Ferns

Alternation of generationsZygote created from egg & sperm

Alternation of generationsZygote divides by mitosis to create adult sporophyte

Alternation of generations

Haploid spores created by meiosis

Alternation of generations

Haploid spores released into air

Alternation of generations

Female gametophyte creates eggs

Male gametophyte creates sperm

Spore grows into male or female gametophyte

Alternation of generations

Sperm & egg create diploid zygote

Alternation of generationsCycle repeats

Group 2: Seedless, Vascular Plants• Evolutionary Advancement:

Vascular system – allows nutrient transport to

greater heights

• Moist environments– Swimming sperm

• Structure:– Rhizoids = primitive roots– Leaves = fronds

• Categories:– Club mosses– Horsetails– Ferns water

glucose

• Sporophyte phase– Dominant stage; Diploid

See appendix B in your text book

Fern Life Cycle

• Sporophyte phase– Dominant stage; Diploid– Fronds house sori

See appendix B in your text book

Fiddlehead

Fern Life Cycle

Fiddlehead uncurling

Frond

• Sporophyte phase– Dominant stage; Diploid– Fronds house sori

• Sorus = Cluster of sporangia

See appendix B in your text book

Fern Life Cycle

• Sporophyte phase– Dominant stage; Diploid– Fronds house sori

• Sorus = 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

• Sorus = Cluster of sporangia• Sporangia make spores• Spores created by meiosis• Spores released into air

See appendix B in your text book

Fern Life Cycle

Sporangia act like catapults

• Sporophyte phase– Dominant stage; Diploid– Fronds house sori

• Sorus = Cluster of sporangia• Sporangia make spores• Spores created by meiosis• Spores released into air

See appendix B in your text book

Fern Life Cycle

Sporangia act like catapults

• Sporophyte phase– Dominant stage; Diploid– Fronds house sori

• Sorus = 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

• Sorus = 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

Fern Life Cycle• Sporophyte phase

– Dominant stage; Diploid– Fronds house sori

• Sorus = 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

• Zygote restarts sporophyteSee appendix B in your text book

AdultSporophyte (diploid)

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..

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1) Spores are released from the sori on the back-side of fronds

ground

ground

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2) Haploid spores land in the soil

ground

3) From the haploid spores, the prothallus (gametophyte) grows

Let’s zoom in

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4) Sperm swim through water from the antheridium to the archegonia

Let’s zoom back out

zygote

ground

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

6) Fiddlehead uncurls into a fronds

ground

7) Cycle repeats -- Sporangia creates spores to be released

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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.