Fern Life Cycle
Alternation of generationsDefined: Plants alternate between a diploid organism
and a haploid organism
Alternation of generationsZygote created from egg & sperm (fertilization begins sporophyte phase)
Alternation of generationsZygote 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
Male gametophyte creates sperm
Spore grows into male or female gametophyte
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• 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 (pl.)
See appendix B in your text book
Fiddlehead
Fern Life Cycle
Fiddlehead uncurlingFrond
• 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
See appendix B in your text book
Fern Life Cycle
Sporangia act like catapults
• 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
Sporangia act like catapults
• 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
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
• Fertilization restarts sporophyte stageSee appendix B in your text book
AdultSporophyte (diploid)
.
..
.
1) Sporophyte creates haploid spores by meiosis. Spores are released from the sori on the back-side of fronds
ground
ground
2) Haploid spores land in the soil
ground
3) From the haploid spores, the prothallus (gametophyte) grows
Let’s zoom in
. .
4) Sperm swim through water from the antheridia (XY) to the archegonia (XX)
Let’s zoom back out
zygote
ground
5) Diploid sporophyte grows from the prothallus
-- prothallus eventually dies
sporophyte
6) Fiddlehead uncurls…fronds open up
ground
7) Cycle repeats…
-- Haploid spores created and released
.
.
..
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.
2
3
45
6
Plant Life Cycle ComparisonsPlant type Gametophyte Sporophyte Dominant Phase?
Moss More familiar, carpet-like plant that produces specialized gametesXX - ArchegoniumXY – 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
Review1) 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?