Double Square Discussion

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Double Square Discussion

Choose 4 questions to answer. Be thorough and complete in your answers. If you choose a problem solving question, be sure to show your work. Other types of questions can be answered with a chart, list, or in a well-developed paragraph.

Each answer is worth up to 5 points for a total of 20 points possible.

  • Albinism is a trait found in many species which reduces or eliminates pigmentation in the skin, hair, and eyes. Albinism is inherited as a recessive trait (only those with aa -homozygous recessive) will show the features of Albinism. (provide percentages and show your work)
    • if two heterozygous individuals reproduce, what are the chances they will have an albino child?
    • if one of their children is homozygous recessive, and grows up to marry and have children with another albino, what are the chances they can have a child who is NOT albino?
    • Imagine a community where people discriminate against albino individuals, and force them to move into their own village, and only marry one another. Would this be a sure way to eliminate albinism in the community? Why or why not?
    • Continuing with the imaginary community above, what do you think would happen to the total number of albino individuals in the population (both villages)? Would it increase, or decrease? Explain.
    • Which of the four evolutionary forces is at work here? Could there be more than one? Explain.
  • Define SPECIES. How do we know if a group of animals qualify as a separate, sub, or semi-species? Thinking about evolution, where do new species come from? What conditions are needed for a new species to emerge?
  • Discuss the key elements and events of human evolution. What makes humans unique? What traits and behaviors do we have that set us apart from other animals?
  1. Two individuals are heterozygous for Sickle Cell Anemia (AS) they live in an area where malaria is common. They have three children together and are preparing for the birth of their fourth. Two of their children have normal hemoglobin (AA), and one has Sickle Cell Anemia (SS), and is receiving treatment.
    1. What are the chances that their next child will be born with Sickle Cell Anemia (SS)? Explain your answer.
    2. One of the children with normal hemoglobin grows up to marry someone who is heterozygous for the trait (AS). What are the chances that one of THEIR children will be able to survive a future outbreak of malaria?Show your work.
    3. Why do some populations have a relatively high frequency of the sickle cell trait, even when they do not live in areas that have much risk of malaria (like for example, the African American population in the United States). What genetic/evolutionary force can explain this?
  2. Use a double square (dihybrid cross) to determine the possible genotypes and phenotypes for this couple’s child. Give percentages and show your work. Remember that blood type A and B are dominant, and blood type O is recessive. The Rh factor is inherited as positive=dominant (Rh+), negative is recessive (Rh-) and you should use (D, d) to track this.
    1. Write out the genotypes of Glenn and Maggie given the following information: Glenn has blood type B- and is heterozygous for B, Maggie has blood type O+ and is heterozygous for Rh).
    2. What are the possible genotype and phenotype outcomes for their child? Show your work and provide percentages or fractions. You will need to create a ‘double square’ or a dihybrid cross.
    3. In this case, is it possible that the child could have a phenotype different than at least one of its parents? Explain.
  1. Discuss at least three things that Darwin needed to know before he could come up with his theory of natural selection. How did he learn these three things? Explain how at least 3 other scientists and researchers contributed to the body of knowledge that informed Darwin’s theory?
  2. Explain how our current understanding of Meiosis helps to support Mendel’s ideas about particulate inheritance. Think about segregation and independent assortment in your answer.
  3. What is taphonomy? Explain what conditions are needed for fossils to form and how researchers look for and find fossils in various environments around the world.