Unit 1 — Evidence of Common Ancestry & Diversity
Description
This unit examines the fossil record and its role in documenting the existence, diversity, extinction, and change of life forms throughout Earth's history. Students analyze patterns in fossils arranged in chronological order and apply scientific ideas to explain anatomical similarities and differences among modern organisms and between modern and fossil organisms. The unit also uses embryological development to reveal evolutionary relationships not evident in fully formed anatomy.
Essential Questions
- What layer of Earth would you find the oldest fossils?
- How do the skeletons of modern animals compare to the skeletons of their extinct ancestors?
- Why do many animals look so similar to developing embryos?
- How can scientists document the change of a species over time?
Learning Objectives
- Analyze and interpret data for patterns in the fossil record that document the existence, diversity, extinction, and change of life forms throughout the history of life on Earth.
- Apply scientific ideas to construct an explanation for the anatomical similarities and differences among modern organisms and between modern and fossil organisms to infer evolutionary relationships.
- Analyze displays of pictorial data to compare patterns of similarities in the embryological development across multiple species to identify relationships not evident in the fully formed anatomy.
- Recognize and identify the thoughts, feelings and perspectives of others regarding scientific concepts.
- Develop and implement effective problem solving and critical thinking skills to analyze evolutionary evidence.
- Use information from a variety of sources to summarize and effectively communicate data about evolutionary relationships.
Supplemental Resources
- Printed images or photographs of fossils for pattern analysis
- Graphic organizers for comparing anatomical structures across species
- Chart paper for displaying fossil record data and evolutionary relationships
- Index cards for sorting organisms by anatomical and embryological similarities
- Highlighters for marking key features in fossil and anatomical diagrams
Crosscutting Concepts
Disciplinary Core Ideas
Life Sciences
Science and Engineering Practices
Students read and analyze informational texts about fossil records, anatomical structures, and embryological development, citing textual evidence to support scientific explanations and engaging in collaborative discussions about evolutionary relationships.
Students use digital tools to analyze and interpret data sets related to fossil records and evolutionary patterns, evaluate sources for accuracy and relevance, and demonstrate openness to diverse perspectives during group scientific investigations.
Students apply design thinking processes and use technology to support scientific inquiry and communication of findings related to biological evolution and diversity.
Formative Assessments
- Students analyze fossil record data to identify patterns of existence, diversity, extinction, and change over time.
- Students construct explanations comparing anatomical similarities and differences between modern and fossil organisms.
- Students analyze pictorial data of embryological development across species to infer evolutionary relationships.
- Students present and discuss interpretations of fossil and anatomical evidence with peers, demonstrating openness to diverse perspectives.
Summative Assessment
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Benchmark Assessment
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Alternative Assessment
Students may demonstrate understanding through verbal explanations of fossil patterns and anatomical similarities recorded in a one-on-one or small group setting. Visual aids such as labeled fossil diagrams, comparison charts, or simplified timeline graphics may be provided to support analysis and explanation.
IEP (Individualized Education Program)
Students with IEPs may benefit from scaffolded graphic organizers that help them sort and sequence fossil record data visually, reducing the cognitive load of tracking patterns across time. Providing pre-labeled diagrams of anatomical structures and embryological stages can support comprehension without eliminating analytical thinking. For written explanations of evolutionary relationships, allowing students to respond orally, through dictation, or with teacher-scribed notes ensures that output demands do not mask scientific understanding. Extended time and chunked tasks should be applied when students are asked to compare multiple organisms or synthesize evidence across sources.
Section 504
Students with 504 plans should be given extended time when analyzing complex fossil or embryological data displays, as these tasks require sustained attention and careful visual comparison. Preferential seating near instructional displays or demonstrations supports engagement during data analysis activities involving pictorial or chronological evidence. Printed copies of any projected data sets or anatomical diagrams allow students to annotate and reference materials without losing their place during discussion.
ELL / MLL
Multilingual learners benefit from a visual word wall or illustrated glossary that anchors key vocabulary—such as fossil record, ancestry, extinction, embryo, and anatomy—with images and, where possible, home language connections. Directions for data analysis tasks should be stated in clear, simple language with visual examples of what a completed comparison looks like. Partnering MLLs with supportive peers during discussions of evolutionary evidence provides both language modeling and an accessible entry point for sharing scientific interpretations.
At Risk (RTI)
Students who need additional support should be given access to simplified or annotated fossil record timelines that highlight key patterns before they are asked to draw independent conclusions. Connecting the concept of physical similarities to organisms students are already familiar with—such as comparing limb structures across common animals—builds the prior knowledge needed to engage with more abstract evolutionary relationships. Breaking the process of constructing an explanation into smaller steps, with check-ins at each stage, helps students experience success and build confidence as they work toward synthesizing evidence.
Gifted & Talented
Advanced students should be challenged to move beyond identifying surface-level patterns in the fossil record and instead evaluate the limitations and gaps in fossil evidence as a scientific tool, considering what the record cannot tell us about evolutionary history. They may investigate how molecular or genetic data compares with anatomical and embryological evidence, exploring cases where these lines of evidence converge or conflict. Encouraging students to develop an original argument—drawing from multiple types of evolutionary evidence—and present it to peers or in written form cultivates higher-order scientific reasoning and authentic research skills.