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Students analyze genetic data to discover which genetic variants are associated with lactose tolerance in different populations. A statistical test (chi-squared) is used to work out whether specific genetic changes have significant effects on lactase persistence.
DNA to Darwin
Teachers will likely wish to supplement this activity with additional discussion of natural selection and how/why lactose persistence might have been favored in certain populations not others. In addition, this activity could be expanded into one that includes discussion and analysis of Hardy Weinberg equilibrium. Use this resource to relate evolutionary concepts to the topic of animal nutrition and digestion (or get more suggestions for incorporating evolution throughout your biology syllabus).
Correspondence to the Next Generation Science Standards is indicated in parentheses after each relevant concept. See our conceptual framework for details.
- There is a fit between organisms and their environments, though not always a perfect fit.
- Not all similar traits are homologous; some are the result of convergent evolution.
- Evolution is often defined as a change in allele frequencies within a population.
- Evolution results from natural selection acting upon genetic variation within a population.
- New heritable traits can result from mutations.
- Inherited characteristics affect the likelihood of an organism's survival and reproduction.
- Over time, the proportion of individuals with advantageous characteristics may increase (and the proportion with disadvantageous characteristics may decrease) due to their likelihood of surviving and reproducing.
- Depending on environmental conditions, inherited characteristics may be advantageous, neutral, or detrimental.