What aspect of species reproduction does Darwin highlight?

Darwin highlights the idea that many species reproduce exponentially, which is a significant aspect of his theory of natural selection. This exponential reproduction means that species have the potential to produce more offspring than the environment can support. Consequently, not all offspring will survive, leading to competition for resources. This competition drives natural selection, where individuals with advantageous traits are more likely to survive and reproduce, thus passing those traits onto the next generation.

This concept is foundational in understanding how species evolve over time and how certain traits become more common within a population due to their beneficial impact on survival and reproduction outcomes. It also underlines the importance of environmental pressures, as not every offspring will reach maturity or reproduce, thereby shaping the evolution of species in response to changing conditions.