Assignment #3 Genetic Material LO: To develop a model and explain inheritance and skin color variation. EQ: Do your genes determine who you are?

Transcription

1 Assignment #3 Genetic Material LO: To develop a model and explain inheritance and skin color variation. EQ: Do your genes determine who you are? AGENDA 10/20-10/21 1. Variation Model 2. Notes HOMEWORK 1. Synthesis (1 day) 2. Project (due M/Tues) 3. RRR LEVEL ZERO VOICE CATALYST (4 minutes, individual work): Define: DNA- Chromosome- Gene- How do proteins get made?

2 Read the quickwrite from our last class about relatedness.

3 Documentary: the students are trying to answer the same question you were.

4 What percentage of your DNA do you share with the peers in your room?

5 What percentage of your DNA do you share with the peers in your room? Humans share ~99.5% of their DNA with other humans So all of our differences are from less than 0.05% difference in DNA What are all of our differences? Why?

6 [Exploration Activity] Skin color is a superficial trait that is often used to identify people and usually pointed out when discussing human diversity. Race as been used to divide the human population into groups and that throughout history individuals have tried to make claims connecting race to biology Race is a biological myth The misunderstanding of race as biology will also be explore this unit, therefore the trait we will try to explain today is skin color.

7 [10 min] Task: Construct an explanation/model to explain the skin color variation in humans. Task Criteria: Include DNA Show/explain how information encoded in DNA leads to the trait of skin color Include internal (physiological) and external (environmental) factors influence skin color Show/explain WHY the variation exists Claim and Reasoning

8 Groups share your claim and reasoning

9 You will be taking notes now. You are learning this skill. Use abbreviations when you can Write down key information Shorten what you can to write as fast as you need to keep up

10 [Explain Why Variation Exists] To full explain this variation we need to think at different scales and understand: a) the history of our species (our ancestry) b) the theory of evolution by natural selection c) how genes are passed down through generations (inheritance) d) d) how traits are expressed. How does this evidence inform our explanation/model of skin color variation? : 1. The Human Journey Migration Routes 2. Global Map of Pigmentation Levels 3. Genetics 101: Where do Your Genes Come From? 4. Genetics 101: What are genes?

11 [Explain Why Variation Exists] Human Migration Routes We are an African species that spent most of our time on Earth in Africa First Homo sapiens: 200,000 years ago in Ethiopia Image from: The Human Journey: Migration Routes

12 [Explain Why Variation Exists] Human Migration Routes You will not be tested on these dates or the migration route. Humans left Africa 60,000 years ago Analyze DNA and fossil record to track the migration of humans India, SE Asia, to Australia (by 50,000ya) 50kya another group left Africa to the Middle East and Central Asia- from there they colonized the world 20kya crossed land bridge to N America Video from: Animated map shows how humans migrated across the globe

13 [Explain Why Variation Exists] How does this evidence inform our explanation/model of skin color variation? : Race/ethnicity does not have biological or scientific backing Labels used to categorize and discriminate Are no biological races Dark brown skin in S. Asia, Australia, New Guinea, islands of Melanesia Image from: Global Map of Pigmentation Levels

14 [Explain Why Variation Exists] How does this evidence inform our explanation/model of skin color variation? : Non-African peoples with dark skin do not share close common ancestry with Africans Skin color differs because of different selective pressures from the environment or mating Image from: Global Map of Pigmentation Levels

15 [Explain Why Variation Exists] How does this evidence inform our explanation/model of skin color variation? : Variation in skin color, height, facial characteristics, and body shape can be affected by: Genetics (DNA) Environment Sun exposure Diet Exercise And many other factors Image from: Global Map of Pigmentation Levels

16 99.9% of your DNA is in your nucleus The rest is in your mitochondria DNA is inside the cell s nucleus

17 If you were to stretch out your DNA in one cell, it would be 6 ft long! DNA is coiled tightly into chromosomes

18 If you were to stretch out your DNA in one cell, it would be 6 ft long! DNA (deoxy ribonucleic acid) Double stranded Made of sugar, phosphate, and four bases: A,T,C,G Bases spell out genetic code

19 Genes are small sections of your DNA that control traits You have 20,000 genes

20 Genes are the instructions to create proteins Proteins perform specific functions in cells Proteins can express traits

21 Gene regulators turn genes on and off

22 DNA is organized into chromosomes

23 Humans have 23 pairs of chromosomes (46 total) Different species have different numbers of chromosomes.

24 Humans have 23 pairs of chromosomes (46 total) One set from mom, one set from dad Different species have different numbers of chromosomes. Sex chromosomes Female: xx Male: xy

25 Homologous chromosomes a pair of chromosomes with same genes 1 from mom, 1 from dad

26 Most cells have 2 sets of chromosomes (2N) Sex cells have 1 set (1N)

27 [How do you make a sex cell?? An egg/sperm] 1. The parent s sets mix during genetic recombination 2. A random single of the set from the parent go into the sperm/egg That s why siblings are different

28 Some background notes When a sperm fertilizes an egg, they form a zygote, the first cell of the baby

29 Some background notes Monozygotic twins: twins that arise from a single zygote that divides in two 1 sperm, 1 egg Dizygotic twins: twins that arise from two separate zygotes 2 sperms, 2 eggs

30 Although we know a lot about DNA and inheritance there are still phenomena that challenge us, sometimes biologically, sometimes sociologically, or both. Why do we usually look like our parents? How can they be so different?

31 Mixed Race Monozygotic Twins Share 100% of DNA but have different skin color, hair color, facial characteristics, etc. Different races

32 Anchor Phenomenon RRR 1.15 min Explore 2: Hand out Anchor Phenomenon RRR and allow students to make their initial explanation and model. Circulate and try to emphasis the different scales of thinking and understanding - pushing students to deepen their explanation as much as possible. For example, if students are focused on the ancestry of the parents, direct them to also explain why the ancestors of the different parents had different skin color and explain how DNA leads to an actual color of someone s skin. x min - Exit Ticket: Hand out the Unit Rubric and go over the Unit Storyline. Have students write one question they have about the unit as they review the unit rubric.

33 Assignment #3 Genetic Material LO: To develop a model and explain inheritance and skin color variation. EQ: Do your genes determine who you are? AGENDA 10/20-10/21 1. Variation Model 2. Notes 3. RRR HOMEWORK 1. Synthesis (1 day) 2. Project (due M/Tues) LEVEL ZERO VOICE PROCESSING TASK (4 minutes, individual work): Choose your processing task. It must: Explain the relationship between DNA, genes, proteins