Chapter 35, Problem 12A

Summary Introduction

To write:

Why humans have an appendix if it has no known useful function.

Introduction:

The digestive system breaks down the food so that nutrients can be absorbed by the body. There are three primary functions of the digestive system. The digestive system absorbs food, breaks it down so that nutrients can be absorbed and removes that cannot be digested.

Explanation of Solution

The appendix is a tiny pocket connected to the large intestine where it meets the small intestine which does not directly help digestion. Biologists agree that the human appendix is a vestigial organ left behind by a plant-eating ancestor. It forms a thin, closed tube which produces mucus and includes lymphatic tissue that is part of the immune system. It also produces useful bacteria.

Conclusion

Thus, the appendix is the vestigial organ left by the plant eating ancestor. It is a small, sac-like appendage.