Transcript Chapter 30: Plant Diversity

Chapter 30: Plant Diversity
The Evolution of Seed Plants
30.1
Admit Slip
3. List 3 words you think of
when you look at the
picture/diagram
2. Write 2 ideas you have
based on the picture and
your words. If possible, use
your words as you write your
ideas.
1. Write 1 question you have.
Seeds and Pollen Grains are Key
Adaptations for Life on Land
Seeds are plant embryos that have a food supply
and are surrounded by a protective coat
5 Crucial Seed Plant Adaptations
1. Reduced gamteophytes: microscopic,
dependent on sporophyte for food and
protection
2. Heterospory: production of 2 types of spores
– Megaspores: female gametophytes-produce eggs
– Microspores: male gametophytes-contain sperm
3. Ovules and the production of eggs: Increases
protection of the egg and developing zygote
5 Crucial Seed Plant Adaptations
4. Pollen and production of sperm:
pollen grains have water-proof
coating which eliminates the need for
water transfer of sperm. Inside the
pollen grain is a male gametophyte
with 2 sperm nuclei.
5. Seeds: multicellular, safe-guarding of
embryo, stored energy for embryo,
can remain dormant while awaiting
good germination conditions
Chapter 30: Plant Diversity
The Evolution of Seed Plants
30.2
Evolutionary trends in land plants
• Reduction in gametophyte
bryophytes
pteridophytes
gymnosperm
angiosperm
Gymnosperms
• “naked” seed, seeds not enclosed in ovaries,
(usually on modified leaves that form cones)
• No fruits
Gymnosperm life cycle
Pollination and Fertilization
1. Pollen lands on ovulate cone, drawn into
micropyle
2. germinates; grows a pollen tube
3. Fertilization
4. Embryo develops
5. Cones open, seeds released
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Chapter 30: Plant Diversity
The Evolution of Seed Plants
30.3
Angiosperms
• Seed plants that produce flowers and fruit
• 90% of all plants are angiosperms
Angiosperms
• Flower structures:
• Stamen: male reproductive structure-produces microspores
that develop into pollen grains
• Carpels: female reproductive struction-produces
megaspores and products (female gametophyte and egg)
Figure 38.9 Growth of the pollen tube and double fertilization
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Angiosperm life cycle
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KEY FEATURES:
Double
Fertilization
3n
endosperm
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Angiosperm Fruits
• Mature ovaries of
plant
– After fertilization, the
seed develops from
ovules. The wall of the
ovary thickens to
become fruit.
• Fruit helps to disperse
seeds
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SEED DISPERSAL
Angiosperm Classification
• Monocot:
– 1 cotyledon in seed
– Parallel leaf veination
– Flowering parts in multiples of 3’s
• Eudicot
– 2 cotyledon in seed
– Net leaf veination
– Flowering parts in multiples of 4’s and 5’s
Monocots vs. dicots
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Land Plant Evolution