Final answer:
The answer to the students' question is 'Fitness,' which is related to an organism's ability to survive and reproduce, thus passing its genes to subsequent generations. This concept is fundamental in understanding natural selection, evolutionary success, and the field of population genetics.
Step-by-step explanation:
Fitness, in the context of evolution by natural selection, refers to the relative ability of an organism to survive and produce fertile offspring. It directly connects to an organism's genetic ability to pass on its traits to the next generation. The concept of fitness is not about sheer strength or might but rather about how organisms are well-adapted to their environments.
Natural selection operates on populations by amplifying traits that increase chances of survival and reproduction. This evolutionary process is driven by the fact that some individuals will be better suited to the environment due to genetic variation. Those with genes that provide an advantage in their specific environments—be it resistance to diseases, ability to find food, or escape predators—are more likely to survive, reproduce, and therefore increase the frequency of those favorable genes in the population.
This refinement over generations can progressively shape the population to be increasingly well-adapted to its environment, reflecting the evolutionary success of the trait. Fitness is key to understanding how these changes occur within populations over time, shaping them through evolutionary change as dictated by the principles of population genetics.