Why is evolution so hard to understand?


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Why is Evolution so hard to understand? Insights from implementing a human evolution case study in a technology-enhanced learning environment.

Abstract :: Many students leave school with a fragmented understanding of biology, which prohibits them from connecting scientific ideas to their everyday lives. Especially one of the core ideas of biology, the theory of evolution, has been found difficult to understand as it incorporates a wide range of ideas from different areas and often gets in conflict with existing contradictory ideas learners' bring to the classroom. Dr. Schwendimann developed an evolution curriculum, "Gene Pool Explorer", using the web-based inquiry science environment (WISE) that combines concept mapping and guided inquiry activities. The WISE curriculum used an example from human evolution as a case study. This talk will discuss the challenges of teaching and learning the theory of evolution and present findings from implementing the WISE "Gene Pool Explorer" curriculum in authentic science classroom environments.

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  • Evolution is central to biology -> Important to scientists.
  • Why is understanding evolution also important for NON-scientists?
  • 4 Arguments: 1) Civic-Democratic-Utilitarian perspective: Scientific literacy is required for a democracy. Democracies build on citizens being able to make informed personal and community decisions about issues in which scientific information plays a fundamental role, and they hence need a knowledge of science as well as an understanding of scientific methodology. Infectious diseases from tuberculosis to wheat rust are making a comeback as they evolve resistance to our defenses; Antibiotic-resistant bacteria are a growing problem; New deadly viruses might evolve the ability to jump species at any time and spread through our globalized world causing a devastating pandemic. Citizens need to be able to make informed decisions on a wide variety of evolution-related issues such as vaccinations, genetically-altered food, gene therapy, cloning, genetic counseling, and stem cell research. Understanding evolution allows us to understand the effects our changes to the environments have on many species: -For example, fishing policies that allow fishermen to keep only large fish are leading to the evolution of smaller fish (Le Page, 2008); -rats are becoming resistant to poison; -and urban songbirds change their songs to counter noise pollution. 2) Vocational perspective: Science education has a dual goal: To produce scientifically literate citizens and to produce scientifically proficient scientists: Evolutionary developmental biology, evolutionary psychology, evolutionary engineering, evolutionary anthropology, evolutionary economics, evolutionary computation, evolutionary ecology, evolutionary medicine, evolutionary microbiology, evolutionary philosophy, evolutionary analysis in law, paleontology, exobiology, climate change, and even evolutionary religious studies. 3) Aesthetic perspective: The world looks different depending on whether you view humans as the perfect finished product or as an imperfect animal thrown up by a cruel evolutionary process. Understanding evolution allows people to see the current world in a historic context and understand the mechanisms that lead to current forms. Appreciation of the complex beauty of nature. 4) Historic-cultural-social perspective: Flammarion engraving (1888) Evolution represents a major cultural achievement and a historic milestone in culturally understanding. Understanding the origins and cultural impacts of evolution is an important aspect of being scientifically literate. Teaching biology without evolution is the equivalent of teaching physics without the theory of gravity, or teaching about diseases without germ theory. -------------- Antibiotic use and HIV/AIDS treatment are examples of evolutionary medicine. One of the typical examples is the idea that is essentially evolutionary when we use antibiotics for our ailments. We should use antibiotics in an intelligent way. For example, we should be using multiple antibiotics in a careful regimen. If we use single antibiotics and we don ’ t use them carefully enough, what we do is cause natural selection in the pathogen to select for resistance. The origin of resistance in antibiotics is an imminently evolutionary mechanism, and if we understand how evolution works, then we can avoid it or at least we can slow it down. The same situation goes for the most successful approaches to complex diseases such as HIV/AIDS. One of the best approaches to fight that kind of battle is, in fact, to bombard the population of viruses with a variety of responses, not just with one. For the same reason as multiple antibiotics. The virus evolves very rapidly to respond with resistance to individual medical solutions or medications. When we use multiple ones, what we are doing is using the basic principle of evolution—living organisms simply cannot evolve resistance to complex environments because they cannot count on multiple divisions happening at the same time. That is an important principle that comes out of evolution.
  • Some educators say: "I don't care if my students accept (believe in) evolution, as long as they understand it". -> Flawed view: Without acceptance, there is no usage. Inert knowledge -> Ideas are quarantened and not used for decision-making and sense-making. Integrated knowledge -> People use evolution ideas.
  • 150 years after Darwin, Evolution is still not well accepted.
  • Why is evolution counter-intuitive? -> Where do intuitions come from? What is wrong with this picture of learning? -> 1) Student is passive. 2) Piaget and Vygotsky showed that even young children are not “ blank slates ” but make sense of the world. Many of these early explanations become established as “ intuitions ” .
  • Intuitions (p-prims) Co-existence of alternative (often contradicting) ideas Knowledge Integration:
  • Lamarck: Two mistakes: 1) Inheritance of acquired (phenotype) traits 2) Evolutionary change due to use/disuse, e.g. blacksmith and callusses.
  • Misconception: Evolution is directed (the opposite of the misconception “ Evolution is random ” ) Mutations (beneficial/neutral/detrimental), migration, and genetic drift can lead to a range of changes. -> Depending on (changing) environment. Short comings of the human body: Blind spot, hiccups, back pain, chocking, Goosebumps, wisdom teeth, obesity, coccyx -> Survival of the fit enough Changes in environment: e.g. being a hair-less ape in Africa is a good adaptation, but once humans moved to cold climates they got cold. (No hair might be an advantage in 1) heat 2) less parasites).
  • Evolutionary changes refer to statistical changes in the gene pool over generations. Populations evolve; individuals develop and adapt.
  • Opposite of “ Evolution happens to individuals ”
  • Humans adaptations to high altitudes Tibetan highlanders (who share ancestors with Han chinese) have no trouble living at 13,000 feet year in year out, and many Nepalese Sherpas (who are ethnically Tibetan) climb parts of Mount Everest without the supplementary oxygen most people require. How do they do it? New research makes it clear that Tibetan highlanders haven't just acclimated to their mountain home; they've evolved unique physiological mechanisms for dealing with low oxygen levels. -_> Change in regulatory gene which protein controls the production of red blood cells. Keeping the number of red blood cells low reduces the risk of blood blockages. 2) Humans protected against malaria and Black Death Sub-Saharan Africa nearly the entire population carries a mutation to a gene known as DARC. The mutation — a single letter change of the gene's sequence — is, however, extremely rare in people descended from ancient European, Asian, and American populations. Like the more familiar sickle cell mutation, which also confers malaria resistance, the mutant DARC gene is most common in Africa because of selection caused by the malaria parasite. 3) Human lactose tolerance High frequency of CCR5-32 allele in Europeans (up to 14-18%), but very low in Asia and Africa. -> Selection through bubonic plague in 1348-1350.
  • Darwin chose the term “ natural selection ” as the counterpart to “ artificial selection ” conducted by animal breeders. However, students ’ experience with selection could imply a selector - some form of intelligence that determines the criteria for the selection. This might foster non-normative ideas of the nature of natural selection. Evolution by natural selection is often associated with the phrase “ survival of the fittest. ” The phrase “ survival of the fittest ” was coined not by Darwin but by British economist Herbert Spencer. Darwin adopted the term starting with the fifth edition of the “ On the Origin of Species ” (published 1869). The phrase “ survival of the fittest ” is misleading in a number of ways {Gregory 2009a}: First, many students use the term “ fitness ” in its vernacular meaning “ most physically fit ” {Bishop 1990}. On the other hand, evolutionary biologists define “ fitness ” as “ best suited to a particular environment . ” Fitness is measured as reproductive success , measured in the number of offspring an organism contributes to a breeding population. The distinction between the scientific and vernacular meaning of “ fitness ” is crucial, especially when the meaning gets further distorted to “ only the strong survive. ” Second, “ survival of the fittest ” places the emphasis on survival not reproduction . Natural selection includes not only “ survival of the fittest ” but also “ death of the least fit. ” From a biological point of view, survival is only important insofar as it means that an organism lives long enough to produce offspring.
  • -The theory of evolution does NOT explain how life came to be (ORIGIN OF LIFE). It only explains changes of life.
  • -In the scientific community, evolution is accepted fact (Law?), the discussion is only about HOW evolution happens.
  • Seminal figures like Ronald Fisher, Ernst Mayr, J.B.S. Haldane, Sewall Wright, Theodosius Dobzhansky, Julian Huxley, and Gaylord Simpson forged a synthesis between Darwin ’ s theory of natural selection, Gregor Mendel's basic understanding of genetic inheritance, genetics, paleontology, population genetics, systematics, and advances in mathematical modeling toward a synthetic theory of evolution, referred to as the “ modern synthesis ”
  • Evolution ideas are often presented for a short period of time. Berkman {Berkman 2008} surveyed a random sample of 2000 high school science teachers across the U.S. in 2007. Of the 939 who responded, 2% said they did not cover evolution at all, with the majority spending between 3 and 10 classroom hours on the subject.
  • Three arguments: Time in the science classroom is very limited. Creationism/ Intelligent design is NOT a scientific theory (comparing apples to oranges) Expanding the argument: Teach all controversial theories….
  • Intuitions (p-prims) Co-existence of alternative (often contradicting) ideas Knowledge Integration:
  • Graf reported that the most likely predictor of creationist thinking wasn ’ t religious belief but a lack of confidence in science, followed closely by a poor understanding of scientific principles. (Graf, D. & Soran, H. (2010). Einstellung und wissen von lehramtsstudierenden zur evolution--ein vergleich zwischen deutschland und der türkei. In Tagungsband einstellung und wissen zu evolution und wissenschaft in europa.)
  • Making connections between genotype and phenotype visible to help students distinguish them. Students need to make decisions (negotiation in dyad): -Where to place it? -Which ones to connect? Which connections are important? -> Experts don ’ t make all 55 possible connections, they make informed decisions.
  • Both ‘ generation ’ and ‘ critique ’ are generative forms of activities. – Compared to studying a pre-made concept map: Knowledge Maps (Danserau)
  • 3rd iteration of this project. Design-based. Week-long High school project. 100 9th/10th graders in one bay area school. Real-life case study: Human lactose intolerance Genetic view of evolution (population genetics) Visualization: Use ideas to make predictions
  • Three experiments: -Natural Selection: Large population; no selection for Allele A1 -Natural Selection: Large population; selection for Allele A1 -Genetic Drift: Small population; selection for Allele A1 (ten different small colonies)
  • Randomly assigned: Generation group; n=41; critique group; n=52 67% were White, 16% were Hispanic or Latino, 10% were Asian, and 3% were Black.
  • Eight two-tiered assessment items that consisted of multiple-choice items followed by short essay items that asked students to explain their choice. The alternative options of the multiple choice items were based on known alternative ideas, for example: The idea of “ need ” to explain evolutionary change; Mutations occur to help an individual organism adapt to new situation; Evolution happens to individuals; and Acquired adaptations are inheritable. The items used real-life examples and a variety of contexts, for example human, animal, or plant evolution. Several items were based on biology content inventories Three short essay items Two KIM critique tasks + One KIM generation task
  • Of students answering item 6 (human evolution) correctly, 1/3 also answered item 9 (plant evolution) correctly, 1/3 were mixed on that item, and 1/3 answered it incorrectly. Students who answered the human evolution item incorrect, also answered the plant evolution question incorrect. -> Findings suggest that students used their ideas consistently in both contexts.
  • The score for normative evolution ideas is a composite of the explanation items 1, 5, 6, and 9 [See appendix chapter 6: study 3]: KI 0, 1, or 2 = used all non-normative ideas; KI 3 = mixed; KI 4 or 5 = used all normative evolution ideas.
  • Why is evolution so hard to understand?

    1. 1. Why is evolution so hard to understand? Beat A. Schwendimann, Ph.D. Coco IISME Seminar August 15 2012FACULTY OF EDUCATION& SOCIAL WORK
    2. 2. What makes understanding evolution so challenging? Think. Discuss with your neighbour. Share.
    3. 3. “Nothing in biologymakes sense but in the light of evolution.” Dobzhansky (1973)
    4. 4. Importance of Understanding Evolution
    5. 5. Understanding vs. Acceptance Acceptance No acceptance (in degrees) No Understanding No Knowledge Authority Seeker Understanding Inert Knowledge Integrated Knowledge (in degrees)Demastes (1995)
    6. 6. Evolution is still not well accepted
    7. 7. Challenges to Understanding Evolution
    8. 8. “Evolution, in a way, contradicts common sense.” Mayr (1982)
    9. 9. “Evolutionary theory is probably one of the most counterintuitive ideas the human mind has encountered, so far.” Evans (2008)
    10. 10. Repertoire of Alternative Ideas
    11. 11. Conceptual Change Knowledge Integration
    12. 12. Alternative Ideas of Evolution
    13. 13. Mechanism: Sources of Variation• Intentionality: Goal directed behaviour (teleology)
    14. 14. Mechanism: Sources of Variation• Need Source: http://evolution.berkeley.edu/evosite/misconceps/IEneeds.shtml
    15. 15. Mechanism: Sources of Variation• Use/ Disuse
    16. 16. Evolution is randomRandom Effects EVOLUTION Non-random Effects-Mutations -Natural Selection-Genetic Drift
    17. 17. Evolution is directed towards perfection
    18. 18. Evolution happens to individuals
    19. 19. Mechanism: Inheritance of variation• Essentialism: Evolution happens to all individuals of a species.
    20. 20. Evolution is over• In the past 10,000 years….
    21. 21. Think. Discuss with your neighbour. Share.
    22. 22. Subject: Humans
    23. 23. Subject: Humans
    24. 24. Subject: Humans• Contextualization: Species-specific reasoning• Human Exceptionalism• Mixed beliefs (Evans 2008)
    25. 25. Terminology• Confusion of scientific and vernacular use of evolution terminology: • Survival of the fittest • Adaptation • Theory
    26. 26. The theory of evolution explains the origin of life
    27. 27. Evolution is a theory in crisis• Scientists do not argue IF evolution happened but HOW it happened.
    28. 28. Don’t call it “Darwinism”• Not just the work of a single person• Substantial extensions: Modern synthetic theory of evolution
    29. 29. Evolution in School• Often taught in isolation• Only for a short amount of time •Teachers’lack of understanding (and acceptance)
    30. 30. Teach the Controversy
    31. 31. Teaching the Controversy
    32. 32. Conceptual ChangeRepertoire of alternative ideas
    33. 33. Evolution Mechanism-Subject Model Active Integrated Knowledge of Modern Theory of Evolution Non-Directed Changes of Allele Frequencies in the Gene Pool Evolution happens to all organisms GenotypeAdd New Selection of tion Mutation Ideas Sort ideas Variation Recombina Random Natural Genetic Variation Selection Drift Source of Phenotype Inheritance of Individual Variation Humans are animals Evolution did and continues to happen Repertoire of Ideas TO WHOM does evolution HOW does evolution happen? -> SUBJECT happen? -> MECHANISM
    34. 34. Challenge ImplementationSubject pillar Human exceptionalism Use human case study Human evolution stopped Human lactose tolerance as an example of recent human evolutionary change Essentialism: Failure to Use human case study detect individual variationMechanism pillar Need/Intention-based Guided inquiry activities of random reasoning mutations, genetic drift, and natural selection Disconnection between A) Cross-connections between genotype and phenotype genotype and phenotype ideas ideas B) Proteins (enzymes)
    35. 35. Genotype - PhenotypeGenotype ? Phenotype
    36. 36. Knowledge Integration Map
    37. 37. Two Treatment GroupsGeneration Critique
    38. 38. Gene Pool Explorer
    39. 39. Dynamic Visualisation Allele A1
    40. 40. Classroom Implementation
    41. 41. Knowledge Integration ScoreWhat changes occur gradually over time in groups offinches that live in different environments?
    42. 42. Knowledge Integration Gains
    43. 43. Integration Across Contexts
    44. 44. Using Evolution Ideas
    45. 45. KIM overall Changes
    46. 46. Student Example: Pre-Test
    47. 47. Student Example: Post-Test
    48. 48. KIM cross-link Changes
    49. 49. Implications• Alternative ideas should be directly addressed.• Human evolution can be used as a pivotal case for evolution instruction• Knowledge Integration Maps can elicit cross- connections between genotype and genotype ideas• Critiquing or generation Knowledge Integration Maps can both support students’ knowledge integration
    50. 50. Recommendationshttp://ncse.comhttp://undsci.berkeley.eduhttp://evolution.berkeley.edu
    51. 51. Thank you!• schwendimann.org• beat.schwendimann@gmail.com