1. Meiosis Chapter 9 1. ________ Male reaches under his mantle with tentacle, removes packet of sperm, and insert it into female’s egg chamber A. Reproduction 2. _______ Larva can become adult of either sex –Depends on conditions 3. __________ Females in summer (from unfertilized eggs) Males in autumn

2. _______Reproduction Single _________ produces offspring All offspring are _________________ to one another and to parent ________ Reproduction Two parents contribute to offspring All offspring are ________________

3. ____________ Chromosomes Carry Different ___________ Cell has two of each___________________ One from mother, other from father Paternal and maternal chromosomes carry different ________ Terminology Offspring inherit new combinations of alleles This variation in traits is the basis for __________________change

4. Gamete Formation Gametes are ___ cells (_______,______) Arise from _____cells testes ovaries anther ovary Chromosome Number Germ cells are ______ (2n) Gametes are ________(n) Meiosis _________ chromosome number

5. DNA replication PROPHASE I METAPHASE I ANAPHASE I TELOPHASE I __________ PROPHASE II METAPHASE II ANAPHASE II TELOPHASE II __________ No DNA _________ 4 ______ nuclei Meiosis: ____ nuclear divisions, ____ DNA replication

6. Each homologue in the cell pairs with its partner, then the partners separate Meiosis I and II very similar to mitosis 1.DNA exchange occurs in ________ - Homologues swap _________ PROPHASE IMETAPHASE IANAPHASE ITELOPHASE I 2. No ________________ prior to Meiosis II

7. Crossing Over _______________ chromosomes exchange segments Creates new allele ______________ in offspring These exchange points are called ___________

8. Meiosis II - Stages Prophase IIMetaphase IIAnaphase IITelophase II

9. Comparison of mitosis and meiosis End result ____ _____ Daughter cells __________________ Chiasmata? MeiosisMitosis _____ _______ are the physical manifestation of crossing over, a form of genetic rearrangement. # of divisions _______ Purpose_______________

10. Fig. 9.10a p. 148 PROPHASEMETAPHASEANAPHASETELOPHASE MITOSIS PROPHASE IIMETAPHASE IIANAPHASE IITELOPHASE II MEIOSIS II

11. Possible Chromosome Combinations or 123 number of possible combinations of chromosomes in a gamete is: ____ (n is number of chromosome types)

12. Factors Contributing to Variation Among Offspring 1. Crossing over during __________ 2. Random _________ of chromosomes at metaphase I 3. Random combination of ______at fertilization

13. Plant Life Cycle multicelled sporophyte multicelled gametophytes zygote gametes spores meiosisfertilization mitosis Diploid Haploid

14. Animal Life Cycle multicelled body gametes zygote meiosisfertilization mitosis Diploid Haploid

15. Spermatogenesis Growth Mitosis I, Cytoplasmic division Meiosis II, Cytoplasmic division spermatids (haploid) secondary spermatocytes (haploid) primary spermatocyte (diploid) spermato- gonium (diploid male reproductive cell)

16. Oogenesis Growth Mitosis I, Cytoplasmic division Meiosis II, Cytoplasmic division ovum (haploid) primary oocyte (diploid) oogonium (diploid reproductive cell) secondary oocyte haploid) first polar body haploid) three polar bodies haploid)

17. Fertilization Male and female ______ unite and nuclei _____ Fusion of two haploid nuclei produces _______ nucleus in the zygote Which two gametes unite is _______ –Adds to variation among offspring