3/31/19 Seedless Vascular Plants The first land plants were probably moss...
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3/31/19 1 Seedless Vascular Plants • Further adaptations to land – Vascular system allows plants to get tall – Origin of leaves (megaphylls) • Lycophytes • Ferns – Life cycle – Homospory and Heterospory • Horsetails etc • Seed Plants April 1, 2019 Carboniferous The first land plants were probably moss-like (bryophytes) plants Nonvascular Plants Liverworts Origin of plants ANCESTRAL GREEN ALGA Mosses Hornworts plants vascular Seedless Vascular plants Lycophytes Origin of vascular plants Ferns, etc. Gymnosperms Origin of seed plants Angiosperms 500 Seed plants 450 400 350 300 50 0 Millions of years ago (mya) 1 2 3 Mosses Sperm Antheridia Male gametophyte (n) Egg Spores Embryo 2 mm Zygote (2n) Archegonia Female gametophyte (n) Sporangium MEIOSIS Mature sporophytes Female gametophytes Young sporophyte (2n) Moss Life Cycle Fertilization The empty niche – vertical growth • Key innovation – vascular tissue for movement of water and nutrients against gravity xylem phloem Fossil vascular plant (420 million years ago) Branching, independent sporophyte
Transcript of 3/31/19 Seedless Vascular Plants The first land plants were probably moss...
3/31/19
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Seedless Vascular Plants
• Further adaptations to land – Vascular system allows plants to
get tall – Origin of leaves (megaphylls)
• Lycophytes • Ferns
– Life cycle – Homospory and Heterospory
• Horsetails etc
• Seed Plants
April 1, 2019
Carboniferous
The first land plants were probably moss-like
(bryophytes) plants N
onvascular
Plants
Liverworts
Origin of plants ANCESTRAL GREEN ALGA
Mosses
Hornworts
plants vascular Seedless
Vascular plants
Lycophytes
Origin of vascular plants Ferns, etc.
Gymnosperms Origin of seed plants
Angiosperms
500
Seed plants
450 400 350 300 50 0 Millions of years ago (mya)
1
2
3
Mosses Haploid (n) Diploid (2n)
Sperm Antheridia
Male gametophyte (n)
Egg
Spores
Embryo
2 m
m
Zygote (2n)
Archegonia Female gametophyte (n)
Sporangium
MEIOSIS Mature sporophytes
Female gametophytes
Young sporophyte (2n)
Moss Life Cycle
Fertilization
The empty niche – vertical growth
• Key innovation – vascular tissue for movement of water and nutrients against gravity
xylem
phloem
Fossil vascular plant (420 million years ago)
Branching, independent sporophyte
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Vascular system allowed the evolution of wood and leaves
(bryophytes) plants N
onvascular
Plants
Liverworts
Origin of plants ANCESTRAL GREEN ALGA
Mosses
Hornworts
plants vascular Seedless
Vascular plants
Lycophytes
Origin of vascular plants Ferns, etc.
Gymnosperms Origin of seed plants
Angiosperms
500
Seed plants
450 400 350 300 50 0 Millions of years ago (mya)
1
2
3
Vascular systems permitted evolution of new specialized plant organs
Roots
Leaves
Lycophytes
Ferns
Horsetails
Three main groups: Early vascular plant forest, carboniferous
period (300 million years ago)
Vascular Plants
The Lycophytes: spore-dispersed plants with microphylls
Lycophytes Ferns etc Seed Plants
microphylls
Here are two Lycophytes you can find in Vermont
Ground cedar Shining clubmoss
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Lepidodendron - the scale tree of the Carboniferous coal swamp
The remains of the Carboniferous scale trees form the great coal deposits of the world
Vascular Plants
The Ferns and friends: spore-dispersed plants with true leaves (megaphylls)
megaphylls
Lycophytes Ferns etc Seed Plants
Figure 21.10 Evolution of Leaves
Ferns - the second-most diverse group of vascular plants
ca. 12,500 species
Homospory and Heterospory
Clumps of sporangia (sori) on the underside of a fern leaf
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Fig. 29-13-3
Key
Haploid (n) Diploid (2n)
MEIOSIS Spore dispersal
Sporangium
Sporangium Mature sporophyte (2n)
Sorus
Fiddlehead
Spore (n)
Young gametophyte
Mature gametophyte (n) Archegonium
Egg
Antheridium
Sperm
FERTILIZATION New sporophyte
Gametophyte
Zygote (2n)
Bryophyte Pteridophytes Gymnosperm Angiosperm
All land plants alternate generations, although the gametophyte became less and less prominent
Fern gametophyte with new sporophyte
ca. 5 mm
Horsetails
Scouring rush
Field horsetail
The Geologic Timetable
<Permian Climate was warming and drying … not a great time to be a spore-dispersed plant!
Vascular Plants
Clubmosses and friends
Ferns and Friends
Seed Plants
megaphylls
seeds
