Who most influenced Darwin's idea that some offspring are better suited to survival than others?

Charles Darwin was significantly influenced by the work of Thomas Malthus, particularly Malthus's ideas on population growth and resource limitations. Malthus argued that populations tend to outgrow their resources, leading to competition and a struggle for existence. This concept helped Darwin formulate his theory of natural selection, where those offspring better adapted to their environment are more likely to survive and reproduce. Additionally, the work of naturalists like Jean-Baptiste Lamarck and George Cuvier also contributed to his understanding of variation and adaptation.