What concept in biology was proven wrong that suggested traits could be altered in individuals through use or disuse?

The concept of Lamarckian inheritance proposed that traits in organisms could be modified based on their use or disuse, suggesting that characteristics acquired during an organism's life could be passed on to its offspring. For example, if an organism developed strong muscles through extensive use, it was believed that this trait could be inherited by its progeny. This idea was a prominent theory before Darwin’s theory of natural selection gained acceptance.

However, this concept has been largely discredited in modern biology, primarily due to advancements in genetics, which demonstrate that inheritance is based on genetic information passed through genes rather than acquired traits. In contrast, Darwinian selection emphasizes that natural selection operates on heritable traits that provide adaptive advantages, while Mendelian inheritance focuses on the predictable patterns of inheritance based on dominant and recessive alleles. Epigenetics, while exploring how environmental factors can affect gene expression, does not support the notion of direct trait alteration through use or disuse being inherited in the way Lamarck proposed.

The rejection of Lamarckian inheritance is critical to our understanding of evolution and genetics today, as it underscores the importance of genetic inheritance over acquired characteristics.