Diversity in Living Organisms

5 Kingdom Plantae

The kingdom plantae is classified as follows:

1. Division Thallophyta orAlgae

2. Division Bryophyta

Bryophytes are small, green, land plants that are multicellular. These plants are confined to shady damp places.
Bryophytes are found in both land and aquatic habitats, hence are known as amphibians of the plant kingdom.
Their body is a flat, green thallus in liverworts. They lack real roots, stems and leaves and have no flower.
A true vascular system is absent in them.
Gametophyte is attached to a substratum by means of hair-like outgrowths, the rhizoids, which absorb water and minerals from the substratum.
Examples are Liverworts and Mosses.

3. Division Pteriodophyta

Ferns

Horsetails

Differences between Bryophyta and Pteriodophyta.

Bryophyta	Pteriodophyta
Plant body is gametophytic	Plant body is sporophytic.
Plant body is either thallose or foliose. However, real stem and leaves are always absent.	Real stem and leaves are present.
Fixation of plant body is carried out by rhizoids.	Fixation of plant body is carried out by roots.
Sporophyte is parasitic over the gametophytic plant body throughout its life.	The gametophyte is small and independent.
Bryophytes are non-vascular in nature.	Pteriodophytes are vascular in nature

Differences between pteriophytes and Phanaerogams (spermatophytes).

Pteriophytes	Phanerogams / Spermatophytes
They are seedless plants.	They are seed-bearing plants.
Gametophytes are small but independent.	Gametophytes are nutritionally dependent on the sporophyte.
Their reproductive organs are inconspicuous.	Their reproductive organs are quite conspicuous.
Fertilization requires An external water source	Fertilization does not require an external water source.

Differences between Cryptogams and Phanerogams.

Cryptogams	Phanerogams
It contains seedless plants.	It contains plants with seeds.
It includes both vascular and non-vasular plants.	It includes only vascular plants.
For fertilization, an external water source is required	For fertilization, an external water source is not required.

Differences between algae and fungi.

Algae	Fungi
Algae contain photosynthetic pigments.	Photosynthetic pigments are absent in Fungi
They are autotrophic.	They are heterotrophic.
Most of the algae are aquatic in habitat.	Most of the fungi are terrestrial in habitat.
The cell wall is made of cellulose.	The cell wall is made of chitin.
Algae contain starch as a stored food material	Fungi contain glycogen and oil as the stored food materials.

4. Divison Gymnospermae

Gymnosperms are plants that have well-differentiated plant body, vascular system and they bear seeds.
The term is derived from Greek words, gymno: naked and sperma: seed.
These are most primitive and simple seed plants.
The seeds produced by gymnosperm plants are naked and are not enclosed within fruits.
These plants are usually perennial, evergreen and woody.
Sporophylls are aggregated to form cones in them. There are separate male and female cones.
Xylem lacks vessels and phloem lack companion cells. e.g, Conifers, pinus (pines), Cedrus (deodar).

Confires

Pine

5. Division Angiospermae

The word is derived from Greek words: angio: covered and sperma: seed.
Angiosperms are highly evolved plants and they produce seeds that are enclosed within the fruit.
Seeds have special structures, called cotyledons.
The reproductive organs (sporophylls) are aggregated in a flower.
Since these plants have flowers, they are called flowering plants.
Endosperm has triploid cells and it supplies nutrients for the developing embryo in the seed.

Differences between gymosperms and angiosperms

Gymosperms	Angiosperms
In gymnosperms, Sporophylls are aggregated to form cones.	In angiosperms, Sporophylls are aggregated to form flowers.
The seeds are naked.	The seeds are enclosed by a fruit wall.
The microspores and megaspores are produced by male and female cones.	Microspores and megaspores are produced in the same or two different types of flowers.
Vascular tissues such as xylem lacks vessels and phloem lacks companion cells.	Vascular tissues such as xylem contain vessels and phloem contains companion cells.
The ovules are not enclosed within an ovary.	The ovules are enclosed within an ovary.
Endosperm cells are haploid.	Endosperm cells are triploid.

Differences between Monocotyledon and Dicotyledon.

Monocotyledon	Dicotyledon
Seeds of Monocotyledon plants have only one cotyledon.	Seeds of Dicotyledon plants have two cotyledon.
These plants have fibrous root.	These plants have tap root.
The leaves show parallel venation.	The leaves show reticulate venation.
The plants are herbs, shrubs with tender stem.	The plants are huge trees with strong stem.
The flowers have three or multiple of three petioles.	The flowers have five or multiple of five petioles.
Vascular bundles are in ring.	Vascular bundles are scattered.

The plant kingdom has been classified into ‘cryptogams’ and ‘phanerogams’ based on their seed formation ability.

Cryptogams

These are plants that do not have well-developed or conspicuous reproductive organs but have hidden reproductive organs and don’t produce seeds.
The thallophytes, the bryophytes and the pteridophytes are ‘cryptogams’.
Reproduction in all the three groups occurs through spore formation.

Phanerogams:

Plants that have conspicuous reproductive organs and produce seeds are called ‘phanerogams’.
Gymnosperms and Angiosperms belong to the group phanerogams.