciation as a gradual process that occurred over more than 400,000 years. It is correct that the two interbred where they were not geographically separate, but over time differentiation continued to a point where the two were distinctly different species.

"'When the Neanderthals died out around 40,000 years ago, the two species were in the final stage of the speciation process and were developing reproductive isolation from each other."

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"Fossil records show that H. sapiens developed in Africa, while Neanderthals evolved in Eurasia for at least 400,000 years, with interbreeding occurring as H. sapiens expanded out of the former region. However, the study argues that by the time of H. sapiens expansion and subsequent interbreeding, differentiation between the two species had occurred to the point where they were distinguishable species. One striking example of differentiation is that their ecological profiles were distinguishable and associated with "minimally different" habitats.

"Neanderthals were better equipped to cope with colder climates—an adaptation that even today we have not yet fully developed without the use of technology. They had to be more physically active and for longer periods, to gather the resources they needed for survival, which helps to explain morphological differences including ribcage and pelvis shapes, inferring bigger internal organs such as the lungs, heart and liver—among a wide range of anatomical distinctions.

"This may have been a factor in their extinction, as the more gracile skeleton of H. sapiens suggests a more economical physiology, less demanding of energy and resources, and aided by complex technology. This could have made the difference between survival and extinction when there was rapid climate change, or a strong competition for resources where the two coexisted."

Comment: That we were close species is obvious in that we could interbreed and produce normal hybrids. Neanderthals were extremely bright but not to our level of conceptual thought. I think they were a separate species. dhw will raise the issue of why Neanderthals existed at all if God only wanted sapiens. It goes back to the issue of why God evolved us over time instead of direct creation. God had His own unknown reasons.