How have living things changed over time?
Learning Targets
Learning Experiences
Learning Targets
Learning Experiences
Misconceptions
107 I can collect and analyze data to identify patterns in survival and trait frequency in a population of organisms. (14) 108 I can develop an argument about which traits in a population will confer an adaptive advantage while going through changing conditions. (14)
Students are first assessed for prior knowledge and misconceptions related to adaptation and natural selection (see resource list for knowledge probes). Students then participate in an activity that simulates population change over time in response to an altered environment. This experience provides students with a foundation for examining scientific principles related to natural selection. As the simulation proceeds, segments of the population respond to the environmental change with differential survival and reproductive success. When the simulation is complete, students compile data to identify changes in phenotype (trait frequency) from the start to the conclusion. Students propose explanations for the results they have observed during the simulation. At the end of this content sweep, students will revisit their explanations for possible modification.
V If the environment selects against a specific phenotype, that phenotype will become extinct. V Species that have no apparent, obvious, or superficial similarities have no similarities at all. V Natural selection is all- powerful; it produces perfection. V Natural selection has a “goal,” i.e. striving to produce a balanced ecosystem or make “progress.” V Natural selection occurs at the individual level not at the population level.
109 I can define variation and categorize the processes (mutation and sexual recombination) that lead to variation. (11,15)
Students explore multiple lines of evidence to explain how variation within a population depends upon genetic mutation, gene flow, and the shuffling of genetic combinations during meiosis and sexual reproduction. They begin by viewing images that illustrate variation in a specific trait across a population – moth or butterfly wing coloration, pigment and whorl patterns on shells, etc. Students generate hypotheses to explain the origin of this variation. Students are reminded of previous activities describing how new genetic variants or combinations of variation are created (new mutation through DNA replication and new combinations of alleles during meiotic crossing-over and independent assortment of chromosomes into gametes). Based on this information, students revisit their hypothesis and modify if necessary.
Teacher Resources
Thumbs Up — NMSI Laying the Foundation Lesson Students measure phenotypic variation in classroom populations. Students uses data to make predictions for the variation within a classroom population. Killer Microbes — NOVA Students model how horizontal gene transfer (e.g., conjugation) contributes to the spread of antibiotic resistance genes in bacteria. bit.ly/killer-microbes
Teacher Resources
Teacher Tips These learning tar- gets will encompass multiple learning experiences over several days. Addressing biological evolution may be challenging in the classroom. It is suggested that teachers provide exposure to scientific evidence without overlapping religion and science. It is essential for teachers to be respectful of student’s beliefs, but it is also the responsibility of the teacher to provide multiple opportunities for students to explore and analyze scientific evidence related to common ancestry and biological evolution.
Probe Strategy A recent issue of Hunting & Fishing magazine reported that populations of male deer (bucks) reaching sexual maturity have smaller antlers than they did in the past. Which statement best explains the decreased antler size of the buck population? A. The bucks grow their antlers slowly and reproduce as quickly as they can. B. More mutations occur to help the deer population. C. Bucks that reproduce with smaller antlers are less desirable to hunters. Indicate which choice best describes your thinking and provide an explanation for your choice. Natural Selection Simulation — The Concord Consortium Students manipulate a computer simulation to draw conclusions about how selection pressures affect populations. bit.ly/natural-selection-simulation Rock Pocket Mouse Coat Color — Howard Hughes Medical Institute This is a data collection and analysis lesson that examines selection for coat color in pocket mouse populations on different color substrates over time. bit.ly/rock-pocket-mouse Peppered Moth — Alabama Science in Motion E6Moth Students replicate the classic peppered moth research to learn about natural selection. bit.ly/AMSTI-ASIM
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Helpful links for teaching evolution: bit.ly/teach-evolution bit.ly/teach-evolution2
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A Field Guide to the Alabama Standards
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The Biology Compendium
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