Multi cellular Plants

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Multi cellular Plants

• Section 18-3, (25-2)

2
What is a Plant?

• Multi cellular
• Photosynthetic
• Eukaryotic
• Cell walls with cellulose
• Alternation of generation
• n to 2n
• Haploid to diploid

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Alternation of Generation
4
Cell Wall Examples

• Plants - polysaccharide is cellulose
• Fungi polysaccharide is chitin
• Bacteria polysaccharide is peptidoglycan
• (Eubacteria True bacteria)

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All Plants
Bryophytes
Tracheophytes
(Mosses)
Vascular tissue
Xylem
Phloem
Gymnosperms
Ferns
Angiosperms
Spores
(Conifers)
(Flowering Plants)
Enclosed Seeds
Naked Seeds
Monocots
Dicots
6
Evolution of Plants

• First fossils found in Ordovician
• Silurian period
• end of global cold period
• large continental drift occurred
• warm areas for plants

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Adaptations for living on land?

• Related to green algae (same chlorophyll)
• Green algae use chlorophyll same as plants.
• Water needed for life.
• plants needed to solve the problem of living in a
  dry environment
• How to prevent water loss?

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Structures to allow for life on land?

• Internal transport system
• products of photosynthesis need to move
  throughout plant.
• Anchoring system
• water, nutrients need to come from soil
• Reproduction
• modification include pollen and seeds

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Two groups

• Bryophytes
• Tracheophytes

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Bryophytes

• Mosses, liverworts, horn worts
• Small - no vascular tissue
• standing water needed for reproduction

Text picture p. 427
Life cycle
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Tracheophytes

• Ferns, Gymnosperms, Angiosperms
• Vascular tissue
• xylem
• phloem

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Ferns (not on exam)

• Spores
• Alternation of generation
• Life cycle

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Gymnosperms

• Conifers, Cycads, Ginkgoes
• Naked seeds
• Male cones produce pollen
• Female cones (seed cones) contain eggs
• Use alternation of generations

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Seed Cone and Pollen cone
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Reproduction in Gymnospermspage 583 - notes

• Alternation of generation when the gametophyte
  develops inside the sporophyte
• It takes a year for seed to be produced.
• Female seeds released after one entire winter.

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Visualizing the Life Cycle of a Gymnosperm

• 1. What are the reproductive structures of
  gymnosperms?
• 2. What is the primary mechanism of pollen
  dispersal for most gymnosperms?
• 3. Is a pine tree diploid or haploid?
• 4. Why do the scales of a pine cone open as it
  matures?
• 5. Why are the male cones found on the bottom of
  a pine tree and the female cones found on the top?

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... Gymnosperm.Answers

• 1. Cones/scales the reproductive structures of
  gymnosperms?
• 2. Wind the primary mechanism of pollen dispersal
  for most gymnosperms?
• 3. A pine tree is diploid.
• 4. The scales of a pine cone open to release the
  seeds.
• 5. This fosters more pollination between
  different individual trees.

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Section Review 25-2

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13

• 14 angiosperms
• 15
• 16
• 17
• 18 True
• 19
• 20

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Seed

• Plant embryo
• Food supply
• Protective coating

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Angiosperms

• Extremely successful
• flowers
• seeds

What is a seed?
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The Flower

• Reproductive organ in angiosperms
• Flowers are formed from four types of specialized
  leaves sepals, petals, stamens, carpels

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Sepals

• Leaflike
• Photosynthetic
• Enclose, protect developing flower bud

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Petals

• Brightly colored
• Attract pollinators

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Stamens

• Male leaves
• Produce pollen
• Filament
• Anther

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Carpels

• Female leaves
• One or many carpels
• Carpel contains ovary
• Ovary contains ovules
• Parts stigma, style, ovary

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Monocots

• One cotyledon
• Flower parts in threes, sixes
• Leaves have parallel veins
• Vascular bundles scattered in stem

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Specialized tissues in a Monocot (corn)
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Dicots

• Two cotyledons
• Flower parts in fours, fives
• Veins in leaves branched
• Vascular bundles in a ring

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Specialized tissues in a woody dicot
Where is the xylem?
Where is the phloem?
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Trends to watch

• Invasion of land - structures
• Alternation of generation - the changes

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Adapting to land

• Roots
• Anchor plant
• Absorb water
• Leaves
• capture sunlight
• waxy cuticle
• stomata
• Vascular tissue
• xylem (water-up)
• phloem (food-down/up)

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Xerox 18-3
18 sexually, generation 19 wetter 20
moist 21 leaf 22 stem 23 water, minerals 24
stomates 25 diploid 26 the pollen grain 27
adaptations

• 1 d
• 2 c
• 3 i
• 4 a
• 5 k
• 6 h
• 7 f
• 8 n
• 9 o
• 10 m

• 11 d
• 12 b
• 13 l
• 14 g
• 15 e
• 16 j
• 17 b

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28

• Certain types of plants need different climate
  conditions. The relative abundance of fossilized
  plants indicates the type of climate that existed.