Heredity: The process in which characteristics or traits pass from parents to offspring. Think, Pair, Share some characteristics that you have in

Transcription

1 Genetics Grade 7 1

2 Heredity: The process in which characteristics or traits pass from parents to offspring. Think, Pair, Share some characteristics that you have in common with either parent 2

3 Tracking Down Traits Learning Experience 1 1. Review Procedures 2. Rule: No person may sign the list more than twice. 3

4 What do you know about DNA? Where have you heard the term? What was the context or situation? 4

5

6 What is DNA? The genetic material that carries information about an organism passed from parent to offspring A complete set of instructions necessary to make and maintain the human body. A Blueprint of the human body 6

7 Why is DNA Interesting? DNA is a nonliving molecule. There are 6 feet of it in every cell. The human body can have as many as ten thousand trillion cells, and almost every one of them has 6 feet of densely compacted DNA. DNA is unique for every individual DNA controls all the activities in the cell from the nucleus. DNA is a nonreactive chemically inert molecule Why is DNA interesting? What is DNA? 7

8 DNA and Crime Solving Because DNA is a nonliving, nonreactive chemical molecule It can be recovered from mummies over 2000 years old. Long-dried blood in murder investigations Ancient bones 8

9 Where is DNA? Cell Nucleus the Control Center Chromosomes Chromosomes are made of DNA 9

10 Where is DNA? Draw and label the location of DNA in the cell Draw and label the relationship between DNA and chromosomes. Make the Chromosome Model 10

11 Each human Cell have 23 pairs of Chromosomes Mother Father 11

12 Chromosomes are made of genes A gene is a section of DNA that controls a trait ( ex. tall /short) that an organism inherits 12

13 A Model of a Chromosome Gene Chromosomes are made up genes. A gene is a section of DNA (section of a chromosome) that controls a trait that an organism inherits. If the string of shapes represents a chromosome what does each individual shape represent? 13

14 Gene for the Trait Brown Eye color Gene for Tall Height Gene for Brown Hair color Gene for Attached vs Unattached Earlobes Gene for the Shape of our Fingers 14

15 Humans Chromosomes What are the dark lines? 15

16 How important are chromosomes? Humans need all 46 chromosomes for normal development and function. Humans that are missing even one of the 46 chromosomes do not survive. Humans with more than two copies of a chromosome will not develop properly. Downs Syndrome is caused by an extra chromosome. 16

17 Compared to a real human chromosome, what are the limitations of the model? 17

18 Active Learning Write a riddle about one or two of the following terms: DNA, Genes, traits, chromosomes Write a Haiku about the importance of DNA (5-7-5 syllable pattern) 18

19 One set of chromosomes come from the mother and one set of chromosomes come from the father. The entire chain of shapes represent a chromosome - the individual shapes represent genes. The offspring inherits a pair of genes for each trait. When the genes are identical the offspring is called homozgous or purebred for that trait. When the genes are different, the offspring is called heterozygous or hybrid for that trait. Which gene pairs would make a homozygous offspring? (similarities) Which genes pairs would make a heterozygous? (Differences) 19

20 What are the limitations of our model compared to the scientific model on the right? Pair of genes 20

21 Gene for the trait Brown Eye color Gene for Brown Eye color Gene for Tall Height Gene for Tall Height Gene for Brown Hair color What is the mother s phenotype? Gene for Black Hair color Gene for the Shape of your Fingers Gene for the Shape of your Fingers Gene for Attached Earlobes Gene for Unattached Earlobes Phenotype-The physical characteristics/traits you can observe 21

22 Gene for the trait Brown Eye color Gene for Brown Eye color Gene for Tall Height Gene for Tall Height Gene for Brown Hair color Gene for Black Hair color Gene for the Shape of your Fingers Gene for the Shape of your Fingers Gene for Attached Earlobes Gene for Unattached Earlobes Genotype- The two genes that determine an organism's (offsprings) traits 22

23 Do Your Earlobes Hang Down? Learning Experience 2 1. After each trait is described mark a check under Yes or No in the Me column. 2. Collect data for each trait from the entire class. 3. Graph class data for each trait 23

24 Vocabulary Genotype the two genes that determine an organisms traits The genotype of a tall plant that has two genes alleles for tallness is TT Phenotype The physical characteristics of an organism you can observe. The phenotype of a tall plant is tall, regardless of the genes it contains 24

25 Transparent Traits Learning Experience 3 This activity models the random selection of a egg and a sperm in producing the genotype and phenotype of offspring. Please model using the overhead prior to the students conducting the lab. 25

26 Transparent Traits Formative Assessment Questions What do the colored squares represent? Why are the genes always removed in pairs? Where does the organism acquire its genes? If two colored squares are drawn, what was the organism s genotype? Is the trait dominant or recessive in this organism? What was the phenotype of this organisms? If two clear squares were drawn, what was the organism s genotype? If one clear and one colored square are drawn, what was the organism s genotype? Is the trait dominant or recessive in this organism? What was the phenotype of this organism? 26

27 Based on what you know about genetics thus far What are the limitations of the model? Each square represents one gene on one of the 23 chromosomes. Each gene is not selected individually they come in packets called? Human traits like eye color and hair color have multiple alleles they are the results of one gene from the mother and one gene from the dad. 27

28 Putting it All Together Homozygous Heterozygous Phenotype Genotype Dominant Recessive Dragon Genetics 28

29 Processing Using the dragon simulation as an example: What was changed in order to change the appearance of the dragon? Therefore, a change in the results in a change in the. Do you have to change the genes on both chromosomes to change the phenotype? Explain How is the phenotype affected by the genes being homozygous or heterozygous? How many different dragon combinations are possible? 29

30 Mastering Terms Homozygous Heterozygous Phenotype Genotype Dominant Recessive Term How can students demonstrate their understanding of these terms? Def. in own words Picture Example 30

31 Gregor Mendel Father of Genetics The Story of Gregor Mendel Mendel s Experiments: genetics/mendel.html Dominant and Recessive Traits genetics/dom_rec.htm l Activities: Interactive Guide to Mendel s Experiments (7 th ) Some Traits are Dominant- Animation/Activity dnaftb/4/concept/ 31

32 Write a radio commerical to advertise a visit to your school by Gregor Mendel. The advertisement should include: Why his research impacts what we know about genetics. Something that would spark the interest of the students to come to the presentation. 32

33 Genes in Action 33

34 The Punnet Square Use To Teach the Punnet Square: Mendel s Punnet Square: Activity: Living Punnet Square Example: 2. Two heterozygous for fingers Martians marry and have four kids. How many of their kids will have three fingers? How many will have two? Build the living Punnett square and when you re ready, call for the teacher. Punnet Squares and Dominant and Reccessive Genes 34

35 Genetic Crosses and Pedigrees Biologica: Web Lab, Mendel s Peas bs_mendels_peas.htm 35

36 Vocabulary Natural occurrence is Natural Selection Natural selection is the process by which certain heritable traits those that make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generations.

37 Reflect back on Cody and Codette s offspring. Which organisms would live to survive and pass on their genes in this environment? Which would not? Which organisms would be naturally selected to survive and which would not?

38 Cody and Codette Reflect back on Cody and Codette s offspring. After the entire class has completed their organism and placed them into an environment. Which organisms would live to survive and pass on their genes? Which would not?

39 Vocabulary Selective breeding: The method of breeding certain organisms together that have desirable traits. The process of manipulating the phenotype of the offspring.

40 Example of Selective Breeding Hardy can thrive in hot climates, the beef is not as good Tender, tasty beef Does not thrive in hot climates Heat resistant cattle with tender beef

41 Selective Breeding - Ancestry Bull Mastiff American Bulldog Staffordshire Bull Terrier American Pit Bull Terrier

42 Try it Out! Dog Breeding Selective Breeding

43 Ethics Think Time Discuss some possible positive outcomes of : Selective Breeding Cloning Genetic Engineering Discuss some possible negative outcomes of: Selective Breeding Cloning Genetic Engineering

44 Putting It All Together Sponge Bob Make an Acrostic from the word Heredity Create analogies using the following pairs of words: Homozygous/heterozygous Phenotype/genotype Dominant/recessive 44

45 Sexual Reproduction in Action Activity: Gene (Wo)Man 45