Adaptive radiation and ecological diversification are the focus of this Grade 10 Science resource, which examines how related populations can evolve into distinct species as they adapt to different ecological niches. Students explore how new habitats, changing environmental conditions, geographic isolation, and the loss of competing species can create opportunities for evolutionary diversification.

How ecological opportunity leads to diversification

The reading passage introduces adaptive radiation as the diversification of one lineage into multiple species occupying different ecological niches. Students examine how differences in food sources, habitats, climates, and predators can favor different inherited traits through natural selection over generations. Examples involving island finches and fish in isolated lakes help connect these processes to observable differences in beak characteristics, body shape, behavior, and physiology.

The resource also develops students' understanding of evolutionary evidence. They consider how branching patterns in phylogenetic trees reveal shared ancestry and relationships between diverging lineages. Importantly, students examine why a branching tree alone cannot establish adaptive radiation. Ecological observations, anatomical comparisons, fossils, and evidence about the timing of diversification are also needed to evaluate an explanation.

Skills students practise

• Define adaptive radiation and explain the role of ecological opportunity in diversification.
• Compare how different food sources and habitats can favor distinct adaptations in related populations.
• Explain how geographic isolation, natural selection, and the extinction of competitors can influence evolutionary diversification.
• Interpret phylogenetic branching patterns as evidence of evolutionary relationships and common ancestry.
• Evaluate why scientists combine ecological observations with phylogenetic and other evidence when investigating adaptive radiation.

What students work through

After the reading, students apply the concepts through multiple-choice questions, true-or-false statements, concise written responses, a matching activity, and a passage-completion exercise. An extended response asks them to explain how an example involving island finches or isolated lake fish illustrates ecological opportunity, natural selection, geographic isolation, and the use of phylogenetic evidence. A Did You Know section adds another opportunity to consider the topic.

Files included for teaching and review

• Student worksheet: Reading and written activities focused on adaptive radiation, ecological niches, evolutionary adaptations, and evidence of diversification.
• Separate answer key PDF: Answers for checking student work and supporting review.
• Student Notes & Lesson Summary: A supplementary resource for reinforcing the main ideas and reviewing key concepts.
• Separate Teacher Guide: Learning Objectives, Teaching Tips, Discussion Questions, and Common Mistakes to support lesson preparation and instruction.

Classroom use

Use this Grade 10 evolution worksheet during an Evolution & Classification unit, after introducing natural selection and evolutionary relationships, or as a focused review of adaptive radiation. The written explanations and extended-response task give students opportunities to connect examples with evolutionary processes rather than simply recall definitions. The notes supplement supports lesson review, while the separate answer key and teacher guidance make it easier to check responses and address common misunderstandings.

Written for the Texas Essential Knowledge and Skills framework, this resource addresses TEKS §112.34(b)(10)(A) and keeps the emphasis on how ecological conditions and evolutionary evidence help explain diversification within related lineages.