Final answer:
Malthus' ideas about population growth and resource limitation influenced Darwin's theory of natural selection by providing a framework for the struggle for existence, which leads to the survival and reproduction of the fittest individuals.
Step-by-step explanation:
The connection between Malthus' ideas about competition and Charles Darwin's theory of natural selection lies in the observation that populations could grow exponentially, but this growth is checked by limited resources, leading to a struggle for survival. Darwin took this concept from Thomas Malthus' work, which argued that human population growth is inherently restrained by the availability of resources such as food, and when these are insufficient, the result is a natural culling of the populace through various hardships or 'Malthusian disasters.' Darwin extrapolated this principle to the natural world, postulating that within any given population, there will be variation among individuals, and those better adapted to compete for limited resources will tend to survive and reproduce. This process of differential survival and reproduction leads to a gradual change in the population over time, or what Darwin called 'descent with modification,' and is the essential mechanism of adaptive evolution.