April 14, 2021 | Jerry Bergman

Rupturing a Myth: The Human Appendix Is Not Vestigial

Darwin’s Story of Useless Organs Was Wrong
Yet the Myth about the Human Appendix Lives On


by Jerry Bergman, PhD

The functions of most claimed vestigial (useless) organs have been empirically documented decades ago, many over a century ago.[1] Nonetheless, the claim that some organs are vestigial is still being made by many evolutionists. The human vermiform appendix is probably the best known example of a supposedly functionless or even allegedly useless organ. A humorous claim made by some is that its main function is to help the surgeon purchase a new Mercedes! This vestigial organ argument was first discussed in some detail by Charles Darwin in The Origin of Species in a chapter section titled Rudimentary Organs.[2] The term rudimentary means that these organs are atrophied relics of what they once were in our supposed animal ancestors. Darwin spent several paragraphs defending his idea that they are not only atrophied, but useless.[3] His list of vestigial organs included examples from both plants and animals.

One of the earliest to tout the appendix as proof of evolution was Germany’s most eminent evolutionist, Ernst Haeckel, who declared that rudimentary organs, including specifically the “vermiform appendage,” are “the most obvious proof of the Theory of Descent, and secondarily, … they most forcibly refute the customary theological” explanation (i.e., creation). He added, “the existence of rudimentary organs admits of no other explanation” including the “ancient fable of the all-wise plan accordingly to which the ‘Creator’s hand has ordained all things with wisdom and understanding.’”[4] The creation “fable,” Haeckel assures us, has now been “completely disproved.” Soon the atheistic evolution of Haeckel spread to theists. Henry Drummond was one of the first theistic evolutionists to have claimed that the human appendix was a vestigial organ.[5]

Ideas on the Evolution of the Appendix

Evolutionists have entertained several hypotheses regarding the continuing existence of the appendix in the human body. One idea claims it is a leftover from a leaf-eating ancestor. Another is that it is an evolutionary remnant of the cecum (one end of the large intestine where the appendix is located). Another idea is it was once used by now-extinct human evolutionary predecessors to help digest certain food types. Darwin taught that all rudimentary organs, “far from presenting a strange difficulty, as they assuredly do for the ordinary doctrine of creation, might even have been anticipated, and can be accounted for, by the laws of inheritance” via evolution.[6]

One of the most detailed early discussions of the appendix is in the book The Structure of Man: An Index to His Past History by Robert Wiedersheim.[7] He used the term ‘vermiform process’ instead of appendix, noting considerable variation exists in this organ, and furthermore, he claimed it becomes corrupted with age. Wiedersheim did not label it vestigial, or claim it had no function. Instead, he did not mention a function.

Darwin’s doctrine about rudimentary organs soon spread, eventually becoming conventional wisdom in leading textbooks, such as Huntington’s The Anatomy of the Human Peritoneum. [8] His doctrine is also widely found in popular publications, even in the Encyclopedia Britannica, which claimed that humans have over 100 vestigial organs including the appendix.[9] The same claim is repeated in Britannica online.[10]

As far back as 1934, Clark correctly recognized that the rich blood supply in the appendix would prove it to be functional.[11] As late as 2012, one popular science website wrote about the appendix that the

human body has a few unneeded parts. We no longer rely on these organs or structures for any serious function, or they have atrophied or degenerated to the point that they don’t serve the function they used to.[12]

Claims Debunked a Century Ago Still Haunt Scientific and Popular Literature

Although experimental evidence of the appendix’s function dates back to the middle 1950s, an article in Live Science by Charles Q. Choi (2021) does not appear to be aware of that fact. Choi admits that this “organ may not be a useless artifact of evolution after all” and notices that the myth of the vestigial appendix is still around after almost 90 years, but only now is being called problematic. Choi begins by implying that it is useless, stating it is a “small pouch attached to your large intestine, at the junction of the small intestine, [that] no longer aids in digestion, and none of the 1 in 20 people who have one removed seems to miss it.”[13]

Of course, many very useful organs can be removed without problems, including tonsils, adenoids, the vomeranasal organ, the spleen, and wisdom teeth. Some people are born with only one kidney and sometimes do not discover that fact until later in life. Less than 1 in 100,000 people are born without an appendix, and appendicitis affects only about 1 in 20 people. This appendicitis level may be due to improved sanitation in our industrialized society, leaving our immune systems with insufficient exposure needed to fine-tune the immune system, opening it up to malfunctions.[14]

The human appendix shown in more detail. From Gray’s Anatomy (public domain)


More Revelations Appear about Its Importance

Choi admits that “the human appendix might be useful, serving as an important storehouse for beneficial bacteria, which can’t wait for a case of diarrhea so they can rush to the gut and save you.”[15]

In another article, Choi wrote that the appendix “served as a vital safehouse where good bacteria could lie in wait until they were needed to repopulate the gut after a nasty case of diarrhea. Past studies had also found the appendix can help make, direct and train white blood cells.”[16]

Note: In his book Foresight: How the Chemistry of Life Reveals Planning and Purpose, Dr. Marcos Eberlin expands on this example, arguing that a system that could repopulate the gut with beneficial bacteria after a “power wash” of diarrhea shows a plan and purpose beforehand. Hear him explain this at the ID the Future podcast.   —Ed.

Thus Darwin’s claim is proven wrong. Choi halfway admits it. He calls it a speculation, recounting how Darwin thought

the appendix was a vestigial organ from ancestors that ate leaves, potentially helping them digest food. As these ancestors evolved to rely on a fruit-based diet that was easier to digest, Darwin speculated the appendix no longer served a function, much like the small triangular coccyx bone at the base of the human spine, a remnant of tail bones found in our distant ancestors.[17]

Darwin and Haeckel used these supposed vestiges of anatomy in humans and other animals as powerful evidence in support of evolution. Choi now says that if “Darwin knew then what scientists know now about the appendix, he would have never suggested it was a worthless vestige of evolution.”[18]

Additional evidence supports the functional importance of the appendix and, simultaneously, causes problems for evolutionary theory. In 2007, Bollinger et al. wrote that

the appendix has been around in mammalian evolution for at least 80 million years, much longer than  expected if the appendix really was a vestige, they reported in 2009 in the Journal of Evolutionary Biology. Moreover, they also discovered the appendix evolved independently at least 32 times among mammals, in species as diverse as orangutans, wombats, platypuses, beavers, koalas, porcupines and manatees.

Of note is the “architecture of the human appendix is unique among mammals, and few mammals other than humans [mostly those noted above] have an appendix at all.”[19]

The Appendix: Now Known to be Critical for Health

As noted, one major evidence of its function includes the fact that the appendix serves as a reservoir for useful gut bacteria. The gut microbiota serves to help the body digest food and manufacture certain required supplements.[20] This finding is important because “When diseases flush both good and bad microbes from the gut, good bacteria can emerge from the safe harbor of the appendix to help restore the gut to a healthy state.”[21] Furthermore, “the appendix possesses a high concentration of lymphoid tissue. This tissue generates white blood cells known as lymphocytes that help mount immune system responses to invading germs, suggesting the appendix may help make, direct and train these immune cells.”[22]

Evidence of this immune function included a study that evaluated species lacking an appendix, finding no commonalities in diet, social ability, or where they lived. Conversely, in species with an appendix, they found that it contained a concentration of immune tissue, thus a common function.[23] The researchers concluded that if the appendix suddenly vanished “you’d see a lot more people dying of infectious diseases than they would otherwise … Then, over a long time, over millions of years, … something would slowly evolve that worked the same as an appendix.”[24] Furthermore, if our

appendix disappeared in a modern society after the Industrial Revolution, people would have antibiotics to help them survive … However, without an appendix, people would not have the appendix’s reservoir of helpful bacteria to help them recover from harmful infections. When that happens, we may need to give people fecal transplants.[25]

Fecal transplanting is a new therapy for people suffering from certain gastrointestinal infections. It works like the appendix by repopulating the gut. It involves transplanting the proper mix of good bacteria

from healthy people into the guts of patients with intestinal problems, via a tube or capsule placed down one’s throat or up one’s bottom. The idea is that the transplant will bring healthy bacteria into guts overrun by harmful microbes. Bodies overrun with harmful microbes may become more common as antibiotics get overused and germs evolve resistance against these drugs. Fecal transplants don’t encourage antibiotic resistance.[26]


The evidence that the appendix is not functionless but serves at least five important roles in the body is now overwhelming. As explained in my book Useless Organs, the issue is, “how long will it be before the biology and evolutionary textbooks reflect that fact not only for the appendix but for other vestigial organ claims?”[27] In my experience teaching anatomy at the college level for over 20 years and reviewing dozens of anatomy textbooks, not a single human anatomy textbook made the claim that humans have vestigial organs. This is not true of textbooks in general biology, nor in evolution—most of which still include the vestigial organ claim.

My supposition is that the vestigial organ argument is too useful for Darwinians to give up. They might modify it a bit in light of the growing evidence for function in these organs. Instead of claiming these organs have no function as Darwin did, they might present the idea that they have less function today than they did in our evolutionary ancestors. This accommodation has its own problems. It could be used to claim that humans have vestigial hearing, smell and sight compared to many of our evolutionary ancestors. Where would that line of reasoning stop?

The researchers quoted in the Choi paper concluded relative to the appendix that “a world without an appendix might leave humanity struggling with germs more often. The idea that the appendix is an organ whose time has passed may have itself become a notion whose time is over.”[28] Its time has been over now for many decades, but the vestigial organ claim is still used to defend the Darwinian worldview.


1] Bergman, Jerry, Useless Organs: The Rise and Fall of the Once Major Argument for Evolution, Bartlett Publishing, Tulsa, OK, 2019.

[2] Chapter 13 in Darwin, Charles, The Origin of Species, John Murray, London, UK, 1859, pp. 450-460.

[3] Darwin, 1859, p. 453.

[4] Haeckel, Ernst, The Evolution of Man, D. Appleton, New York, NY, 1879, pp. 109-111.

[5] Drummond, Henry. The Ascent of Man. James Pott, New York. 1903. p. 95.

[6] Darwin, 1859, p. 456.

[7] Wiedersheim, Robert. The Structure of Man: An Index to His Past History Macmillan, New York, NY, 1895.

[8] Huntington, George S., The Anatomy of the Human Peritoneum, Lea Brothers, Philadelphia, PA, 1902, p. 237.

[9] Encyclopedia Britannica, Vol. 14, 2003, p. 1082.

[10] Rogers, Kara, 7 Vestigial Features of the Human Body, https://www.britannica.com/list/7-vestigial-features-of-the-human-body, 2012.

[11] Clark, Wilfrid Le Gros, Early Forerunners of Man, Tindall and Cox, Baillière, London, UK, 1934, p. 205.

[12] Live Science Staff, 5 Useless Body Parts, https://www.livescience.com/21513-vestigial-organs.html2012, 11 July 2012.

[13] Choi, Charles Q., What if humans didn’t have an appendix? https://www.livescience.com/what-if-no-appendix.html, 2021.

[14] Choi, 2021.

[15] Choi, Charles Q., The Appendix: Useful and in Fact Promising. https://www.livescience.com/10571-appendix-fact-promising.html, 24 August 2009.

[16] Choi, 2009.

[17] Choi, 2021.

[18] Quoted in Choi, 2021.

[19] See Bollinger, R. Randal et al., Biofilms in the large bowel suggest an apparent function of the human vermiform appendix, Journal of Theoretical Biology 249(4):826-831, 2007, p. 826.

[20] See Bollinger, R. Randal et al., 2007.

[21] Choi, 2021.

[22] Choi, 2021.

[23] Choi, 2021.

[24] Choi, 2021.

[25] Choi, 2021.

[26] Choi, 2021.

[27] Bergman, Jerry, Useless Organs: The Rise and Fall of the Once Major Argument for Evolution, Bartlett Publishing, Tulsa, OK, 2019.

[28] Choi, 2021.

Dr. Jerry Bergman has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology for over 40 years at several colleges and universities including Bowling Green State University, Medical College of Ohio where he was a research associate in experimental pathology, and The University of Toledo. He is a graduate of the Medical College of Ohio, Wayne State University in Detroit, the University of Toledo, and Bowling Green State University. He has over 1,300 publications in 12 languages and 40 books and monographs. His books and textbooks that include chapters that he authored are in over 1,500 college libraries in 27 countries. So far over 80,000 copies of the 40 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.

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