Diagram a cell with four chromosomes going through meiosis. Mitosis vs. Meiosis Mitosis • One division • 2 diploid daughter cells • Identical to parent cell http://highered.mcgrawhill.com/sites/0072495855/stu dent_view0/chapter28/animati on__how_meiosis_works.html Mitosis • Two divisions • 4 haploid daughter cells • Genetically different from parent cell Nucleus chromosomes • Get one small, one medium and one large of each color chromosome. • What do the colors represent? • The Beads? • Pair up chromatids with same size and color • • • • Pair up chromatids with same size and color What does this represent? What stage? Haploid or diploid? • Match homologous chromosomes • Match homologous chromosomes • What are homologous chromosomes. Carry the same traits Each homologous pair has one from each parent Demonstrate crossing over during prophase. Demonstrate crossing over during prophase. • Demonstrate metaphase Demonstrate metaphase • Demonstrate the first division • Anaphase I and Telophase I • Demonstrate the first division • Anaphase I and Telophase I • Move your cells through the second division. • Move your cells through the second division. • How many daughter cells do you have? • Are the daughter cells haploid or diploid? • Are the cells genetically Identical or different from the parent cell? 4 Haploid Daughter Cells Parent Cell Daughter Cells Possible Combinations of chromosomes n 2 What does n represent? What was our haploid number of chromosomes? What is the possible number of combinations? 8 In people possible 8388608 combinations. • http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter28/animation__random_orientation_ of_chromosomes_during_meiosis.html Sexual Reproduction • • • • Combines the genetic material of two organisms. Introduces new gene combinations in a population. Leads to genetic Variability in the population. Gametes produced in meiosis fuse to form a zygote. – Gamete-reproductive cell that contains the haploid set of chromosomes…..sperm and egg – Zygote- Cell formed from fusion of gametes that contains the diploid set of chromosomes. Sexual Reproduction Methods • External Fertilization: the eggs are fertilized outside of the body • Internal Fertilization: the eggs are fertilized within the female reproductive tract • Conjugation: cells exchange genetic material – Prokaryotes Asexual Reproduction • • • • • Offspring arise from a single parent. Offspring genetically identical to parent. More likely to inherit mutations. Leads to less diversity. Mitosis Asexual Reproduction Methods • Budding – offspring grows out of the body of the parent. • Spores – a reproductive cell capable of developing into a new individual without fusion with another reproductive cell. • Fission – separation of the body into two new bodies Quiz • Compare and contrast sexual and asexual reproduction.
© Copyright 2020