aristotle writes:
Does a species change more through natural selection if the weaker, less favored individuals reproduce more, or if the stronger, more favored individuals reproduce more?
Hold on, cowboy, hold your thoughts. The best adapted for the environment tend to pass on their genes. Weaker, stronger, etc. all are relative terms in the environment organisms live in. What's weak in one environment is strong in another. What's strong in one environment is weak in another.