1. Introduction
to Plants

2.  Plants have 4 Plant
characteristics
that they all share: Characteristics
 (1) Photosynthesis
– Plants are green
because they
contain
chlorophyll
– Chlorophyll: green
pigment that
captures energy
from sunlight,
found in
chloroplasts

3. – Plants use energy
from sunlight to
make food from
carbon dioxide and
water—this
process is known
as photosynthesis
– Plants are
producers—they
make their own
food

4.  (2) Cuticles
– Plants don’t dry out
because they are
protected by a
cuticle
– Cuticle: a waxy
layer that coats
most of the
surfaces of plants
that are exposed to
air

5.  (3) Cell Walls
– Plants do not have a
skeleton like animals
– They stay upright and
are protected because
they are surrounded by
a rigid cell wall
– Cell wall is made of
carbohydrates and
proteins
– Some plants form a
secondary cell wall
this stops them from
growing larger

7.  (4) Reproduction
– Plants have 2 stages in their life cycle:
sporophyte stage and gametophyte stage
– In the sporophyte stage plant makes spores
– In suitable environment, spores grow & these
new plants are called gametophytes

8. – During gametophyte stage, female gametophytes
produce eggs and male gametophytes produce
sperm.
– Sex cells cannot grow directly into new plants—a
sperm must fertilize an egg
– The fertilized egg grows into a sporophyte, makes
more spores, and the cycle starts again

9. Check for Understanding
 What are 4 characteristics that all
plants share?
Photosynthesis, cuticle, cell wall, and
reproduction

10. 4 Main Groups of Plants
 First they can be classified as nonvascular plants and
vascular plants
 Vascular plants are further divided into 3 groups:
– (1) seedless plants
– (2) nonflowering seed plants (gymnosperms)
– (3) flowering seed plants (angiosperms )

11. Seedless Plants
***2 groups of plants don’t make seeds:
 (1) Nonvascular Plants
– Three groups of plants that lack specialized
conducting tissues and true roots, stems, and leaves
– Depend on diffusion to move materials from one part
of plant to another
– Most are small
– Usually live in damp places
– Don’t have true stems, roots, or leaves

12. – 3 groups of nonvascular plants are
liverworts, hornworts, and mosses
liverworts hornworts mosses

13. Mosses, Liverworts,
and Hornworts
– Have leafy stalks and
rhizoids
– Rhizoid: a rootlike
structure in nonvascular
plants that holds the
plants in place and helps
plants get water and
nutrients
– Have 2 stages to their
life cycle

14. – Importance of Nonvascular Plants
 Usually the first plants to live in a new
environment, such as newly exposed rock
 When they die, they form a thin layer of soil
 Hold soil in place, reducing erosion
 Some animals eat nonvascular plants
 Other animals use them for nesting
material
 Peat mosses are important to humans
because they can be dried out and burned
as fuel

15.  (2)
Seedless
Vascular Plants
– Ferns, horsetails, and
club mosses are
usually much smaller
than in the past—
some ferns grew 8
meters tall in ancient
forests!
– Because they have
vascular tissues, they
are often larger than
nonvascular plants

16.  Ferns
– Have a rhizome
an underground
stem from which
leaves and roots
grow
– Fern leaves are
called “fronds”
– -The end of the
fronds are called
fiddle heads

17.  Club Mosses
– Have vascular tissue, so not
actually a moss
 Horsetails
– Stems are hollow and
contain silica—gives them
gritty texture
– Early Americans used
horsetails to scrub pots and
pans

18. – Importance of Seedless Vascular Plants
 Help form soil & prevent erosion
 Ferns add to soil depth, helping other plants to
grow
 Popular houseplants
 Fiddleheads of ferns and some horsetails can
be eaten
 Horsetails are used in some dietary
supplements, shampoos, and skin-care
products
 Remains of ancient ferns, horsetails, and club
mosses form coal, which humans rely on for
energy

19. Check for Understanding
 Name & describe the 4 main groups of
plants
1)nonvascular: no specialized tissues
2) Seedless vascular: ferns, horsetails,
club mosses
3) Gymnosperms: nonflowering seed
4) Angiosperm: flowering seed

20.  The Origin of Plants
– Green algae may look like a plant, but it isn’t a
plant
– Scientists think that green algae and plants
share a common ancestor because of the
following similarities:
 Both have the same kind of chlorophyll
 Have similar cell walls
 Both use photosynthesis to make own food
 Both store energy in form of starch
 Both have a two-stage life cycle

21. The similarities between a modern green algae
(right) and plants, such as ferns (left), suggest
that both may have originated from an ancient
species of green algae.

22. Check for Understanding
 Explain the origin of plants
-scientists think that green algae and
plants share a common ancestor