5: Ferns & Gymnosperms Flashcards
What kind of plants are ferns?
Seedless vascular
T or F: Ferns produce seeds
FALSE. They produce spores
What is the phylum/division of ferns?
Pterophyta
Do ferns experience alternation of generations?
Yes
Which generation is dominant in ferns?
the SPOROPHYTE (diploid) generation is dominant and those are the fern fronds that we see
Which generation is smaller in the fern life cycle?
the GAMETOPHYTE (haploid) generation is much smaller
What occurs in the sporophyte generation? is this stage diploid or haploid?
DIPLOID.
The sporangia in the sori undergo meiosis
What occurs in the gametophyte generation? is this stage haploid or diploid?
HAPLOID.
sexual reproduction occurs
Is the fern frond haploid or diploid?
Diploid
Describe the fern frond - which generation is it?
It is the “leaf” part that we use to recognize ferns - looks similar to a compound leaf.
it is the sporophyte generation (diploid)
What are the 7 structures of a fern frond?
- Frond Rachis
- Stipe (petiole)
- Pinna
- Pinnules
- Rhizome
- Adventitious roots
- Fiddleheads
What is the frond rachis?
found on fern fronds.
Similar to a rachis in a compound leaf, it is the stem that grows from the stipe (petiole) and where the pinna attach
What is the stipe?
The stipe is the name for the petiole of a fern frond.
It is where the frond attaches to the rhizome.
What are pinna?
The leaflets of the fern frond
What are pinnules?
The subunits of the pinna on a fern frond
What is the rhizome of a fern?
the underground stem that fern fronds are attached to (via the stipe)
What are adventitious roots?
Roots that grow off the main stem
What are fiddleheads?
Uncurled fern fronds
Describe fern sori. What is their function?
Structure: the circular structures made up of clustered sporangia on the underside of the pinna. Each cluster is called a sorus. Multiple clusters are called sori.
Function: they are the site of meiosis –> they produce spores
Describe sporangia. Are they haploid or diploid?
Structure: Small groups of sacs or vessels that are filled with spore producing cells. A cluster of sporangia on the underside of a fern frond is called a sorus.
Function: the cells inside the sporangium undergo meiosis to produce spores
DIPLOID
Describe indusium
Some ferns have well defined shields that protect spores
How do ferns reproduce?
they rely on water for reproduction
Describe spores - what are their ploidy?
A reproductive cell capable of developing directly into a gametophyte
Haploid
How do fern spores germinate?
Spores are released onto the ground to germinate and form the gametophyte stage
Describe the fern gametophyte
A heart-shaped, HAPLOID, structure that produces an archegonia that will contain eggs and the antheridia that produce sperm fastened to the ground by rhizoids
Describe rhizoids
Root-like structure
What happens to the fern gametophyte stage after fertilization?
The gametophyte generation will grow new sporophytes
Describe gymnosperms and provide an example
A type of seed-producing plant that evolved after seedless vascular plants, but before angiosperms.
Gymnosperm = naked seed
they produce seeds without a fruit coating
ex. conifers
What is the main difference between angiosperms and gymnosperms?
the method of pollination and the fruit
What are the four phylums of gymnosperms?
- Coniferophyta (Pinophyta)
- Ginkgophyta (Ginkgo)
- Cycadophyta (Cycads)
- Gnetophyta (Gnetophytes)
What is the method of pollination for gymnosperms?
Wind pollination
in gymnosperms, where are the female gametophytes located?
Inside the ovulate cone
In gymnosperms, where are the male gametophytes found?
Inside the pollen cone
Which is the dominant generation in the gymnosperm life cycle?
Sporophytes (diploid) are the visible trees we see, the gametophyte generation is microscopic and inside cones.
Describe the male cones of a conifer
Called pollen cones.
Structure: papery, covered in scales called microsporophylls
- smaller than the female cones
Describe the microsporophylls of conifer cones
Microsporophylls are the scales on the outside of the male pollen cone. They contain MICROSPORANGIA which contain MICROSPOROCYTES (diploid)
What occurs to the microsporocytes inside the pollen cone?
The microsporocytes (2n) will undergo meiosis to produce 4 MICROSPORES (1n) that will become individual pollen grains
Describe a pollen grain
a structure formed from the microspores that will develop into a male gametophyte
structure: has air sacs that will swell to aid in wind dispersal
- produces pollen tube and generative cells
Describe pollen cone
the male strobilus that produces microsporangia
Describe microsporangium of gymnosperms
where the pollen is produced
Describe the female cones of conifers
Called ovulate cones
- woody, tough cones, that are larger than male cones
- contains ovules that will each mature into a seed and be shed from the cone when they mature (with seed wings to aid in dispersal)
What occurs to the ovules?
The ovules will undergo cell divisions to produce MEGASPOROCYTES
What occurs to the megasporocytes?
undergo meiosis to produce 4 MEGASPORES (1n) = 3 will become degenerate, leaving one survivor for the pollen grain to attach to
What happens to the megaspore?
3 of the 4 will become degenerate.
The surviving megaspore will undergo meiosis to become a MEGAGAMETOPHYTE (1n)
What happens to the megagametophyte?
Undergo more meiosis to produce multiple eggs (up to 6)
T or F: multiple pollen grains can land on the ovule surface and all the eggs can fertilize, but only one embryo will survive?
TRUE
After producing eggs, what is the purpose of the megagametophyte? is the megagametophyte diploid or haploid?
it will provide nutrients for the surviving embryo.
HAPLOID
What is the redundant system?
the production and fertilization of multiple eggs to ensure that one embryo will survive
When does fertilization occur in conifers?
in the second year
What does the seed coat form from?
the integuments surrounding the ovule
How does germination occur in a conifer?
The wing will tear away from the ovulate cone scale and the seed will fall to the ground and germinate (when conditions are right) to produce a seedling sporophyte
T or F: ovules contain the eggs that are fertilized by pollen to produce a zygote that will become an embryo
TRUE
What are the 8 structures of a conifer seed?
- shoot apical meristem
- Procambium
- root apical meristem
- root cap
- embryo (2n)
- pith
- megagametophyte (covering the embryo) (1n)
- seed coat/integuments (2n)
- outer seed wing
T or F: the conifer embryo is haploid?
FALSE. it is diploid
T or F: the conifer seed megagametophyte is diploid?
False. it is haploid
T or F: the conifer seed coat/integuments are diploid?
TRUE
What is the purpose of the root cap?
to protect the embryonic root while it pushes out of the seed coat
What are the finger-like structures in the embryo?
the cotyledons (embryonic seed leaves)
T or F: conifer seedlings can have multiple cotyledons
True
Define hypocotyl
The portion of the stem that is below the cotyledon
Define epicotyl
the portion of the stem that is above the cotyledons
What are 3 conifer families? Give a species example of each
- Cupressaceae - cedars
- ex. red cedar - Pinaceae - Pines
- ex. Scots Pine - Taxaceae - Yews
- ex.
What are the 3 kinds of conifer foliage? Which families have which kind?
- Scale-like: snake-like scales embedded in foliage and smooth to touch
ex. Cedars - Awl-like: sharp tips with a concave and pointed end, not smooth to the touch and fingers will catch if you touch against the grain
- ex. Blue Star Juniper - Needle-like: long, skinny needles
- ex. Pines - Needle-like with petiole: broad flat needle with a petiole at base
- ex. Yews
