How does natural selection negatively impact humans?

The most conspicuous ways in which natural selection has affected our lineage is that is has caused us to become bipedal animals with huge brains, flat faces, long legs and shorter arms, highly dexterous fingers and opposable thumbs. In nature By avoiding changes in the environment, by removing invasive species, or by relocating endangered species to new habitats, humans can affect. the process by which nature rewards those individuals better adapted to their environments with survival and reproductive success. It works at the level of genes, sections of DNA that encode for proteins serve as the software of life. For example, among the genes the researchers predicted to be under negative selection are those involved in muscular dystrophy and in Usher syndrome, the most common cause of congenital blindness and deafness in developed countries.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link: