Population genetics and evolutionary change are the focus of this Grade 12 Science worksheet, where students examine how allele frequencies change across generations and how genetic variation helps explain microevolution. With Hardy–Weinberg calculations, scientific reasoning questions, and written explanations, the resource connects population genetics concepts to the processes that shape real populations.

Designed for Grade 12 Science, this worksheet is useful when teaching biological evolution, reviewing population genetics, or helping students practise quantitative reasoning alongside their understanding of evolutionary mechanisms.

🧬 From Allele Frequencies to Evolutionary Change

The reading passage introduces population genetics and explains how genetic variation changes within populations. Students encounter the relationship between allele and genotype frequencies, the assumptions of Hardy–Weinberg equilibrium, and the meaning of p and q in a two-allele population.

The passage also connects the mathematics to evolutionary processes. Natural selection, genetic drift, and migration are examined as different mechanisms that can change allele frequencies. Founder events and population bottlenecks show how population size and chance can affect genetic variation, while resistance alleles provide a context for examining selection.

Students also work with measures of genetic variation, including heterozygosity, effective population size, and fixation indices. These concepts help them interpret differences between populations and consider how genetic variation is maintained or lost.

📋 What Students Practise

• Hardy–Weinberg calculations: Calculate expected homozygous and heterozygous genotype frequencies using allele frequencies.
• Evolutionary mechanisms: Distinguish natural selection from genetic drift and explain how migration affects populations.
• Measurement and interpretation: Interpret heterozygosity, effective population size, and fixation indices as measures of genetic variation.
• Scientific reasoning: Apply population genetics concepts to insecticide resistance, founder events, and population bottlenecks.

The worksheet combines multiple-choice questions, true-or-false statements, short-answer responses, a labeled diagram, a categorization activity, and a short-note task. This mix gives students practice recalling definitions, applying calculations, distinguishing evolutionary processes, and explaining their reasoning in their own words.

📝 Included for Teachers

• Grade 12 Science worksheet on population genetics and evolutionary change
• Separate PDF answer key for checking student responses
• Student Notes lines at the bottom of the worksheet
• Teacher Guide in the Answer Key PDF, including Learning Objectives, Teaching Tips, Discussion Questions, and Common Mistakes

🔎 Classroom Uses

Use this population genetics worksheet during a lesson on biological evolution, as independent practice after introducing Hardy–Weinberg equilibrium, or for small-group review of evolutionary mechanisms. The calculation and explanation tasks also make it useful when revisiting allele frequencies, genetic drift, and natural selection before an assessment.

Written for the TEKS Grade 12 Science curriculum, this resource addresses the supplied standard code SCI.12.10. The answer key and teacher guide give you reference material for reviewing responses and discussing common difficulties with population genetics concepts.