Transcript Grade 7-Chapter 9

Range in size (microscopic to gigantic)
 Adapted to nearly every environment on
earth
 Shared Characteristics:
 Most have roots or root-like structures
 All need water
 Have a cell wall
 Contain chlorophyll to aid in
photosynthesis
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Land plant ancestors were green algae
that lived in the sea
 Exact origin of flowering plants are not
known
 There was more sunlight and CO2 on land
for plants to use during photosynthesis
than in the sea
 As plants moved onto land more O2
became available for animals to develop
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All adaptations enabled plants to survive
on land
 Cuticle-helps plant conserve water
 Cellulose found in the cell wall helps
plants support itself and provide
structure
 Structures developed that distribute
water, nutrients and food to all plant
cells
 Plants developed water-resistant seeds
or spores to help them reproduce
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2 divisions
1. Vascular Plants
 have tube-like structures that carry
water and nutrients to other parts of
the plant
 2 groups in this division
 Seed vascular and seedless vascular
2. Nonvascular plants
 Do not have tube-like structures
 Are seedless and have no groups
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Developed by Carolus Linnaeus
 Every plant given a unique 2 word name
 Ex: Shasta daisy-chrysanthemum
maximum
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Do not grow from seeds
 Few cells thick
 Rhizoids anchor them to the ground not
roots
 Grow in places that are damp
 Do not have flowers or cones
 Reproduce by spores- waterproof
reproductive cell
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Mosses
 Grow in damp areas
 Grow on rocks, trees and ground
 Some have adapted to live in the desert
 Pioneer species
2. Liverworts
 Rootless plants
 Flattened leaf-like bodies
3. Hornworts
 Less than 2.5 cm in diameter
 Flattened bodies
 Have only 1 chloroplast in each cell
1.
Reproduce with spores
 Has vascular tissue which is made up of
long tube-like structures
 Vascular tissue carries water, minerals,
and food throughout the plant
 This enables plants to grow bigger and
thicker
1. Ferns
 Largest group
 Have stem, leaves and roots
 Leaves are called fronds, where spores
are found
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2.
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3.
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Club Mosses
Related more to ferns than mosses
Needle-like leaves
Spores are produced at the end of the
stem in structures like pine cones
Horsetails
Spores produced in a cone-like
structure
Stem is jointed and has a hollow center
Stem contains silica-gritty stubstance
Used for polishing objects and
sharpening tools
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Peat, remains of moss, is used as a low-cost
fuel in Ireland and Russia
Scientists hypothesize peat could become
coal
Nonvascular plants help build new soil
Parts can be eaten as food, such as
rhizomes and young fronds
Ferns used as weaving material
Ferns used as landscaping and house plants
Ferns also used as folk medicines
Have leaves, stems, roots and vascular
tissue
 Produce seeds
 2 major groups
 Most plants are seed plants
1. Leaves
 Organs where photosynthesis occurs
 Come in many shapes, sizes and colors
 Epidermis covers and protects the leaf
 Cuticle-waxy covering
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Stomata-openings in the epidermis which
allows CO2 and water to enter and exit
 Guard cells-open and close the stomata
 Palisade layer -most of the food is
produced by the cells in this layer
 Spongy layer -veins containing vascular
tissue are found
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2.
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Stems
Located above ground and support the
branches, leaves and reproductive
structures
Vascular tissue in stems moves material
from the roots to the leaves
 Some are herbaceous-soft, and green
 Trees and shrubs have hard, rigid woody
stems
3. Roots
 Water and nutrients enter the plant
through the roots and the vascular
tissue transports the substances to the
other parts of the plant
 Act as anchors, to keep plants from
being blown away
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Sometimes all of the roots can be above
ground
 Can store food
 Plants in dry areas have roots that store
water
 Root tissue absorb oxygen to aid in
respiration
4. Vascular Tissue
 Made up of three tissues
 Xylem: tubes stacked up on top of each
to form a vessel
 Vessels transport substances
throughout the plant
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Xylem cell walls help support the plant
 Phloem: tubular cells stacked to form
tubes
 Tubes move food from where it is made
to the other parts of the plant
 Cambium: tissue that produces the xylem
and phloem cells
 The growth of new xylem and phloem
thicken the stem and roots
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Vascular plants
 Produce seeds, but no flowers or fruit
protect the seeds
 Leaves are needlelike
 Many are evergreens
 Cones are reproductive structures
 Seeds develop on female cones
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4 divisions
1. Conifers (pines, firs, spruces,
redwoods)
 Most diverse group
2. Cycads
 Found in tropical regions
3. Ginkgoes
 Pollution-tolerant
 Are deciduous
4. Gnetophytes (joint fir)
 More than ½ of species grouped into 1
genus
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Vascular plant
 Flowers and produces fruit
 More than ½ of known plant species
belong to this group
 Flowers vary in size, shape and color
 Some flower parts develop into a fruit
 Most fruits have seeds
 2 groups
1. Moncots
2. Dicots
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Monocots
Has 1 cotyledon-used for food storage
in the seed
We get foods from them, such as
bananas, pineapple
Other examples: lilies and orchids
Flower parts in multiples of three
Leaves are narrow
Vascular tissues run parallel to one
another
Vascular bundles are scattered
throughout the plant
2.
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Dicots
2 cotyledon
Produces peanuts, green peas, apples,
oranges
Trees: maple, oak and elm
flower parts are in multiples of four or
five
Vascular tissues are in a bundle
Vascular bundles occur in rings like
the rings of a tree
Paper and wood come from
gymnosperms
 Cotton comes from seed plants
 Fruits, bread, potato chips come from
seed plants
 Diets of most animals come from
angiosperms
 Refer to Table 1 Pg 260 for products of
seed plants
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