1. **these specialized sex cells only have 23 chromosomes**
Sexual Reproduction – each organism has specialized sex cells (and egg or a sperm)
**these specialized sex cells only have 23 chromosomes**

2. Diploid: cells with pairs of chromosomes (46) Haploid: cells with single chromosomes (23)

3. Sexual Reproduction
Fertilization is when a sperm and egg cell meet.

4. Sexual Reproduction Half of genes come from each parent
Produces genetically different offspring

5. Sexual Reproduction Advantages Requires 2 individuals
Disadvantages
Requires 2 individuals
Takes more energy
Takes a long time
Genetic diversity
Organisms can adapt to change

6. Sexual Reproduction
During sexual reproduction each parent produces sex cells which contain half the number of chromosomes as the parent’s body cell

7. Homologous chromosomes – chromosomes that carry the same sets of genes (forms the X shape of a chromosome)
1 from mother, 1 from father
Each cell gets one or the other
Homologous Chromosomes

9. Meiosis
Haploid
Diploid
Diploid
Diploid

10. Meiosis: a process in which one diploid cell divides to make 4 haploid sex cells

11. Description for each stage on the back
Page 416
2 colors for chromosomes
1 maker for cell membrane
1 color for nucleus
1 color for cytoplasm
Labels:
Chromosomes
Nucleus
Scheduled
Description for each stage on the back

12. Steps of Meiosis I Prophase I
Pairs of homologous chromosomes allow for crossing over – genetic material shuffling
Metaphase I
Paired chromosomes line up at equator
Anaphase I
Homologous chromosome pairs separate
Telophase I
Nucleus reforms, chromatid pairs still joined

13. Steps of Meiosis I Metaphase I Paired chromosomes line up at equator
Anaphase I
Homologous chromosome pairs separate
Telophase I
Nucleus reforms, chromatid pairs still joined

14. Steps of Meiosis I Anaphase I Homologous chromosome pairs separate
Telophase I
Nucleus reforms, chromatid pairs still joined

15. Nucleus reforms, chromatid pairs still joined
Steps of Meiosis I
Telophase I
Nucleus reforms, chromatid pairs still joined

16. Steps of Meiosis II (basically mitosis)
Anaphase II
Chromatids pull apart
Telophase II
4 new cells have formed; each new cell has half number of chromos. as original
Prophase II
Each cell has one member of each chromosome pair; chromos. not copied between divisions

17. Chromos. line up at equator of cell
Steps of Meiosis II (basically mitosis)
Anaphase II
Chromatids pull apart
Telophase II
4 new cells have formed; each new cell has half number of chromos. as original
Metaphase II
Chromos. line up at equator of cell

18. Steps of Meiosis II (basically mitosis)
Telophase II
4 new cells have formed; each new cell has half number of chromos. as original
Anaphase II
Chromatids pull apart

19. Steps of Meiosis II (basically mitosis)
Telophase II
4 new cells have formed; each new cell has half number of chromos. as original