Genetic algorithm, confusion with selection/reproduction step.

Hi, im a little confused with the selection/reproduction step in genetic algorithms. Im aware that the initial population has several hundred in it. That the fitness function is used to select a certain number of the possible solutions for cross over/mutation. What i dont get is how the population size, between each successive generation, doesnt get progressively smaller and smaller?

Thanks for your time.
Hi Dason, thanks very much for replying. So say i had 300 possible solutions in the initial population, and i selected 50 with the best fitness function result, Do i just keep selecting, based on their fitness result, pairs (or X number of parents as wiki suggests) until i have a new population of 300?

Are there any cases where you would want a large population to begin with but then narrow it down, ie 300 down to 100.

Thanks again for your help, i really appreciate it.


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I won't lie - I really only know about genetic algorithms theoretically. I've never actually implemented one so I'm probably not the best to ask about implementation details.
no worries, i'll assume i use those 50 with the highest fitness to make a new population of 300 unless someone else can say otherwise. Thanks again for ur ehlp though, i really appreciate it.