Download Lesson 1 – What is a Plant?

Lesson 1 – What is a Plant?
Deborah Luff
Life Science
7th Grade
Before you begin, decide if you agree or
disagree with each of these statements.
1.
2.
3.
4.
5.
All plants produce flowers and seeds.
Humans depend on plants for their survival.
Some plants move water only by diffusion.
Mosses can grow only in moist, shady places.
Some mosses and gymnosperms are used for
commercial purposes.
6. All plants grow, flower, and produce seeds in
one growing season.
Key Concepts for Lesson 1
• What characteristics are common to all
plants?
• What adaptations have enabled plant species
to survive Earth’s changing environments?
• How are plants classified?
Vocabulary Terms
• producer
• cuticle
• cellulose
• vascular tissue
Characteristics
• Plants are made of eukaryotic cells.
• A plant cell differs from an animal cell because
it contains chloroplasts
and a cell wall.
• Chloroplasts convert light energy to chemical
energy.
Characteristics
• The cell wall provides support and protection.
• A mature plant cell has one or two vacuoles
that store a watery liquid called sap.
• Plants are multicellular.
• Some plants are microscopic, while others
are some of the largest organisms on Earth.
Characteristics
• Plants are producers—organisms that use an
outside energy source, such as the Sun, to
make their own food.
• Plants make their own food, a simple sugar
called glucose, during a process called
photosynthesis.
Adaptations
• Scientists hypothesize that present-day land
plants and green algae evolved from a
common ancestor.
• The first land plants probably lived in moist
areas.
• As land plants became more abundant, the
amount of oxygen in the atmosphere
increased because oxygen is a product of
photosynthesis.
• Many plants have a waxy, protective layer on
their leaves, stems, and flowers called the
cuticle.
• The cuticle slows the evaporation of water
from a plant’s surface and provides some
protection from insects.
• A rigid cell wall made of cellulose surrounds
the cell membrane in a plant cell.
• Cellulose is an organic compound made of
chains of glucose molecules.
• Many land plants also produce a chemical
compound called lignin which strengthens
cellulose and makes it more rigid.
• In some plants such as mosses, water and
nutrients can move from cell to cell by the
processes of osmosis and diffusion.
• Other plants such as grasses and trees have
specialized tissues called vascular tissue.
• Vascular tissue is composed of tubelike cells
that transport water and nutrients in some
plants.
• Water carries the reproductive cells of aquatic
plants from plant to plant.
• Some plants have water-resistant seeds or
spores that are part of their reproductive
process.
• Seeds and spores move through environments
in different ways, including animals and
environmental factors such as wind and water.
Classification / Diversity
• Plants that reproduce by spores often are
called seedless plants.
• Seedless plants do not have flowers.
• Some seedless plants do not have vascular
tissue and are called nonvascular plants, but
others, such as ferns, have vascular tissue and
are called vascular plants.
Classification / Diversity
• Some seed plants have flowers that produce
fruit with one or more seeds, but others, such
as pine trees, produce their seeds in cones.
• It is thought that all present-day plants
originated from a common ancestor, an
ancient green algae.
Summary Lesson 1
• Plants are multicellular producers.
• Water carries the reproductive cells of aquatic
plants from plant to plant. Land plants evolved
different reproductive strategies to ensure
their survival.
• Members of the plant kingdom are classified
into groups called divisions.
Lesson Check Question 1
Which term refers to the waxy, protective
layer on the leaves, stems, and flowers of
many plants?
A. cell membrane
B. cellulose
C. cuticle
D. vascular tissue
Lesson Check Question 2
What carries the reproductive cells of aquatic
plants from plant to plant?
A. water
B. oxygen
C. cellulose
D. carbon dioxide
Lesson Check Question 3
Plants that reproduce by spores are often
called which of these?
A. algae
B. lignin
C. producers
D. seedless plants