Transcript Plants

Plant Characteristics
1. Range in size
2. Most have roots or
rootlike structures
3. Are adapted to live
in any environment
4. All plants need
water
Origin of Plants
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Scientists believe that plants & green
algae have a common ancestor
because they both have the same
type of carotenoids &
chlorophyll in their cells.
Green algae are one celled or many
celled organisms that use
photosynthesis to make their own
food.
Carotenoids are red, yellow or orange
pigments that are also used for
photosynthesis (why carrots are
orange)
Photosynthesis is the ability of a
plant, algae or bacteria to make their
own food.
Adaptations to Land
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Many plants have cuticles on their
leaves, stems & flowers
*this is a waxy, protective layer
secreted by cells onto the surface
of the plant that slows water loss
Cells walls contain cellulose that
vie the plant structure & support
*this is a chemical compound that
plants can make out of sugar
Cells of some plants secrete other
substances into the cellulose to
make the cell wall stronger
Plant reproduction
*some plants have water resistant
spores & others produce water
resistant seeds in cones or flowers
that develop into fruit
cuticle
spores
sunflower
seeds
Plant Classification
1. Plants are divided into 2 main groups:
vascular and nonvascular.
2. Vascular plants have tubelike structures that
carry water, nutrients & other substances
through the plant.
3. Nonvascular plants do not have the tubelike
structures & use other ways to move water &
substances through the plant.
Seedless Plants
 Seedless Nonvascular Plants:
*nonvascular plants are not very tall & have stalks &
green, leaflike growths
*have rhizoids instead of roots that anchor them where
they grow
*most grow in damp places (water is absorbed &
distributed through the cell membrane & cell wall)
*they do not have flowers or cones to produce seeds
*they reproduce by spores
Types of Seedless Nonvascular
Plants
1. Mosses
*most are classified as
mosses
*grow on tree trunks,
on rocks or the
ground
*found in damp areas
& some in
deserts
Types of Seedless
Nonvascular Plants cont.
 2. Liverworts
 3. Hornworts
Liverworts
Hornworts
Seedless Vascular Plants
 *reproduce by spores
 *vascular tissue
distributes nutrients,
food & water to the
cells throughout the
plant
 *this tissue is made
up of long, tubelike
cells
Types of Seedless
Vascular Plants
 1. Ferns
*the largest group
*have stems, leaves and have roots
Seedless Vascular Cont.
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2. Club Mosses
*have needlelike leaves
3. Horsetails
Horsetail
Club moss
Seed Plants
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Characteristics of Seed Plants:
1. most have leaves
2. have stems
3. have roots
4. have vascular tissue
Leaves
 1. the organ of the plant where photosynthesis takes
place
 2. leaves come in many shapes, sizes & colors
 3. a leaf is made up of many layers of cells
 4. The epidermis is a thin layer located on the upper &
lower surface of a leaf
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*it covers and protects the leaf
 5. The stomata are small openings in the epidermis
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*they allow carbon dioxide, water & oxygen to
enter and leave the cell
Leaves
 6. Each stoma is surrounded by a guard cell
that opens & closes it.
 7. The palisade layer is under the upper
epidermis
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*long, narrow cells that contain chloroplast
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*most of the food is produced here
 8. The spongy layer is located below the
palisade layer
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*vascular tissue is located here
Leaves
Japanese maple
Beech tree
gingko
Layers of a leaf
Stems
 1. usually located above
ground & support the
branches, leaves & flowers
 2. materials move between
leaves & roots through
vascular tissue in the stem
 3. can either be herbaceous
or woody
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*herbaceous stems are
usually soft & green (ex.
Tulip)
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*woody stems are hard &
rigid (trees and shrubs)
Herbaceous
stem
Woody stem
Roots
 1. water & other substances enter a plant through the
roots
 2. contain vascular tissue that moves water & other
substances from the soil through the stems to the
leaves
 3. act as anchors to prevent plants from blowing away
or being washed away
 4. can store food
 5. can absorb oxygen used in respiration
 6. can be located above ground or underground
Roots
Eastern Gamagrass plant
Canary tree roots
Vascular Tissue
 *There are 3 types of vascular tissue:
 1. xylem tissue is hollow, tubular cells called
vessels that transport water and other
dissolved substances from roots to other parts
of the seed plant
 2. Phloem tissue is made of tubular cells
called tubes that carry food to other parts of the
plant
 3. Cambium is a tissue that makes more
xylem & phloem cells as the plant grows
Vascular Tissue
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Gymnosperms & Angiosperms
 *Seed plants are
classified into 2 main
groups:
gymnosperms &
angiosperms
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gymnosperm
Angiosperm (monkey
flower)
Gymnosperms
 1. They are vascular plants that produce
seeds that are not protected by fruit &
they do not have flowers (ex. Gingko &
pine tree)
 *many are called evergreens because some
green leaves never fall off
 *their leaves are needlelike or scalelike
Gymnosperms
gingko
Pine tree
Pine tree leaf
(needlelike)
Gymnosperms
 2. Conifer is a type of gymnosperm that
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produces 2 kinds of cones, a male
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and female (ex. Redwood tree)
 *the cone is the reproductive structure of
the conifer (seeds develop inside the
cone)
 *conifers have needlelike leaves
 *stay green all year & don’t lose all their
leaves
Conifers
Arborvitae
California Redwood
Angiosperms
 *also known as flowering plants
 1. a vascular plant that produces flowers
 & has a fruit that contains one or more seeds
(ex. Peach)
 2. flowers of angiosperms vary in size, shape
and color
 3. some flower parts develop into fruit
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*most fruits contain seeds (ex. Apple)
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or have them on their surface
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(ex. strawberries
Deciduous Trees
 4. A deciduous tree
has broad, flat leaves
and loses them each
year (ex. Oak tree)
Oak tree
British Bonsai
Angiosperms
 5. Angiosperms are divided into 2
groups: monocots & dicots
 *Monocots have one cotyledon (part of
the seed where food is stored)
 **Examples: bananas & orchids
 *Dicots have 2 cotyledons
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**Examples: green beans & apples
Angiosperms
 6. Lifecycle of Angiosperms:
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*Annuals complete their life cycle in
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one year. Seeds have to be
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re-planted each year. (ex. Petunias)
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*Biennials complete their life cycle in
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2 years. They produce flowers &
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seeds the second year.
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*Perennials take more than 2 years to grow
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to maturity, but they produce flowers &
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fruit year after year (ex. Peonies)
Angiosperms
petunias
parsley
peonies