Fitness proportionate selection means that individuals with the best genes are more likely to survive and have babies than individuals with worse genes. Think of it like a game where the strongest players get to play again and again, while the weaker players get kicked out.
In fitness proportionate selection, the chance of an individual being chosen to have babies is based on how much their genes help them survive and reproduce. Let's say one organism has really good genes for running, while another has good genes for surviving in extreme temperatures. If the environment favors running, the first organism would have a better chance of having babies and passing on their running genes. But if the environment turns really cold, the second organism might have a better chance of survival and passing on their cold-resistant genes.
So, fitness proportionate selection is a way nature selects which genes get carried forward into future generations. The strongest genes are more likely to survive and pass on their traits, while weaker genes gradually get weeded out over time.