In October of 2011, two colleagues and I presented a talk at the National Association of Biology Teachers (NABT) Meeting in Anaheim, California. Our short workshop was both an argument for why it makes sense to weave evolutionary theory into every biology topic (indeed, as Theodosius Dobzhansky famously wrote in The American Biology Teacher in 1973, “Nothing in biology makes sense except in the light of evolution”) and how we accomplish this in our curriculum. The way we approach our curriculum is from the perspective that evolutionary theory is the scientific framework that explains everything in the biological world. For example, evolutionary theory explains, among other phenomena,
- why the natural selection of camouflage and mimicry in plants and animals is so pervasive and predictable. (Community Ecology)
- how variation among individuals in a population is essential to the survival of the population over time, especially in a variable and unpredictable environment. (Population Ecology)
- how the evolutionary story of the human hand and brain has been driven by our ability to use these adaptations to solve problems, yet to the point that now our very survival is at the mercy of the tools we have invented. (Technology and Engineering)
- that small changes in our genome make humans physically and behaviorally distinct from our primate ancestors. (Genetics, Religion, Culture, Art, Technology)
- how unnaturally small populations can enter an extinction vortex and what methods we might try to restore those populations. (Genetics, Conservation Biology)
- how common ancestry allows us to use model organisms like fruit flies (Drosophila melanogaster) and the thousands of genes we share with them to understand how cancer works and to possibly find cures to some human cancers. (Cell Biology, Genetics, Medical Science)
- why testicular descent into the scrotum in mammalian males is a clunky process but is “good enough” to solve the problem of sub-optimum enzyme temperature and to ultimately still allow for survival and reproduction. (Enzyme Function, Embryology, Meiosis, Reproductive Biology)
- why the enzyme ribulose bisphosphate carboxylase-oxidase (RUBISCO) is “good enough” to fix CO2 gas onto sugars and help feed the world, but why it accidentally also chokes on oxygen (photorespiration) because it evolved when the atmosphere was mostly oxygen-free. (Plant Biology, Photosynthesis, Enzyme Function)
Six teachers attended our workshop.
Perhaps our surprisingly low attendance was because high school biology teachers are under the impression that they already do a fine job with their “evolution unit” and think they mention it enough at other times during the year that attending a workshop on the topic is not the best use of their time. However, as Penn State political scientists Eric Plutzer and Michael Berkman reveal in a 2011 Education Forum paper in the journal Science (Defeating Creationism in the Courtroom, But Not in the Classroom), 60% of public high school biology teachers are so cautious in their approach to teaching evolution that they “are neither strong advocates for evolutionary biology nor explicit endorsers of nonscientific alternatives.” Berkman and Plutzer add, “These teachers fail to explain the nature of scientific inquiry, undermine the authority of established experts, and legitimize creationist arguments, even if unintentionally.”
The figure below from their paper shows self-reports of qualifications of teachers, classified by approach to teaching evolution (“advocate of”). The data are based on responses from 926 U.S. public high school biology teachers. Note that the 28% of teachers that are advocates of evolutionary biology were also more likely to have taken a college course on evolution. It is unclear whether taking the course affected how the teachers approached teaching evolution in their classrooms, or the teachers were already advocates of teaching evolution and took the course (or courses) to gather more information.
The phenomenon of the “cautious 60%” and the 13% of all teachers that teach some form of creationism (biblical creationism or intelligent design creationism) is explained by Berkman and Plutzer in their 2010 book, Evolution, Creationism, and the Battle to Control America’s Classrooms. Here, Berkman and Plutzer show that, in the sample of 926 biology teachers mentioned above, 14% identify themselves as young earth creationists, 47% as theistic evolutionists—Eugenie Scott and the National Center for Science Education have defined theistic evolution as “a theological view in which God creates through the laws of nature.”—and only 31% of biology teachers identify themselves as accepting the scientific explanation of organic evolution. These data are illustrated below by a figure from Berkman and Plutzer’s book.
To generate the figure above, the 926 biology teachers were asked to respond to a question that the Gallup organization has been asking the U.S. public since 1982. The history of this poll reveals that the percentage of the public (n = 1,028 responders; 4% margin of error) that believe that “God created human beings pretty much in their present form sometime in the last 10,000 years” has not changed in 32 years. However, it is encouraging to note that the percentage of the public that believes in theistic evolution has decreased to 31% whereas the percentage of the public that accepts organic evolution has increased to 19%. The critical figure from Gallup’s May 8-11 2014 poll is below.
So, what does this all mean for high school biology teachers?
The National Center for Education Statistics reported in 2009 that at most, 68% of graduating high school students in the U.S. have taken a course beyond general biology. This fact suggests that biology may be the only science class taken by as few as 32% of high school graduates. See the figure (and red arrow) below.
The biology classroom is likely the biggest arena within which a K12 student is exposed to scientific topics that are incorrectly and unfortunately perceived as “controversial.” In their most recent publication (March 2015) on the topic of teaching controversial topics in the public school classroom (Enablers of Doubt: How Future Teachers Learn to Negotiate the Evolution Wars in Their Classrooms), Michael Berkman and Eric Plutzer rely on interviews of 35 preservice biology teachers at four U.S. colleges and universities. While the results of their interviews are not intended to be scientific, they do reveal some troubling trends.
In a nut shell, Berkman and Plutzer found that “as early as in the preservice college years, teachers develop attitudes and pedagogical coping mechanisms that lead to support for the anti-evolution movement.” More specifically, Berkman and Plutzer discovered the following trends:
- A large percentage of certified biology teachers, most of whom were biology majors in college, doubt the scientific consensus on evolution and climate change.
- Required college courses for future biology teachers that devote considerable time to evolutionary principles did not translate into more than superficial knowledge and understanding of evolutionary theory.
- Preservice biology teachers think that content knowledge is much less important than skills in classroom management and teaching methods.
- Many preservice biology teachers have an “instinct to downplay certain aspects of evolutionary biology to avoid controversy and confrontation.”
- Most of the preservice biology teachers agreed that the acceptance of the scientific consensus on evolutionary theory undermines a person’s faith and many young biology teachers enter the teaching profession before they themselves have resolved their perceived conflict between accepting the facts of evolution and their personal belief systems.
The authors conclude with three recommendations:
- “Future teachers need to be more engaged in the content of evolutionary science.”
- Future biology teachers need opportunities to work through their perceived science and faith conflicts within the arena of their college courses.
- Preservice teachers need good models in veteran teachers for teaching evolution in the public schools.
The implications of not following these recommendations are clear.
If we aren’t doing a good job teaching biology in general and evolutionary theory in particular, then we are also teaching an impotent and diluted form of science to our students: our future problem solvers of climate change and cancer and voters on hot button issues like food system regulation and energy production. Indeed, if we are to accept the data I present above, then a staggering number of students are leaving our high schools with little or no understanding of how science works.
What is the solution?
One part of the solution is for there to be continued and required professional development in evolution education for young teachers. Excellent professional development is available at regional and national meetings of professional organizations like the National Association of Biology Teachers and the National Science Teachers Association, but attending these meetings is expensive, rarely supported financially, and certainly not required of new teachers by their schools or districts. Thus, good professional development must be available locally and provided for free.
After 24 years of teaching biology it is clear to me that teaching evolutionary theory is not easy. In fact, I am convinced that teaching evolutionary theory well IS rocket science.
Indeed, understanding evolutionary theory in enough detail to teach it effectively is akin to understanding the theory of relativity well enough to teach it.
Another part of the solution is for the high school biology teachers that have worked hard to build their knowledge and understanding of evolutionary theory to approach the teaching of evolution with confidence, evidence-based conviction, and with the attitude that
Everything in biology makes sense when viewed through the lens of evolutionary theory.
In response to the above illustrated statistics, my colleagues and I have made sure that we are teaching evolution every day by designing a sophomore biology curriculum that weaves evolutionary theory throughout the topics from the beginning to the end of the year.
The breakdown of our units and the number of units we cover changes from year to year, but the general approach is outlined below:
- Unit One: Themes of Biology – General Evolutionary Theory, Characteristics of Life, and the Process of Science
- Unit Two: Principles of Ecology and Evolution
- Unit Three: Water and Life’s Adaptations
- Unit Four: Molecules of Life, Metabolic Adaptations, and Human Nutrition
- Unit Five: Evolution of Cell Structure and Function, the Cell Cycle, Mitosis, and Cancer
- Unit Six: Genetics and the Evolution of Sex, Meiosis, and Human Inheritance
- Unit Seven: Evolutionary Connections: Photosynthesis and Cellular Respiration
- Unit Eight: Microevolution (DNA-RNA-Protein-Trait)
- Unit Nine: Macroevolution and the Evolution of Humans
The details of how we pull this off can be seen below in three sample excerpts of our Daily Schedules that we and the students follow. Notice that a key strategy to teaching evolution “every day” is by way of our Warm Up questions that we pose to students at the beginning of nearly every class period. Students spend a few minutes in their table groups at the beginning of class discussing with each other and writing answers to these questions in their notebooks.
Samples from our curriculum:
Unit 1: Themes of Biology – General Evolutionary Theory, Characteristics of Life, and the Process of Science
Starr Biology CH 1, 17.3, 18.1, 18.3-18.5, and 18.12
August 22 – September 16
|Fri8/22||Welcome to PIB Biology!Getting to know your teacher and classmates||Optional: Look over the Chem and SI Review sheet that is posted in the Unit 1 folder.Browse your teacher’s website: Read through PIB Biology Expectations and Safety Expectations Posted on your teacher’s website. You will take an online group quiz on this information on Monday.
Bring a cover for your textbook on Monday.
|Mon8/25||Warm up – Propose two questions, one beginning with “How…” and the other beginning with “Why…” that we can answer using the science of biology and evolutionary theory.(Create a section in your Biology notebook and begin an organized list of answers to these warm up questions. I will occasionally check your participation on these.)
1) Quiz – Classroom Resources and Expectations
2) Hand out textbooks Biology: The Unity and Diversity of Life
3) Pre-Assessment – Understanding Biological Evolution
|Quiz on sections 1.1 – 1.4 in your textbook due Tuesday evening by midnight. Go to your teacher’s website and click on the link to take the quiz.Watch the following 12 minute YouTube video before Block Day:|
|Tues8/26||Warmup: What is an adaptive trait? Give an example of an adaptive trait in Homo sapiens.1) Learning Targets, Developing Note Taking Skills, and Creating your own study guide
2) Exploring Levels of Organization in Biology
|Bring a grid-lined composition notebook to class for Block Day. This will be your lab notebook for the year.Having trouble finding a composition book with graph paper? Here is a link to some notebooks on amazon:|
|Warmup: What unifies all life? In other words, what are the characteristics of all living things?1) Practice with Classification and Nomenclature
2) Scavenger Hunt – Characteristics of Living things.
3) Groups present results
|Friday8/29||Warmup: What is the ultimate source of the variation we can observe among individuals in a population?1) Go over Reading Quiz 1.1-1.4.
2) Discuss material from Chapter 1.1-1.4. Review of Learning Targets and unanswered questions. The PPT for this material is posted.
|Quiz on Sections – 1.5-1.8 of Textbook due by today by midnightPersonal Practice: On page 18 of your textbook, do the Data Analysis Exercise, take the Self Quiz, and answer Critical Thinking questions 2, 3, and 5.|
|Mon9/1||No School – Labor Day|
|Tues9/2||Warmup: What is the difference between a hypothesis and a prediction?1) Discuss scientific methodology
2) Practice writing hypotheses.
3) Walking through the Process of Science: an investigation into the effect of temperature on muscle contraction. We will begin designing the experiment today and conduct it on Block Day.
|Bring your lab notebooks to class with you on Block Day.For Block Day, go to the Statistics Folder on your teacher’s website and read CAREFULLY the 95% Confidence Intervals packet and complete the practice problem.|
|Warmup: Propose an evolutionary hypothesis to explain why certain butterflies have wing spots that resemble eyes. Then propose a prediction you can make given your hypothesis.1) Discuss 95% confidence Intervals
2) Walking through the Process of Science: an investigation into the effect of handedness on motor control function. Conduct experiment today.
|Fri9/5||Warmup: What is standard deviation? How is it used to calculate confidence intervals?1) Analyze Toothpick Experimental Data – record your results, analysis, and conclusion of results in your lab book.
We will be using statistics to analyze data from experiments in this course. You will be provided with packets to help you learn each method and test, but your teacher will also post a “Statistics in Science Primer” on his/her website that you can use as a resource when you need extra help. Please come see any of the PIB Biology teachers when you need help as well!
2) Discuss material from Chapter 1.5-1.8. Review of Learning Targets and unanswered questions.
|Quiz on sections 17.3, 18.1, 18.3-18.5, and 18.12 due Sunday at midnightPersonal Challenge: Do the Data Analysis Exercise, Self Quiz, and Critical Thinking on pages 298 and 299|
|Mon9/8||Warmup: Why is it incorrect to say that individuals evolve?1) Practical Quiz – Characteristics of Living Things and the Process of Science||Use the following resource to support your growing knowledge about natural selection and adaptation:http://www.hhmi.org/biointeractive/recent-adaptations-humans|
|Tues9/9||Warmup: What is natural selection?1) Watch Making of the Fittest: Natural Selection and Adaptation
2) Students work in groups to complete natural selection and adaptation problems.
|Warmup: The rock pocket mice would be an example of which pattern of natural selection (directional, stabilizing, disruptive)? Explain your answer.1) Modeling Natural Selection||Prepare for Unit 1 Exam on Tuesday, 9/16.|
|Fri9/12||Warmups:· What is the difference between gene flow and genetic drift?
· What is the relationship between mutation, allele frequency in a population, and microevolution?
Discuss material from Chapter 17.3, 18.1, 18.3-18.5, and 18.12. Review of Learning Targets and unanswered questions.
|Mon9/15||Review for Unit 1 Exam||Prepare for Unit 1 Exam|
|Tues9/16||Unit 1 Exam|
Unit 5: Evolution of Cell Structure and Function, the Cell Cycle, Mitosis, and Cancer
Starr Biology CH 4, 5, and Sections 9.1-9.5
Jan 6 – Feb 3
|Tues1/6||Warm up: How does evolutionary theory and natural selection explain why cells are so small and often oddly shaped?1. Introduce Bio Vocab words
2. Set up Surface Area to Volume Demonstration (phenolphthalein infused agar cubes and 0.1 M sodium hydroxide)
3. Discuss cell membrane structure while waiting for demonstration results
4. Examine results from Surface Area to Volume ratio demonstration
5. Set-up diffusion/osmosis demonstration
|Read Chapter 5 of your textbook and take the online quiz tonight.Personal Practice: Do the Self Quiz at the end of CH 5 and Critical Thinking question #1.|
|Full Block periodsWarm up: How does cell size relate to diffusion and osmosis?
1. Analyze results from Surface Area to Volume Ratio Demonstration
2. Discuss diffusion and osmosis while modeling these processes.
3. Discuss active and passive transport.
4. If time allows, work on reporting results from this week’s demonstrations in your lab books.
|Please remember to complete your weekly word-roots. Your teacher will check these on Friday.|
|Fri1/9||Warm up: What is the difference between diffusion and osmosis?Practice writing the Conclusion and Evaluation section of an IA report||Go onto your teacher’s website and download the document The ANOVA. Complete this packet for Monday.|
|Mon1/12||Warm up: Describe the meanings of the words, isotonic, hypotonic, and hypertonic and explain the evolutionary adaptations that freshwater and marine fish have that allows them to survive in their particular environments.1. Set up potato-osmosis investigation
2. Discuss the Analysis of Variance (ANOVA) statistical test
|Tues1/13||Warm up: When is it helpful and appropriate to use the ANOVA statistical test?Collect data from Potato Osmosis and begin analyzing.||Tomorrow, you will be working on your IA reports in the classroom. We will have a set of lap-top computers to use, but it is recommended that you bring your own lap-top or tablet to work on your reports.|
|CAT days – shortened block periodsWarm up: Explain how potatoes are an adaptive trait.
1. Work on writing the Data Collection and Processing section and the Conclusion and Evaluation section of your IA report.
IA reports are due on Tuesday, 1/20, by 4:00 p.m. Please email these reports to your teacher and FOLLOW THESE INSTRUCTIONS:
· Save your document as a pdf file with the following name “Period Last Names Osmosis IA.”
· Your file should be an attachment to your email.
· Please use the same name in the subject of your email as the name of your file (see above).
|Work on IA reports with your group members.|
|Fri1/16||Warm up: List all of the parts of a eukaryotic cell that you can remember. Describe the functions of these parts.1. Review what scientific theories are, discuss The Cell Theory and the necessary structural and functional adaptations cells have that allow them to survive and reporduce.
2. Introduce the cell project.
|Read all of Chapter 4 and complete the online practice quizzes for Chapter 4.Do the Self Quiz at the end of CH 4 and Critical Thinking question #1.|
|Mon1/19||No School – Martin Luther King Day|
|Tues1/20||Warm up: What adaptations do plant cells have that animal cells do not?Comparative Cell Structure – Using microscopes to examine plant and animal cells.||IA reports are due today by the end of the school day (4:00 p.m.).|
|Full Block PeriodsWarm up: What components of cells have evolved that allow them to make and transport proteins?
Work on Cell Projects
|Fri1/23||Work on Cell Projects|
|Mon1/26||Work on Cell Projects||Cell Projects are due tomorrow.|
|Tues1/27||Present Cell Projects||Read sections 9.1-9.5 of textbook and take online quiz tonight.Personal Challenge: Self Quiz all, p. 153 and Critical Thinking #2, p. 153|
|CAT days – shortened block periodsWarm up: What process has evolved in cells that allows them to reproduce themselves?
1. Discuss Mitosis
2. Investigate mitosis in Allium root tip cells
|Fri1/30||Warm up: How are cancer cells different from normal cells and how does evolutionary theory explain the existence of cancer?1. Discuss cancer
2. View cell cycle game
|Mon2/2||1. Catch-up day2. Watch Inner Life of a Cell||Study for Unit 5 Exam|
|Tues2/3||Review for Unit 5 Exam|
|Unit 5 Exam|
Unit 6: Genetics and the Evolution of Sex, Meiosis, and Human Inheritance
Starr Biology p. 154, CHs 10, 11, 12.1, 12.2, and 12.4
Feb 4 – March 5
|1) Unit 5 Exam2) Diagram the stages of meiosis in your notebooks (not your lab books – just your notebooks).
Use the following vocabulary words as labels in your diagrams (when applicable): unduplicated chromosome, duplicated chromosome, sister chromatids, homologous chromosomes, spindle fibers, centromere, centrioles. Also include specific labels for crossing over and synapsis.
This animation may help you understand the different stages of meiosis
|Chapter 10 Reading: p. 154 and CH 10.1-10.6Personal Challenge: Do the Data Analysis Exercise, Self Quiz, and all three Critical Thinking questions on page 167.
Quiz questions for chapter 10 will be posted on your teacher’s website for practice and comprehension of the chapter 10 material.
|Fri2/6||Warm up: What evidence is there that meiosis evolved from mitosis?1) Chapter 10 lecture/discussion
2) Using pop beads or clay to simulate meiosis
|A helpful video to review the concepts from todayhttps://www.youtube.com/watch?v=qCLmR9-YY7o|
|Mon2/9||Warmup: What evolutionary legacy can be found in meiosis that requires it to take two sets of cytokinesis divisions to produce a viable gamete instead of one?1) Finish Chapter 10 discussion
2) Begin PBS Why Sex?
3) Answer video questions
|Another helpful video to understand chromosomeshttps://www.youtube.com/watch?v=tsVHWbXqum8|
|Tues2/10||Peer Assessment of Unit 5 Exam||Chapter 11 Reading Assignment: CH 11.1-11.7Personal Challenge: Do the Data Analysis Exercise and Self Quiz on pages 182 and 183
Quiz questions for chapter 11 will be posted on your teacher’s website for practice and comprehension of the chapter 11 material.
|CAT scheduleWarm up: Explain the evolutionary roles played by meiosis and sexual reproduction.
1) Finish PBS Why Sex?
2) Discuss questions
3) Begin Chapter 11 material
|Fri2/13||No School – Professional Development|
|Mon2/16||No School – President’s Day|
|Tues2/17||Course selection talk from counselors|
|Regular Block ScheduleWarm up: What is Mendel’s law of independent assortment? When during meiosis do we now know independent assortment occurs?
1) Continue Chapter 11 discussion
2) Begin Seedgruber Genetics Activity
|Go onto your teacher’s website and download the document named The Chi-Square Test. Complete this packet for Friday.|
|Fri2/20||Warm up: Why is human height not an either/or trait like stem length in pea plants? What evidence is there that human height is still an evolving trait?1) Finish Seedgruber Activity
2) Meet with your teacher to discuss course selection today or next week
|Mon2/23||Wam up: The hitchhiker’s thumb phenotype in humans is uncommon. The more common phenotype is straight thumb. Assume that the trait is Medelian and construct a Punnett square to show the probability that a woman with hitchhiker’s thumb and a man who is heterozygous for the trait will have a straight-thumbed child. Is hitchhiker’s thumb under natural selection? Explain.1) Finish Chapter 11 material
2) Chi – Square test discussion and practice
|Chapter 12 Reading assignment- 12.1-12.4 and 12.6Personal Challenge: Do the Data Analysis Exercise and Self Quiz on pages 200 and 201
Quiz questions for chapter 12 will be posted on your teacher’s website for practice and comprehension of the chapter 12 material.
|Tues2/24||Warm up: What are autosomes, and what are sex chromosomes? Why can the Y chromosome be used to track evolutionary ancestry?1) Course Selection
2) Work on genetics and Chi-Square problems
3) Begin working on Chapter 11 genetics problems (pages 182-183 of your textbook)
|CAT ScheduleWarmup: Explain why it is an adaptive advantage for humans to be carrying the sickle cell trait in parts of the world where malaria can be found.
1) Finish Chi-Square problems and review
2) Collect genetic data and analyze with Chi- Square
3) Finish Chapter 11 genetics problems (pages 182 and 183 of your textbook)
4) Watch HHMI Biointeractive The Making of the Fittest: Natural Selection in Humans
|Finish Chapter 11 genetics problems (pages 182 and 183 of your textbook)|
|Fri2/27||Warm up: Two parents marry and have an albino child. One parent has blue eyes and the other parent has brown eyes. The child’s eyes are a pinkish color. Explain the difference in phenotypes between the child’s eye color and her parents’ eye colors. If albinism is a maladaptive trait, why hasn’t evolution by natural selection removed the allele from the human population?1) Chapter 12 lecture
2) Work on Chapter 12 genetics problems
|Finish Chapter 12 genetics problemsYour Unit 6 Exam is on Block DAy (3/4 or 3/5)|
|Mon3/2||Catch up day and pedigrees||Finish the Biointeractive pedigree practice questions (sickle cell anemia questions)|
|Tues3/3||Review for Unit 6 Exam|
|1) Unit 6 Exam2) Begin Unit 7|