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Invasion of land
• Stomata: opening: allows CO2
into the leaf
• Cuticle: Protects from water loss
• Vascular tissue: xylem and
phloem
• Roots: absorb nutrients and water
vs. rhizoids of moss and holdfasts
of algae that don’t.
• Seeds: dormancy
• Fruit: seed dispersal
• Flowers: pollination/reproduction
Cuticle
– A waxy cuticle covers parts exposed to air to prevent
dessication. Openings in the cuticle (stomata) allow for
gas exchange and are controlled by the guard cells.
Guard cells
Vascular tissue
– xylem (water and
minerals) and phloem
(nutrients).
– Picture shows
vascular tissue in a
leaf in a bundle known
as a vein. These are
the lines you can see
in the leaf.
Carbon dioxide
• Plants lowered the levels of carbon dioxide from 25X
current levels to current levels over a period of 100 million
years as they adapted to and spread on land.
Cuticle, Dermal tissue, ground
tissue, and vascular tissue
Flagellated sperm vs. pollen
• The more primitive plants have flagellated sperm
that allow them to swim to the egg. This means
that the mosses, ferns, and other primitive plants
require water to have fertilization.
Fern sperm
Types of
pollen
PLANT DIVISIONS
Plants
• NOTE: We use the
term Divisions
instead of the term
Phyla when referring
to plants.
• Characteristics of
plant kingdom
members
– Alternation of
generations with the
diploid sporophyte
generation dominant
except in bryophytes
Plant Divisions: Bryophyta
• MOSSES
• Dominant gametophtye
generation (green)
• Also includes liverworts and
hornworts
• Need sperm to fertilize egg
• NO vascular tissue limits
height of the plant and
therefore have no true roots,
stems, or leaves.
• haploid spores are made by
meiosis in the sporangium of
the sporophyte.
Moss
sporophyte
Pterophyta: Ferns
• Homosporous: create one spore that is
bisexual.
• Vascular tissue but no seeds: allows them
to get taller, but limits them to shady moist
areas for reproduction.
• Fronds: big “leaf like” arrangement
• Fiddlehead: emerging sporophyte
• Sporangium make spores on underside of
fronds when reproducing.
Ferns
• Fiddlehead
• Sporangia on
underside of
frond
• Fronds
• Bisexual
gametophyte
Gymnosperms (naked seeds) have no
flowers: gingko, cycad, and conifers
Coniferophyta
•
•
•
•
•
•
Redwoods, firs, pines, yews, cypresses
Naked seeds: not enclosed in fruits
Wind pollination (NEEDS A LOT)
Seeds, vascular tissue
No flowers
Often needles thick with cuticle and small
in size to limit transpiration.
Seed cones vs. pollen cones
Seed cones
seeds
Pollen cones
Oldest and largest
• Redwoods (400 feet tall)
bristlecone pine (4600 years old)
Anthophyta
• Flowering plants
• Flower will develop into fruit that is used for
seed dispersal via wind, water, or animal.
• Pollination can be by wind, bird, bat, insect.
• Most advanced (recent)
• Gametophyte is reduced and within the
flower.
• Most diverse: grasses to trees
Monocot and Dicot
• The subdivisions of angiosperms.
• One cotyledon or two cotyledons
“cot” = cotyledon (seed leaf)
Monocots
• Often grasses and the
relatives of grasses
Dicots
• Garden plants, trees,
Differences
Vascular bundle location in the stem
#4:Flower parts
• Monocot
• Petals: in multiples of 3
Dicot
Petals: 4 or 5
#3: number of seed parts
#2: veination in the leaves
• Parallel veins
• Monocot
Netlike veins
Dicot
Flower structure: reproduction
organ of some plants
Flower parts
• Pistil/Carpel: synonym for female part
– Ovary-makes the eggs within the ovule
– Style-extends from the ovary away from plant
– Stigma-on the end of the style it collect pollen
with its stickiness
• Stamen: male part of flower
– Anther makes pollen
– Filament – holds anther away from plant
• Sepals: protect flower before blooming
• Petals: attract pollinators
Parts: functions
• Female (carpel/pistil)
– Stigma is sticky “top” that collects pollen
– Style is connection between stigma and ovary.
– Ovary is where eggs are made in the ovules
• Male (stamen)
– Anther makes the pollen
– Filament holds anther away from female part to allow for
wind/insect to carry pollen away
• Petals (collectively called corona): attracts
pollinators
• Sepals (collectively called calyx); protects the bud
before blooming
Double Fertilization
• Generative nucleus becomes two “sperm” through
mitosis. First sperm fertilizes egg in the ovule and
second sperm fertilizes polar nuclei to become triploid
endosperm. Endosperm will become “food” for seed.
Seed and Fruit
• Seed: covering (seed coat), food
(endosperm) and embryo.
• Dormancy vs. Germination
• The ripened ovary becomes the fruit after
the fertilization of the egg and formation of
the seed. (Contains the seed)
• Purpose: Seed dispersal
Seed dispersal
Fruit types
• Simple
aggregate
multiple
Review
• What division of plants has no vascular
tissue?
• What is made by the archegonium?
• What part of the flower “catches the pollen?
• What is one gymnosperm other than
coniferophyta?
• What part of a flower becomes the fruit?
• Where do you find the sporangium on a fern?
More review
• What process makes the gametes in a plant?
• What division of plants includes the tallest
trees?
• What is the purpose of the fruit?
• What is the food of a seed called?
• What group of green algae are the closest
relatives to plants?
• What does the cuticle prevent?
• How many flowers lead to an aggregate fruit?
• What is true of plants that are heterosporous?