Download Investigation 19- A survey of plant kingdom

6.2 CLASSIFICATION OF PLANTS
Time required: 2 periods
Name:_____________
Introduction: All plants are placed in the Kingdom Plantae. Plants are then divided in two Divisions: Vascular and Non-Vascular. Vascular plants
known as Tracheophyta have vascular bundles consisting of xylem vessels and phloem vessels. Xylem vessels carry water and minerals and
phloem vessels carry nutrients. Non-vascular plants do not have vascular bundles. Divisions are divided into classes, and they, in turn, into orders,
families, genera and species. The major divisions of plant kingdom are: bryophyta (mosses and liverworts), pteridophyta (seedless plants),
Spermatophyta (produce by seeds) coniferophyta (conifers), angiosperms (flowering plants) and gymnosperms (non-flowering plants).
Angiosperms are again divided into monocotyledons (have one seed leaf) and dicotyledons (have two seed leaves). Fungi are plants, which have no
chlorophyll and are placed in a separate kingdom Fungi kingdom. Algae, like plants, are photosynthetic and manufacture their own carbohydrates,
but they are classified in the kingdom protista. Algae are photosynthetic plant like organisms which are placed in kingdom protista. Fungi are
classified in the kingdom fungi. Fungi, unlike plants and algae, cannot manufacture their own food by photosynthesis. They need an external source
of nutrients. Lichens are also classified in the kingdom fungi, but they are actually mutually beneficial associations between certain fungi and
photosynthetic algae or bacteria. The alga produces sugars by photosynthesis and the fungus creates a thallus or body that houses both organisms.
This collaboration enables lichens to colonise harsh, exposed habitats where few other organisms can survive.
Pre-lab activity: Get yourself familiar with the characteristics of different types of plants prior to the lab and define the key terms.
Key terms: Tracheophyta, bryophyta, pteridophyta, spermatophyta, angiosperm, gymnosperm, vascular plants and non vascular plants
Objectives: To classify plants into different divisions and classes by observing their external characteristics and mode of reproduction.
Apparatus and materials:
Moss with spores
and rhizoids
Pine with leaves
and cones
Magnifying glass
Liverwort with spores
Lichen
Geranium plants with leaves
and flowers
Lab coat
Lily plant with leaves
and flowers
Disposable gloves
Fern with roots
and leaves with spores
Bean plant with
roots and seeds
Magnifying glass
Corn plant with
roots and seeds
Note: If live or preserved specimens (which are preferable) are not available, use clear photographs or diagrams.
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Plant kingdom
Bryophyta
No vascular bundles
Bryopsida
e.g. moss
Hepataopsod
a
e.g. liverwort
Traceophyta
Have vascular bundles
Arthoceropsi
da
Pteridophyta
No seeds
Spermatophyta
Have seeds
e.g. hornwort
Pteridopsida
e.g fern
Psilopsida
Sphenopsida
e.g whisk fern
e.g horse tail
Gymnosperms
Have no flowers
Penopsida
e.g Pine tree
Psycadopsid
a
e.g Cycad
Angiosperms
Have flowers
Gingkopsid
a
Gnetopdida
Monocot
s
e.g ginkgo
e.g gnetophyte e.g wheat plant
Figure 1- Plant classification flow chart
Dicots
e.g flowering plant
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Table 1- Distinguishing features of plants in different divisions, classes and subclasses
Phylum
Division
Non vascular
plants
Have no
vascular
bundles
Bryophyta
Class and subclass
Class- Bryopsida-Mosses
Class- Hepatopsida-Liverworts
Class-Arthoceropsida-hornworts
Pteridophyta
Seedless plants
Class-Pteridopsida -Ferns
Class- Psilopsida – whisk ferns
Class- Sphenopsida - Horse tails
Class- Gymnospermae
Nonflowering plants
Subclass – Pinopsida- conifers
Tracheophyta
Vascular
plants
Have vascular
bundles
Subclass-Cycadopsida- cycads
Spermatophyta
Seeded plants Subclass-Ginkgopsida- ginkgo
Subclass-Gnetopsida- Gneto
phytes
Distinguishing features
Bryophytes do not have true stems. roots, leaves and vascular bundles.
Mosses have a thalloid (stem like structure) and rhizoids (root like
structures) which anchor them. Spores are produced in spore sacs. Have no
vascular bundles. Gametophytic generation alternates with the sporophytic
generation
In leafy liverworts the stems-and leaves make up the gametophyte, while
the sporophyte is typically a blackish spore capsule.
In hornworts the elongated horn-like structure, is the sporophyte. The
flattened, green plant body of a hornwort is the gametophyte plant.
Pteridophytes are simple vascular plants lacking true roots and, in some
species, leaves. They reproduce by spores. They have rhizoids to anchor
them. In all Pteridophytes the dominant plant is the sporophyte which
produces by spores with the gametophyte which produces male and female
gametes
Ferns do not have true leaves as many plants do, but have structures called
fronds. Ferns reproduce by spores. The fern itself is the sporophyte, which
produces asexual spores. The spores are held in special sacs scattered on the
bottom part of fronds.
Whisk fern is a rootless, green-stemmed epiphyte. The plant is regularly
branched, with scale like outgrowths that resemble small leaves. A
subterranean rhizome anchors the plant
Horse tails resemble the tail of a horse. In these plants the leaves are
greatly reduced and are arranged in whorls...
Gymnosperms are a group of vascular plants whose seeds are not enclosed
by a ripened ovary (fruit). They have true roots, stems and leaves.
Conifers have needle-like leaves, spirally arranged. Large trees with woody
stems. Do not produce flowers. Stems are usually unbranched.
Cycads have palm like compound leaves. Produce seeds in cones
The gingko is a tall tree with deciduous fan-shaped leaves; the only living
descendant of a once-large group. Produces seeds in cones
Gnetophytes are cone-bearing desert plants. Resemble flowering plants in
many ways; were once thought to be link between conifers and
angiosperms.
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Class- Angiospermae
Flowering plants
Subclass- Dicotyledonae
(2 cotyledons)
Subclass- Monocotyledonae
(1 cotyledon)
Angiosperms are flowering plants. They have true roots, stems, leaves and
flowers. They also have seeds which are enclosed in the ovary. They are
divided into monocots and dicots.
Dicot flower parts are in multiples of 4 or 5. Leaf veins are net like, seeds
have two cotyledons, have tap root system
Monocot flower parts are in multiples of 3. Leaf veins are parallel, seeds
have one cotyledon, have fibrous roots
Method:
Note: Plants are classified by observing their physical characteristics and mode of reproduction.
1. Collect various plant specimens and place them on your table.
Observe the following features while classifying plants:
a. Stem: woody, soft (herbaceous), hollow or solid.
b.
Roots: fibrous or tap root system
c. Leaves: long, narrow or broad, needle like, small or large
d.
Thallus: leaf like structure
e.
Rhizoids: root like structures
f. Veins: parallel or net like
g.
Flower parts: multiples of three or multiples of 4 or 5
h.
Spores: under the leaf or in spore sacs
i. Seeds: inside cones or enclosed in a fruit
j.
Cotyledons: two cotyledons or one cotyledon
k. Vascular tissue: present or absent
2. Look at the external features of each specimen and record your observations in table 1.
3. After completing the table, identify the division and class to which each specimen belongs to.
Caution:
 Do not dispose of plant specimens in the sink. Place them in a specified container.
 Wash your hands after handling specimens
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Results: Table 2 –Complete the table with the characteristics of plants:
Structures
observed
Type of
stem
Thallus
Type of
Roots
Rhizoids
Type
leaves
Moss
Liverwort
Lichen
Fern
No true
stem
No true stem No true
stem
No true stem
Present
No true
roots
Present
No true
roots
Present
No true
roots
Present
Present
Present
Small
Liver shaped Crusty
leaf like
leaves
structures
Type of
Veins
Absent
Vascular
bundles
Absent
Number of
floral parts Absent
Pine
Has woody
stem
Geranium
Lily
Bean
Corn
Has
herbaceous
stem
Has
herbaceous
stem
Has
herbaceous
stem
Has hollow
stem
Absent
Absent
No true roots Has tap root
system
Absent
Has tap root
system
Absent
Has tap root
system
Absent
Has tap root
system
Absent
Has fibrous
roots
Present
Absent
Large fronds Needle like
leaves
Absent
Large leaves
Absent
Narrow long
leaves
Absent
Large leaves
Absent
Narrow long
leaves
Absent
Absent
Absent
Absent
Net like
Parallel
Net like
Parallel
Absent
Absent
Present
Present
Absent
Absent
Absent
Absent
Present
Multiples of
5
Present
Multiples of
3
Present
Multiples of
5
Present
Multiples of
3
Absent
Absent
Absent
Absent
Present
Absent
Absent
Absent
Absent
Spores
Present
Naked
seeds or
Absent
seeds in a
fruit
Number of
cotyledons Absent
Present
Present
Present
Absent
Absent
Absent
Absent
Absent
Absent
Naked seeds
in a cone
No seeds
No seeds
Absent
Seeds in a
pod
Absent
Seeds on a
cob
Absent
Absent
Absent
Absent
None
None
Two
One
Bryophyta
Kingdom Pteridophyta
Spermatophyta
fungi
Pteridopsida Gymnosperm
Cones
Division
Class
Bryophyta
Bryopsida Hepatopsida
Spermatophyta Spermatophyta Spermatophyta Spermatophyta
Angiosperm
Dicot
Note Refer to your biology book or ask your teacher to help you when classifying lichen.
Angiosperm
Monocot
Angiosperm
Dicot
Angiosperm
Monocot
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2. Table 3 Complete the table given below with distinguishing features of three major divisions of plants( Refer to table 1)
Spermatophyta
Bryophyta
Pteridophyta
Gymnospremae
Angiospermae
(mosses, liverworts)
(ferns)
Cone bearing plants
Flowering plants
Bryophytes do not have true Pteridophytes have
Gymnosperms have
Dicotyledonae
Monocotyledonae
stems, roots and leaves.
vascular bundles. Ferns
vascular bundles. They
Dicots have vascular
Monocots have vascular
They also do not have
have large fronds, but do
have large woody stems,
bundles. They have woody
bundles. They have
vascular bundles. They
not have true stems and
taproots and confers have
or herbaceous stems, tap
hollow, herbaceous stems,
reproduce by spores held in roots. Spores are found in needle like leaves. They
roots and large leaves. The
fibrous roots and long,
spore sacs
spore sacs under the
have seeds in cones.
leaves have net like veins.
thin leaves. The leaves
leaves.
Their flowers have floral
have parallel veins. Their
parts in multiples of 4 or 5. flowers have floral parts in
Their seeds have two
multiples of 3. Their seeds
cotyledons.
have one cotyledon.
3. Convert the branching dichotomous key given in figure 1, to word dichotomous key.
1a. vascular tissue
go to
2
1b. no vascular tissue
go to
Bryophyte
2a. has seeds
2b. no seeds
go to
go to
3
Pteridophyta
3a. has flowers
3b. no flowers
go to
Angiosperm
4
go to
Fern
5
go to
Gymnosperm
6
4a. has large fronds
4b. no large fronds
5a. has cones
5b. has no cones
6a. has seeds in fruit
6b. seeds not in fruit
7a. Has 2 cotyledons
7b. has 1 cotyledon
go to
7
Gymnosperm
Dicot
Monocot
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Discussion questions:
1. What are the differences between vascular and non-vascular plants?
Vascular plants have vascular bundles such as xylem and phloem vessels and non vascular plants do not have vascular bundles.
2. Name two major divisions in phylum Tracheophyta. Pteridophyta (seedless plants) and spermatophyta (plants with seeds)
3. Which characteristics of plants helped you to identify and classify plants? The presence or absence of vascular bundles, external characteristics
and their mode of reproduction helped in identifying plants.
4. What are bryophytes? Give three examples. Bryophytes are plants without vascular bundles. They do not have true stem, true roots and leaves.
Mosses, liverworts and hornworts are bryophytes.
5 In which major plant group are the following plants classified:
(a) Flowering plants- are spermatophytes and angiosperms
(b) Conifers – are spermatophytes and gymnosperms
c) ferns- are pteridophytes
6. Why are fungi placed in a different kingdom? Fungi are placed in kingdom fungi because they do not have chlorophyll and cannot
photosynthesise. They are saprophytes.
7. Why is it difficult to classify lichen? Lichen contains both alga and fungus living together in a symbiotic relationship. So it is difficult to
classify them as belonging to kingdom protista or kingdom fungi. But they are placed in kingdom fungi.
Conclusion:
1. Which distinguishing features did you use in classifying plants?
The following distinguishing features were used in classifying plants: presence or absence of vascular bundles, type of stem, type of roots, type
of leaves and the arrangement of veins, presence or absence of thallus, rhizoids, spores, seeds, flowers, cones and number of floral parts and
cotyledons.
2. List the differences between bryophyta, pteridophyta and spermatophyta.
Spermatophyta
Bryophyta
Pteridophyta
Gymnospremae
Angiospermae
Cone bearing plants
Flowering plants
Bryophytes do not have true Pteridophytes have
Gymnosperms have
Dicots have vascular
Monocots have vascular
stems, roots and leaves.
vascular bundles. Ferns
vascular bundles. They
bundles. They have woody
bundles. They have
They also do not have
have large fronds, but do
have large woody stems,
or herbaceous stems, tap
hollow, herbaceous stems,
vascular bundles. They
not have true stems and
taproots and confers have roots and large leaves. The
fibrous roots and long,
reproduce by spores held in roots. Spores are found in needle like leaves. They
leaves have net like veins.
thin leaves. The leaves
spore sacs
spore sacs under the
have seeds in cones.
Their flowers have floral
have parallel veins. Their
leaves.
parts in multiples of 4 or 5. flowers have floral parts in
Their seeds have two
multiples of 3. Their seeds
cotyledons.
have one cotyledon.
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Websites:
http://farm4.static.flickr.com/3145/2571238669_a5c5ebb0c3.jpg?v=0 for gnetophyte
http://www.gocek.com/christiansymbols/images/wheat.gif for wheat plant
http://en.wikipedia.org/wiki/File:Equisetopsida.jpg for horse tail
http://www.diytrade.com/china/4/products/122380/Ginkgo_Biloba_Extract.html for ginkgo
http://www.liveaquaria.com/images/categories/product/p-11285-hornwort-15498.jpg for hornwort
http://www.alientravelguide.com/science/biology/life/plants/tracheo/psilopsi/whiskfer.htm for whisk fern
http://www.amnh.org/learn/biodiversity_counts/class_prep/plants.htm
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