Transcript Class - Educast

Class IX
Bryophytes And Tracheophytes
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Content
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Bryophytes
General Characteristics
Classification
Tracheophytes(Vascular Plants)
General Characteristics
Classification
Spermatophytes(The Seed Producing Plants)
Angiosperm
Monocot Plant
Dicot Plant
Importance Of Vascular Plants
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•All of these are land plants (terrestrial) with some
aquatic forms.
•They are very small. The sporophyte and gametophyte
have very different morphologies (heteromorphic
alternation of generations) and the sporophyte is usually
partly dependent on the gametophyte.
•Photosynthetic, non-vascular plants
•Plant body is either :•Thalloid and attached to the substratum by hair-like
structures called rhizoids (true roots are absent) or
•is differentiated into leaf-like structures (phyllids),
true stems and leaves lacking.
 Cuticle
and stomata are absent.
 The bryophytes show alternation of generations the haploid gametophyte (producing gametes for
sexual reproduction) alternates with diploid
sporophyte (producing spores for asexual
reproduction).
 Gametophytes homothallic or heterothallic.
 Thallus dichotomously branched.
 They are Monoecious or Dioecious
 The gametophyte generation is dominant, and
independent.
 The female organ is the archegonium.
 The male organs are antheridia.
The ovum remains in the archegonium and
spermatozoids swim to it by chemotaxis.
 Although bryophytes are land plants, they are still
dependent upon water for fertilization, as the sperm
swim in a water film.
 The sporophyte is attached and dependent upon the
gametophyte for nutrition i.e. is parasitic on the
gametophyte
 The diploid sporophyte usually consists of a basal foot,
an elevating seta and a terminal sporangium - the
capsule
 Spores are produced as a direct result of meiosis.
 Spores dispersed by a mechanism which ensures
dispersal in dry weather only.
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Reproduction
•Vegetative( fragmentation)
•Asexual Reproduction
•Sexual Reproduction
Alternation of generation
bryophyte life cycle
1. Gametophyte
2. Sporophyte
Classification
1. Hepaticae (liverworts)
2. Musci (Funaria)
3. Anthocerotae (Hornworts)
Oogamous type
 Gamets
1.Male Gamete (Antheridia)
2. Female Gamete (Archigonia)
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 Zygote
represents the first cell of the
sporophytic phase.
 Sporogonium
 The wall of venter forms a protective
covering to the sporogonium, called calyptra.
 the sporogonium is differentiated into a foot,
a seta and a capsule.
 The sporogonium produces haploid spores
(meiospores) which get released from the
capsule.
 hey germinate to produce new gametophytes
either directly or through a juvenile stage
called protonema.
Antherozoid mother cells are:______________
(a) Androgonia (b) antherozoids (c) Androcytes (d) None
 The basal swollen portion of the archegonium is______
(a) Venter
(b) Neck
(c) Jacket
(d) Oospere
 Which of the followings is absent in
bryophytes? _____
(a) Archegonia (b) Oosphere (c) Zoospore (d) Antheridia
of
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 Questions
What is bryophytes?
Ans.
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2. Define non vascular plants.
Ans._____________________________________
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1.
3. What do you understand about the term
Dorsiventral?
Ans.
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What is alternation of generation?
Ans.____________________________________
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5.
What is meaning of dichotomous term?
Ans.____________________________________
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6. Define the term Thallus.
Ans.____________________________________
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4.
 Cooksonia,
the first vascular land
plant
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Appeared about 420 MYA
Phylum Rhyniophyta
 Only
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a few centimeters tall
No roots or leaves
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 Xylem
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Conducts water and dissolved minerals upward
from the roots
 Phloem
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Conducts sucrose and hormones throughout the
plant
 Enable
enhanced height and size in the
tracheophytes
 Develops in sporophyte but not gametophyte
 Cuticle and stomata also found in land plants
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 Vascular
plants include seven extant phyla
grouped in three clades
1.
2.
3.
Lycophytes (club mosses)
Pterophytes (ferns, whisk ferns, and
horsetails)
Seed plants
 Gametophyte
has been reduced in size
relative to the sporophyte during the
evolution of tracheophytes
 Similar reduction in multicellular
gametangia has occurred as well
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 Stems
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Early fossils reveal stems but no roots or leaves
Lack of roots limited early tracheophytes
 Roots
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Provide transport and support
Lycophytes diverged before true roots
appeared
 Leaves
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Increase surface area for photosynthesis
Evolved twice
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Euphylls (true leaves) found in ferns and seed plants
Lycophylls found in seed plants
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 400
million years between appearance of
vascular tissue and true leaves
 Seeds
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Highly resistant
Contain food supply for young plant
Lycophytes and pterophytes do not have seeds
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Chlorophytes
Charophytes
Liverworts
Mosses
Hornworts
Lycophytes
Ferns + Allies
Gymnosperms
Angiosperms
Seeds
Flowers
Fruits
Euphylls
Stems, roots, leaves
Dominant sporophyte
Vascular tissue
Stomata
Multicellular embryo
Antheridia and archegonia
Cuticle
Plasmodesmata
Chlorophyll a and b
Ancestral alga
 Fruits
in the flowering plants (angiosperms) add
a layer of protection to seeds and attract
animals that assist in seed dispersal, expanding
the potential range of the species
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BIOLOGY FOR CLASS IX
 Gymnosperms
do not have seeds enclosed in fruit.
– most gymnosperms are cone-bearing and evergreen.
– the cone is reproductive structure of most gymnosperms.
– pollen is produced
in male cones.
– eggs are produced in
female cones.
– seeds develop on scales
of female cones.
 Cycads are gymnosperms in phylum
– look like palm trees with large cones
– grow in tropical areas
Cycadophyta.
 Ginkgos
are gymnosperms in phylum Ginkgophyta.
– only one species alive today, Ginkgo biloba
– grown in gardens and used in urban landscaping
 Conifers
are gymnosperms in phylum Coniferophyta.
– most common gymnosperms
alive today
– includes pines, spruce, cedar,
fir, and juniper
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Angiosperms have seeds enclosed in some type of fruit.
– A flower is the reproductive structure of angiosperms.
– A fruit is a mature ovary of a flower.
• Angiosperms, or flowering plants, belong in phylum Anthophyta.
Kingdom
Phylum
Class
Angiosperms- flowering plants
“angi” = enclosed
sperma=
“seed”
 seeds are enclosed in a fruit
 Examples: grasses, tulips, oaks,
dandelions
 Divided into two main groups:
Monocots & Dicots
Gymnosperms- cone bearing plants
“gymno” = bare
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sperma= “seed”
seeds grow on cones
needle like leaves
usually stay green year round
Examples: pine trees & evergreens
[blue]
[green]
[brown]
[red]
[yellow]
[green]
[blue]
[red]
[yellow]
Scientific name : Phaseolus lunatus
Scientific name : Zea mays
Examples: peanut, peas, apples, oak t
Examples: grass, wheat, palms, bananas, lily
roses, cactus
Most of the advantages of vascular tissues stem
from this functional one: A tracheophyte's xylem
and phloem--which comprise the vascular system
and are housed in the stem--enable liquids,
nutrients and energy to be transported and
distributed throughout the whole of the plant.
Bryophytes depend on diffusion to distribute any
acquired liquids, nutrients or energy.