Final answer:
A mutation that decreases an individual's Darwinian fitness will reduce their ability to survive, reproduce, and contribute to the gene pool of the next generation, potentially leading to an increased chance of elimination by natural selection.
Step-by-step explanation:
When a mutation arises in an individual that can decrease that individual's Darwinian fitness, it means that the individual's ability to produce offspring and contribute to the gene pool of the next generation will decrease. This reduction in fitness can manifest in various ways, including decreased lifespan, increased chance of offspring dying, or decreased chances of mating between individuals. Essentially, the individual's ability to survive, reproduce, and contribute to the gene pool of the next generation will decrease.
It's key to understand that not all mutations are equal; while many mutations may be deleterious, reducing an organism's fitness, others might be neutral with no effect on fitness, or even beneficial, increasing the organism's chances of survival and reproduction. However, in the context of this question, a mutation that decreases Darwinian fitness could lead to a higher probability of the individual facing elimination by natural selection, as it may hinder their survival or reproductive capabilities in comparison to individuals without such mutations.