1. Chapter 29 Plant Diversity
What are the characteristics of plants?
Photosynthetic autotrophs
Cellulose in cell walls
Starch as storage polysaccharide
PROBLEM – light, CO2 & air are above ground
- water & minerals are below ground
SOLUTION – evolution of specialized structures
What adaptations do plants have for survival on land?
Stomata – pores used for gas exchange
Roots – absorb water & minerals from underground
Apical meristems – tips of shoots & roots where growth occurs
Cuticle – waxy covering to prevent water loss thru leaves
Jacketed gametangia – gamete producing organ with protective jacket of cells to prevent dehydration
Sporopollenin – polymer that formed around exposed zygotes & forms walls of plant spores preventing dehydration
Lignin – structural polymer that provides strength for woody tissues of vascular plants
Algae also

2. Alternation of generations: a generalized scheme
Chapter 29 Plant Diversity
What are the characteristics of plants?
What adaptations do plants have for survival on land?
Stomata – pores used for gas exchange
Roots – absorb water & minerals from underground
Apical meristems – tips of shoots & roots where growth occurs
Cuticle – waxy covering to prevent water loss thru leaves
Jacketed gametangia – gamete producing organ with protective jacket of cells to prevent dehydration
Sporopollenin – polymer that formed around exposed zygotes & forms walls of plant spores preventing dehydration
Lignin – structural polymer that provides strength for woody tissues
Describe alternation of generations
Alternates between sexual
& asexual reproduction
Gametophyte (n) make gametes
by mitosis
Sporophyte (2n) makes spores
by meiosis
Haploid multicellular
organism (gametophyte)
Mitosis
Gametes
Zygote
Diploid multicellular
organism (sporophyte)
Alternation of generations: a generalized scheme
MEIOSIS
FERTILIZATION 2n n
Spores

3. Chapter 29 Plant Diversity
What are the characteristics of plants?
What adaptations do plants have for survival on land?
Describe alternation of generations
What is the evidence that plants evolved from charophytes (green algae)?
rose-shaped complexes for making cellulose
Proteins in the plasma membrane that make cellulose microfibrils
Linear arrays found in non-charophytes
Similar %age of cellulose found in plants & charophytes
30 nm

4. Chapter 29 Plant Diversity
What are the characteristics of plants?
What adaptations do plants have for survival on land?
Describe alternation of generations
What is the evidence that plants evolved from charophytes (green algae)? Similarities??
rose-shaped complexes for making cellulose
Proteins in the plasma membrane that make cellulose microfibrils
Linear arrays found in non-charophytes
Similar %age of cellulose found in plants & charophytes
Peroxisome enzymes
Sperm structure – flagella
Formation of phragmoplast
Phragmoplast – an alignment of cytoskeletal elements & Golgi-derived vesicles at a dividing cell’s midline
Used in making cell plates during cell division
Genetic evidence
“Deep Green”
Nuclear & chloroplast genes

5. Chapter 29 Plant Diversity
What are the characteristics of plants?
What adaptations do plants have for survival on land?
Describe alternation of generations
What is the evidence that plants evolved from charophytes (green algae)?
How did plants evolve from green algae?
Natural selection
Algae best suited genetically for a drier climate (low water in a lake) could reproduce & pass along those genes to create a new population of better adapted “algae”
What were the highlights/adaptations of plant evolution?
Movement to land led to Bryophytes (mosses & worts)
Tougher spores (sporopollenin)
Jacketed gametangia
Vascular tissue (ferns)
Cells joined to transport water & nutrients
Lacked seeds
Development of seeds (Gymnosperms)
More protection of embryo
Embryo w/ food
Development of flowers (Angiosperms)
Complex reproductive structure

6. Figure 29.7 Highlights of plant evolution
Bryophytes
(nonvascular plants)
Seedless vascular plants
Seed plants
Vascular plants
Land plants
Origin of seed plants
(about 360 mya)
Origin of vascular
plants (about 420 mya)
Origin of land plants
(about 475 mya)
Ancestral
green alga
Charophyceans
Liverworts
Hornworts
Mosses
Lycophytes
(club mosses, spike mosses, quillworts)
Pterophytes
(ferns, horsetails, whisk ferns)
Gymnosperms
Angiosperms

7. Table 29.1 Ten Phyla of Extant Plants