Genetic variations in organisms

The performance expectations in Topic 4: Genetic Variations in Organisms help students in formulating answers to these questions:

How are the characteristics of one generation related to previous and future generations?

How does genetic variation contribute to biodiversity?

Students explain the relationship of DNA and chromosomes to cellular division, protein synthesis, and mutations. Students analyze the mechanisms of inheritance and gene expression, as well as environmental and genetic causes of gene mutations. Students formulate questions and construct arguments about ethical issues related to the genetic modification of organisms. Students develop conceptual models for the role of DNA in the unity of life on Earth and use statistical models to explain the importance of variation within population for the survival and evolution of species.

Students who demonstrate understanding can:

• LS1-4: Use a model to illustrate the role of cellular division (mitosis) and differentiation in producing and maintaining complex organisms

• LS3-1: Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring

• LS3-2: Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors

• LS3-3: Apply concepts of statistics and probability to explain the variation and distribution of expressed traits in a population