Why Don't Antibiotics Work Like They Used To? [v1.0]
(Bend 1): In the first part of this unit on evolution, students investigate the case of a young girl with a life-threatening infection of pan-resistant bacteria. Her case sparks questions that lead to discoveries about the growing prevalence of similar cases over time. It also leads to discoveries about the discrepancy between antibiotic use in student's communities and the Center for Disease Control (CDC) recommendations. Students decide to take on a mission to serve as citizen scientists to figure out why this is happening in order to develop more effective infographics to sway individual health choices related to the (mis)use of antibiotics. They begin to conduct investigations with antibiotics and bacteria to understand these phenomena further.
(Bend 2): In second part of this unit, students investigate the case of a population of urban Juncos that has recently settled on the University of California at San Diego (UCSD) campus. These birds appear to far bolder than the population of Juncos that they descended from just a few decades ago. This case sparks questions about whether behavior can be inherited. Students analyze data from this case study, as they wrap up their experiments with antibiotics and bacteria from the first part of the unit (bend 1). They use what they figure out from these experiments and from their investigations of the Juncos to develop a deeper model of natural selection. They visit their mission as citizen scientists, developing more effective infographics related to the (mis)use of antibiotics for dissemination in their community.
(Bend 3): In this third part of this unit, students investigate why the UCSD juncos and their closely related cousins, don’t appear to be mating with each other, even though their cousins still migrate to the UCSD campus for part of the year. Their investigations lead them to investigating other juncos populations across North America, which, in turn, lead to discoveries about speciation and the mechanisms of evolution that contribute to it. Students apply these mechanisms of evolution, back to bacteria to explain where new strains of bacteria come from and to explain the growing prevalence of antibiotic resistant bacterial infections in our society.
What students figure out
By the end of the unit, students develop ideas on natural selection & evolution including:
- Natural selection occurs only if there is both (1) variation in the genetic information between organisms in a population and (2) variation in the expression of that genetic information—that is, trait variation—that leads to differences in performance among individuals. The traits that positively affect survival are more likely to be reproduced, and thus are more common in the population. Natural selection leads to adaptation.
- Evolution is a consequence of the interaction of four factors: (1) the potential for a species to increase in number, (2) the genetic variation of individuals in a species due to mutation and sexual reproduction, (3) competition for an environment’s limited supply of the resources that individuals need in order to survive and reproduce, and (4) the ensuing proliferation of those organisms that are better able to survive and reproduce in that environment.
- Changes in the physical environment, whether naturally occurring or human induced, have contributed to the expansion of some species, the emergence of new distinct species, and the decline–and sometimes the extinction–of some species.
- Genetic information provides evidence of evolution; multiple lines of descent can be inferred by comparing the DNA sequences of different organisms.
- Vicki Brown, High School Biology Teacher, Denver Public Schools, Denver, CO.
- Jill F. Carter, Science and Environmental Education Consultant, Pekin, IL
- Jennifer Jacobs, Research Associate, University of Colorado Boulder, Boulder, CO
- Mike Kraft, High School Biology Teacher, Denver Public Schools, Denver, CO.
- Katy Fattaleh, K-8 Instructional Coach, South Park School, Deerfield, IL
- Mike Fumagalli, Assistant Dean of Students, Glenbard East High School, Glenbard, IL
- Kent Hups, High School Biology Teacher, Adams 12 Five Star School, Thornton, CO
- Kevin Lindauer, High School Biology Teacher, Denver Public Schools, Denver, CO.
- TJ McKenna, Science Specialist, Connecticut Science Center, Hartford, CT and University of Connecticut, Storrs, CT
- Tara McGill , Curriculum Development Specialist, Northwestern University School of Education and Social Policy, Evanston, IL
- Michael Novak, Senior Curriculum Developer, Northwestern University School of Education and Social Policy, Evanston, IL
- William Penuel, Professor of Learning Sciences, University of Colorado Boulder, Boulder, CO
- Brian Reiser, Professor of Learning Sciences, Northwestern University School of Education and Social Policy, Evanston, IL
- Kristin Rademaker, Life Science & Special Education Teacher, Harlem High School, Machesney Park, IL
- Tricia Shelton, High School Biology Teacher, Randall Cooper High School, Union, KY
- Stephanie Spiris, High School Biology Teacher, Denver Public Schools, Denver, CO.
- Katie Van Horne, Postdoctoral Researcher, University of Colorado Boulder, Boulder, CO
- Dan Voss, High School Chemistry Physics Teacher, Boone High School, Boone, IA
- Douglas Watkins, High School Science Curriculum Specialist, Denver Public Schools, Denver, CO.
- David Quigley, Graduate Researcher, University of Colorado Boulder, Boulder, CO
- Holly Devaul, Mgr. of Educational Programs at University Corporation for Atmospheric Research, Boulder, CO
- Tammy R Sumner, Professor of Cognitive and Computer Science, University of Colorado Boulder, Boulder, CO