This is very interesting. I would argue that it falls under evolution, but I would also caution the accuracy of the figure 11% in 1918 vs 39% today given the obvious vast difference in investigative capabilities now compared to those available a century ago. My reason for evolution is as stated by the authors - heavier and taller humans, and the fact that when a body part is developing in the evolutionary context, it will take a long time and "fine tuning" for nature to eventually get it right. Lack of specific knowledge of its function at this time does not necessarily negate evolution.

Based on the discussion, it is clear that the trait does not have genetic basis. In order for this to be evolution, the trait must be inherited to the next generation. In other words, this seems like just an acquired trait that does not get transmitted to the offspring(s).

Well, if the fabella is more likely to be associated with disease, (which could also be due to lifestyle changes), then it is difficult to say if it has any survival value. So it is less likely to be selected in the gene pool under evolutionary pressure. Also, paradoxically, this looks like a "loss of function mutation" scenario, since the fabella disappeared in great apes during the course of evolution. So it is difficult to reconcile the re-emergence of fabella with the evolutionary theory. In addition to this, there has to be a genetic basis of inheritance as well (DNA->RNA->Protein, and not the other way round), as pointed out quite nicely by Dr. Nepal.

This is an interesting research. I think this can be categorised under biological evolution or biological development instead of evolution. They are different concepts. Evolution means we evolve and we may show sudden changes like mutation...etc. but biological development is something scientific and natural happening in the world and the first polymath who analyzed it was Al Jahiz in his encyclopedia The Book of Animals of better yet, The Book of Living. He analyzed that biological development is called biological determinism because: 1 the development is determined, ie: don't expect humans to have wings or so...it would be a logical, calculated, anticipated development, and 2: it is determined by natural processes, the most important of which are a: Environmental determinism (eg: u move to a hot environment it influences ur physiology and psychology, or eg: a village that drinks polluted water it's people develop skin abnormalities. ..etc.), b: Struggle for Existence ( eg: a strong lion develops strong biological characteristics based on his engagements in fights when it lives with multiple other predators for example, and the lion transmits these biological characteristics to its offspring), c: Defense Mechanisms ....there's also lifestyle and so on. U can relate to these more with AL-JAHIZ AND THE RISE OF BIOLOGICAL EVOLUTION

by Dr. Mehmet BAYRAKDAR and Jim Al Khalili' s researches on Al Jahiz's The Book of Animals, there's also

Lunde, Paul. ‘‘Science, The Islamic Legacy: The Book of Animals

Sultan Shah, Muhammad. “Pre-Darwinian Muslim Scholars’ Views on Evolution

Tschanz, David W. ‘‘Al Jahiz, the First Islamic Zoologist’’

Friedrich Dieterici 's Der Darwinismus im X und XIX Jahrhundert (Darwinism in the 10th and 19th Century)

And E. Wiedemann in his Darwinistisches bei Gahiz (Darwinism by Al Jahiz)

What I'm trying to say is that what u may call evolution, biological evolution or biological development of course exists, but certain scientists use it to prove creationism as they do with Natural Theology and the watchmaker analogy...because it's a defined exact scientific calculated expected natural process...so after all, 1- not all evolutionists are atheist, and 2- the defined determined methodological process of evolution proves the existence of God, not negates it...

Hope u can find something interesting in these ideas...

Question, can this trait in the article be considered atavistic? What is the relationship between atavism and evolution?

evolution --coupled with modification/adaptation

Hello Jack; Here are some of the things I'd like to see;

1. If nutrition and body size are invoked as possible causes, let's see some surveys of these independent variables in statistically valid sample sizes in a range of ethnic groups.

2. Bilateral appearance of the trait probably varies considerably. Bilateral presence might be informative.

3. Do other sesamoid bones show a similar pattern.

When some more evidence is available we might be able to discuss mechanisms. Best regards, Jim Des Lauriers