how have guns and cannons evolved their separate ways begining at gun powder propellants?

Well the first firearms were very large, looking almost like mini handheld cannons. They were heavy and inaccurate so they tried to make them smaller. Early firearms were lit with matches. A rope was inserted and the rifleman lit a match, ignited the rope and the gun was fired. There was no trigger and reloading was long as not only did you have to insert the powder and cartridge, but you also had to insert the rope and light it (which was not easy considering wind could easily blow out a match.

Eventually a new revolutionary design was invented. the flintlock. Instead of using fire from a rope to ignite the powder a spark was used instead. When you pulled the trigger, the hammer fell on a flint stone. the friction between the 2 caused a spark which ignited the gunpowder. Over the years this design was modified such as adding a rifled barrel (a barrel with groves) that spun the bullet, making it more accurate than a conventional smooth-bore.

Shortly before the civil war new firearms were invented. They used a similar spark process as muskets but carried multiple rounds. These were generally known as repeater rifles. Rifles capable of carrying multiple rounds that were manually chambered after each shot (by manually I mean you had to pull back the hammer or cock the handle, etc after every shot) [*note later they invented automatic chambered the next round*]. Examples of Repeaters include the Spencer rifle, Henry Rifle, and Colt rifle.

Around the 1880s a new type of rifle was invented. The bolt action (unlike the repeater and muskets that used round balls) used the ammo we see today, long, pointy and cylindrical (no this is not a phallus joke). They were much more accurate, had better penetration, and were easier to reload. Bolt actions required manual chamber after each shot. After bolt action we had semi auto (which fires every time you pull the trigger), burst (fires a burst of 2 or more every time you pull the trigger) and fully automatic (holding the trigger produces a volley of inaccurate fire)

Now cannons

Early cannons deviated from firearms shortly after gun powder was first used with weapons. The point was mostly to be used as siege equipment to knock down castle walls. Their evolution was not as exciting as guns. The only major modifications until the late 19th century was just longer barrels, larger sizes, and again experimentation between smooth and rifled barrels.

In the late 1800s a new form of cannons was starting to emerge. Instead of loading from the front and adding gunpowder, a cartridge was loaded from the back (making it safer from enemy fire). The cartridge already had the projectile and powder inside so it got ignited by the cannon. That design pretty much stuck to today. We still use rear loading artillery and they range in size from small ones the size of a car to alrge ones the size of a school bus and bigger.