Transcript Section 1 What Is a Plant?

Chapter 6
Introduction to Plants
Preview
Section 1 What Is a Plant?
Section 2 Seedless Plants
Section 3 Seed Plants
Section 4 Structures of Seed Plants
Concept Mapping
Chapter 6
Section 1 What Is a Plant?
Bellringer
There are four major types of plants. Try to identify
all four types, and give at least two examples for
each one. Do all four types of plants grow near
your home? Where will you most likely find each
type of plant?
Write your responses in your science journal.
Chapter 6
Section 1 What Is a Plant?
Objectives
• Identify four characteristics that all plants share.
• Describe the four main groups of plants.
• Explain the origin of plants.
Chapter 6
Section 1 What Is a Plant?
Plant Characteristics
• Photosynthesis Plants use energy from sunlight
to make food from carbon dioxide and water. This
process is called photosynthesis.
• Cuticles A cuticle is a waxy layer that coats most
of the surfaces of plants that are exposed to air.
Chapter 6
Section 1 What Is a Plant?
Plant Characteristics, continued
• Cell Walls Plant cells are surrounded by a rigid
cell wall.
• Reproduction Plants have two stages in their life
cycle — the sporophyte stage and the gametophyte
stage.
Chapter 6
Section 1 What Is a Plant?
Chapter 6
Section 1 What Is a Plant?
Plant Classification
• Nonvascular Plants A nonvascular plant is a
plant that doesn’t have specialized tissues to move
water and nutrients through the plant.
• Vascular Plants A plant that has tissues to
deliver water and nutrients from one part of the
plant to another is called a vascular plants.
Chapter 6
Section 1 What Is a Plant?
Chapter 6
Section 1 What Is a Plant?
The Origin of Plants
• Plants Are Cousins of Green Algae Because
they exhibit many similarities, scientists think that
green algae and plants share a common ancestor.
Chapter 6
Section 2 Seedless Plants
Bellringer
If plants can make their own food, why do people
add fertilizer to soil? What happens when you
plant crops in the same field over and over again?
Does fertilizer ever stop working?
Write your answers in your science journal.
Chapter 6
Section 2 Seedless Plants
Objectives
• List three nonvascular plants and three seedless
vascular plants.
• Explain how seedless plants are important to the
environment.
• Describe the relationship between seedless
vascular plants and coal.
Chapter 6
Section 2 Seedless Plants
Nonvascular Plants
• Mosses Mosses often live together in large
groups. They cover soil or rocks with a mat of tiny
green plants.
• Mosses have leafy stalks and rhizoids. A rhizoid
is a rootlike structure that holds the plants in place
and helps plants get water and nutrients.
Chapter 6
Section 2 Seedless Plants
Nonvascular Plants, continued
• Ferns Ferns grow in many places, from the cold
arctic to humid tropical forests.
• Most ferns have a rhizome. A rhizome is a
horizontal, underground stem that produces new
leaves, shoots, and roots.
Chapter 6
Section 2 Seedless Plants
Nonvascular Plants, continued
• Liverworts and Hornworts Like mosses,
liverworts and hornworts are usually small,
nonvascular plants that usually live in damp places.
• The Importance of Nonvascular Plants
Nonvascular plants are usually the first plants to
live in a new environment, such as newly exposed
rock. When these nonvascular plants die, they form
a thin layer of soil.
Chapter 6
Section 2 Seedless Plants
Chapter 6
Section 2 Seedless Plants
Seedless Vascular Plants, continued
• The Importance of Seedless Vascular Plants
Ferns, horsetails, and club mosses help form soil.
They also help prevent soil erosion.
• Some ferns and horsetails can be eaten.
Horsetails are used in dietary supplements,
shampoos, and skin-care products.
Chapter 6
Section 2 Seedless Plants
Seedless Vascular Plants, continued
• The remains of ferns, horsetails, and club mosses
that lived and died 300 million years ago formed
coal. Humans rely on coal for energy.
Chapter 6
Section 3 Seed Plants
Bellringer
Since plants cannot get up and walk around to
disperse their seeds, what kinds of strategies do
plants employ to spread their seeds? How do some
plants protect their seeds from being destroyed or
eaten?
Explain your answer in your science journal.
Chapter 6
Section 3 Seed Plants
Objectives
• Describe three ways that seed plants differ from
seedless plants.
• Describe the structure of seeds.
• Compare angiosperms and gymnosperms.
• Explain the economic and environmental
importance of gymnosperms and angiosperms..
Chapter 6
Section 3 Seed Plants
Characteristics of Seed Plants
• Seed plants differ from seedless plants in the
following ways:
• Seed plants produce seeds.
• The gametophytes of seed plants do not live
independently of the sporophyte.
• For sexual reproduction, the sperm of seed
plants do not need water to reach an egg.
Chapter 6
Section 3 Seed Plants
The Structure of Seeds
• A seed is made up of three parts. The first part is a
young plant, or the sporophyte. The second part is
stored food. Finally, a seed coat surrounds and
protects the young plant.
Chapter 6
Section 3 Seed Plants
The Structure of a Seed
Chapter 6
Section 3 Seed Plants
Gymnosperms, continued
• The Importance of Gymnosperms Conifers
are the most economically important
gymnosperms. People use conifer wood for
building materials and paper products.
• Resin, a sticky fluid produced by pine trees, is
used to make soap, turpentine, paint, and ink.
Chapter 6
Section 3 Seed Plants
Gymnosperms, continued
• Gymnosperm Life Cycle Sperm from pollen in
the male cone fertilize the eggs of the female
cone. A fertilized egg develops into a young
sporophyte within the female cone.
• Pollination is the transfer of pollen from the male
reproductive structures to the female structures of
seed plants.
Chapter 6
Section 3 Seed Plants
Chapter 6
Section 3 Seed Plants
Angiosperms
• Angiosperms are vascular plants that produce
flowers and fruit.
• Angiosperm Reproduction Flowers help
angiosperms reproduce. Flowers attract animals that
help spread pollen.
• Fruits surround and protect the seeds.These fruits
help angiosperms distribute their seeds.
Chapter 6
Section 3 Seed Plants
Angiosperms, continued
• Two Kinds of Angiosperms Angiosperms are
divided into two classes— monocots and dicots. The
next slide shows the two kinds of angiosperms.
Chapter 6
Section 3 Seed Plants
Chapter 6
Section 3 Seed Plants
Angiosperms, continued
• The Importance of Angiosperms Flowering plants
provide many land animals with the food they need to
survive.
• People use flowering plants in many ways. Major
food crops, such as corn, wheat, and rice, are
flowering plants.
•Flowering plants are used to make cloth fibers, rope,
medicines, rubber, perfume oil, and building materials.
Chapter 6
Section 4 Structures of Seed Plants
Bellringer
In your science journal, draw a cactus. Point out the
spines, and explain their purpose. Are there other
plants besides cacti that have spines, or spine-like
structures? What other means do plants use to
protect themselves?
Write down your answers in your science journal.
Chapter 6
Section 4 Structures of Seed Plants
Objectives
• List three functions of roots and three functions of
stems.
• Describe the structure of a leaf.
• Identify the parts of a flower and their functions.
Chapter 6
Section 4 Structures of Seed Plants
Characteristics of Seed Plants
• There are two types of vascular tissue in plants:
• Xylem is the type of tissue in vascular plants that
provides support and conducts water and nutrients
from the roots.
• Phloem is the tissue that conducts food in
vascular plants.
Chapter 6
Section 4 Structures of Seed Plants
Transporting Materials Throughout the Plant
Click below to watch the Visual Concept.
Visual Concept
Chapter 6
Section 4 Structures of Seed Plants
Roots
• Root Functions The following are the main
functions of roots:
• Roots supply plants with water and dissolved
minerals.
• Roots hold plants securely in the soil.
• Roots store surplus food made during
photosynthesis
Chapter 6
Section 4 Structures of Seed Plants
Roots, continued
• Root Structure The layers of cells that cover the
surface of the roots is called the epidermis.
• After water and minerals are absorbed by the
epidermis, they diffuse into the center of the root
where the vascular tissue is located.
• A root cap can be found at the end of the root. The
root cap protects the tip and helps the root continue
to grow.
Chapter 6
Section 4 Structures of Seed Plants
Chapter 6
Section 4 Structures of Seed Plants
Roots, continued
• Root Systems There are two kinds of root
systems— taproot systems and fibrous root systems.
• Taproot systems have a main root, or tap root, that
grows downward. Dicots and gymnosperms usually
have tap root systems.
• Fibrous systems have several roots that spread out
from the base of the stem. Monocots usually have
fibrous root systems.
Chapter 6
Section 4 Structures of Seed Plants
Stems
• Stem Functions A stem connects a plant’s roots to
its leaves and flowers. A stem also has the following
functions:
•Stems support the plant body.
•Stems transport materials between the root system
and the shoot system.
•Some stems store materials.
Chapter 6
Section 4 Structures of Seed Plants
Stems, continued
• Herbaceous Stem Many plants have stems that are
soft, thin, and flexible. These stems are called
herbaceous stems. A cross section of an herbaceous
stem is shown on the next slide.
Chapter 6
Section 4 Structures of Seed Plants
Chapter 6
Section 4 Structures of Seed Plants
Stems, continued
• Woody Stems Trees and shrubs have rigid stems
made of wood and bark. These stems are called woody
stems.
Chapter 6
Section 4 Structures of Seed Plants
Chapter 6
Section 4 Structures of Seed Plants
Leaves
• Leaf Functions The main function of leaves is to
make food for the plant.
• Leaf Structure The structure of leaves, shown on
the next slide, is related to their main function—
photosynthesis.
Chapter 6
Section 4 Structures of Seed Plants
Chapter 6
Section 4 Structures of Seed Plants
Leaves, continued
• Leaf Adaptations Some leaves have functions
other than photosynthesis.
•The leaves of many cactuses are modified as
spines. These spines keep animals from eating
the cactuses.
• The leaves of sundews are modified to catch
insects, which the sundew digests.
Chapter 6
Section 4 Structures of Seed Plants
Flowers
• Flowers are adaptations for sexual reproduction.
• Sepals and Petals The modified leaves that make
up the outermost ring of flower parts and protect the
bud are called sepals.
• Petals are broad, flat, thin leaflike parts of a flower.
Chapter 6
Section 4 Structures of Seed Plants
Flowers, continued
• Stamens and Pistils The male reproductive
structure of a flower is called a stamen.
• A pistil is the female reproductive structure of a
flower.
Chapter 6
Section 4 Structures of Seed Plants
Chapter 6
Section 4 Structures of Seed Plants
Flowers, continued
• The Importance of Flowers Flowers help plants
reproduce.
• Humans use flowers for arrangement. Flowers are
also used to make spices, perfumes, and lotions.
• Broccoli, cauliflower, and artichokes are flowers that
people eat. Chamomile and hibiscus flowers are used
to make tea.
Chapter 6
Introduction to Plants
Concept Mapping
Use the terms below to complete the concept map
on the next slide.
angiosperms
vascular
plants
sporophyte
pollen
gametophyte
xylem
nonvascular
Chapter 6
Introduction to Plants
Chapter 6
Introduction to Plants