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Four main groups of Land Plants. Bryophytes (mosses, etc.) Ferns and relatives Gymnosperms Angiosperms. Bryophytes. There are three groups of bryophytes Mosses 12,000 species Liverworts 6,500 species Hornworts 100 species. Bryophyte diversity. Hornworts 100 species.

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four main groups of land plants
Four main groups of Land Plants

Bryophytes (mosses, etc.)

Ferns and relatives

Gymnosperms

Angiosperms

bryophytes
Bryophytes
  • There are three groups of bryophytes
    • Mosses 12,000 species
    • Liverworts 6,500 species
    • Hornworts 100 species
bryophyte diversity

Bryophyte diversity

Hornworts

100 species

Liverworts 6,500 species

Mosses

12,000 species

mosses

Mosses

Mosses - 12,000 species

Widely distributed, especially in alpine, boreal,

temperate, and tropical forests

Able to live in very dry or very cold habitats

Many can dry out entirely, then rehydrate

famous mosses sphagnum

Famous mosses:Sphagnum

Wetland moss -

“peat moss”

Boggy regions dominated by it known as peat bogs or peatlands

liverworts and hornworts
Liverworts and hornworts
  • Liverworts are even less conspicuous than mosses. Some have a lobed appearance.
  • They reproduce both sexually and asexually from small bundles of cells known as gemmae.
  • Hornworts have elongated sporophytes that are hornlike in appearance. They are unusual in that each photosynthetic cell contains one large chloroplast rather than many smaller ones.
bryophytes8
Bryophytes
  • Bryophytes arose at least 400 mya and possess two adaptations that allow them to survive on land.
    • Waxy cuticle reduces water loss
    • Gametes are protected and develop within gametangia.
bryophytes9
Bryophytes
  • Bryophytes do not have a vascular system and so cannot grow very large.
  • They also need moisture to reproduce because fertilization depends on sperm being able to swim through water to reach the egg.
slide11
In bryophytes the gametophyte (haploid n) is the dominant generation and the sporophyte (diploid 2n) is dependent on the gametophyte.
bryophytes13

Bryophytes

Gametophytes only a few cells thick. No true “leaves”.

Directly absorb water & minerals.

No lignified vascular tissue.

bryophyte gametophyte

Bryophyte gametophyte

Close to the ground.

Anchored by rhizoids.

Long, tubular single cells - not tissues.

bryophyte sporophyte

Bryophyte sporophyte

3) Capsule

3 parts

2) Stalk

1) Basal foot

bryophyte life cycle

Bryophyte life cycle

meiosis

sporophyte

spores

2n

n

embryo

gametophyte

zygote

eggs

sperm

bryophyte reproduction

Bryophyte reproduction

Spores produced in capsule (sporangium)

Spores released to germinate into gametophytes.

bryophyte reproduction18
Bryophyte reproduction
  • Male gametophytes produce sperm and female gametophytes produce eggs.
  • When there is sufficient moisture sperm swim to the egg and fertilize it. Fertilized egg develops into a zygote and ultimately into a sporophyte.
seedless vascular plants ferns and fern allies
Seedless vascular plants: Ferns and fern allies

First vascular plants originated about 420 mya.

First seed plants came later about 360 mya.

Seedless vascular plants dominated the planet during the Carboniferous period (300-350 mya).

seedless vascular plants ferns and fern allies22
Seedless vascular plants: Ferns and fern allies
  • Giant tree ferns, horsetails and lycopods were the dominant vegetation of the Carboniferous period.
  • Their fossilized remains formed extensive coal beds.
  • They were ultimately superseded by the seed plants and far fewer survive today.
present day fern allies
Present day fern allies
  • Lycopods: About 1,000 species. Includes tropical epiphytes and northern hemisphere low growing club mosses.
  • Horsetails: today about 15 species of Equisetum occur in northern hemisphere in damp conditions.
slide24

Lycopod

Equisetum

ferns
Ferns
  • A very diverse group about 12,000 species most abundant in the tropics, but distributed worldwide.
  • Most are small to moderately large plants, but tree ferns are many meters tall.
common ferns
Common ferns

Staghorn fern

Maidenhair fern

Pteris

Boston fern

fern morphology
Fern morphology

Dominant generation: sporophyte

fern morphology28
Fern morphology
  • Body consists of three organs:
  • Underground rhizome (stem)
  • Adventitious roots
  • Fronds (leaves)
fern morphology29
Fern morphology
  • Underground rhizome (stem)
fern morphology30
Fern morphology
  • Adventitious roots
  • Roots that grow from anywhere but the primary root.
  • Like out of stems.
fern morphology31
Fern morphology

“fiddlehead”

  • Fronds (leaves)
fern life cycle

Fern life cycle

Independent and

dominant sporophyte

meiosis

spores

2n

n

embryo

Free-living gametophyte

zygote

eggs

sperm

slide34

Fern life cycle - spores

  • Unit of dispersal = spores
  • Produced by sporangia
  • Sporangia clustered in sori
  • (singular = sorus)
  • Usually small button-like
  • dots on backs of fronds
fern morphology37
Fern morphology
  • Free-living gametophyte
  • Also called a prothallus
  • Produces sperm and eggs
  • Sporophyte starts attached to gametophyte. Gametophyte dies after sporophyte detaches.

Sporophyte

spores and seeds
Spores and seeds
  • The spores of ferns are tiny and vast numbers are produced. However, their prospects of survival are low.
  • A new evolutionary innovation, the seed, arose in the Carboniferous Period. Seeds and later fruit proved to be enormously successful and seed plants especially angiosperms came to dominate the planet.