Evolution and Diversity of Plants

Chapter 24
Evolution and
Diversity of
Plants
Outline
Evolutionary History
Alternation of Generations
Nonvascular Plants
Vascular Plants
Seedless
Seed
Angiosperms
- Monocots and Eudicots
- Flowers
Evolution and
Diversity of Plants
2
Evolution and
Diversity of Plants
Evolutionary History of Plants
More than 98% of all biomass is plants
Multicellular photosynthetic eukaryotes
Thought to have evolved from freshwater
algae over 500 mya
3
4
Common Plants Today
5
Alternation of Generations
6
Evolution and
Diversity of Plants
Evolutionary History of Plants
1. Nonvascular Plants (Mosses)
Advent of nourishment of a multicellular embryo
within the body of the female plant
2. Seedless vascular plants (Ferns)
Advent of vascular tissue
7
Nonvascular Plant Life Cycle
Vascular Plants
Evolution and
Diversity of Plants
Most seedless vascular plants are
homosporous producing windblown capable
spores which develop into hermaphrodite
gametophytes
• All seed plants are heterosporous and have
male and female gametophytes
9
Seedless vascular plant life cycle
Evolution and
Diversity of Plants
Evolutionary History of Plants
3. Gymnosperms and angiosperms (Conifers and
Cicads)
Produce seeds
4. Flowering Plants (Fruits and Flowers)
Attract pollinators that give rise to fruits
11
Seed Plant Life Cycle
Reduction in the Size of the Gametophyte 13
Nonvascular Plants
Evolution and
Diversity of Plants
Nonvascular plants (Mosses -bryophytes)
Lack specialized means of transporting
water and organic nutrients
Do not have true roots, stems, and leaves
14
Nonvascular Plants
Evolution and
Diversity of Plants
Gametophyte is the dominant generation
Sperm swim to egg in film of water to make
zygote
15
Moss
16
Vascular Plants
Evolution and
Diversity of Plants
Vascular tissue transports water and nutrients
to the body of the plant
 Xylem
conducts water and dissolved
minerals up from roots
 Phloem
conducts sucrose and other organic
compounds throughout the plant
17
18
Leaf Vascular Tissue
19
20
C – 3 Plant
C – 4 Plant
CAM Plant
Root Vascular Tissue
21
Root Vascular Tissue
22
Stem Vascular Tissue
23
Vascular Tissue
24
Seedless Vascular Plants
Evolution and
Diversity of Plants
Seedless Vascular Plants (Ferns)
Horsetails (phylum Sphenophyta)
- Rhizome produces tall aerial stems
25
Fern (Horsetail)
26
Seed Plants
Evolution and
Diversity of Plants
Seed plants are the most plentiful plants in
the biosphere
Seed coat and stored food allow an embryo
to survive harsh conditions during long
period of dormancy
- Ovule develops into seed
27
Seed Plants: Gymnosperms
Evolution and
Diversity of Plants
Gymnosperms have ovules and seeds
exposed on the surface of sporophylls
Conifers
Cycads
Ginkgoes
28
Gymnosperms
30
Gymnosperm diversity
Evolution and
Diversity of Plants
Flowering Plants: Angiosperms
Became dominant group of plants in the late
Cretaceous and early Paleocene periods
• Monocots and Eudicots
32
Monocots and Eudicots
Evolution and
Diversity of Plants
Two classes of flowering plants
Monocotyledones (Monocots)
- One cotyledon (first leafs) in seed
Eudicotyledones (Dicots)
- Two cotyledons in seed
34
Monocot and Dicot Flower Parts
petal
sepal
petal
stamen
stigma
stamen
pistil
Trillium
Monocot
Flower Parts in Multiples
of Three
Cydonia oblonga (quince)
Dicot
Flower Parts in Multiples
of Four or Five
Monocot and Dicot Seedling Growth
cotyledons
Zea mays (corn)
Phaseolus limensis (lima bean)
Monocot
One Cotyledon
Dicot
Two Cotyledons
Monocot and Dicot Root Systems
Zea mays (corn)
Monocot
Fibrous Root System
Phytolacca americana (pokeweed)
Dicot
Taproot System
Flower
38
Flowers and Diversification
Evolution and
Diversity of Plants
Fruits of flowers protect and aid in dispersal
Utilize wind, gravity, water, and animals for
dispersal
39
Ground Tissue
They function in
• Photosynthesis
• Storage
• Regeneration
• Support
• Protection.
Evolution and
Diversity of Plants
40
Ground Tissue
Evolution and
Diversity of Plants
The three types of ground tissue
• Parenchyma
• Collenchyma
• Sclerenchyma
41
Plant Cells
Evolution and
Diversity of Plants
Parenchyma
• Generalized plant cell type
• Palisade parenchyma
Spongy mesophyll
• irregularly shaped and have large
intracellular spaces.
42
Plant Cells
Evolution and
Diversity of Plants
Collenchyma
• Specialized plant cell type
• Helps support the plant
• They tend to occur as part of vascular
bundles
• Thick cell walls
44
Collenchyma
Plant Cells
Evolution and
Diversity of Plants
Sclerenchyma
• They often occur as bundle cap fibers
• Helps support the plant
• Thick cell walls that are hardened with
the protein lignin
46
Sclerenchyma
Ground Tissue
48