Final answer:
Charles Darwin named his theory the theory of evolution by natural selection, as presented in his 1859 book On the Origin of Species. This theory describes how species change over time through the natural selection of favorable traits, leading to what Darwin called descent with modification. Concurrently developed with Alfred Russel Wallace, it has been a foundation of evolutionary biology.
Step-by-step explanation:
Charles Darwin's Contribution to Evolutionary Theory
Charles Darwin named his groundbreaking theory the theory of evolution by natural selection. In his seminal book On the Origin of Species, published in 1859, Darwin explained how species evolve over time through natural selection. After extensive observations and research during his voyage on HMS Beagle, and considering the work of other scientists such as Lamarck, Lyell, and Malthus, Darwin proposed that in the natural world, organisms with variations that give them an advantage in their environment are more likely to survive and reproduce.
These favorable traits are then passed on to future generations, leading to changes in the population over time - a process he termed descent with modification. Darwin's ideas were concurrently developed by Alfred Russel Wallace, who also observed this pattern of selection in the natural world. Together, they introduced the scientific community to the concept of natural selection - the mechanism by which evolution takes place.
Darwin also introduced the notion of fitness, meaning an organism's relative ability to survive and produce offspring. He compared natural selection to artificial selection, wherein humans breed plants and animals for specific traits. This comparison helped him infer that natural selection could lead to the emergence of new species through the accumulation of changes over time.