How does adaptation fit into Darwin's theory of evolution

According to Charles Darwin's theory of evolution by natural selection, organisms that possess heritable traits that enable them to better adapt to their environment compared with other members of their species will be more likely to survive, reproduce, and pass more of their genes on to the next generation. So, with a process called Natural Selection, the species who adapts better to their environment survive for more time, until the environment change or until appear another species better to adapt than the first one