Transcript Group 3: Seed producing, Vascular Plants

Group 3: Seed producing, Vascular Plants
• Gymnosperms
– Cycads
– Ginko
– Conifers
• Angiosperms
Group 3: Seed producing, Vascular Plants
• 1) Seed plants don’t depend
on water to reproduce
– Pollen (contains sperm)
combines with egg
– Egg hardens into a seed
• 2) Nourishment and
protection
– Nourish: Nutrients inside seed
for the embryo
– Protection: Hard shell
• 3) Allow dispersal
– Carried by wind, water, animals
Group 3: Seed producing, Vascular Plants
• Type 1: Gymnosperms
• Seeds not enclosed in a
fruit
– produced inside cones
• Cone = reproductive
structure
• Male cones: produce
pollen
• Female cones: produce
eggs and seeds
Group 3: Seed producing, Vascular Plants
• Gymnosperm example:
Conifers
– Cone plants
– Needle-like leaves
– Common to lumber
industry
– Evergreen, Pine,
Redwood, Cedar
Conifers
• Seed advantages
– Don’t depend on water
– Protects & nourishes
embryo
– Allow plants to grow in
new locations
• Conifers: woody cone
houses seeds
– Male cones: produce
pollen
– Female cones: produce
egg
• Pines, redwoods,
spruce, cedar
• The sporophyte is the dominant phase for seed plants.
1) Male and female seed cones grow in adult sporophytes
2) Pollen grains released from the male seed cones
-- Pollen is the male gametophyte
Let’s zoom into the female seed cone
3) Pollen grain sticks to the female ovule
4) Pollen tube grows from the male spore
5) Two nuclei transfer into female spore
- one fertilizes the egg
6) Diploid embryo develops (sporophyte stage restarts)
7) After seeds harden, the cone
reopens and the seeds are released
8) Seed will land
ground
9) Seedling grows into (sporophyte)…the cycle repeats
ground
Plant Life Cycle Comparisons
Plant type
Sporophyte
Gametophyte
Dominant?
Moss
Stalk with cup
(capsule) at tip,
which is where
spores are
produced.
More familiar,
GAMETOPHYTE
carpet-like plant
that produces
specialized gametes
Fern
More familiar, leafy
plant with clusters
of spore producing
sacs (sori)
Haploid plant body SPOROPHYTE
(prothallus) is size
of a finger nail,
produces both male
and female parts
Conifer
More familiar- like
pine trees,
produces male and
female cones that
produce spores
Pollen grains are
male
gametophytes
sperm, female
gameotphytes are
microscopic eggs
SPOROPHYTE