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Angiosperms: One Division, the Anthophyta,
characterized by Economy, Efficiency and
Elegance
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Intro to Angiosperms:
Amber and Insects
The (Sudden) Rise of
Angiosperms
Vascular specialization
Floral Structure
‹ 6 evolutionary trends
Fruits and Species Dispersal
Angiosperm Life Cycle
Pollination strategies: a
mutualistic coevolution
4 Principal Areas of
Adaptation
The Evolutionary Rise of
Angiosprems
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The Flower: 4 whirls of modified leaves
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Vascular tissue
) tracheids to vessel
elements
) Fiber cells and lignin
Flowers
Fruits
Life Cycle changes
6 Evolutionary Trends in Floral
Structure
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Reduction in the number of floral
parts: perfect to imperfect
flowers
Fusion of parts
Radial to bilateral symmetry
Retraction of ovary below corolla
amd calyx
Move toward separate sexes:
Monoecious to dioecious plants
Generic pollination to high
selectivity/specialization for
pollinators
Cretaceous fossils (120 mya)
2 theories on sudden
appearance:
‹ Artifact of fossil record
‹ Punctuated equilibrium
Classification: Anthophyta
‹ Descendants of
Gnetophytes?
Gnetophytes?
‹ 2 classes: Monocots and
Dicots
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sepals and calyx
petals and corolla
stamen: microspore
mother cells
carpel: stigma, style,
ovary (ovule w/
megaspore mother
cells)
6 evolutionary trends
in the angiosperm
lineage
Evolutionary Trends in Flowers
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The Fruit: the ripened ovary
grows into a dispersal agent
Pollination Strategies
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Wind vs vector pollination
Generalists vs specialization
and selectivity
Mutualistic coevolution:
coevolution:
pollen, nectar and colorful
and fragrant ads.
‹ Examples:
) maggot bearing stapelia
) Orchids
) Broom flowers
) Bucket orchid
) Yucca
) Carnivorous plants
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Dry fruits: wings and burrs
Fleshy fruits: edible flesh
with digestion resistant
seeds:
‹ Simple fruits - one
ovary/flower eg.
eg. apple
‹ Aggregate fruits - more
than one ovary from 1
flower eg.
eg. raspberry
‹ Multiple fruits - many
ovaries from many
flowers eg.
eg. pineapple
Angiosperm Life Cycle
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Angiosperm Alternation of Generations
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Male Gametophyte: mMC to pollen
‹ tube nucleus and generative nucleus
Female Gametophyte: MMC to 8 celled MgMg-phyte
‹ egg and polar nuclei
Pollination and Fertilization
‹ generative nucleus yields two sperm nuclei
‹ Double Fertilization: zygote and triploid
endosperm
) Conservation of resources
The Seed: the mature ovule found within the ovary
consisting of 2n embryo (mono(mono- or dicot),
dicot), 3n
endosperm and 2n seed coat.
Forming male and female gametophytes
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Angiosperm’s Double Fertilization
Seed Structure in Monocots and Dicots
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Germination in Monocots and Dicots
Angiosperms: Global Significance
Benefits in agriculture and medicine
„ Historical Global Impact
„ Modern Global Impact
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