Every block are getting black

What i expected to hapend was that every blocks should have their own texture, and i was using the deafult texture-pack.

What actually happened was that the blocks were getting black, just the blocks and things u can set out, without animals.

1. I pressed on the save i was going to use.
2. When i came into it, everything was fine, all the textures were there.
3. I was setting out the new blocks.
4. I walked and looked on the blocks, and then suddenly the blocks got a black texture.