Final answer:
Charles Darwin's book 'The Descent of Man' argued that humans evolved from great apes and are linked to other species through evolution by natural selection. His theory was initially met with skepticism, but it became a cornerstone of modern biology, especially after genetic mechanisms were discovered, affirming his concepts.
Step-by-step explanation:
In his seminal work The Descent of Man, Charles Darwin concluded that humans evolved from other hominids, namely the great apes. Darwin linked human evolution to his earlier model presented in On the Origin of Species, proposing that evolution occurs by natural selection. Darwin's groundbreaking theory stated that individuals with traits beneficial to their survival would reproduce more, passing these advantageous traits to subsequent generations. He compiled evidence from fossil records and his research during the voyage of the HMS Beagle to support his ideas.
Despite the initial controversy and backlash from those who found the concept of descent from apes difficult to accept, Darwin's theory laid the foundation for modern biological science. It wasn't until the rediscovery of Mendel's work on genetics in 1900 that the mechanisms of evolution became clear, confirming Darwin's ideas about the inheritance and variation of traits.