Complex Punnett Squares

• The genetic makeup of two parents determines their offspring's genotype. Punnett squares allow scientists to determine the probability of offspring carrying certain alleles and displaying specific traits. The simplest Punnett square is a 2-by-2 grid that shows a child's possible genetic outcomes for one gene. More complex Punnett squares require students to determine the genetic outcomes for two or more genes. Provide students with the parents' genotypes for each gene and ask them to fill out a complex Punnett square. Discuss the probability of each genotype occurring as well as the chance of offspring having a specific phenotype, or set of displayed traits.
  
  

Population Genetics

• A teddy graham population genetics activity helps students learn how natural selection causes changes in a population over time. A box of teddy grahams contains some bears with their arms up and others with their arms down. Assume upward arm placement is a genetic trait that increases bears' evolutionary fitness. Give students a random population of bears and have them record the frequency of each genetic type. Progress through several "seasons" in which less fit bears die and bears with higher fitness reproduce. Model the changes in the genetic makeup of the bear population and determine whether they fit theoretical models of population genetics.
  
  

Fruit Flies

• Many geneticists use fruit flies as a model organism because of their short life spans and fast reproduction. Introduce AP biology students to fruit fly genetics to teach them about dominant and recessive traits. Purchase fruit flies from a biology supply company such as Carolina Biological. Choose wild-type flies and several types of mutations, such as recessive sex-linked white eyes or vestigial wings. Teach students to sort flies by sex and mate different fly types. Ask them to predict the frequency of the progeny's phenotypes. Progress through several generations of fruit flies to map the results of their reproduction.
  
  

Murder Mystery

• A murder mystery is an excellent way to teach AP biology students about the differences between blood types. Purchase synthetic blood of each blood type: A, B, AB and O. Set up a murder mystery in your classroom in which there is a murder weapon with the murderer's and victim's blood on it. Challenge students to solve the mystery by testing each suspect's blood type by mixing it with type A and type B antiserum. Type A antiserum coagulates blood types A and AB, while type B antiserum coagulates blood types B and AB. Give a prize to the student or lab group that solves the mystery first.