Fern Life Cycle Alternation of generations Defined Plants

Fern Life Cycle

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

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

Alternation of generations Zygote divides by mitosis to create adult sporophyte

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

Alternation of generations Haploid spores released into air

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

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

Alternation of generations Cycle repeats

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

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

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

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

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

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

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

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 • Gametophyte phase – Spore grows into prothallus See appendix B in your text book

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 • 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

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 • 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 • Fertilization restarts sporophyte stage

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

2) Haploid spores land in the soil ground

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

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

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

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

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

Plant Life Cycle Comparisons Plant type Gametophyte Sporophyte Dominant Phase? Moss More familiar, carpetlike 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 SPOROPHYTE

Review 1) What is the major difference between moss and ferns? 2) What are the leaves of ferns called? 3) What is needed for moss and ferns to reproduce? 4) Which stage is the main stage of ferns: sporophyte or gametophyte? 5) What stage is created when sperm and egg fuse: sporophyte or gametophyte? 6) Name the gametophyte of ferns. 7) Which process begins the gametophyte stage? 8) What structure on the fern creates spores?