Period 4 Do Now: Use the concepts from the lab to write an short answer explaining how genetic diversity for a particular trait can be achieved in a population.

Period 5 Do Now: Explain how these concepts promote genetic diversity within a population. Random fertilization Gamete formation Gene Interactions and Control Mutations. Sexual reproduction and Mutations are the source of phenotypic variation in a population. Phenotypic variation drives natural selection and is the mechanism of evolution over long periods of time.

Do you find the same frequency of sickle cell trait in Phenotype: all normal Phenotype: normal and sickle Phenotype: all sickle cell Do you find the same frequency of sickle cell trait in different areas of the world or even a country? How many cases in the United States? After reading question, do you know how many people have sickle cell in the US and in Kenya?

Are you fit? Here lies the answer… Natural Selection is the process whereby organisms better adapted to their environment tend to survive and produce more offspring. Survival of the fittest is the idea that individuals within a population with a trait that encourages survival will reproduce and pass on their genes. Are you fit? Click to the next slide to watch a video about the natural selection of humans…

Making of the Fittest: Natural Selection in Humans https://www.hhmi.org/biointeractive/making-fittest-natural-selection-humans A video created by HHMI showing the evolutionary biology work of Tony Allison and his data showing a correlation between the diseases sickle cell anemia and malaria. Click on the link to find out more.

Link between Sickle Cell and Malaria Use this info to explain why sickle cell persists in higher numbers within certain areas of the world compared to others?

Post Video Activity: Requires knowledge from the baby lab, notes on meiosis, and the video about Sickle Cell in a Population Points to remember: 1. Meaning of codominance 2. Parents only give one allele to offspring 3. Definition of “Fitness” 4. Sexual reproduction genetic and Size affect on a population 5. Randomness of inheritance 6. definition of a Favorable Phenotype/Trait 7. Relationship between Natural Selection and the Frequency of phenotypes

Do Now: Break into groups of four Do Now: Break into groups of four. Discuss and create answers to these questions. Your group has 20 minutes to complete this task. Think before you write on the sheet. This is a classwork grade. Why is the heterozygous genotype an advantageous one where the disease malaria is a persistent threat? Can the heterozygous genotype ever lose the advantage? Will the homozygous recessive genotype ever be good to inherit? What type of genotype will always pass on the sickle cell allele? Create a diagram to illustrating an area of Africa that has both malaria and a high frequency of sickle cell trait and disease individuals. Then create an illustration showing how the area came into existence and is maintained. Your diagram should include stick figure people, the genotype of individual persons, meiosis/gametes and fertilization, survive or die

A area maintains a high frequency of sickle cell trait and sickle cell disease because the heterozygote has the advantage. Natural selection is at work. Illustration on the right are of those with a high degree of fittness.

What you should have learned from the Baby Lab and the Sickle Cell-Malaria Connection Video The Baby lab showed us that meiosis creates gametes with only one chromosome within the cell. A sperm will only have one allele for a given gene. The Baby lab demonstrated the randomness of inheriting an allele and the randomness of how a genotype is inherited. The Baby lab showed us that the genotype inherited determines the phenotype of the individual. The Baby lab introduced the concept of gene interactions: simple dominance, incomplete dominance and polygenic inheritance. The Baby lab illustrated that gene interactions can be a source of variation for a trait, which appears in the heterozygous genotype. *Genetic diversity of a population for given traits arises from sexual reproduction and mutations. Mutations can be the source of a new phenotype. *Natural Selection drives populations to evolve. Nature selects for a trait and selection can also be against a given trait.

Is the heterozygote a friend and/or foe for those living in malaria prone regions?