Kingdom: Plants
Domain Eukarya
Domain
Bacteria
Domain
Archaea
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Common ancestor
Domain
Eukarya
The first plants
 For more than 3 billion years, Earth’s
terrestrial surface was lifeless
life evolved in the seas
 1st photosynthetic organisms were
aquatic green algae

Chlamydomonas
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Present day relatives to ancient plants
Chara
Spirogyra
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Protists
Volvox
Coleochaete
Evolution of Land Plants
 500 mya land plants evolved

special adaptations for life on dry land
 protection from drying = desiccation
 waxy cuticle
 gas exchange (through cuticle)
 stomates
 water & nutrient conducting systems
 xylem & phloem
 protection for embryo
 seeds
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Plant Diversity
Bryophytes
non-vascular
land plants
Pteridophytes
seedless
vascular plants
Gymnosperm
pollen &
“naked” seeds
conifers
mosses
Angiosperm
flowers & fruit
flowering plants
ferns
seed plants
vascular plants
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colonization of land
Animal vs. Plant life cycle
Animal
Plant
diploid
multicellular
2n
diploid
multicellular
sporophyte
2n
fertilization
meiosis
mitosis
meiosis
fertilization
haploid
unicellular
gametes
1n
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gametes
1n
spores
1n
mitosis
mitosis
haploid
multicellular
gametophyte
1n
alternation of generations
First land plants
 Bryophytes: mosses & liverworts

non-vascular
 no water transport system
 no true roots

swimming sperm
 flagellated sperm

Where must
mosses live?
lifecycle dominated by
haploid gametophyte stage
 fuzzy moss plant you are
familiar with is haploid

spores for reproduction
 haploid cells which sprout
to form gametophyte
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haploid
diploid
Bryophytes: mosses & liverworts
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Peat Bog
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“Peat Moss”
diploid
First vascular plants
 Pteridophytes: ferns

vascular
 water transport system
 xylem, phloem, roots, leaves

swimming sperm
 flagellated sperm

life cycle dominated by
sporophyte stage
Where must  leafy fern plant you are
familiar with is diploid
ferns live?
 fragile gametophyte

spores for reproduction
 haploid cells which sprout
to form gametophyte
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haploid
Pteridophytes: Ferns
Selaginella
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Horsetails
Psilotum
Ferns
Alternation of generations
 Fern gametophyte (1n)
small haploid plant which produces gametes
 homospory: male & female on same plant

archegonia
antheridia
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Alternation of generations
diploid
produces male
& female gametes
haploid
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Early Pteridophytes: Tree Ferns
Fossil fuels…
I get it!
Carboniferous forest – 290-350 mya
Forests of seedless plants decayed into deposits of coal & oil
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Pteridophytes: Tree ferns
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With fronds
like these who
needs enemies!
First seed plants
 Gymnosperm: conifers


vascular
heterospory
 male vs. female gametophytes

seeds
 naked seeds (no fruit)

pollen
 contain male gametophyte

life cycle dominated by sporophyte stage
 coniferous trees you are familiar with are diploid
 reduced (microscopic) gametophyte
 reduction of gametophyte protects delicate egg &
embryo in protective sporophyte
 protected from drought & UV radiation
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Early Gymnosperm: ginkgo
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Early Gymnosperm: cycads
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Gymnosperm: conifers
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Cones & naked seeds
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sporangium & pollen
male
male (pollen) cones
female
female
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cones
pine embryo
Pollen
 Pollen
eliminated the
requirement for
water for
fertilization

spread
through wind
& animal
Where can
conifers live?
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First flowering plants
 Angiosperm: flowering plants


vascular
heterospory
 male vs. female gametophytes

flower
 specialized structure for sexual reproduction



seeds within fruit
pollen
life cycle dominated by
sporophyte stage
 trees & bushes you are familiar
with are diploid
 reduced (microscopic)
gametophyte
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Angiosperm: flowering plants
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Polar
nuclei
Angiosperm life cycle
male
gametophyte
in pollen
(haploid)
Pollen
grains
Egg
cell
fertilization
female
gametophyte
in ovary
(haploid)
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sporophyte
in seed
(diploid)
Flower
 Modified shoot with 4 rings
of modified leaves
sepals Stamen
 petals
 stamens

Stigma
Style
Ovary
Anther
Carpel
Filament
 male

carpel
 female
sepals
petals
stamens
Petal
Ovule
Sepal
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carpel
Identify the flower structures…
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Flower variations
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Co-evolution: flowers & pollinators
How a bee sees a flower…insects see
UV light = a bulls-eye to the nectar
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Angiosperm: fruiting plants
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Other fruits…
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Seed & Plant embryo
 Seed offers…
seed coat
endosperm
protection for
embryo
 stored nutrients
cotyledons
for growth of
embryo

embryo
cotyledons = “seed” leaves,
first
leaves of new plant
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Monocots & dicots
 Angiosperm are divide into 2 classes

dicots (eudicot)
 2 cotyledons (seed leaves)
 leaves with network of veins
 woody plants, trees, shrubs, beans

monocots
 1 cotyledon
 leaves with parallel veins
 grasses, palms, lilies
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Modified from: Kim Foglia, Explore
Biology