Yehren says:
In biology, no one refers to "lower animals" or "higher animals."
No. Look though the literature, instead of cheat sites for students doing term papers. It's not there.
Not since modern evolutionary theory. See above.
We see that from creationists, but not biologists. No one who understands evolution and genetics would say that. Again, see above.
Eugenicists also latched onto Christianity for the same reason.
Not real evolutionary theory, either. As you learned, Darwinists debunked eugenics.
In 1917 Punnett again sought Hardy’s help over a similar problem, and this time Hardy himself calculated how slowly a recessive lethal is eliminated from a population, thus apparently discrediting the eugenicists’ claim that deleterious recessives could be eliminated in a few generations (Punnett 1917b).
Reginald Crundall Punnett: First Arthur Balfour Professor of Genetics, Cambridge, 1912
Davenport and his contemporaries failed to recognize that not all familial traits are biologically inherited, and that even traits that are inherited can have complex causes. This, coupled with an evangelical commitment to create a society molded in their own image, led the eugenicists to make simplistic and unsupportable claims about human heredity. Punnett made an early indictment of the methods during a presentation at the First International Congress on Eugenics in 1911 – the year The Trait Book was published: "Except in very few cases, our knowledge of heredity in man is at present far too slight and too uncertain to base legislation upon…It must be clearly recognized that the collection of such [accurate] pedigrees is an arduous undertaking demanding high critical ability…"
Social Origins of Eugenics
Actually, he scandalized creationists by declaring that if one moved a population of Africans to England, in a few generations, they'd be just like Englishmen. And as you learned, he declared eugenic ideas to be an "overwhelming evil."
If you had read Darwin's Descent of Man, you'd have learned that he saw altruism as an important part of human evolution.
It must not be forgotten that although a high standard of morality
gives but a slight or no advantage to each individual man and his
children over the other men of the same tribe, yet that an increase in
the number of well-endowed men and an advancement in the standard of
morality will certainly give an immense advantage to one tribe over
another. A tribe including many members who, from possessing in a high
degree the spirit of patriotism, fidelity, obedience, courage, and
sympathy, were always ready to aid one another, and to sacrifice
themselves for the common good, would be victorious over most other
tribes; and this would be natural selection.
Charles Darwin,
The Descent of Man,
Chapter V - On the Development of the Intellectual and Moral Faculties
If you had actually read that chapter, you'd have known what came next...
Nor could we check our sympathy, even at the urging of
hard reason, without deterioration in the noblest part of our
nature. The surgeon may harden himself whilst performing an operation,
for he knows that he is acting for the good of his patient; but if
we were intentionally to neglect the weak and helpless, it could
only be for a contingent benefit, with an overwhelming present evil.
ibid
You are no doubt unaware that you are misrepresenting Darwin's true thoughts on the matter. I suggest you actually read his book, instead of reading what dishonest people represent it to be. You'll find that Darwin was not what your sources say.
He along with the racist Henry Morris, founded the ICR.
https://www.amazon.com/Heredity-Study-Science-William-Tinkle/dp/B0012G9CEG
From a creationist website:
It should be worth mentioning there seems to be credible evidence a few creationists have also supported eugenics. Dr. West meet Dr. Tinkle...I’ve provided this not because I think the creationists are in any way as guilty as Darwinists in eugenics (or abortion), but to suggest caution if one is going to play the genocide and eugenics cards. Playing what you think are good cards may not be as easy as one supposes. I know that from experience on many levels.
Creationist support of eugenics and genocide in the past
Nor is Tinkle an isolated case. As late as the 1990s, ICR co-founder Henry Morris was publishing drivel about the supposed intellectual and spiritual inferiority of black people:
Yet the prophecy again has its obverse side. Somehow they have only gone so far and no farther. The Japhethites and Semites have, sooner or later, taken over their territories, and their inventions, and then developed them and utilized them for their own enlargement. Often the Hamites, especially the Negroes, have become actual personal servants or even slaves to the others. Possessed of a genetic character concerned mainly with mundane matters, they have eventually been displaced by the intellectual and philosophical acumen of the Japhethites and the religious zeal of the Semites.
Henry Morris The Beginning of the World Second Edition (1991), pp. 147-148:
This is one of the major differences between science and creationism.