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How are plants classified?
Lesson 3
Vocabulary
• Gymnosperm: a seed plant that does not
produce a flower. They include pines, firs, and
other cone-bearing trees.
• Angiosperm: a seed plant that produces
flowers. All angiosperms have seeds that are
covered by some kind of fruit.
• Xylem: a series of tubes that move water and
minerals up the stem. (From the plant roots
to the leaves)
Gymnosperm, Angiosperm, Xylem
Vocabulary
• Phloem: moves sugars that are made in the
plant’s leaves to other parts of the plant.
Phloem tissue is a two-way transport route. It
flows both up and down in a plant.
• Cambium: xylem and phloem cells are
produced in the cambium, then move inward.
• Photosynthesis: the process of making food.
Leaves need three raw materials: sunlight,
water, and carbon dioxide from air.
Cambium, Phloem
Photosynthesis
Vocabulary
• Transpiration: the loss of water through a
plant’s leaves. Picture on page 58.
• Cellular respiration: energy is released when
the cells of organisms use oxygen to break
down the sugars stored as starch.
Transpiration, Cellular respiration
How are plants classified?
• Nonvascular plants are small and survive
without a transport system. (Moss)
• Vascular plants do not have size limitations.
Trees can grow to heights of more than 200
feet.
• Vascular plants are divided into seed plants
and seedless plants.
Nonvascular, Vascular
How are plants classified?
• Two main types of seed plants: gymnosperm
(does not produce a flower), and angiosperm
(does produce a flower).
What are roots?
• A root is part of the plant.
• Root hair is a threadlike projection from a
plant root. Root hair absorbs moisture like a
sponge.
• Root cap covers the tip of the root. It protects
the root tip while it pushes into the ground.
• Epidermis is the skin of the root. Just like our
epidermis is our skin.
What are roots?
• Cortex layer is located just under the
epidermis. The cortex stores food and
nutrients.
• The vascular system of the root is located in
the center of the root. Just like our vascular
system is in the center of our body.
• Aerial roots are roots that never touch the
ground. Orchids have aerial roots.
What are roots?
• Fibrous roots are thin, branching roots. They
do not grow deep, but they often cover a very
wide area. (Marigold plants)
• Taproots have a single, main stalk-like root
that plunge into the ground. (Poplar Tree)
• Prop roots usually grow at the bottom of a
plant’s stem. They prop up and support the
plant so it cannot be knocked over. (Corn
plants and mangrove trees)
Fibrous roots, Taproots
Prop roots
What are stems?
• The plant’s stem has two functions. First, is a
support structure. The stem of a tree must
support the weight of the entire tree. Stems
must be sturdy enough to support leaves,
flowers, and branches.
• Stems come in two basic forms-soft stems and
woody stems.
• Soft stems, green, and can bend.
• Woody stems are often covered with bark and do
not contain chlorophyll.
Plant and Stem
Allows sugar from the leaves
of the tree to flow to the rest
of the tree.
Allows water and nutrients
from the ground to flow to
the rest of the tree.
What are leaves?
• Many leaves are flat and broad, which allows
the leaf to collect the most sunlight possible.
• The top of the leaf is covered with a waxy
cuticle, or waterproof layer that prevents
moisture from evaporating.
• Leaves use stomata, a single pore which opens
and closes to regulate the amount of water
and air loss in the plant.
Plant leaf
What are leaves?
• As water evaporates from the leaves, more
water is carried from the bottom of the plant
to the top.
• Photosynthesis, the production of sugar and
oxygen while absorbing carbon dioxide and
water.
How are photosynthesis and
respiration related?
• Cellular respiration: the process of using
oxygen to break down the sugars stored as
starch in the process.
• Cellular respiration occurs in the mitochondria
of the cells.
Cellular respiration in plants