Similarly, #PhysicalAnthropology has recently become more popularly known as #BiologicalAnthropology, both of which are alternate terms for the same child field of the parent discipline of #anthropology. 'Physical anthropology' takes its name from 1a) the field's object of study, i.e. *physical* variation within and between communities. Meanwhile, 'biological anthropology' takes its name from 3a) the field's causal model of *biological* processes, e.g. genetics, osteology, odontology, etc.

The upshot (if we can call it that) is that we have been left with a very clear distinction between two different child fields within the parent discipline of #anthropology:

One of these fields, #PhysicalAnthropology, is now defined by 1) an object of study comprising physical variation within and between communities of people; 2) parameters of study comprising the known history and known geographic extent of both individuals and communities, and; 3) a causal model comprising *intra-species biological processes* e.g. genetics, osteology, odontology, etc.

In the 70 years leading up to World War 2, there developed a gradual but increasingly clear divergence between #anthropology that focused on human physicality, and anthropology that focused on human sociality.

Much of the research in #PhysicalAnthropology consolidated its focus on fossils and prehistoric human remains, giving rise to the specialised branch known as #Paleoanthropology. This is a branch of anthropology that uses a causal model of biological evolution to focus on *inter-species variation* between different evolutionary branches of our genus, all of which are now extinct apart from our own species, Sapiens.

Simultaneously, much of the research in #SocialAnthropology consolidated its focus on distinct variations in communally-shared ideas, and the links between those ideas and observable patterns of social interaction in regionally distinct communities.

However, until World War 2 there persisted a stubborn strain of research that continued to assert a link between human biology and sociality. This research tended to orbit around the pseudoscientific #philosophy of eugenics, and so-called 'social Darwinism'. Anthropologists who supported this pseudoscience claimed that certain forms of social organisation, which they alleged to be 'dysfunctional', were the result of biological evolutionary failures.

Anthropologists who endorsed eugenics were prominent all over the world, not only in Nazi Germany, but also in the USA, Australia, South Africa and elsewhere.