This document discusses the key characteristics of plants. It outlines that plants share four main characteristics: (1) photosynthesis using chlorophyll, (2) a protective cuticle layer, (3) rigid cell walls, and (4) a reproductive cycle with sporophyte and gametophyte stages. It then describes the four main groups of plants as nonvascular plants, seedless vascular plants, nonflowering seed plants, and flowering seed plants. Finally, it discusses how scientists believe plants originated from ancient green algae due to their many similarities.

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