Final answer:
Charles Darwin was not aware of the concept of sperm competition during his lifetime. His work predated the modern synthesis, which integrated natural selection with Mendelian genetics. Darwin's insights into artificial selection and natural selection nonetheless laid the foundation for later understanding of evolutionary processes like sperm competition.
Step-by-step explanation:
The concept of sperm competition was not known to Charles Darwin. During Darwin's time, the mechanisms of inheritance, including how traits like fertility and mating behavior were passed on to offspring, were not yet understood. The modern understanding of genetics, and thus sperm competition, came to light with the rediscovery of Gregor Mendel’s work in the early twentieth century, which was after the publication of Darwin's On the Origin of Species. This work ultimately led to the modern synthesis, which integrated the ideas of natural selection with Mendelian genetics. Had Darwin known of Mendel's work and the concept of sperm competition, it might have refined his theory of evolution by providing a mechanism for how certain traits increase in prevalence within a population due to differential reproductive success. Despite his lack of understanding regarding sperm competition, Darwin did understand concepts related to reproductive success. He established the principle that in nature, offspring with certain variations might be more likely to survive the 'struggle for existence' and reproduce, passing their favorable variations to their offspring. This concept is embodied in the term fitness, which Darwin used to describe an organism's ability to survive and produce fertile offspring, leading to natural selection. Darwin also had knowledge of artificial selection, where selective breeding in domestic species can lead to changes over time. This knowledge, along with the eventual integration of genetics into evolutionary theory, shows that while Darwin was not familiar with sperm competition specifically, his ideas laid groundwork for understanding the importance of reproductive success in evolution.