Simple enough takeaways to help cause not one but two world wars.
One takeaway was that all the members of each of the higher species had all descended, in an unbroken and un-intermingled line, from an single and unique originating mother and father.
This suggested that the vertical and unbroken inheritance of that pair's founding genes was the key driving force behind daily life , understood as competition within and between all those differing species.
After Darwin, Free Will nearly died
This conclusion caused the implied consequences of human Free Will to take a decided nosedive.
For no longer did it matter if one freely decided to take up the religion of Judaism - what really mattered now was whether your ancestors also descended from one of the original twelve wandering desert Jewish tribes.
No longer one could freely decide to reside in Germany, and freely decide to obtain German citizenship --- now what truly mattered was the question whether you were also a direct descendant of one of the twelve Germanic tribes wandering through the forest of Mittel Europa.
Bad enough proving yourself to be a religious Jew, but without the genetic bloodline to go with it.
Bad enough to prove yourself a political and cultural German, but without the Aryan bloodlines to back it up.
Both these 'problems' stem from a mere absence.
Mixed Race child were seen as literally defective and Monsters
Worse - far far worse : imagine claiming to be a political German with your pa a pureblooded Aryan and your ma a mixed race Pole !
For if you truly believed that each genetic ethnicity was a race and a race was a species that couldn't successfully breed ,for long, with other species/races/ethnicities, the mixed race person seemed a literal defect and monster.
In fact if formal mixed marriages were relatively rare because of official opposition, informal and secret child-producing relationships between ethnicities were always and everywhere far far more common than most men and women were ever willing to admit to their spouses.
Based on this well known recent evidence, no current 19th century ethnicity was very pure and as for the distant past of that 'imagined' ethnicity, one simply did not know anything.
Still in the late nineteenth century, as the world claimed it was moving into an new Age of evidence-based Science, in reality the total uncertainty of genetic ethnicity replaced the virtual certainty of religion or residency based ethnicity.
For a law court, implicitly operating on a philosophy of positivism, can quickly examine religious and residency records and issue a judgement that can be accurately conveyed in a short newspaper headline.
Even DNA testing can't speak with much certainty
Not so tracing reputed unbroken genetic connections back 10,000 years.
Today, in 2016 and at the dawn of DNA testing, the mass media newspaper headlines are far far far more confident in their conclusions of unbroken ethnicities than the evidence (revealed in the data set of the scientific articles those headlines are based on) would allow.
And this human DNA testing is only a decade or two old ---- for the 120 years before that, the wild-eyed claims of genetic scientists (along with the intellectuals & politicians who loved them) was based on nothing more than wishful thinking.
The claim that unbroken genetic-based ethnicity exists has been supported by Science for over 150 years now - not really by the active work of few scientists but almost entirely by the tacit silence of the rest.
So I must repeat : technology and modernization simply is, but Science and Modernity were invented/fabricated and in turn invent/fabricate....