Description
Cichlid speciation in Lake Victoria introduces the investigative phenomenon of variation and distribution of expressed traits in a population and how this might lead to evolution. Over the course of 2 investigations, students use a card set and genetic corn to gather data about allelic frequencies and phenotypes in a stable population. Then in a third investigation, student groups plan, model, and present the results of genetic exchanges that disrupt genetic equilibrium. Students work toward answering the driving question, “How do scientists recognize that a population is evolving?”
Time Requirement
300 minutes. Approximately 6 50-minute blocks, one for each of the following: prelab activity, 3 investigations, group presentation, and assessment. Could be conducted in approximately 3 90-minute blocks as well. Some portions may be completed as homework.
Digital Resources
Includes 1-year access to digital resources that support 3-dimensional instruction for NGSS. Digital resources may include a teacher manual and student guide, pre-lab activities and setup videos, phenomenon videos, simulations, and post-lab analysis and assessments.
Performance Expectation(s)
HS-LS3-3
HS-LS4-2
Crosscutting Concepts
Stability and Change
Disciplinary Core Ideas
LS3.B: Variation of Traits
LS4.B: Natural Selection
LS4.C: Adaptation
Science and Engineering Practices
Analyzing and Interpreting Data
Developing and Using Models
Learning Objectives
Apply mathematical concepts to calculate and describe changes in the frequency of alleles within real and model populations. Construct graphs and analyze population data to identify patterns or relationships in the frequency of expressed traits within a population over time. Model disruptions of allelic equilibrium in natural populations to analyze their effects on the evolution of model populations. Observe and count phenotype frequencies to describe changes in the genetic makeup of a model corn population. Engage in argumentation from evidence to evaluate evolutionary claims.
Prerequisite Knowledge and Skills
Understanding of Mendelian patterns of inheritance—including the terms “gene,” “allele,” “genotype,” and “phenotype.” Ability to use basic algebraic equations, including calculating relative frequency. Familiarity with the theory of evolution by natural selection. Familiarity with population biology—including the terms “species” and “population.”