Transcript Plant Classification

Plant Classification
Alternation of generations
• Sporophyte (diploid)
– Begins when sperm
fertilizes egg (zygote)
– Diploid zygote
divides by mitosis to
create a mature
sporophyte
– Meiosis produces
haploid cells called
spores
– Haploid spores
released
Alternation of generations
• Gametophyte (haploid)
– Begins with spores
created by meiosis
– Spore grows into
gametophyte
• Male gametophyte
creates sperms
• Female gametophyte
creates eggs
– Sperm & egg create
diploid zygote
(process repeats)
Group 1: Seedless, Nonvascular Plants
• Live in moist
environments
• Liverworts
• Hornworts
• Mosses
Mosses
• Nonvascular, seedless
• Grow low to ground to
retain moisture
• Lack true leaves
– Leaf-like structures
only 1 cell thick
• Rhizoids anchor into
soil
• Early inhabitant of new
ecosystems
(succession)
• Gametophyte phase
– Dominant stage
– Carpet of moss growing
near ground
Moss Life Cycle
• Archegonium:
produces female egg
• Antheridium: produces
male sperm
– Sperm swims through
water to fertilize egg
• Sporophyte phase
– Stalk grows up from the
gametophyte
– Sporangia houses
haploid spores
– Spores land and new
gametophyte grows
See appendix B in your text book
1) Moss
gametophytes
grow near the
ground (haploid
stage)
2) Through water,
sperm from the male
gametophyte will swim
to the female
gametophyte to create
a diploid zygote
3) Diploid sporophyte
will grow from the
gametophyte where
the zygote is located
.. .
sporophyte
gametophyte
4) Sporophyte will
create and release
haploid spores
5) Spores land
and grow into
new
gametophytes
6) The process
repeats
gametophyte
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
Group 2: Seedless, Vascular Plants
• Vascular system allows
nutrient transport to
greater heights
• Club mosses
• Horsetails
• Ferns
Ferns
• Seedless, vascular plants
– Vascular: allows taller growth
• Rhizoids: underground stems draw nutrients
• Fronds: leaves uncurl
– sporangia on underside
• Sori: clusters of sporangia
Fern Life Cycle
• Sporophyte phase
– Dominant stage
– Sporangia produces haploid
spores
– Spores released into air
• Gametophyte phase
– Spore grows into prothallus
• Archegonium: produces
female egg
• Antheridium: produces male
sperm
– Sperm swims to egg
– Zygote begins sporophyte
stage
See appendix B in your text book
1) Sporophyte creates and releases haploid spores
.
.
. .
Adult
Sporophyte
(diploid)
ground
2) Spores land in the soil
ground
3) From the haploid spores, a prothallus (haploid gametophyte) grows in the soil
-- Rhizoids anchor
Let’s zoom in
ground
4) Sperm swim through water from the antheridium to the archegonia
Let’s zoom back out
5) Diploid sporophyte (fiddlehead) grows from the prothallus
-- prothallus eventually dies
ground
6) Fiddlehead uncurls into fronds of ferns.
7) Cycle repeats
-- Sporangia creates spores to be released
.
.
.
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