Mead AP Biology
Lap 8A Plant Diversity
Chapter 29-30
29.1 Evolution of Land Plants
A. Share traits with algae
◦ Examples
◦ Key difference
◦ Closest relative is type of green algae
 (Rhodophyta)
 Chlorophyta
 Charophyta
B. Evidence
1. Rose-shaped complexes that build cellulose
 Fig 29.2
2. Peroxisome enzymes
3. Structure of flagellated sperm
4. Similarities in cell division
 Formation of cell plates
5. Gene analysis
C. Adaptations enabling move to land
◦ Charophytes inhabit shallow waters
◦ Develop sporopollenin
◦ Remember: Plants did not descend from Charophytes, but instead share a common
ancestor
29.2 Land Plants and Terrestrial Adaptations
A. Derived Traits of Plants, Fig 29.5
1. Apical Meristem
 Def
 Structures to collect substances
 Specialized aerial and subterranean structures
 Differentiation
2. Alternation of Generation
 Both multicellular haploid and diploid stages
 Sporophyte generation
 Gametophyte generation
3. Walled spores produced by sporangia
 Spores
 Sporopollenin
 Sponangia
4. Multicellular gametangia
 Gametes
 Archegonium
 Antheridium
5. Multicellular, Dependent Embryos
 Zygotes within females
 Embryophytes
6. Cuticle
7. Secondary compounds
 Alkaloids, terpenes, tannins
 Flavanoids
 Human use
B. Highlights of Plant Phylogeny, Fig 29.7
1. Origin of true land plants: 475 million years ago
 Bryophyta (moss)
 Nonvascular plants
2. Origin of vascular plants: 420 mya
 Pterophyta (ferns)
 Lycophyta (club moss, horsetails)
 Seedless vascular plants
3. Origin of Seed plants: 360 mya
 Anthophyta
 Gymnosperms (cones)
 Angiosperms (flowers and fruit)
29.3 Bryophytes
A. 3 Phyla
◦ Bryophyta = moss
◦ Hepatophyta = liverworts
◦ Anthocerophyta = hornworts
B. Gametes develop within Gametangia
◦ Antheridium: flagellated sperm
◦ Archegonium: 1 ovum
◦ Ovum + sperm  zygote  embryo
◦ Need water
C. Gametophyte is dominant generation
 Lacks vascular tissue
 Lacks lignin fortified tissue for height
 Contains rhizoids
 Embryo continues to grow from tip of female gametophyte
 Becomes sporophyte generation
D. Sporophyte generation
◦ Grows from tip of gametophyte (female)
◦ Foot and seta (stalk)
◦ Capsule
 Sporangia
◦ Produces spores
 Sporopollenin
◦ Protonema
E. Moss Life cycle, Fig 29.8
F. Ecological and Economic Importance
◦ Provide habitat
◦ Diverse environments
◦ Resistant to dessication, can rehydrate
◦ Sphagnum (peat) moss many uses, Fig 29.10
 Resist decay, resist bacteria mummies
 Fuel
 Gardening retain moisture in soil
29.4 Ferns and Vascular Plants
A. Origins and Traits of Vascular Plants
1. Vascular Tissue
 Function
 Xylem
 Phloem
2. Roots
3. Leaves
4. Lignin
5. Sporophyte is dominant
 Branched sporophyte
 More spores
 Allows evolution
B. Phyla of Seedless Vascular Plants, Fig 29.14
◦ Lycophyta: Club moss
◦ Sphenotphyta: Horsetails
◦ Pterophyta: Ferns
C. Ferns
◦ Sporophyte dominant generation
◦ Life cycle Fig 29.12
◦ Mature sporophyte: Frond
 Rhizome
 Fiddleheads
◦ Sori contains sporagnia that release spores
◦ Grow into gametophyte
◦ Antheridium: flagellated sperm
◦ Archegonium
D. Significance of Seedless Vascular Plants
◦ First forests in Carboniferous, Fig 29.15
◦ Evolution of vascular tissue increased rate of photosynthesis
 Increased CO2 removal form atmosphere
 Caused global cooling  glaciers
◦ Remnants of fern become coal
30.1Reproductive Adaptations of Seed Plants
A. Gametophyte is reduced
◦ Fig 30.2 Gametophyte/ Sporophyte relationship
◦ Sporophyte dominant: ferns and seeded plants
◦ Gametophyte small and surrounded
◦ Sporophyte provides nutrition
B. Seed replaces spore
◦ Seed: def
◦ All heterosporous
 Def
 Megaspore
 Microspore
◦ Megasporangium
◦ Ovule includes:
◦
◦
 Megaspore
 Megasporangium
 Sporophyte/ integument
Seed
Pollen and sperm
 Microspores  pollen grains  male gametophyte
 Sporopollenin
 Most lack flagella
 Pollen tube
30.2 Gymnosperms
A. Evolution, Fig 29.7 (page 29.7)
B. Gymnosperm Phyla, Fig 30.4
◦ Cycadophyta
◦ Ginkgophyta
◦ Gnetophyta
◦ Coniferophyta
C. Life cycle of pine
◦ Fig 30.6
1. Sporophyte
2. Ovulate cone
 Scales= 2 ovules
3. Pollen cone
 Microsporangia
 Microsporocytes
 Meiosis
 Microspores
 Pollen grains
4. Pollen grain enters
 Micropyle
 Pollen tube
5. Megasporocyte undergoes meiosis
 4 haploid cells
 1 Megaspore
6. Female gametophyte forms
 Inside megaspore
 Multiple archegonium with eggs
7. Sperm fuses with egg
8. Seed
 Embryo
 Food reserves
 Seed coat
30.3 Angiosperms
A. Flowers
◦ Animal pollination (wind)
◦
4 whorls of modified leaves, Fig 30.7
 Sepals
 Petals
 Stamen
 Carpel (pistil)
 Receptacle
◦
◦
◦
Def
Various structures, Fig 30.8
Dispersal strategies, Fig 30.9
B. Fruit
C. Life Cycle, Fig 30.10
1. Anther contains microsporangia
 Microsporocyte (2n)meiosis  Microspores (n)
2. Microspores form pollen grains
 Contain male gametophyte
3. Ovule (in ovary) contains megasporangium
 Megasporocyte (2n)  meiosis 4 Megaspores (n)
 1 forms female gametophyte = embryo sac
4. Pollen forms 2 sperm
5. Double fertilization occurs
 Sperm + egg = Zygote (2n)
 Sperm + other cells = Endosperm (3n)
6. Seed forms
 Embryo, food supply, seed coat
7. Seed germinates Sporophyte
D. Diversity
◦
◦
One phylum: Anthophyta
Main classes, Fig 30.12
 Water lilies
 Magnolias
 Monocots
 Eudicots
Characteristic Monocot
Embryo
Leaf venation
Stems
Roots
Pollen
Flowers
Eudicot
E. Importance
◦ Co-evolution
 Fig 30.13
◦ Human uses
 Table 30.1