Because there is a large body of evidence to support it.
It's apt enough.
Survival of the fittest / natural selection
natural selection
Charles Darwin was a revolutionary scientist who proposed the theory of evolution through natural selection. His work laid the foundation for modern biology and our understanding of how species adapt to their environments. Darwin's ideas have had a profound impact on multiple fields, from genetics to ecology.
The diversity seen in Darwin's finches is a good example of adaptive radiation, where a single ancestral species diversifies to fill multiple ecological niches. This phenomenon highlights the role of natural selection in driving evolutionary change and the importance of environmental pressures in shaping the evolution of species.
Well, scientists, for starters. And most higher educated people. And a good portion of the general populace as well. People who don't accept natural selection generally reject it because they don't know or understand what it is, or because they don't want to know what it is for religious reasons.
Charles Darwin's theory of evolution by natural selection influenced the eugenics movement by providing a scientific basis for the idea of improving the human race through selective breeding. Some eugenicists misinterpreted Darwin's ideas to justify their beliefs in promoting "good" traits and eliminating "undesirable" traits in the human population.
Charles Darwin's discovery of natural selection and evolution by means of natural selection revolutionized our understanding of the diversity of life on Earth. It laid the foundation for modern biology and has improved our knowledge of how species adapt to their environments over time. Darwin's work continues to inspire research in genetics, ecology, and conservation biology.
I already had a good grasp of geology and paleontology when I carefully read Charles Darwin's The Evolution of Species. I studied his conclusions, how he arrived at them and what methodologies he used, and was interested in his collaboration with other scientists and with breeders. I have read extensively the reviews and publications by supporters and opponents of Darwin's Theory of Evolution by Natural Selection - including a number of Creationist authors.I have absolutely no doubt that Darwin was right in his understanding of the evolution of species.
Actually, it was Lamarck who earlier introduced the giraffe as an example for evolution - Lamarckian evolution, to be sure. Lamarck proposed that there was some mechanism by which the short-necked ancestors of giraffes could acquire a change such that their offspring would have necks better suited to their needs. Darwin applied natural selection to the same example mainly because it had already been discussed in such detail.
They didn't. What you are speaking of is called social Darwinism and it should have been called social Spencerism because Herbert Spencer mistakenly applied the theory of evolution by natural selection to social theory and thus committed the naturalistic fallacy and Lamarckism at the same time. Just because something is natural does not mean it is good and how this " superior " social class viewed hereditary was straight out of Lamarck. Darwin wanted nothing to do with this mistaken notion.
Natural selection doesn't reduce variation. Variation is regulated by the rate of mutation.Natural selection reduces the chance of bad variation from being passed on and increases the chances for good variation to be passed on.