Tree Evidence for Common Ancestry and Divergence gives Grade 6 Science students a focused way to examine how scientists use phylogenetic trees, anatomical traits, DNA sequences, and fossils to investigate evolutionary relationships. Aligned with the NGSS framework, the resource connects evidence of common ancestry with lineage splitting, divergence, and trait change.

What Students Explore

Students interpret branching patterns in phylogenetic trees, including how a branch point represents a shared ancestor and how more recent branch points can indicate closer evolutionary relationships. They examine homologous structures as anatomical evidence, recognizing that similar underlying patterns can occur even when structures have different functions. Vestigial organs are also introduced as reduced structures that can provide clues about ancestral forms.

The lesson extends evidence-based reasoning to conserved DNA sequences and fossil evidence. Students consider how molecular similarities can support hypotheses about evolutionary relationships and how fossils can provide information about ancestral forms and changes through time. The resource emphasizes comparing multiple lines of evidence when interpreting evolutionary history.

Student Tasks

The worksheet combines a reading passage with multiple-choice questions, true-or-false statements, short-answer responses, a labeled diagram, a categorization activity, and short notes. Questions ask students to identify relationships in branching trees, explain the significance of homologous and vestigial structures, interpret molecular evidence, and connect fossil evidence to changes after populations diverge.

The visual analysis component brings several evidence types together through a branching tree, forelimb comparison, and DNA sequence comparison. The categorization task reinforces the distinction between anatomical and molecular evidence, while the short-answer section gives students opportunities to explain evolutionary reasoning in complete sentences.

Teacher Support and Classroom Use

Use this Grade 6 evolution worksheet for lesson practice, independent work, review, or formative assessment within a unit on biological evolution, unity, and diversity. The included student notes lines provide space for recording key ideas. The Answer Key PDF also includes a Teacher Guide with learning objectives, teaching tips, discussion questions, and common mistakes to support instruction and follow-up discussion.

This resource helps students move beyond memorizing vocabulary by using evidence to explain relationships, ancestry, lineage splitting, and modification through time. It provides a structured opportunity to connect phylogenetic trees with anatomical, molecular, and fossil evidence in one coherent lesson.