Convergent Evolution Is a Theory Rescue Device, Not an Explanation
New experimental work
only explains the loss of
similar structures,
not their origin
by Jerry Bergman, PhD
Recent experimental work by James Satterlee, et al., [1] claimed that their results support convergent evolution. Convergent evolution is defined as
the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups.[2]
One common example of convergent evolution cited by Darwinians is that dolphins and penguins first evolved, then later both animals evolved flippers to serve a similar purpose, namely to navigate ocean travel.
Convergence is a widely used theory which, its supporters claim, explains the independent evolution of the similar design of wings in insects, reptiles, birds, and mammals, all which evolved separately due to convergent evolution.
How did powered flight originate 4 times in different animal groups? How many coordinated mutations did that take?
Convergent evolution is similar to parallel evolution, in which two independent species separately and independently evolve in the same direction and independently acquire similar characteristics. Convergent evolution creates analogous structures in organisms that have similar form or function or both, but were not present in their respective last common ancestor. The problem is, this explanation cannot be definitely documented and is actually a rescuing device employed in an attempt to salvage Darwinian evolution.
The Research
The experiment reviewed here claimed to provide evidence for convergent evolution in regards to thorns and “prickles” in plants. As we will see, it failed to do so. Satterlee, et al., by using phylogenetic analyses, identified
enzymes underlying cytokinin biosynthesis, which when disrupted result in prickle loss in multiple species …. The authors performed CRISPR experiments in several species, including an indigenous crop, and found that loss of these genes greatly reduces or eliminates prickles without off-target phenotypic effects. This study sheds light on convergent evolution and provides a genetic target for prickle removal in crops.[3]
The loss of, in this case the sharp epidermal projections called thorns or prickles, can easily be explained by similar mutations that cause their loss in those plants that have these structures. Plants that have prickles or thorns include the rose barberry, stinging nettle, plum, cacti (family Cactaceae), and some holly species such as American holly (Ilex opaca) and English holly (Ilex aquifolium).[4] Convergent evolution asserts that the thorns on these unrelated plants evolved independently after the plants had evolved. Satterlee et al. write that
Mutations in a cytokinin hormone biosynthetic gene caused at least 16 independent losses of prickles in eggplants and wild relatives in the genus Solanum. …. By developing new Solanum genetic systems, we leveraged this discovery to eliminate prickles in a wild species and an indigenously foraged berry. Our findings implicate a shared hormone activation genetic program underlying evolutionarily widespread and recurrent instances of plant morphological innovation.[5]
Implications of the Experiments’ Findings
The loss of prickles resulted from a specific mutation in 16 cases that allowed Satterlee, et al. to extrapolate the cause of the loss. Thus, the implication is that the evolution of the system that was mutated can explain the origin of the prickles trait in all of the plants that have this trait. But none of these findings, nor those of similar findings, prove the case for convergent evolution. The evolutionary model requires a previous commitment to evolution by natural selection. If evolutionism is true, they reason, convergent evolution must also be true. The experimental results of Satterlee et al., however, started with the assumption of evolution – not from direct evidence of the independent evolution of thorns in very different plants that evolutionists believe had very different evolutionary histories.
Problems With the Convergent Evolution Theory
One major drawback in interpreting the natural world by Darwinian assumptions is that evolution cannot explain the enormous number of similar traits in both living and extinct organisms that do not have a recent common ancestry. For example, many insects, bats, and birds all have wings that enable them to fly. Evolutionists reject the argument from homology in this case—i.e., the logic that insects first evolved wings and then insects eventually evolved into birds with wings, and, later on, birds evolved into bats with wings. This approach of common ancestry, based on the evolutionary belief that insects are a very primitive life-form, birds are the next-most complex, and, lastly, mammals are the highest evolved, is challenged by numerous traits that cannot be due to common ancestry. Thus explaining similarities according to homology is very problematic, which is why it was not seriously proposed by evolutionists.
The more-common explanation is that convergent traits evolved independently: e.g., insects evolved wings very early in the fossil record and, many years later, some flightless pre-birds evolved wings, and even later, some mammals, such as bats, evolved wings.[6] This view of independent origins for wings is challenged by the probability of multiple similar mutations arising by chance, but illustrates why the concept of convergent evolution was adopted.
Some examples of convergent evolution. Placentals and marsupials have a very different evolutionary history, yet as shown in the illustration some examples have numerous similar traits as well as morphology. From Wikimedia Commons.
Other Problems with the Convergent Evolution Theory
Another problem is that it is just as difficult to disprove convergent evolution as it is to prove it. It can sound reasonable, but no fossil record or other evidence exists to demonstrate that it occurred, even though soft tissue in fossils is rare. Convergence is not observable. It exists only in someone’s mind as an imaginary picture. It is a mental construct which, as described by Randy Guliuzza, president of ICR, is a
wholly imaginary fabrication …. the idea that the same traits evolved independently in completely different organisms. …. evolutionists … write about it so matter-of-factly that it has taken on a genuine life of its own in all their willing minds. Why do they embrace convergent evolution so eagerly? Because it serves as a rescuing device for an important dogma of evolutionary theory. (A rescuing device is a completely fabricated conjecture devised to save someone’s theory from contrary evidence.[7])
Guliuzza added that
this highly revered tenet greatly needs rescuing because so many nonhereditary similarities contradict it. Convergent evolution is the fabricated conjecture evolutionists invoke to explain very similar characteristics between creatures that could not have been inherited from a common ancestor and that evolutionists will never accept as having been produced by an intelligently designed internal programming that is specified for common purposes.[8]
Phylogenetic reconstruction routinely assumes that evolution has occurred without convergence.[9] As C. Tristan Stayton admits: “Although convergence is recognized as a central concept in evolutionary biology, very few tools are available for the quantitative study of this phenomenon.”[10] Even so, convergence is so commonly invoked throughout the theoretical tree of life that its dominance serves as the foundation for many evolutionary stories.
In summary, the results of the Satterlee paper do not support the convergence concept; instead, they rather illustrate the problems of this particular rescue device.
References
[1] Satterlee, J., et al., “Convergent evolution of plant prickles by repeated gene co-option over deep time,” Science 385(6708), DOI: 10.1126/science.ado1663, August 2024.
[2] “Convergent evolution,” Wikipedia, https://en.wikipedia.org/wiki/Convergent_evolution#.
[3] Simonti, C.N., “Editor’s summary of Satterlee, et al.,” 2024.
[4] Brown, C., “Armed by nature: Thorns, spines, and prickles,” Ohio State University, https://bygl.osu.edu/node/2263#, 4 October 2023.
[5] Satterlee, et al., 2024.
[6] Ironically, today it is widely accepted by evolutionists that birds evolved from dinosaurs, which is not logical, but evolutionists have no better option.
[7] Guliuzza, R. “Major evolutionary blunders: Convergent evolution Is a seductive intellectual swindle, Acts and Facts, https://www.icr.org/article/major-evolutionary-blunders-convergent, February 2017.
[8] Guliuzza, 2017.
[9] Stayton, C.T., “The definition, recognition, and interpretation of convergent evolution, and two new measures for quantifying and assessing the significance of convergence,” Evolution 69(8):2140–2153, 2015.
[10] Stayton, C.T., “Is convergence surprising? An examination of the frequency of convergence in simulated datasets,” Journal of Theoretical Biology 252(1):1-14, 7 May 2008.
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 1,900 publications in 14 languages and 40 books and monographs. His books and textbooks that include chapters that he authored are in over 1,800 college libraries in 27 countries. So far over 80,000 copies of the 60 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.