What is the main difference between the muscles built through push-ups pull-ups and those built through weightlifting?

It all depends on repetitions. If you can Bench press 'X' amt of weight 10 times and you can only perform 10 push ups, then you're most likely going to get the same trianing effect out of it. The typical trained athlete can perform many push ups and will perform a similar weight lifting exercise for lower reps, example a Bench Press... The effect on these two types of training and the effect on the type of muscle it would build are as follows: Say you can push up 30 times, this is going to help build your endurance, now let's say you can bench press 150lbs 30 times....you're still going to be imporving muscular endurance, now let's say you rack so more weight on the bench press and you have on 225lbs and you can only lift it 10 times, it will give the training effect of hypertrophy, MEANING. growth of your muscle. Most exercise scientists agreee that these rep ranges give these following effects to the body: 12 reps and higher = more endurance work 8-10 reps = muscle mass training 7-5 reps = strength training 4 reps and lower = power training

This is all a little dependent on genetics as well and if you're drug free or not, but this is a pretty sure fire way to know what kind of effect you're going to get from exercising.

Your muscles are composed of two different types of fibers for two different types of workouts. These two types are fast-twitch and slow-twitch. Fast-twitch muscle fibers are used when you are lifting a large amount of weight only a few times (strength). Slow twitch muscle fibers are used when you are lifting a smaller amount of weight many times (endurance). When you do push-ups and pull-ups, you may be utilizing your fast-twitch muscles if you are weak and can only do a few reps. As your endurance increases, you will likely start using your slow-twitch muscles as they develop.