Activity: Working in small groups, students observe and describe one trait in a population of plants (the length of radish rootlets) and one in a population of animals (the whorl color on snail shells). They discuss situations in which a particular trait variant (e.g., shorter rootlet, darker whorls) might be helpful, harmful, or neutral to an individual’s capacity for survival and reproduction.

Materials to Have Ready

• 5 petri dishes

• 50 radish seeds

• Roll of paper towels

• 5 plastic ziploc bags or plastic wrap to put the petri dishes in

• 18 snail shells 

Video Overview (2:06)