1. Introduction to Plants
Mrs. M. Rightler

2. Earliest Plants
Algae
Phytoplankton
Lived in the sea

3. Problems with life on land
Drying Out
Making Food
Reproduction
Gravity & Support
Getting water & nutrients
Solution
Waxy cuticle, stomata
Formed leaves
Develops spores & seeds
Bark (cork) & vessels
Roots & vessels

4. Avascular Tracheophytes Types of Plants Bryophytes nonseed plants
vessels for transport and support

5. Mosses & Liverworts: The Bryophytes
First land plants
AVASCULAR = very small
500 m.y.a.
Must grow in moist environments
Used for fuel (peat)

6. Reproduction in Bryophytes
Mosses have a protonema (liverworts do not)
Sexual reproduction
Antheridium – makes sperm
Archaegonium – makes eggs
Asexual reproduction
Fragmentation
Formation of gemmae

7. Tracheophytes Vessels Spores or seeds for reproduction
XYLEM = transports water & dissolved minerals from roots to leaves
PHLOEM = transports sugars from leaves to rest of plant
Spores or seeds for reproduction

8. Club Mosses (Lycophyta)
Leaves produce spores
Strobilus = spore-bearing leaves
Prothallus = produces antheridia & archaegonia

9. Horsetails (Sphenophyta)
Jointed stems
Reproduction similar to club moss

10. Ferns (Pterophyta) 400 m.y.a. Dominant form = sporophyte Structure
Rhizome = underground stem
Fronds = leaves
Sori = store spores on underside of fronds

11. Gymnosperms Gymno = “naked” Sperm = “seed”
First plants to produce seeds
No flowers
No fruit

12. Why Make Seeds? Has own food supply
Protective coat against harsh conditions
Some are designed for travel to new areas

13. Sporophytes produce: MICROSPORE MEGASPORE Produce male gametophyte
Produce pollen
MEGASPORE
Produce female gametophyte
Produce ovule (makes archaegonia with egg cells)

14. Gymnosperm Reproduction
Pollen grains carried by wind
Land on ovule, develop pollen tube
Sperm move through tube to fertilize egg
Fertilized egg = ZYGOTE
EMBRYO = young, diploid sporophyte plant
COTYLEDONS = food storage for embryo, become first leaves

15. Why Pollen Instead of Spores?
Plant can live in very dry areas
Fertilization does not require water
Pollen has protective coat and food supply for sperm

16. Why Ovules Instead of Archaegonia?
Protective tissues prevent drying out
Ovule holds archaegonia and protects eggs from elements

17. Minor Gymnosperm Groups
Cycadophyta (1st in Triassic Era)
Ginkgophyta
Only one species today Ginkgo biloba
Most lived 200 m.y.a.
Gnetophyta – only three genera
Gnetum – house plants
Ephedra – weight loss, allergies & asthma
Welwitschia

18. Coniferophyta (largest group)
Needle or scale-like leaves
Bear seeds in woody cones
Can live in very cold climates
Most are evergreens
Have wood
Made of thick-walled vessels (TRACHEIDS)
Tracheids are xylem

19. Angiosperms Angio – “flower” Sperm – “seed” Extremely diverse
All have seeds enclosed in fruit

20. Cambium Any growth tissue in plants Types of cambium
Vascular = produces xylem & phloem
Cork = produces cork (bark)

21. Overall Structures [121]
Roots
Stems
Leaves
Flowers

22. Roots [124] Absorb water & nutrients Hold plant in place Root types:
Fibrous
Tap
Prop
Aerial

23. Stems [123] Support leaves & flowers Sometimes photosynthesis
Transport (contain xylem & phloem)
Types
herbaceous – green & flexible
Woody – stiff, have cork layer, usually brown

24. Leaves [119] Cuticle = protection
Stomata = gas exchange, water loss (transpiration)
Epidermis = protection, color
Mesophyll
Palisade = most PHOTOSYNTHESIS
Spongy = Vascular bundles run through it

25. Flowers [131] Pistils = female reproductive structures
Stamens = male reproductive structures
Complete flowers
Have petals & sepals
Have male and female parts
Incomplete flowers = missing one or more parts

26. Types of Angiosperms [115]
Monocots
mono = “one”
cot = “seed leaf”
Approx. 60,000 species
Flowers = multiples of 3
Leaf veins parallel
Dicots
di = “two”
cot = “seed leaf”
Approx. 170,000 species
Flowers = multiples of 4 or 5
Leaf veins branching

27. Plant Tropisms Tropism = plant response to external stimulus Types:
Positive: plant moves toward stimulus
Negative: plant moves away from stimulus
Types:
Phototropism = light
Gravitropism = gravity
Thigmotropism = touch
(nastic movement – direction does not matter)

28. Plant Hormones
Hormone – chemical produced in one part of an organism that has an effect on a different part of the organism
Types
Auxins – regulate growth
Gibberellins – speeds growth, germination
Abscisic acid – dormancy, close stomata, stress
Ethylene – ripens fruit