• In this kingdom, are included all non cellular or acellular living beings having incapient nucleus i.e. Genetic mass or DNA is not confined in a nuclear membrane bounded nucleus.

• Such living beings are called Prokaryotes e.g virus, bacteria and blue algae.

It is non cellular smallest organism and probably the most primitive creature on earth. The word virus is a Latin word which means Poison. A Russian scientist "Ivanowsky" discovered it as a living organism and a particle in 1892 A.D. An American biologist "Stanley" isolated "Tobacco Mosaic Virus" from infected leaves in the year 1935 A.D.

Virus has dual characters i.e. within host cell it is living, active and replicating but outside the host. It is a dead crystal, completely inactive and may remain so for centuries. Virus never grows and reproduces outside the host cells. Therefore it is an "Obligatory Prasite".

Virus is a very tiny creature whose structure activities and types can only be studied by means of an "Electron Microscope" with a magnification power more than 0.1 million nanometer. Virus measures about 17-450 milli microns.

According to the type of host, virus are of three types namely:

1. Animal virus
2. Plant virus
3. Bacteriophage

Viruses are of different shapes i.e. spherical, Tetrahedral, Polygonal, Rod shape, polyhedral or Tadpole shaped. Here, structure of a bacteriophage tadpole virus is given as an example.

Virus is neither animal nor plant therefore it is deovoid of cell membrane or cell wall. Externally it is covered with a rigid protein coat called "Capsid". It is broader at one end and narrower at the other. Broader end is called "Head" and narrower end is called "Tail". The inner cavity contains DNA. The tail is also hollow internally, this cavity is called "Core". Tail also has got protein fibrils for movement and Antigenic proteins for attachement with the host.

Bacteriophage means "bacteria eater". The name is given due to the fact that these viruses infect bacteria and live as their parasite.

Phage virus attaches itself with the bacterial cell wall by means of "tail piece" and secretes enzyme called Lysosome, it dissolves the bacterial wall through which DNA takes control of Bacterial DNA and its Biochemical acitivities. In this "Master slave" relationship, viral DNA initiates Bacterial enzyme system to produce nucleic acids and proteins required for viral "Replication." Therefore a large number of viruses are produced on expense of Bacteria, as a result Bacteria is "Internally eaten" and finally disintegrades, Newly formed viruses set free and attack other bacteria for a new cycle. Such a cycle is called Lytic cycle.

In some instances, viral DNA combines with the bacterial DNA in such a way that instead of "Master slave relationship" a "great host" relationship takes place in which bacterial DNA is not harmed. When bacterial DNA repticales, viral DNA also replicates simultaneously. So a number of generation can be produced unharmed. This mutual cycle is called Lysogenic cycle.

Sometimes the "guest" viral DNA reactivates to star Lytic Cycle.

Bacteria or Schizomycophytes were first discovered by Antoni Van Leeuwenhock as the smallest and simplest known living creatures.

Bacteria are omnipresent i.e. they are present every where except five. They are able to survive in extremes of environmental conditions i.e. below 0° C and upto 150° C.

Bacteria are very small, nearly 0.2 to 2 in width and 2 to 10 in length. Bacteria are classified according to their shape as follows;

These bacteria are spring or "Cork screw" shaped and are always solitary.

Structurally, bacteria are almost similar. A typical bacillus is given as an example.

Each bacterium posses a cell wall as an outer covering. It is made up of a complex of sugar with amino acids or sometimes contains "Chitin". Cell wall is thick and rigid. In unfavourable conditions, some of the bacteria enclose themselves in a polysaccharide capsule.

It is also called "Plasma Membrane," it surrounds the cytoplasm. It is made up of lipo-protein; a complex of lipid and proteins. Cell membrane is "Osmo-regulatory" and porous. It also performs respiration.

It is the fluid ground substance, which fill the inner space of cell. Cytoplasm appears granular containing "Ribosomes". However endoplasmic reticulum, mitochondria and Colgi body are absent. Few small vacuoles are found scattered in the cytoplasm. They contain Glycogen particles as reserved food.

Being Prokaryote, Bacteria are devoid of membrane bounded complete nucleus. They lack nucleolus and Nuclear membrane. Genetic material or DNA is found in the centre of cell as cencentrated mass or strands called "Chromatin bodies." Such type of incomplete nucleus is called "Incapient Nucleus."

Some of the bacteria are provided with cytoplasmic fibrous structures called "flagella," they are meant for locomotion.

According to the mode of nutrition, bacteria are of two type:

1. Autotrophic Bacteria
2. Heterotrophic Bacteria

Heterotrophic bacteria are of following three types:

These bacteria obtain food from dead organic material by decomposing their complex compounds like proteins, fats and carbohydrates into simpler compounds like H₂O, CO₂, NH₃ and Nitrates.

These bacteria live on living hosts i.e. animals or plants and obtain their nutrition from them and ultimately harm them by producing serious diseases. Parasitic bacteria may be obligate or facultative parasites.

These are the Bacteria and live in association with another living being taking benefit from him and providing the same in return. Examples are Rhizobium Radiciols which live in nodules over roots of Leguminous plants taking shelter and food from these plants and produce and provide fertilizer in the form of Nitrates.

Bacteria reproduce by two methods:

1. A sexual Reproduction
2. Sexual Reproduction

It is of two main types which are explained below:

It is the method of survival in unforable circumstances rather than reproduction. In this method, cytoplasm along with DNA shrinks and accumulates at one side within the cell of Rod Shape bacteria. Later on a hard impervious "Cyst" is formed around cytoplasmic mass, the rounded confined encysted mass is called "Endospore." On return of favourable condition cyst breaks and cytoplasm activates and enlarges to form new bacteria. Endospore can survive for months without any harm to bacteria.

It is not true sexual reproduction but exchange of DNA or genetic recombination between bacteria. It can take place by means of following methods:

Joshua and Fatum in 1946 selected a "wild type" of E. Coli bacteria for their experiment. These bacteria were capable to sybthesize different Amino acids (say A, B, C, D, E and F)

These wild type bacteria were irradiated by X-Rays by which two new strains are obtained. These strains are:

1. Mutant X (capable to synthesize A, B and C amino acids)
2. Mutant Y (capable to synthesize D, E and F amino acids only)

In the next step these bacteria were cultured together in a nutrient medium. By careful analysis it was found that a new strain came into existence which is unable to synthesize any of the amino acids A, B, C, D, E or F. Similarly parent wild type bacteria were also obtained. The only logical explanation about this happening is that the Bacteria conjugated i.e. exchange their DNA through a conjugation tube.

This type of DNA recombination was discovered by Joshua Lederberg and Zinder in 1952. When a bacteriophage virus attacks a bacterium (donor) and combines its injected DNA with bacterial DNA, during DNA replication, viral DNA receives some of the bacterial DNA i.e. of donor. When viruses are released or set free from destroyed bacteria, they have got not only viral DNA but some amount of Donor (Bacterial) DNA too.

When these "mixed DNA" phage viruses attack some new bacteria (recipient) and start "Lysogenic cycle", the recipient not only replicates its own DNA but also the DNA of phage and donor’s DNA. The progency not only shows characters of its own but also the character of donor. Thus phage virus is the 3^rd party in this recombination.

A British Nobel prize winner bacteriologist "Fred Griffith" discovered the phenomena of transformation of Genetic charters in bacteria. According to him:

Griffth discovered this phenomena accidentally during his work on two shains of Pneumo Cocci one of the specie was smooth, capsulated example virulent i.e. Fatal. Other specie was Rough, non-capsulated and non-virulent. These were labeled as S-type and R-type bacteria. By injecting these bacteria in two separate rats, it was observed that S-type bacteria killed their host rat while R-type failed to harm their host rat. Later on S-type bacteria were killed with heat and they were injected in another rat along with some living R-type Bacteria. It was observed that the rat got pneumonia and got killed. On elimination of blood, it was found that the rat has got living S-type bacteria along with R-type specie. It was concluded by Griffth that:

Different type of bacteria not only causes diseases but some of the bacteria are also economically important for us. Some useful and harmful bacteria are as follows:

Bacteria living in the nodules over roots of Pea, Beans and other legumes convert atmospheric nitrogen into nitrate and Nitrite fertilizer, similarly other soil bacteria (generally called decomposes) convert dead plants and animal bodies into simpler compounds. Both above-mentioned bacteria increase soil fertility.

Certain antibiotic drugs are also obtained from Bacteria.

Some important proteins and amino acids are also obtained from bacteria.

Certain Symbiotic bacteria live in the alimentary canal of herbivorous where they produce live in the alimentary canal of herbivorous where they produce Cellulase enzyme required for the hydrolysis of cellulose into glucose.

Bacteria perform different functions in different industries such as convertion of milk into curd and curd into cheese, ripening of tobacco leaves, tea fermentation, tanning of skins into leather etc.

Every day a large quantity of food stuff like vegetables, fruits, meat, milk are spoiled by ferments released by bacteria.

A large number of diseases are caused by bacteria such as Furuncles, Sorethroat, Bronchitis, Pneumonia, Tuberculosis, Cholera and Typhoid etc. certain plant diseases are also caused by bacteria such as fine blight of apple and pear, back rot of cabbage , wild fine of tobacco.

Nostoc is a fresh water algae commonly found in ponds, lakes, ditches and pools. Sometimes it also grows in damp soil.

Nostoc is a unicellular plant, a number of cells join to form long filaments. Each filament is few inches upto few feet long. A large number of filaments entangle in a gelatinous mass to form colony.

Each filament is beaded in appearance and is always unbranched. It is surrounded by a layer of Gelatin, which prevent filament from the rotting action of water.

Each cell is rounded in shape with a double cell wall, the outer thicker gelatin coated wall is made up of cellulose and Pectine whereas inner layer is composed of cellulose only. Cell membrane is absent.

Cytoplasm is differentiated into two parts, the outer cytoplasm contains pigments like Chlorophyll, Xanthophyll, Phycocyanin etc mixed in the cytoplasm and not contained in membrane bounded Plastids. This outer coloured cytoplasm is called Chromoplasm. The inner cytoplasm is called Centroplasm. It is colourless and contains fragments of DNA.

True or complete membrane bounded nucleus is absent, instead of it incapient nucleus is present composed of fragments of DNA. There is no membrane bounded organelle in cytoplasm.

In each filament there are some larger colourless cells called heterocyst are present. These cells convert atmospheric nitrogen into proteins and also serve to store food and multiplication.

Nostoc contains chlorophyll therefore it is capable to manufacture its own food material by means of Photosynthesis. Heterocysts also perform nitrogen fixation for filaments.

Like other blue green algae, Nostoc also reproduces asexually. Different methods of asexual reproductions are as follows.

Juctions of normal cells with Heterocysts are weak, therefore filaments often break at these points forming smaller fragments of filament, and each fragment is called Hormogonium. Hormogonium grows in length by means of mitosis and form new filaments.

In unfavourable conditions, some of the Nostoc cells become larger and thick walled containing reserved food. These cells are called Akinetes.

Each Akinete is surrounded by a thick layer, the outer wall is called Exospore and the inner wall is called Endospore. On return of favourable conditions, exospore bursts and endospore germinates to give rise to new filament.

• These organisms may be aquatic or terrestrial. Free living organisms are found singly or in colonies.

• Some of the organisms are parasite and cause fatal diseases.

• Protistans may be Autotrophic having Chlorophyll, capable to produce their own food material while others are Heterotrophic and cannot produce their own food material.

• On the basis of mode of nutrition, Protistans are classified into two divisions:

1. Phylum Protozoa: Mostly Heterotrophic and Motile.
2. Unicellular algae: All Autotrophic and Sessile

Unicellular algae are considered as the ancestor of multicellular plants. These plants have got miniature models and details of multicellular plants in a single cell and its organelles. On of the example is Chlamydomonas.

It is a unicellular green algae found in fresh water ponds, lakes, ditches and pools.

It is an autotrophic algae.

It is unicellular and solitary. Each single cell is capable to live by its own. Each cell is pear shaped with a pointed anterior end. Each cell is composed of following parts:

It is the outer most covering of the cell made up of cellulose and pectin. It is responsible for the distinct shape of the cell.

It is the inner ground substance of the cell which fills the inner space.

It is single in number and cup shaped. It is large and occupies the major part of the cell lying towards the posterior end. It is filled with Chlorophyll.

It is large distinct protoplasmic body lying inside the Chloroplast. It functions to convert glucose into insoluble starch for storage.

It is central and lies in the belley of chloroplast. It is complete i.e. surrounded by the nuclear membrane.

Antero laterally, there is an orange –red spot on the cytoplasm called eye spot or stigma. It is sensitive to light.

These are two in number located at the anterior end at the base of Flagella. They are meant for excretion of water and respiration. They are pulsatile and osmo-regulatory.

These are two cytoplasmic lash like structure meant for locomotion. Each flagellum arises from a granular body called Blepheroplast.

Chlomydomonas reproduce by two methods:

1. A Sexual Reproduction
2. Sexual Reproduction

A sexual reproduction takes place by following two methods:

During favourable conditions especially at night, cytoplasm of chlamydomonas shrinks and separates from the cell wall. It condenses with the disappearance of flagella and vacuoles and divides mitotically to form 2 to 16 small uninucleated structures similar to the parent cell known as Zoospores. They are set free in water here each matures into a new chlamydomonas cell.

During unfavourable conditions the contents of chlamydomonas contract and collect in the centre where the cytoplasmic mass divides repeatedly to form large number of cells. These daughter cells are held together by a gelatinous mass. This is called Palmella stage. On return of favourable conditions daughter cells are released and develops into a complete chlamydomonas cell.

During favourable condition, two chlamydomonas take part in sexual reproduction by means of gametes. These gametes are morphologically similar. Therefore there is no distinction of male and female gametes. Such gametes are regarded as positive and negative for identification purpose. Fussion of these gametes are called Isogamy and gametes are called Isogametes.

Rhizopus is a Eukaryotic Thalloid Fungi belonging to division Eumycophyta.

It is cosmopolitan i.e. found all over the world but especially in warm moist climate. It easily grows over decaying organic matter like bread, moist paper and leather etc.

It is saprophytic fungi which grows over decaying organic matter.

Plant body is called Mycellium composed of thread like hyphae. Each hyphae is coenocytic in nature i.e. lacks cross walls between the cells. It is composed of single row of cells with the inner connected cytoplasm, hyphae are unbranched and are of three types:

They are meant for attachment with substretum, absorption of moisture and food, secretion of enzymes for hydrolysis of food etc. They are branched.

They grow obliquely or along substratum and are meant for vegetative reproduction.

They grow upward and straight in air and are provided with sporangium. They are meant for spore formation and Asexual Reproduction.

Microscopically, each hyphae has got a boundary wall which is made up of a different type of cellulose called Fungal –cellulose. The tube like cairty of hyphae is filled with granular cytoplasm. It contains many nucleus freely moving with the flow of cytoplasm. Vacuoles are many containing Glycogen particles and Fats droplets.

Being a true fungi Rhizopus reproduces by means of following methods:

1. A sexual Reproduction
2. Sexual reproduction

Being a fungus, Rhizopus reproduces asexually be means of spores in favourable condition. In this reproduction, aerial branches arise which are called "Aerial Hyphae." Some of the aerial hyphae become swollen at their tip and now known as "Sporangiophore". In the swollen tip, nuclei along with a little dense cytoplasm began to collect. This cytoplasm and nuclei containing tip is called Sporangium. Soon after, fat globules containing vacuoles began to collect in Sporangium with separate the marginal part containing nuclei from the remaining hyphae. This marginal part is called capsule while the inner dome shaped non-nucleated portion is called Collumela.

Each nucleus of capsule is surrounded by a little cytoplasm and dries up to form spore. With increasing pressure of cytoplasm in Collumela, capsule burst to liberate spores.

The dry and light weight spores disperse in air and when they get any organic decomposing medium, germinate to give rise to a new Rhizopus Mycellium.

In unfavourable conditions, Rhizopus also reproduces "Sexually". In this reproduction two mycellia produce from two different sproes take part, these mycellia are morphologically similar but physiologically different. Such mycellia are called Hetero Thallus and sexual reproduction is regarded and Hetero Thallic Conjugation between positive and negative strains.

When two hyterothallic hyphae come in contact they produce finger like outgrowths lying opposite to each other, these are called Progametangia. Nuclei along with little cytoplasm began to collect at the tips of these tubular progametangia which become swollen, later on a septum develops in each progametangium by which the swollen tip haivng nucleus separates and looses connection with the rest of the tube. This swollen tip is called Gametangium, its nucleus is regarded as Coenogamete, rest of the hollow tube of progametengium is called Suspensor. The two oppositely lying gamentangium fo the hyphae unite with each other and their intermediate walls get dissolve. The two similar looking coenogametes fuse to form zygote. The diploid (2n) zygote encloses itself in a cyst and becomes "Zygospore".

Each zygospre has got an outer thick wall or Exosporium and an inner delicate membrane or endosporium. After some rest, exosporium bursts and the endosporium grows out to form a single and erect Hyphae the "Promycellium." It develops a "Sporangium" without columella having haploid spores produced by which meiosis. Soon, Sporangium bursts and spores are set free. Half of the spores germinate to form positive strains and the remaining half give rise to negative strains of Rhizopus.

Fungi have a harmful and beneficial effects in many ways, these are given below:

Fungi decompose dead bodies of plants and animals and make the soil fertile. Leaf compost and manure is also made in the same way.

Some of the Saprophytic fungi release enzymes, they ferment different organic compounds into alcohol, acids, esters etc. For this purpose these fungi are used on industrial scale.

Some of the fungi, like Mushrooms are edible and are used throughout the world as food. Yeast is used in Bakery for fermentation of doe for bread and cakes.

Some of the well known antibiotics are obtained from fungi like Penicillin, Neomycine, Streptomycine etc. Some of the fungi synthesize vitamin B.

Some of the fungi cause human diseases like Athlete’s foot, Ring worm of skin, Candydiosis of tongue and throat, Moniliasis of lung etc.

Most of the saprophytic fungi grow over edibles like vegetables, cooked food and fruits and spoil a large quantity per year.

Stormy attack of fungi over crops destroy a number of crops, eg smut of wheat black powdery rust of cotton, Mildew etc.

Fungi also destroy cotton, wool, leather and wood, paper etc.

It is a Eukaryotic, Thallophytic filamentous algae.

It is found in stagnated fresh water like ponds, lakes, pools and ditches. It is also found in slow running streams.

It is a Thallophyte belonging to the class Algae. Due to its green colour it is kept in the family chlorophycese. It is Autotrophic plant.

Plant body is called "Thallus" which is undifferetiated into roots, stem or leaf. Thallus is composed of row of cells called filament. Filaments are of two types i.e. Heterotrichous; one of the filament is attached with the substratum while the other (branch) is fibrous and grows vertically in water, these branches or filaments are called Protstate and Erect Branches respectively, Both type of filaments are surrounded by mucilagenous layer. Prostatic branches grew diffusely and Psendo parenchymatons whereas Erect branches terminate on hyaline hairs.

Each cell is rectangular i.e. longer than the breadth. It is surrounded with a cell wall. Cytoplasm forms a thin film with the inner lining of cell wall. A single large girdle like chloroplast is found in the middle of the cells having many Pyrinoids. A complete nucleus is present in the centre suspended with cytoplasmic strands.

Stigeoclonium reproduces by two methods:

1. A sexual Reproduction
2. Sexual reproduction

In each cell of prostate branch, four to eight Zoospores are produced mitotically. Each zoospore is Quadriflagellate i.e. bears four flagella. After liberation, each zoospore grows to form a new plant.

In the cells of porstate branches sexual cells or gametes are produced. These gametes are usually Biflagellate. They are similar in morphology and physiology, therefore regarded as Isogametes. Two isogametes fuse to form Zygote, fusion of these isogametes is called Isogamy.

Zygote usually after a period of rest germinates Meiotically to form haploid quadriflagellate four Zoospores. Each zoospore after liberation grows into a new thallus.

It is a multicellular, Eukaryotic thalloid algae commonly known as Sea-Lettuce.

Ulva is a marine algae which grows attached to rocks in intertidal pools.

It is a thalophytic algae which cannot be differentiated into root, stem or leaf. Being an algae, it is autotrophic in nature.

Each thallus is a blade like wrinkled structure almost 20 to 30 cm in length. The lower part of thallus remains attached with rocks by means of "Hold Fast" having elongated cells.

Thallus is composed of two layers of cells i.e. outer epidermal layer of cells containing chlorophyll and an inner layer of cells i.e Medulla serving as storage tissue.

It is of two types namely:

1. A sexual Reproduction
2. Sexual reproduction

It takes place by means of quadriflagellate zoospores produced by asexual diploid (2n) plant called Sporophyte. Zoospores are produced in all cells of plant by means of Meiosis. Usually each cell produces 8 – 16 zoospores. Each zoospore on germination gives rise to a new haploid (n) plant.

The haploid plants thus produced are called Gametophytes. Two similar looking gametophytes are produces. They are also morphologically similar to Sporophyte except their number of chromosomes. Two Isomorphic gametophytes are regarded as negative and positive strains.

Both gametophytes produce haploid gametes, these gametes are smaller than the zoospores and Biflagellate. Similar looking negative and positive gametes or isogametes fuse to form a quadriflagellate zygote i.e. isogamy takes place.

The zygote after rest and repeated divisions gives rise to a new diploid sporophytic plant.

In Ulva Sporophyte bears 2n i.e. Diploid Chromosomes which is 26. This plant reproduces by means of spores produced by means of Meiosis, Each spore bears haploid (n) or 13 chromosomes. On germination spores give rise to Gametophyte plants which are similar to Sporophyte in morphology but differ in the number of chromosomes.

Gametophytes produces isogametes which fuse to form zygote having Diploid (26) chromosomes. Zygote gives rise to zoospores which germinate to form Diploid Sporophyte and thus whole cycle is repeated.

In Ulva, Sporophyte and Gametophytes are of the same morphology therefore, life cycle is called Isomorphic alternation of Generation.

Marchantia is a land plant generally found in moist shady and cold areas.

Marchantia is a Bryophute live wort. Plant body is Thalloid in nature without distinction of root, stem and leaf. It contains chlorophyll, therefore it is autotrophic in nature.

Plant body is Thalloid i.e. no distinct roots, stem and leaves are found but Dorsal and ventral surfaces are distinct. Ventral surface bears unicellular Rhizods while Dorsal surfaces bears a Pseudo Midrib. Rhizoids are meant for absorption and fixation of plant. Ventral surface also bears chloroplast and air chambers for exchange of gases.

Marchantia reproduces by three methods:

1. Vegetative Reproduction
2. A sexual Reproduction
3. Sexual reproduction

It takes place by means of Gemmae. On each plant, small cup shaped structures are produced along with the Midrib known as Gemma cup. In each gemma cup a large number of microscopic Gemmae are produced, each gemma detaches from the cup and germinates to form a new plant.

Sporophyte of Marchantia is a small atypical plant consisting of three parts i.e. basal Fout, stalk like Seta and swollen Capsule. Within capsule a large number of spore mother cells are present these Diploid cells divide meiotically to produce haploid tetrads of spores. On maturation, capsule bursts and spores are set free. Each spore germinates to give rise to a new Gametophyte plant.

The basic or dominant phase of the life cycle of Marchantia is sexual or Gametohytic. Plants are Dioecious i.e. Male and Female plants are separate.

Male plant produces an erect branch called Antheridiophore while female plant produces Archigoniophone. Both of these branches bear Male and Female receptacles respectively.

Male receptacle is disc shaped and bears on its upper surface Male reproductive organs called Antheridia. Each anteridium is club shaped with a stalk and capsule. Each capsule bears a large number of haploid Antherozoid mother cells, which give rise to male gametes or biciliated sperms.

Female receptacle is star shaped and bears on its lower surface inverted flask shaped Archigonium. They belley of the flask or venter contains a single large female gamete of egg having haploid chromosomes.

Biciliated sperms escape after maturation when antheridium bursts. They swim towards archigonium and enter through the neck to reach the egg cell in venter. One of the sperm fuses with the egg i.e. fertilization takes place. After fertilization, zygote encloses itself in a thick wall and becomes Oospore.

After sometime, oospore germinates over the female receptacle as a parasite and gives rise to a Diploid Sporophyte plant.

Marchantia shows a distinct alternation of generation. The dominant place of life is haploid Gametophytic phase alternating with indistinct Diploid Sporophytic phase for a short time.

As male and female gametes as well as Male and female plants (Gametophytes) are totally different from Sporotphyte, thereofe this life cycle may be regarded as Heteromorphic, Heterogamous life cycle.

Seed is a reproductive part of Phanerogams as a result of fertilization of ovule of the ovary. It germinates to give rise to a new plant of the same specie.

Seeds are of two types:

1. Dicotyledonous or Dicot Seeds
2. Monocotyledonous or Monocot Seeds

Examples of Monocot seed are Rice, Maize and Wheat etc.

Structure of a monocot seed is as follows:

In maize grain, Pericarp of fruit and seed coat are fused together forming a single outer protective coat. In such seeds, hilum and Micropyle are absent. Such combined seed and fruits are generally called grains.

A single thin layer of cells called Epithelium obliquely divides the grain into unequal parts, the upper larger food and fat containing portion is called Endosperm and the smaller shield shape lower portion is called Scutellum representing the cotyledon. Embryo lies in the Scutellum which is composed of upper plumule and lower radicle. Both these structures re covered with cap like protective sheaths called Coleoptile and Coleorhiza respectively.

Germination is of following three types:

In the especial type of germination, seeds usually grow within the fruit and nourished by the fruit and parent plant. Radicle of the seed becomes elongated, stouter and swollen. The seedling becomes heavier and gets separated from the plant. It falls vertically down in the mud or marsh where radicle gets embeded and seedling starts to grow into a plant. Examples are Mangrooves like Rhizophora and Coconut.

A typical angiosperm is divided into two parts:

1. Vegetative Parts
2. Floral or Reproductive Parts

These are the parts which usually do not take part in reproduction. However they form the mass of an Angiosperm. These parts are:

The parts of plant, which usually take active part in the sexual reproduction of the plant, are called Reproductive Parts. These are:

1. Flower
2. Fruit
3. Seed

Root is the underground part of the plant, generally non-green and positively Geotropic (grows towards earth and Negatively Phototropic (grows away from the light). It is actively Hydrotropic i.e. grows towards water or moisture.

Roots are of two types:

1. Tap Root which develops from the radicle of a seed.
2. Adventitious Root which develops from any part of the plant other than the radicle i.e. from stem, branch or leaf.

It the aerial part of the plant which develops from the plumule of the seed or sometimes from the stem cutting. Stem gives rise to branches which develop from the axillary bud. It is positively Phototropic, negatively geotropic; it is exogenous in nature. Stem always possesses nodes and internodes and a terminal bud at its tip. It gives rise to branches, leaves and buds (vegetative and floral).

These are outgrowths of nodes of the stem, generally flat and green in colour. They contain green pigment called Chlorophyll and are provided with an axillary bud in its axil.

These are outgrowths of nodes of the stem, generally flat and green in colour. They contain green pigment called chlorophyll and are provided with an axillary bud in its axil.

Stem (or branches) of a plant sometimes modify to perform storage of food and water. These modification are as follows;

In some plants, under unfavourable conditions the stem develops underground and remains dormant. However at the approach of favourable conditions they give aerial shoots and strike flowers. Such dormant growing sub soil stems are called under ground modified stems.

Underground stem gives off lateral branches which strike roots and when separated from the parent plant, produce new plants thus increasing the number.

Following are the different types of underground stems:

Bulbs are of two types:

In this bulb, scale leaves are arranged in a concentric manner and the whole bulb is surrounded by a thin, dry and papery scale known as Tunic. Examples are Onion and Lilly.

In this bulb, scale leaves or scales are arranged in an "Imbrieate fashion" i.e. overlapping each other. Each scale is separately covered by a dry cover. Examples are Tube rose and Garlic.

Axillary buds normally grow into vegetative or floral branches. In some plants, these axillary buds modify extremely to give rise to specialize structures, which perform definite functions. These structures are called aerial modifications of stem. They are as follows:

In xerophytes (i.e. desert plants) leaves soon wither or modify into spines to reduce the rate of transpiration. Due to modification, leaves become unable to manufacture food. In such cases, stems become flat, green and leaf like. Such stems are called Leafy Stems. They perform the functions of leaves i.e. manufacturing of food, transpiration and respiration. These leafy stems are of two types;

Sometimes whole leaf or a part of it modifies into a specialized structure to perform some important function. These modifications are as follows:

Animals of this phylum are the most developed according to the Evolutionary point of view. They have the most advanced body organs. These animals may differ in their morphology but share some common features, which are as follows:

During development an ectodermal invagination takes place dorsally in these animals which is called Notocord. It is slender and rod shaped. In some animals it may persist during embryonic period while in others it is persisted or may organize into vertebral column.

Nervous system is well developed and lies dorsally. It is hollow internally forming chambers or ventricles.

During development, al these animals bear Pharyngeal gill’s Clefts on both sides. These gill’s Clefts soon disappear after combination of development but in some animals they persist and convert into respiratory organs.

Chordates are developed from Auricittaria Larva of Echinoderms. According to some workers, this larva was non-motile and due to Neoteny developed reproductive organs. Soon, reproduction started in these larva and the off springs became Adults having advanced characters. This whole phenomenon is called Paedomorphosis.

Phylum Chordata is divided into following three sub Phyla;

1. Urochordata
2. Cephalo Chordata
3. Vertebrata

Sub Phylum Vertebrata is divided into following seven classes.

1. Prototheria or Egg laying Mammels – eg: Duck nill platypus
2. Metatheric or Pouched Mammels – eg: Kangaroo
3. Eutheria or Placental Mammels – eg: Human, Squerrel, cat, Dog, sheep etc.