• [History of life: Grades 9-12] Present-day species evolved from earlier species; the relatedness of organisms is the result of common ancestry. (LS4.A)
• [History of life: Grades 13-16] Present-day species evolved from earlier species; the relatedness of organisms is the result of common ancestry.
• [History of life: Grades 9-12] Biological evolution accounts for diversity over long periods of time. (LS4.A, LS4.D)
• [History of life: Grades 9-12] Through billions of years of evolution, life forms have continued to diversify in a branching pattern, from single-celled ancestors to the diversity of life on Earth today.
• [History of life: Grades 9-12] Life on Earth 3.8 billion years ago consisted of one-celled organisms similar to present-day bacteria.
• [History of life: Grades 9-12] The early evolutionary process of eukaryotes included the merging of prokaryote cells.
• [History of life: Grades 13-16] Biological evolution accounts for diversity over long periods of time.
• [History of life: Grades 13-16] Through billions of years of evolution, life forms have continued to diversify in a branching pattern, from single-celled ancestors to the diversity of life on Earth today.
• [History of life: Grades 13-16] Life on Earth 3.8 billion years ago consisted of one-celled organisms similar to present-day bacteria.
• [History of life: Grades 13-16] The early evolutionary process of eukaryotes included the merging of prokaryote cells.
• [Evidence of evolution: Grades 9-12] There are similarities in the cell function of all organisms. (LS4.A)
• [Nature of science: Grades 9-12] Scientists can test ideas about events and processes long past, very distant, and not directly observable.
• [Nature of science: Grades 13-16] Scientists can test ideas about events and processes long past, very distant, and not directly observable.
• [Studying evolution: Grades 9-12] Our knowledge of the evolution of living things is always being refined as we gather more evidence.
• [Studying evolution: Grades 9-12] Our understanding of life through time is based upon multiple lines of evidence.
• [Studying evolution: Grades 13-16] Our knowledge of the evolution of living things is always being refined as we gather more evidence.
• [Studying evolution: Grades 13-16] Our understanding of life through time is based upon multiple lines of evidence.

• Disciplinary Core Idea LS4.A: Evidence of Common Ancestry and Diversity
• Disciplinary Core Idea LS4.D: Biodiversity and Humans

Additional in-class discussion may enhance student learning based upon this article. Key questions at the beginning of the article could be used to stimulate discussion.

Additional teaching tips for 13-16:
Use this resource to relate evolutionary concepts to the topics of organelle structure and function (or get more suggestions for incorporating evolution throughout your biology syllabus).

• Classification/Phylogenetics
• History of Life
• Nature of Science