ANGIOSPERMS FLOWERING PLANTS

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Transcript ANGIOSPERMS FLOWERING PLANTS

ANGIOSPERMS
FLOWERING PLANTS
 EVOLUTIONARY ADVANTAGES
 1. Seed production
 2. Seed dispersal
 3. Broad leafs-loose leaves
 4. Root modified for storage
ANGIOSPERMS VS GYMNOSPERMS
 Angiosperm
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vs
Xylem in abundance
Flowers and fruit
Form pistil for pollen tube
Triploid endosperm
Have vessels-long narrow
Leaves lost in cold climates
Gymnosperm
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Mostly tracheids
Naked seed-cone
Grows directly to ovule
Haploid endosperm
Have tracheids
MONOCOTS
 1. Monocotyledones: lilies, grasses, cattails, palms
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a. Leaves exhibit parallel veins
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b. Flower parts in threes or multiples of 3
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c. Embryos have one cotyledon
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d. Monocots more often possess swollen underground storage
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e. Endosperm usually present in mature monocot
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h. Scattered vascular bundles
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i. No secondary growth
FLOWERS
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A. Corolla- petals
1. Composed of petals
2. Functions to attract pollinators to flower
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B. Calyx
1. Composed of sepals
2.
Similarities in leaves and sepals, share common evolutionary origin
a. Pattern of veins
b. Coloration and form
C. Carpel-traditionally called pistil(female)
1.
Primitive plants have leaf like carpels
2.
Slender style between ovary and receptive stigma
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Ovary
a. Megasporangium(2N)
b. Meiosis produces megaspores
c. Develop into ovules
1. 2 polar nuclei(2N total)
2. 1 egg nuclei(N)
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F.
Stamen(male)
1. Composed of filament plus anther
2. Pollen produced in and matures in anthers
3 Anther contains microsporangia or pollen sacs
a. Microspore mother cells produce microspores-develop into
pollen grains
b. Mature microgametophytes
1. Two are sperm nuclei
2. Third is tube nucleus that grows into pollen tube
3.Pollen carried by numerous animals
Enhanced by various reward systems like nectar from nectaries
Evolution of floral characteristics associated with pollination
DICOT
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Dicotyledones: trees, shrubs, snapdragons, mints
a. Leaves exhibit netlike veins
b. Flower parts in fours or five's or multiples
c. Embryos have two cotyledon-starch and food
source for embryo
 d. No endosperm in mature seed
 e. Concentrated vascular tissue
 f. Cambium provides secondary growth