Final answer:
Darwin's theory of evolution by natural selection describes how traits that improve survival and reproduction become more common in a population, leading to evolution over generations. This theory emerged from Darwin's observations of natural variety and the competition for limited resources.
Step-by-step explanation:
Understanding Darwin's Theory of Natural Selection
Charles Darwin developed the theory of evolution by natural selection after making pivotal observations during his voyage on the HMS Beagle, particularly on the Galápagos Islands. This theory posits that living organisms with advantageous traits are more likely to reproduce successfully, leading to a gradual change in the population's characteristics over time. Darwin's theory is built on three principles:
- Most characteristics of organisms are inherited and variation exists among individuals in a population.
- Organisms produce more offspring than can survive due to limited resources, resulting in competition.
- Offspring with inherited traits that confer a competitive advantage for these limited resources are more likely to survive and reproduce, thereby passing on these traits to future generations.
This process of natural selection leads to populations evolving and becoming better adapted to their environment, a concept Darwin described as 'descent with modification'. Alfred Russel Wallace independently conceived a similar theory of evolution by natural selection, leading to a joint presentation of their findings before Darwin's publication of 'On the Origin of Species'.