The truth is that all the intermediates between humans and their ancestors (which diverged from the common ancestor of humans and chimpanzees) are now extinct (and there was likely no fundamental distinction between humans and their ancestors).
Rim brakes. Rim brakes are so called because braking force is applied by friction pads to the rim of the rotating wheel, thus slowing it and the bicycle. Brake pads can be made of leather, rubber or cork and are often mounted in metal shoes. Rim brakes are typically actuated by a lever mounted on the handlebar.
Here is a drawing of the brake disk. The wheel, which consists of a rim and a tire, bolts directly to this structure. Brake pads sit on both sides of the disk, ready to grab onto it when someone pushes on the brake. Here is a side view. The brake pads are usually designed to only grab in one spot on the disk.