1. Fern Life Cycle

2. Alternation of generations
Defined: Plants alternate between a diploid organism and a haploid organism

3. Alternation of generations
Zygote created from egg & sperm (fertilization begins sporophyte phase)

4. Alternation of generations
Zygote divides by mitosis to create adult sporophyte

5. Alternation of generations
Haploid spores created by meiosis (beginning of gametophyte stage)

6. Alternation of generations
Haploid spores released into air

7. Alternation of generations
Spore grows into male or female gametophyte
Female gametophyte creates eggs
Male gametophyte creates sperm

8. Alternation of generations
Sperm & egg create diploid zygote (sporophyte stage restarts)

9. Alternation of generations
Cycle repeats

10. Group 2: Seedless, Vascular Plants
Evolutionary Advancement: Vascular system
allows nutrient transport to greater heights
Live in moist environments
Swimming sperm
Structure:
Rhizoids = primitive roots
Leaves = fronds
Categories:
Club mosses
Horsetails
Ferns
glucose
water

11. Fern Life Cycle Sporophyte phase Dominant stage; Diploid
See appendix B in your text book

12. Fern Life Cycle Sporophyte phase Dominant stage; Diploid
Fronds house sori (pl.)
Fiddlehead uncurling
Fiddlehead
Frond
See appendix B in your text book

13. Fern Life Cycle Sporophyte phase Dominant stage; Diploid
Fronds house sori (pl.)
Sorus (sing.) = Cluster of sporangia
See appendix B in your text book

14. Fern Life Cycle Sporophyte phase Dominant stage; Diploid
Fronds house sori (pl.)
Sorus (sing.) = Cluster of sporangia
Sporangia make spores
Spores created by meiosis
Spores released into air
See appendix B in your text book

15. Fern Life Cycle Sporophyte phase Dominant stage; Diploid
Fronds house sori (pl.)
Sorus (sing.) = Cluster of sporangia
Sporangia make spores
Spores created by meiosis
Spores released into air
Sporangia act like catapults
See appendix B in your text book

16. Fern Life Cycle Sporophyte phase Dominant stage; Diploid
Fronds house sori (pl.)
Sorus (sing.) = Cluster of sporangia
Sporangia make spores
Spores created by meiosis
Spores released into air
Sporangia act like catapults
See appendix B in your text book

17. Fern Life Cycle Sporophyte phase Gametophyte phase
Dominant stage; Diploid
Fronds house sori (pl.)
Sorus (sing.) = Cluster of sporangia
Sporangia make spores
Spores created by meiosis
Spores released into air
Gametophyte phase
Spore grows into prothallus
See appendix B in your text book

18. Fern Life Cycle Sporophyte phase Gametophyte phase
Dominant stage; Diploid
Fronds house sori (pl.)
Sorus (sing.) = Cluster of sporangia
Sporangia make spores
Spores created by meiosis
Spores released into air
Gametophyte phase
Spore grows into prothallus
Prothallus contains:
Archegonium: produces female egg
Antheridium: produces male sperm
Sperm swims to fertilize the egg
See appendix B in your text book

19. Fern Life Cycle Sporophyte phase Gametophyte phase
Dominant stage; Diploid
Fronds house sori (pl.)
Sorus (sing.) = Cluster of sporangia
Sporangia make spores
Spores created by meiosis
Spores released into air
Gametophyte phase
Spore grows into prothallus
Prothallus contains:
Archegonium: produces female egg
Antheridium: produces male sperm
Sperm swims to fertilize the egg
Fertilization restarts sporophyte stage
See appendix B in your text book

20. Sporophyte creates haploid spores by meiosis
Sporophyte creates haploid spores by meiosis. Spores are released from the sori on the back-side of fronds . . . .
Adult
Sporophyte (diploid)
ground

21. 2) Haploid spores land in the soil. .
ground

22. . . 3) From the haploid spores, the prothallus (gametophyte) grows
Let’s zoom in
ground . .

23. 4) Sperm swim through water from the antheridia (XY) to the archegonia (XX)
Let’s zoom back out
zygote

24. 5) Diploid sporophyte grows from the prothallus
-- prothallus eventually dies
sporophyte
ground

25. . . . . 6) Fiddlehead uncurls…fronds open up 7) Cycle repeats…
-- Haploid spores created and released . . . .
ground

26. Place the steps of the fern life cycle in order, from the step started for you:
__ 1 ___ Spores land on soil. _______ Sporophyte releases spores. _______ Through water, sperm swim from antheridium to archegonium on prothallus. _______ Prothallus grows. _______ Fertilization occurs. _______ Diploid sporophyte begins to grow. 6 3 2 4 5

27. Plant Life Cycle Comparisons
Plant type
Gametophyte
Sporophyte
Dominant Phase?
Moss
More familiar, carpet-like plant that produces specialized gametes
XX - Archegonium
XY – Antheridium
Stalk with cup at tip, which is where spores are produced.
GAMETOPHYTE
Fern
Haploid plant body (prothallus) is size of a finger nail, produces both male and female parts
More familiar, leafy plant with clusters of spore producing sacs (sori)
SPOROPHYTE
Conifer
Pollen grains are male gametophytes sperm, female gameotphytes are microscopic eggs
More familiar- like pine trees, produces male and female cones that produce spores

28. Review What is the major difference between moss and ferns?
What are the leaves of ferns called?
What is needed for moss and ferns to reproduce?
Which stage is the main stage of ferns: sporophyte or gametophyte?
What stage is created when sperm and egg fuse: sporophyte or gametophyte?
Name the gametophyte of ferns.
Which process begins the gametophyte stage?
What structure on the fern creates spores?