Final answer:
Charles Darwin's 'On the Origin of Species' introduced the concept of evolution through variations in species and the mechanism of natural selection, which preference traits that increase survival and reproduction, leading to species adaptation over time.
Step-by-step explanation:
In 1859, Charles Darwin's seminal work, On the Origin of Species, articulated two main points that became the foundation of evolutionary biology. Firstly, Darwin presented the concept that species evolve through changes in their physical and mental structure, a process driven by random variations among individuals. Secondly, he introduced the mechanism of natural selection, explaining how beneficial traits enhance an organism's chances of survival and reproduction, leading to the preferential survival of those traits in subsequent generations.
Darwin's insights were based on his observations during his voyage aboard the HMS Beagle, including the diverse wildlife of the Galapagos Islands. These observations, coupled with the influence of Thomas Malthus's principles on population growth and resource limits, led Darwin to conclude that a 'struggle for existence' facilitates natural selection. Darwin's work laid the groundwork for understanding the dynamics of species adaptation and speciation, transforming our understanding of life's diversity.