1. is a term used for various late nineteenth century ideologies which, while often contradictory, exploited ideas of survival of the fittest.It especially refers to notions of struggle for existence being used to justify social policies which stressed competition between individuals in capitalism but it is also connected to the ideas in which many promoted eugenics or scientific racism or imperialism, or a struggle between national or racial groups. In sociology it has been defined as a theory of social evolution which asserts that "There are underlying, and largely irresistible, forces acting in societies which are like the natural forces that operate in animal and plant communities. One can therefore formulate social laws similar to natural ones. These social forces produce evolutionary progress through the natural conflicts between social groups. The best-adapted and most successful social groups survive these conflicts, raising the evolutionary level of society generally. (source: Wikipedia)
Explanation:
Social Darwinism is a theory that suggests that certain human beings are better (more advanced) than other human beings. This theory used Darwin's theory of evolution and applied it to society. It was used to suggest that some ethnic groups (especially white/caucasian Europeans) were a higher caliber of human. This theory was used to support the ideas like white supremacy (think Hitler) and Eugenics (sterilizing mentally handicapped people and criminals).
Metaphor:
Everyone has a favorite Smarties colour. Sometimes we leave our favorite colour to eat last or first but normally we eat ALL the Smarties. If we applied Social Darwinism ideas to eating Smarties all the colours we didn't like we would crush under our muddy boots and only eat the colour we thought was best.