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18.1F: Misconceptions of Evolution - Biology


There are many misconceptions about evolution, including the meaning of the word theory, the way populations change, and the origin of life.

Learning Objectives

  • Discuss misconceptions about the theory of evolution

Key Points

  • Attacks on the theory of evolution sometimes take issue with the word “theory”, which in the vernacular means a guess or suggested explanation. In scientific language, “theory” indicates a body of thoroughly-tested and verified explanations for a set of observations of the natural world.
  • Evolution does not take place on an individual level; evolution is the average change of a characteristic within an entire population.
  • Evolution does not explain the origin of life; the theory of evolution instead explains how populations change over time and how traits are selected in order to increase the fitness of a population.
  • Favorable traits do not arise as a result of the environment as these traits are already present; individuals with favorable traits are more likely to survive and, thus, will have greater fitness than individuals with less desirable traits.
  • Evolution and natural selection are not synonymous. Natural selection is just one mechanism by which evolution occurs.

Key Terms

  • theory: a well-substantiated explanation of some aspect of the natural world based on knowledge that has been repeatedly confirmed through observation and experimentation

Misconceptions of Evolution

Although the theory of evolution generated controversy when it was first proposed, it was almost universally accepted by biologists within 20 years of the publication of On the Origin of Species. Nevertheless, the theory of evolution is a difficult concept and misconceptions about it abound.

Evolution is Just a Theory

Critics of the theory of evolution dismiss its importance by purposefully confounding the everyday usage of the word “theory” with the way scientists use the word. In science, a “theory” is understood to be a body of thoroughly-tested and verified explanations for a set of observations of the natural world. Scientists have a theory of the atom, a theory of gravity, and the theory of relativity, each of which describes understood facts about the world. In the same way, the theory of evolution describes facts about the living world. A theory in science has also survived significant efforts to discredit it by scientists. In contrast, a “theory” in common vernacular is a word meaning a guess or suggested explanation; this meaning is more akin to the scientific concept of “hypothesis. ” When critics of evolution say evolution is “just a theory,” they are implying that there is little evidence supporting it and that it is still in the process of being rigorously tested. This is a mis-characterization.

Individuals Evolve

Evolution is the change in genetic composition of a population over time, specifically over generations, resulting from differential reproduction of individuals with certain alleles. Individuals do change over their lifetime, obviously, but this is called development and involves changes programmed by the set of genes the individual acquired at birth in coordination with the individual’s environment. When thinking about the evolution of a characteristic, it is probably best to think about the change of the average value of the characteristic in the population over time. For example, when natural selection leads to bill-size change in medium-ground finches in the Galápagos, this does not mean that individual bills on the finches are changing. If one measures the average bill size among all individuals in the population at one time and then measures the average bill size in that population several years later, this average value of the population will be different as a result of evolution.

Evolution Explains the Origin of Life

It is a common misunderstanding that evolution includes an explanation of life’s origins. The theory of evolution explains how populations change over time. It does not shed light on the beginnings of life, including the origins of the first cells, which is how life is defined. The mechanisms of the origin of life on earth are a particularly difficult problem because it occurred a very long time ago and, presumably, it occurred just once. However, while evolution does not explain the origin of life, it may have something to say about some of the processes operating once pre-living entities acquired certain properties. Once a mechanism of inheritance was in place in the form of a molecule like DNA, either within a cell or pre-cell, these entities would be subject to the principle of natural selection. More effective reproducers would increase in frequency at the expense of inefficient reproducers.

Organisms Evolve on Purpose

Statements such as “organisms evolve in response to a change in an environment” may lead to the misunderstanding that evolution is somehow intentional. A changed environment results in some individuals in the population, those with particular phenotypes, benefiting and, therefore, producing proportionately more offspring than other phenotypes. This results in change in the population if the characteristics are genetically determined.

It is important to understand that the variation that natural selection works on is already present in a population and does not arise in response to an environmental change. For example, applying antibiotics to a population of bacteria will, over time, select a population of bacteria that are resistant to antibiotics. The resistance, which is caused by a gene, did not arise by mutation because of the application of the antibiotic. The gene for resistance was already present in the gene pool of the bacteria, probably at a low frequency. The antibiotic, which kills the bacterial cells without the resistance gene, strongly selects individuals that are resistant, since these would be the only ones that survived and divided. Experiments have demonstrated that mutations for antibiotic resistance do not arise as a result of antibiotics.

In a larger sense, evolution is not goal directed. Species do not become “better” over time; they track their changing environment with adaptations that maximize their reproduction. The characteristics that evolve in a species are a function of preexisting variation and the environment, both of which are constantly changing non-directionally. A trait that is fit in one environment at one time may also be fatal at some point in the future.

Evolution = Natural Selection

The terms “evolution” and “natural selection” are often conflated, as the two concepts are closely related. They are not, however, synonymous. Natural selection refers to the process by which organisms better suited for their environment are more likely to survive and produce offspring, thereby proliferating those favorable genetics in a population. Evolution is defined more broadly as any change in the genetic makeup of a population over time. As expounded by Darwin, natural selection is a major driving force of evolution, but it is not the only one.

Genetic drift, for example, is another mechanism by which evolution may occurs. Genetic drift occurs when allelic frequency is altered due to random sampling. It is evolution by chance, and the smaller the population, the more significant the effects on genetic distribution due to sampling error. For example, a population bottleneck, which occurs when an event such as a natural disaster dramatically reduces the size of a population, can result in the elimination or significant reduction of a trait within a population, regardless of how beneficial that trait may be to survival or reproduction. Thus evolution can occur without natural selection.


Teaching evolution (and all of biology) more effectively: Strategies for engagement, critical reasoning, and confronting misconceptions

The strength of the evidence supporting evolution has increased markedly since the discovery of DNA but, paradoxically, public resistance to accepting evolution seems to have become stronger. A key dilemma is that science faculty have often continued to teach evolution ineffectively, even as the evidence that traditional ways of teaching are inferior has become stronger and stronger. Three pedagogical strategies that together can make a large difference in students' understanding and acceptance of evolution are extensive use of interactive engagement, a focus on critical thinking in science (especially on comparisons and explicit criteria) and using both of these in helping the students actively compare their initial conceptions (and publicly popular misconceptions) with more fully scientific conceptions. The conclusion that students' misconceptions must be dealt with systematically can be difficult for faculty who are teaching evolution since much of the students' resistance is framed in religious terms and one might be reluctant to address religious ideas in class. Applications to teaching evolution are illustrated with examples that address criteria and critical thinking, standard geology versus flood geology, evolutionary developmental biology versus organs of extreme perfection, and the importance of using humans as a central example. It is also helpful to bridge the false dichotomy, seen by many students, between atheistic evolution versus religious creationism. These applications are developed in detail and are intended to be sufficient to allow others to use these approaches in their teaching. Students and other faculty were quite supportive of these approaches as implemented in my classes.


Student Misconceptions about Plants - A First Step in Building a Teaching Resource

Plants are ubiquitous and found in virtually every ecosystem on Earth, but their biology is often poorly understood, and inaccurate ideas about how plants grow and function abound. Many articles have been published documenting student misconceptions about photosynthesis and respiration, but there are substantially fewer on such topics as plant cell structure and growth plant genetics, evolution, and classification plant physiology (beyond energy relations) and plant ecology. The available studies of misconceptions held on those topics show that many are formed at a very young age and persist throughout all educational levels. Our goal is to begin building a central resource of plant biology misconceptions that addresses these underrepresented topics, and here we provide a table of published misconceptions organized by topic. For greater utility, we report the age group(s) in which the misconceptions were found and then map them to the ASPB - BSA Core Concepts and Learning Objectives in Plant Biology for Undergraduates, developed jointly by the American Society of Plant Biologists and the Botanical Society of America.


Teaching evolution (and all of biology) more effectively: Strategies for engagement, critical reasoning, and confronting misconceptions

The strength of the evidence supporting evolution has increased markedly since the discovery of DNA but, paradoxically, public resistance to accepting evolution seems to have become stronger. A key dilemma is that science faculty have often continued to teach evolution ineffectively, even as the evidence that traditional ways of teaching are inferior has become stronger and stronger. Three pedagogical strategies that together can make a large difference in students' understanding and acceptance of evolution are extensive use of interactive engagement, a focus on critical thinking in science (especially on comparisons and explicit criteria) and using both of these in helping the students actively compare their initial conceptions (and publicly popular misconceptions) with more fully scientific conceptions. The conclusion that students' misconceptions must be dealt with systematically can be difficult for faculty who are teaching evolution since much of the students' resistance is framed in religious terms and one might be reluctant to address religious ideas in class. Applications to teaching evolution are illustrated with examples that address criteria and critical thinking, standard geology versus flood geology, evolutionary developmental biology versus organs of extreme perfection, and the importance of using humans as a central example. It is also helpful to bridge the false dichotomy, seen by many students, between atheistic evolution versus religious creationism. These applications are developed in detail and are intended to be sufficient to allow others to use these approaches in their teaching. Students and other faculty were quite supportive of these approaches as implemented in my classes.


Many people assume that the small intestines are short, and the large intestines are long. The opposite is true. The small intestines are about 20 feet long and about an inch in diameter, whereas the large intestines are about 5 feet long and about 3 inches in diameter.

Some people believe, understandably, that blood in arteries is red because it is oxygenated and the blood in veins is blue because it is not oxygenated. This is probably because your veins actually look bluish through your skin. In actuality, the blood in veins is light red, as opposed to the bright red, oxygenated blood in arteries. The skin and fatty tissue between our eyes and the veins make them appear bluish.


“Why?” questions

Let us begin with a simple question: “Why do we have a heart?”. If you ask students, but also scientists, this question, a likely answer to receive is: “In order to pump blood.” We usually ask “Why?” questions in our attempt to explain a phenomenon, in other words in order to identify its causes. However, does the phrase “In order to pump blood” causally explain the fact that we have a heart? This is a conceptually tricky issue that teachers and educators need to approach thoughtfully in order to make students understand the issues at stake. Let this be our guiding question in exploring what teleology is. The question I therefore intend to answer in this essay is the following: Is the explanation “We have a heart in order to pump blood” a scientifically legitimate one for the presence of a heart?

Generally speaking a “Why?” question can be answered with reference to three kinds of causes (based on Mayr 1961 Ariew 2003): ultimate causes, proximate causes, and final causes. Ultimate causes are to be found in the distant past and relate to the evolution of a species. Thus, an explanation based on ultimate causes answering the question “Why do we have a heart?” could be “Because this organ provided an advantage to its bearers and there was selection for it, which resulted in this organ becoming prevalent in our ancestors”. This is an explanation of the fact that we have hearts as the outcome of a selective advantage of this organ for our ancestors. Proximate causes are to be found in the recent past and relate to the development of individuals within a species. Thus, an explanation based on proximate causes answering the question “Why do we have a heart?” could be “Because the cells in that area of the body of the individual were differentiated to become heart muscle.” This is an explanation of the fact that we have a heart as the outcome of a developmental process that resulted in the formation of this organ in one’s body. Both explanations based on ultimate and proximate causes are backward-looking, and refer to evolutionary and developmental causes and processes, respectively. Therefore, there exist both evolutionary and developmental explanations for the existence of hearts.

However, there is a third type of causal explanation that is based on final causes and that is forward-looking, as it refers to a specific contribution that this organ makes. Given that a function can be defined as an effect that makes a specific contribution, and that pumping blood is a contribution that the heart makes to our body, we can consider pumping blood as the function of the heart. Therefore, the question “Why do we have a heart?” can also be given the answer “In order to pump blood”. This is a teleological explanation for the existence of the heart according to this, the heart exists for performing a function, which can be considered as a final cause because it is the reason for which the heart exists. This kind of teleological explanations has been found to be prevalent among students of all ages (see e.g. Kelemen 2012). Table 1 summarizes the features of the causal explanations for the existence of a heart.

Many science educators, myself included (see e.g. Kampourakis and Zogza 2008, 2009), have used the adjective “teleological” to describe students’ misconceptions. However, this can be misleading. To understand why, we need to look at the nature of teleological explanations in some detail. Students usually describe the function of an organ or another part of the body by providing a teleological explanation for its existence. For instance, if a student states that eagles have wings in order to fly, this is a teleological explanation for the existence of wings that relies on the function that the wings perform (in this case, the effect of their movement that contributes to flight). Whether or not the parts of organisms perform functions is a question that has been debated among philosophers of biology, but in this essay I side with those who have argued that they do (e.g. van Hateren 2017, Weber 2017). Of course, not all of our body parts have functions but some do perform functions that are important for the respective organism. The question then becomes: is the reference to the function of the heart a sufficient grounding for explaining its existence? In this essay, I argue that the problem in biology education is not the use of teleological/functional explanations rather, the problem lies in the underlying etiology that relates to how these functions came to be. The issue here is that the teleological explanation that we have a heart in order to pump blood can actually be a scientifically legitimate explanation for the presence of the heart. Let us now see why.


The Biggest Misconceptions About Evolution, And What We Can Do About Them (Part 1)

Outright denialism is part of the problem of America’s issue with evolution. Another part, which involves misconceptions about evolution, is far subtler.

Despite the fact that 2015 is the tenth anniversary of the pivotal Kitzmiller v. Dover Area School District decision prohibiting the practice, creation science and intelligent design are still taught in far too many classrooms: perhaps more than one in eight, according to a 2011 survey . Outright denialism and overt teaching of non-science, however, is only part of the problem at the heart of America’s issue with evolution. Another part, which involves misconceptions about evolution, is far subtler. Such misconceptions have a variety of sources, but their effect, building up slowly over time, is to impair student understanding of evolution. As a result, the students are vulnerable to confusion and doubt about evolution in particular, or even science in general, after they leave school.

So what are some of the biggest misconceptions about evolution, how do you spot them, and what can you do about them? We’ll cover the first two in this installment, and three more in the next one.


MISCONCEPTIONS ARE “SO YESTERDAY!”

The title of this essay is excerpted from a broader set of statements one of the organizers of the 2012 Society for the Advancement of Biology Education Research (SABER) Summer conference posed at the closing discussion of the meeting. The attendees were charged with moving biology education research (BER) into its second generation, and one of the suggestions was to strengthen our research foundations by drawing from the learning sciences literature. While discussing the future of BER, the organizer stated: ``Misconceptions are so yesterday.” For some biology instructors, this may have seemed to be an odd statement. It certainly cannot be that students in the 21st century no longer have incorrect conceptions. The speaker's statement, however, may have stemmed from the fact that the word “misconceptions” is very rarely used in current science education and learning sciences literature (e.g., Journal of Research in Science Teaching, Science Education, Journal of the Learning Sciences, Cognition and Instruction), even though it is still common in practitioner-based BER. Why this discrepancy? The goal of this paper is to inform the growing BER community about the discussion within the learning sciences community surrounding misconceptions and to describe how the learning sciences community's thinking about students’ conceptions has evolved over the past decade. We close by arguing that one's views on how people learn will necessarily inform pedagogy. If we view students’ incorrect ideas as resources for refinement, rather than obstacles requiring replacement, then this model of student thinking may lead to more effective pedagogical strategies in the classroom.


[email protected] of Nebraska - Lincoln

This document is a class project designed to provide answers to common misconceptions about biological evolution. Copyright (c) 2017 by the authors.

Abstract

“When you have an established scientific emergent truth, it is true whether or not you believe in it.” Neil deGrasse Tyson, Science in America. Very few people outside of a particular scientific discipline can actually say they understand it, because most do not have the training to “speak the language.” They are then not particularly bothered by its tenets and predictions. Of all the major branches of science, however, evolutionary biology is an exception to this generalization because even though people are not versed in the field, they sometimes have a negative, knee-jerk objection. This objection is often because they are told that evolution conflicts with their faith-based beliefs. To the contrary, it is actually the case that most of the world’s religions accept evolution, especially theistic evolution, where life was created and then evolved. However, to a few who do not understand the biology of evolution, even this is unacceptable. In this book we identified a number of misconceptions that we think at least some of the general public has about evolutionary biology. Our intent is to present how evolutionary scientists approach these specific questions and what their consensus of the evidence shows to be true. We hope that those who have heard of the misconceptions we address will come to appreciate the evidence that scientists actually discovered and interpreted.


How to address it?

The best way to addressing such misconception is by providing the students with real life examples. Start of with a small discussion with your student about whether or not they believe that organisms get better through evolution. Let the student write down a few points that supports their opinion on this misconception then take it up as a class. Students may still not grasp that not all organisms are always getting better through evolution. Use the link below as an acitivty to address such misconception. The "Golden Toad" article discusses the reasons behind the extinction of this species. Even though one reason was due to human activity, the other was due to nature and the changing environment. The article discuss in details how their environmental climate changed and lead to this species going extinct. Read this article as a class and have a discussion by using the Golden Toad as an evidence that NOT all organisms get better through evolution