Misconceptions of Evolution

Alyssa Anderson, Aaron Avery, and Stephen Hill
*All authors contributed equally 

As humanity embarks into the twenty-first century, the importance of understanding the theory of evolution has never been greater. This importance is not rested solely in understanding human existence, but on the natural world as a whole. If humanity hopes to tackle such issues as curing cancer, fighting antibiotic resistant bacteria, and finding crops better adapted to global climate change, then we must impart a broad understanding of the theory of evolution to the next generation. Misconceptions in the understanding of evolution are a common occurrence and can be difficult to approach in the classroom, but because of the importance of this issue the scientists and educators of today should be well versed in how to teach evolution in both a confident and equitable manner that does not foster resentment from their students. This article seeks to address some of the more common misconceptions and supply responses to them, for educators and for evolution learners

1) Evolution is a theory, not a law

This misconception stems from a mix-up between casual and scientific use of the word theory. In everyday language, theory is often used to mean a hunch with little evidential support. Scientific theories, on the other hand, are broad explanations for a wide range of phenomena. In order to be accepted by the scientific community, a theory must be strongly supported by many different lines of evidence. Evolution is a well-supported and broadly accepted scientific theory; it is not ‘just’ a hunch. Evolution is a theory and it is also a fact- meaning that it is extremely well supported in scientific studies. 

2) Evolution goes against religious beliefs

Accepting religion does not discredit evolution and science, and vice versa. Many may believe that science is inherently atheist or agnostic, or that science requires one to forgo their faith entirely. Not true! Evolution is a means to explain an unknown phenomenon in the world by using what we can test in the world around us; in this case, evidence that shows organisms changing over time. It’s the same way people use science to understand nature today, such as answering why the sky is blue instead of only wondering. Religion seeks to explain phenomena outside of nature. But understanding how nature works does not discredit faith! The goal of scientific theory and explanation is not to prove something wrong, it simply seeks to understand by testing naturally occurring phenomena around us. 

3) Evolution doesn’t explain the origin of life 

Evolutionary theory discusses ideas and evidence surrounding the idea of the origin of life, but this is not central to what evolutionary studies aim to learn. Evolution describes the processes involved in life changing over time, not how it started. Evolution considers factors such as adaptation, mutation, and natural selection as mechanisms for driving biotic change throughout Earth’s history. Random (mutation) and non-random (selection) processes contribute to evolutionary change. The idea that the study of evolution seeks to understand how life changed after it started gives us an advantage when teaching science to students who may have differing opinions on how life appeared on this planet. Science and religion are not at odds as they each seek to answer fundamentally different questions in fundamentally different ways. Science and religion in this way do not have to be diametrically opposed, and therefore we are able to discuss the principles of evolution without engaging in dialogue refuting any particular belief system on creation.

4) Evolution is Slow and Gradual

Evolution occurs at many different rates. Yes, it is a gradual process that is constantly taking place over millennia. However, it can also be a rapid process, geologically speaking. One thing to remember that is always hard to fathom, is just the sheer massive scale of time being discussed whenever talking about evolution on geologic time scales. When we see “rapid” evolutionary change, it is often rapid relative to longer time scale phenomena. However, rapid geologically often means hundreds of thousands or even millions of years. We find evidence for this in the fossil record. The Cambrian Explosion is one such example. This was a time period of exceptional adaptive radiation that resulted in a figurative “explosion” in the number and type of organisms we find in the geologic record. This “explosion” should be considered relative to what we see in the fossil record during other time periods. This never indicates a sudden rise of a brand new species from an existing one, as if a chicken laid an egg that hatched an eagle.

However, we do observe instances of rapid evolution going on around us all of the time. The most prescient example of this would be microbes, like bacteria, developing resistances to antibiotics in very short time frames. There have also been experiments conducted watching bacterial colonies respond to toxins that show they are able to adapt to deal with an environment that includes the toxins in only a few bacterial generations! Additionally, most of us can simply look into our backyards to find some species (even squirrels) that have developed adaptations to climate change over only a few decades. One example would be that red squirrels have been observed to have changed their breeding habits to adapt to warmer temperatures earlier in the year as the climate has warmed progressively. 

5) Organisms aren’t always optimally adapted

Good enough is fine! Organisms do not need to achieve perfection, and it is not a race to climb up the ladder. They just need to be ‘fit’ enough to survive and reproduce (in fact, fitness truly refers to the number of offspring one has: the more offspring, the higher fitness). Also, ‘fitness’ depends on the environment. When the environment changes, a fit organism’s adaptation may become less successful (thus, the organism may no longer be adapted to the environment).

6) The goal of evolution is always to improve organisms

Evolution never “seeks” a specific goal. Evolution doesn’t have conscious thought; no matter how wonderfully complex nature may seem, it can’t force progress and can’t make decisions. Natural selection works on a scale of “more likely”—when random processes such as mutation and genetic drift occur, it can make organisms more likely to survive, but it’s not a guarantee. Most genetic shifts are minor or benign anyways, and don’t even result in what we may perceive as progress within single generations. Evolution is not a race, and there’s certainly no finish line to create the perfect organism! Evolution (much like a jedi) simply doesn’t deal in absolutes. 

It is important to remember that when a student or individual brings up a misconception about evolution, it is not okay to alienate or ridicule them. It is often the case that this could be a person’s first time encountering this concept and their background or upbringing could make this a difficult subject to approach. By embarrassing or making someone feel alienated, a person will often not want to learn more on the subject. Above all, be respectful and help people learn about the amazing world around us! 

How Much Bias Exists in Fossil Research?

Phylogenetic Signal and Bias in Paleontology

By Robert J. Asher and Martin R. Smith

Summarized by: Alyssa Anderson, a senior geology major at the University of South Florida. Her dream is to work with environmental sciences and geology in water-related fields, such as oceanography or hydrology. In her spare time, she enjoys writing or sketching.

What data were used? Six sets of morphological data (i.e., data about the physical characteristics of organisms) from previously published fossil studies were gathered and the genetic data (i.e., the DNA) from living examples of those organisms were matched with the fossils. This was used to create rudimentary evolutionary trees of mammals and birds, the primary subjects of the studies. The trees retained all of the character codes from previous studies, even if there had been critiques.  

Methods: This study only used taxa that had at least 50% of the molecular and morphological characters present. Researchers tested how missing data would affect the outcomes of the phylogenetic trees. To do this, researched used artificial extinction and artificial fossilization techniques. This means, the researchers used various computer programming packages to artificially remove all molecular data from fossil taxa (as most fossils do not have any molecular data preserved) and some of the morphological data was also removed, as is also common with fossils. 

Results: The researchers worked to test three hypotheses. The first hypothesis studied the reconstruction of evolutionary trees based on the missing fossil data and molecular data. The results found that the experiment created fairly accurate evolutionary trees from this. The second hypothesis tested how accurate morphological studies are without molecular data in creating evolutionary trees. This was also found to uncover accurate results. Finally, the third hypothesis tested if poorly fossilized data leads to misinformed conclusions. Results demonstrated that including poor fossil data with missing information created better trees than trees that had no fossil data. In summary, any data helps make the trees more accurate, and it generally does not result in inaccurate evolutionary relationships. The most accurate evolutionary trees are made when molecular data and morphology data are combined.

A picture of six different evolutionary trees of bird and mammal genera, each from previously published data. The trees are well resolved; broader clades (e.g., marsupials) are highlighted in each of the trees
Figure: Six trees gathered from the five studies investigated in this research paper. The animal groups focused on here are birds and mammals. The tips of the tree are the genera used in this study.

Why is this study important? Determining how important including fossil data is, even in cases of the fossils’ inevitable missing data, was important in this study. An additional question that researchers wanted to know was if fossil breakdown creates situations where unrelated fossils appear more similar to each other than they actually are. Many morphological features can look similar across species, even if they are not closely related, so the process of fossil decay can make it even more difficult to piece out how similar or different certain features are. However, it doesn’t seem that this bias of fossil decay affects the dataset very much. Their placement on the evolutionary tree were usually quite similar to the known trees the researchers used. 

The big picture: Identifying bias or limitations in scientific studies is one of the most important things scientist can do. Bias can never be fully removed, and limitations won’t ever be either, but investigating sources of bias and the ranges of our limitations can help reduce it in future studies. Studying fossils is a vital science as it shows the history of the world and how species have evolved over time. If the information gained from the fossils is misleading in evolutionary analyses, due to the fossils inability to provide DNA or or do not retain clear features that mean it can’t be properly identified, then that could mess up our study of history and evolution. Through this study, it was discovered that using multiple sources of data (i.e., morphology and molecular data) create far more accurate evolutionary trees than trees that don’t use both. The study of paleontology and other sciences can benefit from this knowledge to improve other experiments in the future and broaden our understanding of the world.

Citation: Asher, J. R. and Smith, R. M. 2021. Phylogenetic Signal and Bias in Paleontology. Syst. Biol. 0(0):1–23. DOI:10.1093/sysbio/syab072