Teaching and Learning of Evolution in the Primary Grades

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1 Teaching and Learning of Evolution in the Primary Grades Kathleen Metz Research funded by the REESE Program of the NSF

2 Thanks to members of the research team Mark Wilson Stephanie Sisk-Hilton Eric Berson Amy Cardace Dan Furr Uyen Ly Hyo Jeong Shin Tia Madkins Nicole Wong Sarah Metz

3 Learning Progressions Learning progressions are descriptions of successively more sophisticated ways of thinking about a topic that can follow one another as children learn about & investigate a topic over a broad span of time (e.g. 6 to 8 years). They are crucially dependent on instructional practices if they are to occur. Taking science to school (2007)

4 EVOLUTION: Why learning progressions? 1. Core to understanding of biology 2. Broad spread misunderstandings at end of K-12 & beyond. 3. Continuity in conceptual challenges across ages 4. Possibility early strategic intervention (primary grades) might have an advantageous impact on understandings long-term

5 Our project: Design early steps of evolution learning progression What might 2 nd -3 rd graders be able to understand of evolution? How can we leverage these young children s intellectual resources to: begin to build understanding of evolution mitigate common misunderstandings Strategically position them to more fully understand the theory at subsequent grade levels

6 Specifically: Frame 2nd-3rd grade evolution LP in terms of increasingly powerful explanations of fit between organisms and their environment. Frame LP at system level of microevolution Evolution on a small scale within a single population.. - Understanding Evolution Website

7 Why microevolution? Mechanism of natural selection underlies both microevolution & macroevolution But microevolution is conceptually more accessible, given scope & scale of the changes Microevolution focus helps mitigate against common misunderstandings of the mechanism

8 How microevolution could help mitigate common misconceptions 1. Minor changes in the organisms & relative transparency of the mechanism at the microevolution system level mitigates against attribution to external agent / God. 2. Relative transparency of variation in the system level of population mitigates against type / essentialist reasoning. 3. Relative transparency of shifting survival value of traits as a function of environmental changes mitigates against finalism / progressing toward ideal form reasoning. With the environment changing incessantly, natural selection never commits itself to a future goal. - Ernst Mayr

9 Research Design Students: Urban, predominately low income, multi-ethnic Two kinds of sites: Project-run summer school 3-week half-day program Two successive summers Public school classrooms (3-4 classrooms each yr) Spring: Year 1 Fall: Year 2 Instructional modules in two domains: Animal behavior Botany Approximately 1/3 of students participate in both modules, revisiting same conceptual terrain in second domain

10 Taking science to school 4 strands of scientific literacy Know, use and interpret scientific explanations of the natural world. Generate and evaluate scientific evidence and explanations. Understand the nature and development of scientific knowledge. Participate productively in scientific practices and discourses. NEED EXPLANATORY POWER AT EVERY GRADE.

11 Current version of learning progression Fit of organisms & their environment

12 Scientific practices in which to use & generate explanations re fit between organisms & their environment Empirical research (lab & field) Text-based research Thought experiments

13 Example of pedagogy: From empirical investigation to thought experiment Part I: How are these dandelion seeds different from each other? What trait do you think would help it travel far on the wind? Part II: Design of experiment to test prediction.

14 Part II. Thought experiment scaffolding LP4-LP7 (Cody & Overton, 1996) A storm blows some of these dandelion seeds out to sea. Some land on an ocean island.

15 Part 3. Empirical Investigation Case magnitude plot of distance traveled: Heavy / light seeds Analysis: Range & median

16 Predict how distribution of seed traits would change across subsequent generations after seeds land on the island Predict distribution in next generation Explain what trait you think would be a survival advantage & why. Predict distribution after many generations on the island Compare your predictions to what the scientist saw.

17 Prediction for seeds in next generation What I think will happen is: most of the heavy seeds will fly on the island and most of the light seeds will fly to the water. Because: the heavy seed won t travel that far and the light seed would fly too far to reach the island.

18 Pairs take up their own micrevolution thought experiment for Mustard Plants (Brassica Rapa) Choose an environmental change Sheep arrived, caterpillars arrived, bees got sick or canopy grew & blocked out most of the sunlight Select & explain which trait they think would be a survival advantage, given this change Drawn from characteristics/ traits based on their observations of BR Color (green, yellow. Purple); Days to first flower; Height; Hairiness; # of flowers Represent distribution of characteristic in current population (that they grew) Predict & explain expected distribution shift over time

19 Thought experiment component How might the sickness of some bees affect the height of the first flower in future generations? Distribution of Trait in Current Population: Representation of Brassica trait data Prediction of Trait in Future Generations: We think in future generations the Brassica that are tall will be more common because when the bees fly they will see the tall Brassica plants instead of the small. The babies of the babies of the babies of the tall plant will probably be tall too. We think the median height will got higher in future generations.

20 Pre & post interviews with each child One-on-one structured interviews with standardized probes to encourage elaboration Approximately minutes in length Problems based in photographs and/or realistic icons With one exception, all required transfer of ideas taught to new contexts & organisms Tasks in forms of: Predict & explain what population will look like post environmental change Explain good fit of organisms & their environment Explain the change of organism-kind today in contrast to its ancestors

21 Interview Analysis Misconceptions: X item; within & across subjects LP Scoring Detailed coding book, specifying rules for attribution of learning progression levels Double independent coding of all episodes Scoring complete on 4 tasks (7 items) of two rounds of summer school (4 cohorts total) LP-based Patterns LP X item Pre to post: across subjects; within-subject Highest LP Composite LP

22 Pre- & post interview max LP levels: 2009 LP 8 Natural selection as explanation of organisms well adapted to their environment. LP7 Over many generations, inherited traits that help organisms chances of surviving & reproducing become more common LP6 In offspring generation traits that help the organism survive and reproduce tedn to become more common LP5 Within-population variation & differential survival value LP4 Differential survival advantage of traits LP3 Differences in structures help organisms get what they need where they live LP2 Live where they get what they need LP1 Negligible understanding

23 Pre- & post-interview max LP levels: 2010 LP 8 Natural selection as explanation of organisms well adapted to their environment. LP7 Over many generations, inherited traits that help organisms chances of surviving & reproducing become more common LP6 In next generation traits that help the organism survive and reproduce tend to become more common LP5 Within-population variation & differential survival value LP4 Differential survival advantage of traits LP3 Differences in structures help organisms get what they need where they live LP2 Live where they get what they need LP1 Negligible understanding

24 Pre to Post Individuals Change in Max Scores 2009 Cohort 2010 Cohort

25 Max level at post-test % at LP6 or above 61% at LP7 or above

26 Composite Estimates: Pre & Post

27 Distributions of Children on the Learning Progression Across All Items: Pre/ Post

28 Conclusions Young children have intuitions that are fruitful basis for beginning to develop an understanding of the mechanism of natural selection No need to postpone consideration of mechanism to middle or high school We can advance their understanding of the mechanism within the practices of science -- at level of microevolution