The concept describes characteristics or features of an organism gained during its lifespan, subsequent to genetic inheritance. These characteristics arise from environmental influences, behaviors, or experiences. An example includes the increased muscle mass developed through weightlifting or scars resulting from injuries. These modifications are typically non-heritable, meaning they are not passed down to offspring through genetic mechanisms.
Understanding the nature of these characteristics is fundamental to distinguishing between phenotypic plasticity and evolutionary change. The capacity for organisms to adapt to their surroundings is crucial for survival; however, changes to the organism itself are often temporary and do not alter the genetic composition of the germline. The historical context reveals a long-standing debate about the heritability of such changes, with earlier theories suggesting a potential for inheritance, views that have been largely discredited by modern genetics.
