My definition of intelligence

I guess I should make it clear what I mean by intelligence or thinking, when I speak of plants or animals. I do not mean instinct, where an animal does something automatically, like a bird building a nest, the way her grand-grand-grand-mother did. What I mean by intelligence is ability to react in a creative way to a given situation; to learn new things and to problem-solve. Let me give you a couple of examples:

I had a cat years ago, who figured out all by herself how to play fetch. I was lazy back then, and practically lived on the couch in front of the TV when I came home from work. One time I tossed a crumbled piece of paper across the room, and my cat ran after it and brought it back to me. Surprised, I threw it again, and the cat did the same thing. From then on, my cat was playing fetch with me whenever I was watching TV.

There was a tree growing out of the side of a rock from a tiny crack. About 3 or 4 feet above the crack there was another crack. The tree grew a root straight out at a 90-degree angle at the exact height of the second crack - a single thick root aiming directly for that crack. There is no way it was a chance, trial and error thing - it took a lot of juice to grow that root; it was a life & death decision for the tree - it had to be right on the first try! The crack not only provided the nutrients, but also enabled the tree to grab onto the rock, so it wouldn't fall off. How did the tree know there was a second crack? It couldn't see it or smell it, that's for sure.