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Chapter 29 Plant Diversity
Chapter 29 Plant Diversity
1. What are the characteristics of plants?
- Photosynthetic autotrophs
Algae also
- 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
2. 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
Chapter 29 Plant Diversity
1. What are the characteristics of plants?
2. 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
3. Describe alternation of generations
Haploid multicellular
- Gametophyte (n) make gametes
organism (gametophyte)
Mitosis
Mitosis
by mitosis
n
n
n
- Sporophyte (2n) makes spores
n
n
Spores
Gametes
by meiosis
MEIOSIS
FERTILIZATION
- Alternates between sexual &
2n
asexual reproduction
Zygote
2n
Mitosis
Diploid multicellular
organism (sporophyte)
Alternation of generations: a generalized scheme
Chapter 29 Plant Diversity
1.
2.
3.
4.
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
Chapter 29 Plant Diversity
1.
2.
3.
4.
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 & Golgiderived vesicles at a dividing cell’s midline
- Used in making cell plates during cell division
- Genetic evidence
- “Deep Green”
- Nuclear & chloroplast genes
Chapter 29 Plant Diversity
1.
2.
3.
4.
5.
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”
6. 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
Figure 29.7 Highlights of plant evolution
Land plants
Vascular plants
Angiosperms
Origin of seed plants
(about 360 mya)
Origin of vascular
plants (about 420 mya)
Origin of land plants
(about 475 mya)
Ancestral
green alga
Seed plants
Gymnosperms
Pterophytes
(ferns, horsetails, whisk ferns)
Lycophytes
(club mosses, spike mosses, quillworts)
Seedless vascular plants
Mosses
Hornworts
Liverworts
Charophyceans
Bryophytes
(nonvascular plants)
Table 29.1 Ten Phyla of Extant Plants