Transcript Gymnosperms and Angiosperms

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Why is moss so
short?
How does moss
utilize water?
Where are you likely
to find moss? Why is
this the case?
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How is the fern
more
advanced than
the moss?
In terms of
height, how
does the fern
compare to
moss and the
pine tree?
Gymnosperms and Angiosperms
The Seed Plants
Gymnosperms
• Seeded land plants
• Contain an ovule & seed
• Pollinate for reproduction – male nonflagellated pollen grains (wind dispersal)
• Contain a “naked seed” NOT contained
within an ovary.
Gymnosperm Life Cycle
• The diploid (sporophyte) stage produces cones.
• Male and female cones (the reproductive structures)
produce two different kinds of haploid spores:
– microspores (male) and
– megaspores (female).
• These spores give rise to gametophytes of the same
sex, which in turn produce the gametes.
• Fertilization occurs when pollen grains are carried to
the open end of an ovule.
4 Gymnosperm Divisions
1. Pinophyta or Coniferophyta (pines, firs,
spruces)
2. Cycadophyta (cycads)
3. Ginkophyta (ginko)
4. Gnetophyta (a mix of traits found in the
three previous divisions AND they contain
some angiosperm traits, the “dumping”
ground)
Pinophyta or Coniferophyta
• woody plants,
usually trees
• wood compact
• Many have woody
cones
Pinophyta/Coniferophyta
• All other pinophytes are more common
• for example: Pines, firs, spruce, even
giant redwoods
Cycads
• Possess large cones
• Found in Florida and
Australia (possibly
others)
• palmlike plants
• leaves usually
pinnately compound
• 11 existing genera
• Dioecious (separate
sexed plants)
Ginkgophyta
• Only one living
species- the
“supposed” oldest
tree around
• fan-shaped leaves,
bilobed or with more
lobes,
• Found initially in
China and now allover
• dioecious
The Angiosperms (Anthophyta)
• 260,000 living species classified in 453
families
Angiosperm Characteristics
Angiosperms, although very diverse all
share several common characteristics:
1. Ovules that are enclosed within a flower
2. Double fertilization, which leads to the
formation of an endosperm
3. Stamens with two pairs of pollen sacs
Monocots v. Dicots
• MONOCOTS
– One cotyledon (seed
leaf)
– Parallel (usually)
venation
– Flower parts in
multiples of 3’s
– Scattered
arrangement of
vascular bundles
– No secondary growth
– Roots are
adventitious, often
fibrous
• DICOTS
– Two cotyledons (seed
leaf)
– Netlike venation
– Flower parts in
multiples of 4’s of 5’s
– Vascular
bundles
are in
rings
– Secondary (woody)
growth
– Root develops from
radicle, often a tap
root
Corn Stem
Monocot –
scattered bundles
Medicago Plant
Dicot –bundles
arranged in rings
Rananculus
Dicot – Root
X-shaped xylem
Corn Root
Monocot
ringed array of vascular
bundles in this
Angiosperm Reproduction
• Meiosis in the sporophyte generation produces
two kinds of spores.
• microspores
– which will germinate and develop into the male
gametophyte generation and
• megaspores
– will develop into the female gametophyte generation.
Flowers develop from flower buds.