In Animal Farm, what are the original commandments and how have they changed at the end of the story?

In Chapter Two of Animal Farm, the animals come together and create their own set of commandments which are written on the side of the barn "in great white letters that could be read thirty yards away." These seven commandments represent the animals' attempt at organising their new and liberated society and are based on the principles of equality and separation from humans:

1. Whatever goes upon two legs is an enemy.
2. Whatever goes upon four legs, or has wings, is a friend.
3. No animal shall wear clothes.
4. No animal shall sleep in a bed.
5. No animal shall drink alcohol.
6. No animal shall kill any other animal.
7. All animals are equal.

But, by Chapter 10, the commandments (and the animals) have taken a very different turn as Clover and Benjamin find that a single commandment has replaced the original seven. It simply reads:

"All animals are equal but some animals are more equal than others."

This dramatic change in the commandments represents the destruction of the animals' utopian society. This idea is also supported in the change from Animal Farm to Manor Farm. Furthermore, this change in the commandments also corresponds with the animals' adoption of human characteristics. We find Squealer, for example, walking on two legs and Napoleon drinking alcohol and playing cards with Mr Pilkington. The animals' utopia is lost and the pigs have truly become the new masters.