Human Evolution STEM case study Course Essential Question ● How do small changes lead to so much diversity? Big Ideas: ● Individual uniqueness, inheritance ● Change over time Background Throughout this course, we have explored many topics that explain the reasoning behind and the benefit for the vast diversity of all living things. From the struggle to survive, to random genetic events and the selective pressures of the environment, the existence of every organism and every allele is truly a marvellous feat. In this evaluation, you will explore the evolution of one human trait, connecting this topic to three (maybe 4) units in our Biology class. This is the first of 2 similar tasks. The second will be at the end of the semester. The results of your best STEM case study will count as an evaluation. Task You will watch this video related to the biology of race and then complete the following tasks to apply your biology knowledge to explain our current understanding of the evolution of skin colour using principles of genetics.. You should provide clear, concise and complete responses to each of the prompts below. Here are the prompts for which you should provide full written responses. Your final product should be a well organized google doc that you turn in to today’s post. At the end of this document you will find the Learning goals and Success criteria from the Genetics and Evolution units that should be addressed. You may also consider any of the other LGs and SCs from the units that we have covered if you like. You may add these into the table. Evolution concepts ● Describe how nature selected light skin colour in northern regions (or dark skin colour in regions along the equator) by applying Darwin’s 4 observations and 2 inferences. (Be sure to explain fully using relevant terminology) 4 marks ● Describe what mode of selection took place and how you can tell. (Hint: Is this macro or micro evolution? What kind of selection takes place?) 2 marks ● Identify the type of evidence for evolution that supports the evolution of skin colour. Explain how the evidence supports these ideas. 2 marks Genetics ● Identify the gene involved including ○ What chromosome it is on (Hint: how can you relate this to nucleotides, karyotypes and DNA structure? 2 marks ○ What happened at the DNA level and how this gene became prominent in the population. (Hint: What other terms and concepts can you include here to demonstrate your knowledge of DNA?) 3 marks Extra enrichment questions to consider: 1. Why can’t we use a phylogenetic tree to display the change in human skin color with time? 2 marks 2. The production of melanin is also crucial for the coloration (and often functioning) of our eyes, skin and hair. Oculocutaneous albinism is inherited in an autosomal recessive pattern. Oculocutaneous albinism (OCA) results from the inability of the normal pigment cells in the eyes and hair to produce melanin. A person with this disorder may appear to have red eyes, white hair and very fair, white skin. A person who is a carrier for this genetic disorder, mates with another carrier. They have 4 children. Display the probable genotypes and phenotypes of the F1 with a pedigree (and the 4 children they have). Below each individual in the pedigree, indicate their genotype. 3 marks 3. Repeat question 1, but with Ocular albinism type 1, which is a sex-linked trait (that only affects the eye). A male who is normal for eye pigmentation mates with a carrier of ocular albinism type 1. 3 marks GENETICS Learning Goal: to explain how genetic information is stored and copied. I can use and apply the terms: trait, gene, allele chromosome, chromatin, chromatid, centromere, homologous chromosomes. I can describe the structure of DNA. Learning goal: to explain the transmission of hereditary traits using Laws of Inheritance. I can compare and contrast genotype and phenotype. Learning Goal: to explain how sexual reproduction leads to genetic variation. I can explain how meiosis can create genetic variation. Learning goal: to follow the transmission of a heritable trait over many generations using a pedigree. I can analyse pedigrees to determine the genotype/phenotype of an individual within that pedigree. I can analyse pedigrees to determine whether a trait is recessive, dominant or sex-linked recessive. EVOLUTION Learning goal: Students will be able to explain how the genes of one individual can lead to changes in a population over several generations. I can apply the terms “adaptation,” “variation,” “evolution,” “gene”, “selective advantage” and “fitness” to explain how the survival/reproduction of certain individuals over others can change in response to a selective pressure in the environment. I can apply Darwin’s 4 observations and 2 inferences to explain how species change over time I can identify the role of the environment in evolution I can explain the importance of variation for evolution Learning goal: Students will be able to discuss the different ways natural selection can affect a population, with relevant examples. I can compare, contrast, identify examples of and sketch graphs illustrating disruptive, directional and stabilizing selection I can explain how the length of a generation can influence how quickly a population evolves Learning goal: Students will be able to analyse the evidence for evolution that confirms it as a major scientific Theory. I can effectively discuss the use, strengths and short-comings of each of the 5 major pieces of evidence for evolution. Learning goal: Students will be able to analyse how to use evidence for evolution to explain how the 5 mechanisms influence the evolution of populations over time. I can describe the 5 mechanisms of change and how they contribute to microevolution vs. macroevolution I can identify which mechanisms must be the major factors at work in different species’ evolution.
