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Teaching and learning evolutionary biology: Tracking the invisible.

August 2nd, 2021

How statistical reasoning is related to evolutionary knowledge and the degree to which visualizations can help understand evolution.


Daniela Fiedler & Ute Harms

The theory of evolution describes the origin and development of all life forms on earth. In-depth understanding of evolutionary processes is therefore of substantial importance for many areas of individual, social and scientific life. Nevertheless, many people find it difficult to grasp the complexity of evolution. Unimaginably long periods of time and biological system levels that cannot be directly grasped with the human senses, as well as the interplay of random and probabilistic evolutionary processes such as mutation and selection, often represent obstacles to learning. The studies presented here focused on the importance of these aspects for the development of evolution understanding.

Throughout the world, the corona virus SARS-CoV-2 has changed lives from one day to the next. For months, new scientific findings have been published and disseminated to the public within short intervals. All the while, conspiracy theories have been circulating about the origin of the virus. But anyone who suspects a plan behind the Covid-19 outbreak is ignoring the central aspect of life: biological evolution. Many students, however, find it difficult to grasp evolutionary theory and its dimensions. The IPN project EvoVis investigated the importance of so-called threshold concepts in understanding evolutionary processes and to what extent interactive visualizations can help to better understand evolution.

Threshold concepts in the context of evolutionary biology.

School children, students and even teachers show many scientific inadequate ideas about biological evolution. Especially aspects are misunderstood that are linked to rather abstract concepts such as randomness and probability or related to time scales that are difficult for humans to imagine and system levels that cannot be grasped with our own senses. These aspects (randomness, probability, temporal scales, and spatial scales) are also referred to as "threshold concepts" in teaching-learning research and metaphorically described as portals that - once crossed - open a new and previously inaccessible path of thinking. To date, however, there is a lack of empirically based knowledge about the extent to which understanding these concepts is related to understanding evolution and how to make these concepts tangible. The German-Swedish cooperation project EvoVis aims to find answers to these questions.

To what extent does statistical reasoning influence evolution understanding?

Evolutionary knowledge and acceptance of evolution are influenced by a variety of cognitive, affective, and situational factors (e.g., confidence in research and researchers, educational attainment, epistemological beliefs). Although the concepts of randomness and probability are generally recognized as central to evolutionary biology, and life science learners benefit from a trained knowledge of mathematical concepts, little research has examined how statistical reasoning relates to evolutionary knowledge and specifically to acceptance of evolution. Moreover, no known instruments existed to measure statistical reasoning in the context of evolutionary biology. Therefore, two measurement instruments were developed in the project and tested for their goodness of fit with German and North American students. The results show that statistical reasoning correlates positively not only with evolutionary knowledge, but also with acceptance of evolution. Moreover, regression analyses indicate that statistical reasoning can not only be regarded as a relevant predictor of knowledge and acceptance, but also elucidates proportions of variance that cannot be explained by other factors such as demographic information or evolutionary knowledge (in the case of acceptance). This provides initial evidence for the importance of statistical reasoning in evolutionary teaching and learning.

Three evolutionary biological phenomena, one scientific explanation?

Explanations of evolutionary biological phenomena are judged based on the use of certain key concepts (e.g., individual variation, differential survival) and naive explanatory patterns (e.g., teleological explanations). In this context, trait gain is usually better explained than trait loss, although the same evolutionary biological principles underlie both phenomena. However, to date, the extent that threshold concepts are included in such explanations has gone unnoticed. Therefore, students in Germany and Sweden were asked to formulate written explanations for three evolutionary biological phenomena: (a) antibiotic resistance in bacteria, (b) running speed of cheetahs, and (c) loss of vision in cave salamanders. Although all threshold concepts were found, they were more likely to be found in explanations of trait gain than trait loss. Especially in more complex organisms, linking changes at the genetic (submicro) level (e.g., through mutations) with the resulting phenotypic changes in the individual (macro level) is a challenge. Many also seem unaware of the importance of stochastic evolutionary processes (concepts of randomness and probability) or do not consider them central enough to include these concepts in their explanations. Since evolutionary biological phenomena are still rather explained on the basis of superficial features such as trait polarity, many lack a profound understanding of evolutionary biological processes.

Making randomness and probability tangible

Dynamic visualizations can help visualize scientific processes and thus make them comprehensible. An interactive, web-based application called EvoSketch was developed to help learners understand the significance and interplay of random and probabilistic processes such as mutation and selection. In EvoSketch, learners are asked to trace a lineage (reproducing organism) over 20 generations. Based on the combination of deviations (mutations) in drawing and the selection process (selection), the line will shift either to the right or to the left (i.e., evolve). An experimental study with tenth grade students examined the effect of self-regulated learning with EvoSketch on the development of statistical reasoning and evolutionary knowledge. Self-regulated learning with EvoSketch appeared to produce slightly better test scores on statistical reasoning than without EvoSketch. Contrary to previous expectations, additional support, such as in the form of an example or reflective questions, did not lead to any improvement. For EvoSketch to serve as a conceptual framework for the interplay of mutation and selection, it should be used in several lessons and with treatment of different evolutionary biology phenomena.

Summary and outlook

The findings emphasize the importance of threshold concepts in understanding evolution. Specifically, visualizations that explicitly explain the interplay of random and probabilistic evolutionary processes can help in developing a deeper understanding of biological evolution. Nevertheless, many questions remain open concerning the treatment of threshold concepts in digital media, which will be addressed in future studies. In addition, naïve explanatory patterns about evolution often emerge in childhood and can thus hinder further learning about evolution. In another project (EvoPrime: Evolution in Elementary to Primary Education), we search for ways to initiate scientifically adequate knowledge about evolution in young children to facilitate the development of knowledge in school. For this, we are currently examining children's books on evolution for content that may promote or hinder learning.

The EvoVis project

The EvoVis project (Challenging Threshold Concepts in Life Science - enhancing understanding of evolution by visualization) is a collaborative project between the IPN and Linköping University (Sweden) and has received funding for four years from the Swedish Research Council, the Swedish equivalent of the German Research Foundation (DFG).

Two central goals are pursued in the project:

(1) To generate insights into the importance of the concepts of randomness and probability as well as temporal and spatial scales for the development of knowledge in evolutionary biology.

(2) To obtain information on how these concepts can be made comprehensible to learners through dynamic visualizations (e.g., animations or simulations) by means of intervention studies.

Dr. Daniela Fiedler is a postdoctoral researcher in the Department of Biology Education at the IPN. In her research she deals with different factors influencing the teaching and learning of biological evolution. The results presented here are partly based on her dissertation integrated in the EvoVis project.

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Prof. Dr. Ute Harms is director at the IPN and professor for biology education. Teaching and learning evolution across the lifespan is one of her research interests.

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