Plants are multicellular, eukaryotic organisms that perform photosynthesis. Early plants evolved on land from green algae and lacked vascular tissue. Vascular plants later evolved and had vascular tissue that transported water and nutrients. Modern plants are divided into three groups: bryophytes like mosses that reproduce via spores, pteridiophytes like ferns that have vascular tissue but reproduce via spores, and seed plants including gymnosperms like conifers that produce seeds in cones and angiosperms that produce seeds in flowers. Angiosperms are further divided into monocots and dicots. Plant tissues include dermal tissue, vascular tissue, and ground tissue that have different structures and functions.

1. Chapter 22: Plant Diversity

2. Intro to Plants
I. What is a Plant?
A. Basics
1. Multicellular
2. Eukaryotic
3. Autotrophic
4. Cells have cell walls made of
cellulose

3. B. Autotrophic
1. Photosynthesis – produces organic
compounds (a.k.a. food) using
sunlight and CO2
2. Requires Chloroplasts – organelles
where photosynthesis takes place

4. II. Establishment of Plants on Land
A. Nonvascular Plants – 1st evolved
from a multicellular green algae
1. Lack vascular tissue for transporting
water & nutrients
2. Grow close to the soil to get moisture

5. B. Vascular Plants – later evolved from
a group of nonvascular plants
1. Have vascular tissue for transporting
water & nutrients from roots to leaves
and organic material back down to the
roots.
2. 1st vascular plant was named Cooksonia

6. 3. Vascular Tissue
1. Xylem
• Composed of thick-walled cells that
conduct water/minerals from roots
through stems to the leaves.
• At maturity, xylem cells are dead,
leaving only cell walls.

7. 2. Phloem
• Composed of cells that conduct sugars
&nutrients throughout plant’s body.
• Cells are alive at maturity, & contain
cell walls, cell membrane, &
cytoplasm. Cells lack most organelles.

8. C. Absorbing Nutrients
1. Early plants lacked roots. Relied on fungi
for nutrients from the soil.
D. Preventing Water Loss
1. Cuticle – waxy covering that covers
leaves & stems to prevent water loss
through evaporation
2. Stomata – pores in leaves that allow O2,
CO2, & water to move in/out of plant
3. Roots obtain water from soil, replacing
water lost to the atmosphere

9. Cuticle
Stomata

10. E. Dispersal on Land
1. Spores – early plants produced spores
that dried out & were carried by wind
2. Pollen – special type of spore used by
seed plants; carries sperm cell
3. Seeds – plant embryo packaged with a
food source that can be carried by wind,
water, or animals

11. F. Overview of Plant Evolution
1. 1st plants lacked vascular tissue &
reproduced by spores = Bryophytes
(mosses)
2. 2nd group of plants developed vascular
tissue, but still reproduced by spores =
Pteridiophytes (ferns)
3. 3rd group of plants had vascular tissue
and reproduced by seeds
• Gymnosperms – seeds made in cones
• Angiosperms – seeds made in flowers

12. Overview of Plant Evolution

13. 3 Groups of Bryophytes:
1. Mosses 2. Liverworts
3. Hornworts

14. 2 Groups of Seedless Vascular Plants
(Pteridiophytes)
1. Club Mosses
2. Ferns

15. 2 Groups of Seed Plants
1. Gymnosperms
• Seeds do not develop with in a fruit
• Most seeds develop inside a cone

17. 2. Angiosperms
• Seeds develop within a fruit
• Fruits develop from part of a flower
• Angiosperms are also called
flowering plants

18. Flowering Plants
I. Kinds of Angiosperms
A. Monocots
1. Seeds have 1 cotyledon – embryonic
leaf
2. Long, narrow leaves with parallel veins
3. Flower parts are in multiples of 3

19. B. Dicots
1. Seeds have 2 cotyledons
2. Broader leaves with branching veins
3. Flower parts are in multiples of 4 or 5

20. II. The Flower
A. What is a flower?
1. Specialized reproductive structure

21. B. Flower Structures
1. Sepals – small leaves that protect the
outside of the flower
2. Petals – colored leaves to attract
pollinators
3. Stamen – male part; produces pollen
• Anther – top of stamen where
pollen is produced
• Filament – stalk that supports of the
anther

22. Plant Sepals Anther

23. 4. Pistil/Carpel – female part;
produces ovules
• Stigma – sticky tip of pistil to grab
pollen
• Style – stalk that supports stigma
• Ovary – base of pistil where
ovules develop

24. C. Attracting Pollinators – animals pick
up pollen & carry it to another plant
1. Brightly colored petals – bees, birds
2. Sugary nectar
3. Strong odors - bats, moths that feed at
night
4. Attractive shapes
**Wind can also disperse pollen.

25. Exploding Seeds

26. Plant Tissue Systems
I. Plant Tissue Types
A. Dermal tissue – protective, outer
layer of a plant
B. Vascular tissue – forms strands
that conduct water, minerals, &
organic compounds through plant
C. Ground tissue – makes up inside
of nonwoody plants (roots,
stems, leaves)

27. II. Dermal Tissue
A. Epidermis – “skin” of nonwoody
plants
1. Usually a single layer of cells
2. Can form hair-like extensions
• On stems & leaves, hairs trap
moisture close to surface to
prevent water loss
• On root tips, root hairs increase
surface area for more absorption

28. B. Cuticle – waxy covering over
epidermis
1. Protects plant
2. Prevents water loss by repelling
water

29. C. Dermal Tissue of Woody Plants
1. Several layers of cells and is called
cork.
2. Contains a waterproof chemical.
3. Lacks a cuticle
4. Protects plant, exchanges gases, &
absorbs minerals

30. D. Stomata
1. Cuticle will not allow gases to pass
though it, so plants need a way to
bring CO2 in and let O2 out.
2. Stomata are pores that permit the
exchange of these two gases.
3. Guard cells border each stomata
and open/close them.
4. When open, plants gain CO2 but lose
water.
5. When closed, plants conserve water,
but photosynthesis slows (no CO2).

31. Stomata

32. III. Vascular Tissue System
A. Xylem
1. Composed of thick-walled cells that
conduct water/minerals from roots
through stems to the leaves.
2. At maturity, xylem cells are dead,
leaving only cell walls.

33. B. Phloem
1. Composed of cells that conduct sugars
&nutrients throughout plant’s body.
2. Cells are alive at maturity, & contain
cell walls, cell membrane, &
cytoplasm. Cells lack most organelles.

34. IV. Ground Tissue
A. Location
1. Found between dermal and vascular
tissue.
2. Most abundant in nonwoody plants.
3. Most cells remain alive with thin cell
walls and nuclei.
4. Cells with thicker cell walls lose
their nuclei & cell contents as they
mature (they die ).

35. B. Function depends on location in a
plant
1. In leaves, ground cells perform
photosynthesis.
2. In stems & roots, ground cells mainly
support the plant & store water,
sugar, & starch.
3. In angiosperms, ground tissue makes
up the flesh of fruits.
4. Ground tissue is mainly absent in
woody plants.