1. Evolution and Diversity of Plants
Chapter 24

2. Evolution
Modern day plants evolved from freshwater green algal species
Evidence
both contain chlorophyll a and b
store excess energy as starch
have cellulose cell walls
Stone warts are the closest DNA relative

3. Evolution had 4 major events
1-Nonvascular plants have multicellular embryos that are protected and nourished within structures that produce eggs
2- Seedless vascular plants- Vascular tissue conducts water and organic nutrients within its roots, stems, and leaves Approx- 430 million years ago

4. Evolution had 4 major events
3- Gymnosperms- Seeds produced in cones. These highly resistant structures are capable of waiting for a favorable environment before germinating. Approx- 400 million years ago
4- Angiosperms- Seeds protected by fruits and the presence of flowers with a need for pollinators. Approx- 135 million years ago

5. Alternation of Generations

6. Alternation of Generations
2 multicellular individuals alternate, each producing each other.
sporophyte (2n)- produces spores through meiosis
gametophyte (n)- produces gametes

7. Alternation of Generations
Meiosis produces haploid spores in sporophytes. Spores go through mitosis and become gametophytes. Zygotes go through mitosis to produce sporophytes

8. Alternation of Generations
Plants differ as to which generation is dominant.
Archegonia→ female gametophyte
Antheridia→ contain flagellated sperm
Pollen Grains→mature sperm from seed plants

9. Other adaptations
Cuticles
Stomatas

10. Nonvascular Plants
lack a specialized means of transporting water and nutrients
lack true roots, stems, and leaves.
Bryophytes is used to describe nonvascular plants.
Gametophytes are the dominant generation.
Sperm must swim in film of water to archegonia.
May reproduce asexually, allowing them to live in harsh environments

11. Hornworts- Phylum Anthocerophyta
“Herb”
Live in moist, well-shaded trees
May have symbiotic relationship with cyanobacteria
Can reproduce asexually through fragmentation

13. Liverworts- Phylum Hepatophyta
Terrestrial, epiphytic, or aquatic
Majority have leafy bodies
Thallose grow on creek banks after a fire

15. Marchantia Lower surface has hair like extensions called rhizoids.
Rhizoids are for anchorage and limited absorption.
Sexually and asexually reproduces.

16. Moss- Phylum Bryophyta
3 Distinct Classes:
Peat Moss
True Moss
Rock Moss
May live in almost any environment.

17. Moss reproduction May reproduce asexually through fragmentation
Sexual reproduction is depicted to the right

18. Vascular Plants- Phylum Rhyniophyta
Early vascular plants were homosporous
Dominant sporophyte generation has several characteristics that allowed for successful colonization of land
Xylem- water and dissolved minerals upward
Phloem- sucrose and other organic materials throughout the plant
Lignin- strengthens plants
Now seed plants are heterosporous.

19. Seedless Vascular Plants
Dominant through the Devonian period to the Carboniferous period

20. Club Moss- Phylum Lycophyta
Dominant generation is the sporophyte
Rhizome- horizontal underground stem
3 genera:
Ground Pines-microphylls, homosporous
Spike Mosses-macrophylls, heterosporous
Quillworts-macrophylls, heterosporous

21. Horsetails- Phylum Sphenophyta
Inhabit wet, marshy environments
Strobilus
Branches
Node
Leaves
Rhizome
Roots

22. Whisk Fern- Phylum Psilotophyta
Live in southern climates as epiphytes or on the ground
Have no leaves
Sporangia found on short side branches

23. Ferns- Phylum Pterophyta
Found in warm, moist, tropical regions
Fronds are leaves of ferns divided into leaflets
Can be used to remove formaldehyde from the air, expel tapeworms, and have medicinal value

24. Seed Plants -Devonian period
-Seeds contain sporophyte embryo and stored food within a protective coat
can remain dormant for hundreds of years
-Heterosporous
pollen grains contain multicellular male gametophyte

25. -No exterior water required for fertilization
-Female gametophyte develops in ovule

26. Gymnosperms (naked seed)
All have ovules and exposed seeds
Carboniferous period- became dominant during Triassic period

27. Life cycle- see page 425 Figure 24.18

28. Conifers- Phylum Coniferophyta
contains pines, spruces, firs
majority bear cones
phylum contains oldest tree and tallest tree
tough needle-like leaves conserve water due to thick cuticle and recessed stomata

29. Phylum Coniferophyta
sporophyte generation is dominant- pollen is wind blown and seed dispersal is in dispersal stage
monoecious- tree produces both pollen and see
used in construction, as fungal and insect repellant

30. Cycad- Phylum Cycadophyta
native to tropical and subtropical areas
resemble palms
dioecious
risk for extinction because of slow growth rate

31. Ginkgos- Phylum Ginkgophyta
1 surviving species
dioecious

32. Gnetophyta- Phylum Gnetophyta
extremely diverse phylum
all have
similar xylem
no archegonia (evidence to support them being closest relative to angiosperms)
cones have similar construction

33. Angiosperms ovules always enclosed within diploid tissues
DNA sequencing is being used to determine ancestry
2 classes
Monocotyledones- monocots- 1 seed leaf in seeds. Corn, tulips, and pineapples are examples
Eudicotyledones- dicots- 2 cotyledones in seeds. Strawberries, cactus are examples.

34. Monocots Dicots One Cotyledon Two Cotyledon
Flower parts in threes or multiples of three
Flower parts in fours or multiples of fours
Usually herbaceous
Woody or herbaceous
Usually parallel venation
Usually net venation
Scattered bundles in stem
Vascular bundles in ring
Fibrous root system
Taproot system

35. Flower parts
Sepals- (calyx) protect the flower bud before it opens. May fall off or remain attached. May be green or colored
Petals- (corolla) attract a particular pollinator. Very diverse
Stamens- consist of the anther, saclike, and filament (slender stalk)
Carpel- vaselike- made of stigma, enlarged sticky knob; style, slender stalk; ovary, enlarged base that encloses one or more ovule. Ovule becomes seed and ovary becomes fruit
Flowers may or may not have all the above parts (incomplete)

36. Life cycle- see page 430 Figure 24.26