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Classification of Plants
Plants
Aquatic Plants
• Ex. green algae
Similarities between green
algae and land plants:
• A) have chlorophylls a
and b
• B) cellulose cell walls
• C) store food energy in the
form of starch (rather than
glycogen)
Plants to Land (400MYA)
Adaptations that needed to be evolved before
plants could live on land:
• A) protection from drying out
• B) system of transport from outside
environment to cells in the body of plant
• C) system to support the body of plant
Adaptation to Land
3 organs that developed to adapt to life on land:
• A) roots: penetrate soil to anchor plant; reach
water source
• B) leaves: greater surface area for
photosynthesis
• C) stems: rigid tissue to raise and support
leaves
Land plants:
non-vascular
vs. vascular
Vascular plants appeared 360MYA
A vascular tissue :
• a system of tubes that carry water and
dissolved nutrients through a plant
Land plants:
non-vascular
vs. vascular
Non-vascular (bryophytes)
• No vascular (transport) tissue
• Have root-like, stem-like and
leaf-like structures (poorly
developed roots, leaves and
stems)
• Grow short, small
• ex. mosses, liverworts,
hornworts
Vascular (tracheophytes)
• has vascular tissue to
transport water and
nutrients
• Have true roots, stems and
leaves
• Grow taller, larger
• 1) seedless (spore producing)
• Ex. ferns
• 2) seed producing
• Ex. conifers, flowering
plants
Non-Vascular
vs. Vascular
Advantage of vascular plants?
• - can live in drier environment
• - can grow larger (water and nutrients can
reach far with the vascular tissue)
Non-vascular plants live in moist environment
and have smaller sizes.
Non-vascular (bryophytes)
Mosses
•
Liverworts
Hornworts
Vascular (tracheophytes)
1) Seedless (spore-producing) ex. ferns
• Grow in marshes and edges of shores;
requires water for reproduction – spores
(sperm) swim in water to the female organ
(in different plant or same plant)
Advantages of having seeds
• A) food storage
• B) tough waterproof coat – protection against
harsh conditions
• C) remain dormant- survive exposure to harsh
conditions
• D) sexual reproduction without needing water
Gymnosperm- “naked seed”
ex. ginkgoes, conifers
Angiosperms-flowering plants
Examples
Gymnosperms vs. Angiosperms
• Conifers: produce cones in the
spring and summer
• Male vs. female cones
(in clusters)
(scattered, hidden seeds)
• Flowering plants
• Also grass and herbs
Seed Structure
Gymnosperms vs. Angiosperms
• Means “naked seed”
• Means “seed in a vessel”
• Seeds that are exposed • Seed = embryo
to the environment
+nutrient storage+ coat
(often as cones)
• Seeds that are not
• Thin cover of protection exposed to the
environment (drought,
fire…)
• Seed protected with
body of fruit
Preferred Environment
Gymnosperms vs. Angiosperms
• Environments with long, cold
winters and low amounts of
nutrients in the soil
• Found in Canada and northern
Europe and northern Asia
• Found all over the world
Number of species
Gymnosperms vs. Angiosperms
• Smaller in number
• Approx. 1000 species
• Larger in number
• Approx. 250 000 species
. 2 groups
Flowering
Plants
(Angiosperms)
Monocotyledons
Dicotyledons
.
roots, stems, leaves
.
vascular tissues (transport)
.
flowers, fruits (contain seeds)
Two peanut seeds
in the hard ovary
vs
Two apple seeds
in the fleshy fruit
Monocotyledons and Dicotyledons
Cotyledon: the structure in a plant’s seed that
stores carbohydrates for the seedling
• It’s known as “seed leaf” because the plant’s
first leaf develops from it.
• ex) onion- single leaf monocot
•
alfalfa- two leaves  dicot
Monocotyledons
Parallel veins
Dicotyledons
Veins in network
Structure
Monocots
Dicots
Number of
cotyledons
1
2
Number of
flower petals
Multiples of 3
Multiples of 4
or 5
Number of
species
Fewer
More
Examples
Tulip, lily, corn, Rose, maple
onion, grass,
tree, carrot,
rice, banana
potatoes,
beans
Root structure
Structure
Monocots
Root cross- Vascular bundles
section
are arranged in a
ring
Root system Fibrous rootsmany thin roots
Dicots
xylem in the center of
the root (with an X
shape) and phloem
outside the xylem.
Tap roots – one large
vertical root with
smaller branches
Stem
crosssection
Vascular bundles
are scattered
Vascular bundles are
arranged in a ring
Tissue
Herbaceous –soft
& flesh stems
Only about 10%
are woody
Woody- tough, rigid
Monocot Stem vs. Dicot Stem
vascular bundles- scattered vs.
in a ring
Leaf
Structure
Monocots
Dicots
Leaf crosssection
Spongy
mesophyll
Leaf structure
Long strips
Parallel veins
Palisade
mesophyll +
spongy
mesophyll
Broad leaf
Net-like veins
Double fertilization
• 1) between a sperm(1n) and the egg (1n) becomes
the zygote (2n)develops into an embryo
• 2) between a sperm(1n) and the two polar nuclei (n
+n) becomes the endosperm (3n) provides
nutrients for the embryo
• each ovule forms a seed (there are many ovules in
the ovary)
• the ovary develops into a fruit
Gametes
• Inside the anther, microspores are produced through meiosis.
These microspores give rise to the pollen grain (1n).
• The female reproductive organ, the ovary, contains
developing ovules. Each ovule produces megaspores (haploid)
through meiosis. One megaspore survives in each ovule and
develops into an egg (1n).
• When pollen reaches the stigma, it grows a pollen tube to
extend down the style.