1. Sexual reproduction Life cycles and the alternation of generations

2. Sexual reproduction in animals  Animals have diploid body cells and haploid gametes  The diploid body cells are made by mitosis  The haploid gametes are made by meiosis  At fertilization the haploid sperm and egg fuse to produce the diploid zygote.  This then divides many times by mitosis to grow into a new individual

4. Sexual reproduction in plants  In flowering plants there are two distinctive phases of life cycle:  the diploid sporophyte and the haploid gametophyte

5. Sexual reproduction in plants  The diploid sporophyte produces haploid spores by meiosis.  The spores develop into the haploid gametophyte, which then produces haploid gametes by mitosis

7. Sexual reproduction in plants  In plants such as mosses and ferns, the main plant is the diploid sporophyte.  It produces (genetically different) haploid spores by meiosis

8. Sexual reproduction in plants  The spore grows into the gametophyte, which produces (genetically identical) gametes by mitosis.

9. Sexual reproduction in plants  In flowering plants the water dependent gametophyte stage in the life cycle is much reduced.  The dominant stage in the life cycle is the sporophyte

10. Essential terms to know Spore  A haploid cell that can be dispersed  It is the product of meiosis of a diploid cell

11. Essential terms to know Gamete  A haploid cell, produced by mitosis of haploid cells.  It can fuse with another gamete to produce a diploid zygote

12. Essential terms to know Sporophyte  A multicellular plant that is diploid and produces spores.

13. Essential terms to know Gametophyte  A multicellular plant that is haploid and produces gametes

14. Essential terms to know NB These terms have been defined in terms of plant kingdoms. A fungal spore is very different!!!!

15. Essential terms to know Alternation of generations  Terrestrial plants that have a life cycle with a multicellular gametophyte and multicellular sporophyte generation which alternates are said to have a life cycle that shows “alternation of generations”