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Units 22 and 23 SEED PLANTS.

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Presentation on theme: "Units 22 and 23 SEED PLANTS."— Presentation transcript:

1 Units 22 and 23 SEED PLANTS

2 Nonseed Plant Life Cycle Seed Plant Life Cycle
Life Llife Cylce of Nonseed Plant Life Cycle Flagellated sperm must swim Seed Plant Life Cycle Pollination

3 Highlights in the History of Seed Plants
Late in the Devonian, some plants developed secondary growth: thickened woody stems of xylem

4 How Did Seed Plants Become Today’s Dominant Vegetation?
Surviving seed plants fell into two groups: Gymnosperms: pines and cycads Angiosperms: flowering plants

5 Gymnosperms Any vascular plant that reproduces by means of an exposed seed, or ovule “Naked Seed”

6 Gymnosperm

7 Four major phyla of living gymnosperms:
(a)Cycads: Cycadophyta Sago palm Cone-bearing palm like tropical dinosaur food ?

8 Gymnosperms b)Ginkgos: Ginkgophyta One living species, Ginkgo biloba Seed coat stinks Polluted areas 1945 atom bomb The ginkgo is a living fossil, recognizably similar to fossils dating back 270 million years.

9 Ephedra *ephedrine Gymnosperms (c) Gnetophytes: Gnetophyta
Shrubs , trees, or vines the group is a small one, consisting of three families, each with one genus, totaling 68 species Ephedra *ephedrine

10 (D)Conifers Coniferophyta
Gymnosperms (D)Conifers Coniferophyta largest group of gymnosperms pines, hemlock, spruce, evergreen conifers leaves stay all season sap ----antifreeze first real development of wood dead transport tissue

11 Gymnosperms Softwood

12 Flowering plants are the dominant plant today
Angiosperms Flowering plants are the dominant plant today

13 Angiosperms They are the largest group of plants with about 90% of all plant species. .

14 A Angiosperm Protected Seeds

15 FLOWERS are the exclusive reproductive organ of angiosperms
“The earth laughs in flowers” Ralph Waldo Emerson

16 What Features Distinguish the Angiosperms?
Angiosperm: “enclosed seed”

17 Angiosperms Female reproductive structures Carpel
Stamen Anther Filament bear microsporangia - sperm ( pollen) Female reproductive structures Carpel Stigma, style, and ovary bear megasporangia -egg (one or more carpel make up a pistil)

18 Angiosperm Pollen B - Dandelion (Taraxacum sp.) Transmission electron microscopy F Pine (Pinus sylvestis): Light microscopy G Mixed pollen grains (bright field light microscopy, stained)

19 Anigosperms Flowers may have contributed to the enormous success of angiosperms. The flowers attract a pollinators which carry pollen to other individuals of the same species

20 Angiosperms Attracted to sweet smells Need landing platform Can hover
Need bigger landing platform Like bright colors Attracted to strong smells Can hover; nocturnal Can hover Prefer red color

21 Angiosperms Double fertilization
Sperm A leads to the formation of a Seed Sperm B leads to the formation of an endosperm (a nutritive tissue within the seed that feeds the developing plant embryo)

22 Flowering plants are divided into two groups

23 Cotyledon? Embryonic seed is the first leaf or set of leaves that sprout from a seed Store nutrients for the embryo

24 A cotyledon – “seed leaf”
contain nutrients for growth during embryonic development upon germination, the cotyledon may become the embryonic first leaves of a seedling.

25 Dry fruit vs. Fleshy fruit

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