Multi cellular Plants
Section 18-3, (25-2)
What is a Plant?
• • • • • Multi cellular Photosynthetic Eukaryotic Cell walls with cellulose Alternation of generation
– n to 2n – Haploid to diploid
Alternation of Generation
Cell Wall Examples
• Plants - polysaccharide is cellulose • Fungi – polysaccharide is chitin • Bacteria – polysaccharide is peptidoglycan
– (Eubacteria – True bacteria)
All Plants
Bryophytes (Mosses) Tracheophytes Vascular tissue Xylem Phloem
Ferns Spores
Gymnosperms (Conifers) Naked Seeds
Angiosperms (Flowering Plants) Enclosed Seeds
Monocots
Dicots
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
Two groups
• Bryophytes • Tracheophytes
Bryophytes
Text picture p. 427
• Mosses, liverworts, horn worts • Small - no vascular tissue • standing water needed for reproduction
Life cycle
Tracheophytes
• Ferns, Gymnosperms, Angiosperms • Vascular tissue
– xylem – phloem
Ferns (not on exam)
• Spores • Alternation of generation • Life cycle
Gymnosperms
• • • • • Conifers, Cycads, Ginkgoes Naked seeds Male cones produce pollen Female cones (seed cones) contain eggs Use alternation of generations
Seed Cone and Pollen cone
Reproduction in Gymnosperms page 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.
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?
…... 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.
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
Seed
• Plant embryo • Food supply • Protective coating
Angiosperms
• Extremely successful • flowers • seeds
What is a seed?
The Flower
• Reproductive organ in angiosperms • Flowers are formed from four types of specialized leaves: sepals, petals, stamens, carpels
Sepals
• Leaflike • Photosynthetic • Enclose, protect developing flower bud
Petals
• Brightly colored • Attract pollinators
Stamens
• • • • Male leaves Produce pollen Filament Anther
Carpels
• • • • • Female leaves One or many carpels Carpel contains ovary Ovary contains ovules Parts: stigma, style, ovary
Monocots
• • • • One cotyledon Flower parts in threes, sixes Leaves have parallel veins Vascular bundles scattered in stem
Specialized tissues in a Monocot (corn)
Dicots
• • • • Two cotyledons Flower parts in fours, fives Veins in leaves branched Vascular bundles in a ring
Specialized tissues in a woody dicot
Where is the xylem?
Where is the phloem?
Trends to watch
• Invasion of land - structures • Alternation of generation - the changes
• Roots
– Anchor plant – Absorb water
Adapting to land
• Leaves
– capture sunlight – waxy cuticle – stomata
• Vascular tissue
– xylem (water-up) – phloem (food-down/up)
Xerox 18-3
18 sexually, generation • • • • • • • 19 wetter 11 d 12 b 13 l 14 g 15 e 16 j 17 b 20 moist 21 leaf 22 stem
• • • • • • • • • •
1 d 2 c 3 i 4 a 5 k 6 h 7 f 8 n 9 o 10 m
23 water, minerals
24 stomates
25 diploid
26 the pollen grain 27 adaptations
28
• Certain types of plants need different climate conditions. The relative abundance of fossilized plants indicates the type of climate that existed.