A grain of wheat?

After years of psychotherapy, John no longer believes he is a grain of wheat. However, one day he and a friend came across a chicken, and John was terrified. "Why are you so afraid, you're not a grain of wheat after all," his friend asked. John replied, "You know it and I know it, but the chicken doesn't know it."

Ant with Frog Legs

Q:  What do you call an ant with frogs legs?
A:  An antphibian!

The Essential Difference

One day the zoo-keeper noticed that "Cheech" the orangutang was reading two books -- the Bible and Darwin's Origin of Species. In surprise he asked the ape, "Why are you reading both those books?" "Well," said the orangutang, "I just wanted to know if I was my brother's keeper or my keeper's brother."