Download Seed Plants

Seed Plants
Seed Plants
• Seed - an embryo of a plant encased in a
protective coating & surrounded by a food
supply
General Characteristics
• Life cycles alternate between gametophyte
& sporophyte generations
• Do not require water for fertilization
Seed Plants
• Seed plants are divided into 2 groups:
– Gymnosperms
• Cones – sporophyte structure where
gametophytes grow & mature
• Seeds exposed directly on the surfaces of cones
– Angiosperms
• Flower - sporophyte structure where gametophytes
grow & mature
• Seeds within a layer of tissue that protects the
seed
Pollination
•
Pollen Grain
1. Contains the male gametophyte
2. Pollination – when pollen grain is carried to
the female reproductive structure by wind,
insects, or small animals
Gymnosperms – “Naked Seed”
• Most gymnosperms & some angiosperms
are wind pollinated
Groups of Gymnosperms
• Gnetophytes
– About 70 present-day species
– Mostly desert-type habitats
• Cycads
– Palm-like plants that produce large cones
– Mostly tropical & subtropical habitats
Groups of Gymnosperms
• Ginkgoes
– Only one species, native to China
– Survives because of cultivation
• Conifers
– The largest & most common gymnosperms are the
conifers – more than 500 known species
– Includes pines, spruces, firs, cedars, sequoias,
redwoods, junipers, & yews
– Most are evergreens, retaining their leaves
throughout the year
Lifecycle of Gymnosperm
Angiosperms
Angiosperm Facts
• Angiosperms have a unique reproductive organ called
FLOWERS
• Many produce fruit = a wall of tissue surrounding a seed
• The seed leaves of plant embryos are called cotyledons
• Flowers that complete an entire life cycle within one
growing season are called –annuals
• Most are pollinated by animals
Monocots and Dicots – 2 classes of Angiosperms
• Named for the number of seed leaves
(cotyledons) in the plant embryo
• Cotyledon helps provide a food source for
the developing plant
Monocots
Seed
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Root
Stem
Leaves
Flower
Cotyledons = 1
Root = Fibrous root
Stem = vascular bundles scattered throughout
Leaves = Parallel venation
Flower = parts in multiples of 3
Dicots
Seed
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•
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Root
Stem
Leaves
Flower
Cotyledons = 2
Root = taproot
Stem = vascular bundles arranged in a ring
Leaves = Branched venation
Flower = parts in multiples of 4 or 5