Unit 6: Plants
Chapter 21: Intro to plants
I.
Plant Evolution and adaptations
II.
Nonvascular plants
III. Seedless Vascular plants
IV. Plant Evolution and adaptations
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I. Plant Evolution and
Adaptations
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Definition
Plants are multicellular
eukaryotes with tissue and
organs that have specialized
structures and functions
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Differences between Algae and Plants
◍ Algae can be unicellular
◍ Algae does not have a root and shoot
system
◍ Algae are classified under the kingdom
Protista whereas Plants are under the
kingdom Plantae
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Common characteristics for plants and
algae
◍ Cell wall made of cellulose
◍ Telophase include the formation of cell plate
◍ Same type of chlorophyll used in photosynthesis
◍ Genetic similarities in ribosomal RNA
◍ Food stored as starch
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Adaptations to land
Plants have evolved to survive on land
Evidence shows that plants have evolved
from an ancestor that first evolved to have
characteristics to reisist drought. Along
with algae they have from these drought
resistant aquatic plants through evolution.
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Adaptations to land
◍ Cuticles: Waxy exterior
preventing evaporation
◍ Stomata: openings that
control gas exchange
◍ Vascular Tissues:
specialized transport
tissue allows faster
diffusion
◍ Reproductive strategies:
Adaptations for sperm
cells to reach egg cells
without the presence of
water
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Alternation of
Generations
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Alternation of Generations
Key
Haploid (n)
Diploid (2n)
MEIOSIS
Spore
dispersal
Sporangium
Sporangium
Mature
sporophyte
(2n)
Sorus
Fiddlehead (young leaf)
Alternation of Generations
Key
Haploid (n)
Diploid (2n)
MEIOSIS
Spore
dispersal
Rhizoid
Underside
of mature
gametophyte
(n)
Sporangium
Sporangium
Mature
sporophyte
(2n)
Sorus
Fiddlehead (young leaf)
Antheridium
Spore Young
(n)
gametophyte
Sperm
Archegonium
Egg
FERTILIZATION
Alternation of Generations
Key
Haploid (n)
Diploid (2n)
MEIOSIS
Spore
dispersal
Rhizoid
Underside
of mature
gametophyte
(n)
Sporangium
Sporangium
Antheridium
Spore Young
(n)
gametophyte
Mature
sporophyte
(2n)
Sorus
New
sporophyte
Sperm
Archegonium
Egg
Zygote
(2n)
Gametophyte
Fiddlehead (young leaf)
FERTILIZATION
Plant Classification
•
•
•
•
Bryophytes
Ferns
Gymnosperms
Angiosperms
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Non Vascular Plants
◍ Usually small enabling easy transport of
nutrients
◍ No xylem
◍ Lacks true roote, stem and leaves
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Byrophytes
◍ Nonvascular land plants
◍ Mosses, liverworts and hornworts
◍ Gametophyte (n) is photosynthetic ,
dominant generation
◍ Typically ground-hugging plants
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Seedless Vascular Plants
◍ Contains a developed vascular system
◍ Include Club Mosses, Whisk Ferns and
Ferns.
◍ Sporophytes produce a compact cluster
of spores called “Strobilus”
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Ferns
◍
◍
◍
◍
Seedless vascular plants
Horsetails and ferns
Sporophyte (2n) is dominant generation
Most common in damp areas due to
flagellated sperm that must swim to
reach eggs
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Vascular Seed Plants
◍ Produces Seeds containing tiny
sporophyte surrounded by a protective
tissue
◍ Seeds contain cotyledons that store
food/ help absorb food
◍ Either flower bearing or not
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Gymnosperms
◍ “Naked” seeds not enclosed in ovaries
◍ Conifers, ginkgos, and cycads
◍ Sporophyte (2n) is the dominant
generation
◍ Seeds are exposed on modified leaves
that usually form cones
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Angiosperms
◍ Flowering plants
◍ Pecan trees, roses, peach trees,
tomatoes
◍ Sporophyte (2n) generation is dominant
◍ Flowers and fruit
◍ Most abundant of all plant species
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