While some biologists may know how to calculate the information content of sequence, most are not familiar with how to calculate amount of information. According to Shannon's information concept, information is to decrease uncertainty. The more uncertainty information decreases, the more the information. Information is the difference between the entropy of known and unknown. How much uncertainty you need to decrease, how much information you need. If you know everything, you do not need information. The less you know, the more you need to know, the more information you need. The uncertainty can often be calculated as possibility. The certainty means only one possibility. The uncertainty means many possibilities. The more possibilities excluded, the more the information.