Final answer:
Haeckel and others challenged the traditional valuation of human life through ideologies like Social Darwinism and eugenics, which promoted the idea that only the fittest individuals or groups deserve success and protection, ultimately leading to justifications for selective breeding and euthanasia.
Step-by-step explanation:
The views presented by Haeckel and others, particularly during the late 19th and early 20th centuries, challenged traditional views of human life protection and value by endorsing controversial ideologies such as Social Darwinism and eugenics.
Herbert Spencer, an advocate for Social Darwinism, appropriated Darwinian theories of natural selection to propose the concept of 'the survival of the fittest' in social and economic contexts. This view held that certain individuals or groups were inherently superior and therefore more deserving of success, thereby justifying wide economic disparities and even policies that led to selective breeding and euthanasia.
These ideologies were used to rationalize the reductive view that poorer or less successful people were naturally inferior and unworthy of assistance or moral consideration, reflecting a shift toward anthropocentric ethical perspectives that privileged human interests over the well-being of nonhuman entities and biodiversity.