 1. Using the concept of chromosome sets, explain briefly how mitosis conserves chromosome number whereas meiosis reduces the number of chromosome by half.  2. How are the chromosomes in a cell at metaphase of mitosis similar to and different from the chromosomes in a cell at metaphase of meiosis II? 1/20 Daily Catalyst Pg. 71 Genetic Variation

 1. Using the concept of chromosome sets, explain briefly how mitosis conserves chromosome number whereas meiosis reduces the number of chromosome by half.  In mitosis, replication is followed by ONE division of the cell so the number of chromosome sets in the daughter sets equals the parent cells ( 46  96  46)  In meiosis, replication is followed by TWO divisions of the cell so the number of chromosomes is haploid.  2. How are the chromosomes in a cell at metaphase of mitosis similar to and different from the chromosomes in a cell at metaphase of meiosis II?  The chromosomes are both composed of sister chromatids and lay on the metaphase plate. In mitosis, the chromatids are identical and in meiosis they are different because of crossing over. 1/20 Daily Catalyst Pg. 71 Genetic Variation

 Quiz #16 make up TODAY, no exceptions  Please track your data on the poster AND in your notebook  Quiz #17 this FRIDAY  Genetics test February 2 nd or 3 rd  Study guide due test day  Notebook check test day  Tutoring after/before school, during lunch and 4 th period  Study paper due Friday, 1/30 1/20 Class Business Pg. 71 Genetic Variation

 Daily Catalyst  Class Business  Agenda  Essay prompt  Genetic Variation notes  Homework: Essay prompt 1/20 Agenda Pg. 71 Genetic Variation

 1. The cell cycle is fundamental to the reproduction of eukaryotic cells.  (a) Describe the phases of the cell cycle.  (b) Explain the role of THREE of the following in mitosis or cytokinesis.  Kinetochores  Microtubules  Motor proteins  Actin filaments  (c) Describe how the cell cycle is regulated and discuss ONE consequence of abnormal regulation. Essay Prompt #1

 Properly label the phases of _____________ 1/21 Daily Catalyst Pg. 71 Genetic Variation

 Please track your data on the poster AND in your notebook  Quiz #17 this FRIDAY  Genetics test February 2 nd or 3 rd  Study guide due test day  Notebook check test day  Tutoring after/before school, during lunch and 4 th period  Study paper due Friday, 1/30 1/21 Class Business Pg. 71 Genetic Variation

 Daily Catalyst  Class Business  Agenda  Genetic Variation notes  Discuss homework  Homework: 1/21 Agenda Pg. 71 Genetic Variation

 Read the introduction to 13.4 together as a group. After you have read the introduction, each member of your team will take a topic. Read about the topic and outline BRIEF notes. Share these notes with your tablemates.  Independent Assortment of Chromosomes  Crossing Over  Random Fertilization  Evolutionary significance  Time: until 12:30 Pg. 71 Genetic Variation

 1. Sexual reproduction requires that half of the chromosomes in a zygote come from one parent and the other half from the second parent.  (a) Describe the process by which a germ cell’s complement of chromosomes is halved in the formation of the gametes. (6 points maximum)  (b) Choose one organism or group of organism the reproduce asexually. Describe the mode of asexual reproduction in that organism and explain the advantages to the organism of asexual reproduction. (3 points maximum)  (c) Choose one organism or group of organisms that reproduce sexually. Describe the mode of sexual reproduction in that organism and explain the advantages to the organism of sexual reproduction. (3 points maximum) Homework Essay Prompt

 13.4 Genetic Variation produced in sexual life cycles contributes to evolution  What are THREE mechanisms that create genetic variation?  Crossing over  Independent assortment of chromosomes  Random Fertilization Class Wrap-up

 Crossing Over  Segments of chromatids cross over, resulting in new genetic combinations   these new combinations will line up randomly during metaphase

 Independent Assortment of chromosomes  Homologous chromosomes line up RANDOMLY during metaphase  The possible combinations in 2 n  n is haploid number

 Random Fertilization  Random egg and sperm from parents will randomly meet and combine  A zygote can produce 64 trillion different combinations of chromosomes

 Relate Darwin’s Theory of Evolution to genetic variation from today’s lesson.  Genetic variation= adaptations of the MOST FIT organisms  Sexual reproduction and mutation create this variation Crossing over, random fertilization, and indie assortment of chromosome

 Complete concept check 13.4 on page 71  Test your Knowledge  Answer 1-6 and 9 on page 71  You may work with a partner Pg. 71 Genetic Variation