The following points highlight the five major kingdoms of flowering plants in India. The kingdoms are: 1. Kingdom Monera — The Kingdom of Procaryotes 2. Kingdom Protista — The Kingdom of Unicellular Eucaryotes 3. Kingdom Fungi — The Kingdom of Multicellular Decomposers 4. Kingdom Plantae — The Kingdom of Multicellular Producers 5. Kingdom Animalia—The Kingdom of Multicellular Consumers.
Contents
Flowering Plants in India: Kingdom # 1.
Kingdom Monera — The Kingdom of Procaryotes:
Most organisms in this kingdom are made up of a simple, procaryotic cell.
Some monerans make their own food, while others take in food from an outside source.
The monerans include the smallest, the simplest, and the most widespread groups of organisms on Earth. Except for one species of bacteria {i.e., Escherichia coli) that lives in our intestines less is known about this kingdom than all of the others. There are two major phyla in this kingdom.
Bacteria:
They are the smallest organisms in the five kingdoms. Most bacteria are either round (cocci), rod-shaped (bacilli), or spiral-shaped (spirilli). Some kinds form colonies of chains, others form clusters. Some bacteria are capable of dividing in half every 20 minutes. At this rate one bacterium can give rise to one million bacteria in just six hours.
Bacteria are omnipresent and found almost everywhere on Earth. They are found even on the surface of human body and inside the alimentary canal. Most bacteria feed on dead organisms and cause them to rot.
Bacteria are used to make industrial chemicals, to treat sewage, and to make foods like yogurt, cheese, butter and curd. However, certain bacteria are also the cause of many human infections such as tooth decay, pneumonia, tuberculosis, etc.
Cyanobacteria:
They are also called blue-green bacteria. They are bigger than most bacterial cells. They also contain pigments in them which absorb sunlight and enable the organisms to make their own food. Blue-green bacteria are commonly found growing in water and on wet surfaces.
Commonly, they reproduce in large numbers. The Red Sea was named after blue-green bacteria containing red pigments. When these bacteria increase in great numbers, the water looks red in colour.
Other forms:
The Actinomycetes (filamentous bacteria) and Archaebacteria are also included in the kingdom Monera. The Archaebacteria thrive under extreme environmental conditions such as high temperature (80°C), absence of oxygen, high salt concentration and acidic pH. They are thought to be early forms of life.
The members of kingdom Monera are the important decomposers and mineralisers in the biosphere.
Flowering Plants in India: Kingdom # 2.
Kingdom Protista — The Kingdom of Unicellular Eucaryotes:
The protists are much more complicated than monerans. A protist cell is somewhat like the whole body of a plant or an animal stuffed into a single cell. They are mostly unicellular and aquatic eucaryotes. They contain typical eucaryotic cell organelles such as nucleus, mitochondria, plastids, endoplasmic reticulum and Golgi bodies.
Very commonly they are flagellate with 9 + 2 internal micro-tubular structure of flagella. Protist cells are so complex that they are often thousands of times larger than human body cells. The main groups of this kingdom are—Diatoms, Dinoflagellates, Euglena, Sarcodines, Ciliates, Flagellates and Sporozoans.
Diatoms:
The bodies of such protists have two shells which fit together like a pill box. They float on the surface of fresh and salt water.
Dinonagellates:
These protists have two whip-like tails for movement. Like diatoms they also make their own food.
Euglena:
For a long time, biologists could not decide whether these protists were plants or animals. They contain green pigments and make their own food.
Sarcodines:
They resemble small masses of cloudy gelatin. They move by pushing out parts of their cell membranes.
Ciliates:
They are covered with short, hair like structures called cilia. The cilia contract in waves to push the organisms along.
Flagellates:
They move by using one or two whip-like projections or flagella. The flagella possess 9 + 2 internal micro-tubular structure. Most of these protists live independently, but some live inside other organisms. The causal organism of African sleeping sickness belongs to this group.
Sporozoans:
They live inside other organisms. Most have no structures for moving about. They depend on their hosts for transportation, e.g., malaria protozoans in the human blood stream.
Flowering Plants in India: Kingdom # 3.
Kingdom Fungi — The Kingdom of Multicellular Decomposers:
More than 100,000 kinds of fungi have been described and named. Biologists estimate that at least another 10,000 remain to be discovered. The members of this kingdom are diverse kinds of eucaryotic, predominantly multicellular hetetrophic organisms. They feed by absorbing the dead or living material of other organisms.
They are termed saprobes when they live on decaying organic matter, and parasites when they assimilate tissues of living things. They produce thread like structures (mycelia) that grow deep into their food materials. Chemicals from the mycelia dissolve the food. The fungi then absorb the dissolved food through these mycelia.
When the food is part of a living organism, the fungus may cause disease to its host, such as atheletes foot in humans and rusts in cereals.
However, the yeasts have a single-celled body. They are involved in fermentation. Their mode of sexual reproduction shows their relationship with multicellular fungi.
The fragmentation of hypha helps in multiplication where each fragment grows into new mycelium. The fungi also reproduce by asexual spores such as zoospores, aplanospores, conidia, gonidia, ascospores and basidiospores. Sexual reproduction takes place by the fusion of similar gametes (isogamy) and dissimilar gametes (oogamy).
Fungi are grouped into following important classes:
Class Myxomycetes:
They are frequently found in the rainy season in cool, shady moist places in the woods, on manure or other decomposing plant material which holds abundant moisture.
These organisms are naked during all stages of development except the spore stage. This naked vegetative phase consists of a naked amoeboid multinucleate free living Plasmodium. They ingest particles of food and reject the portions remaining after digestion. The plasmodia and fructifications of many species of slime molds are very colourful.
The spores are provided upon or within aerial sporangia and are more or less dispersed by wind. The asexual spores called zoospores produced in sporangia are also means of reproduction. Sometimes these motile spores also act as compatible gametes which fuse and form zygote. The thalloid body called Plasmodium represents a diploid (2k) stage.
Class Phycomycetes:
They are frequently found in damp places. They reproduce asexually by biflagellate zoospores. The zoospores are borne in zoosporangia of various types. Sometimes, aplanospores are produced within sporangia. The sexual reproduction takes place by fusion of similar (isogamy) or dissimilar (oogamy) gametes.
The mycelium is coenocytic (multinucleate) and aseptate.
The main examples are — Saprolegnia, Mucor, Albugo, etc.
Class Ascomycetes:
They are known as sac fungi. They may be unicellular {e.g., yeasts) and multicellular (e.g., Aspergillus) fungi. The asexual reproduction takes place by means of conidia. The conidia are generally produced in chains. The spores are formed exogenously, i.e., outside sporangium.
The conidia germinate immediately after their detachment from the conidiophores when they fall upon suitable substrata in appropriate atmospheric conditions producing germ tubes.
Sexual reproduction is through ascospores which are formed endogenously within an ascus. The gametes involved in sexual reproduction are non-motile and represented by + and – strains. The fusion of gametes is followed by meiosis that produces haploid (n) ascospores.
The fruiting body called ascocarp is generally cup shaped and contains spore bearing structures the asci. The examples of this class are — yeast, Aspergillus, Penicillium, Claviceps, etc.
Class Basidiomycetes:
They are also called club fungi. The Basidiomycetes include the fungi which bear their spores exogenously on basidia (singular basidium). The basidia may occur singly or be variously arranged by hymemia. These fungi have septate mycelia. The asexual spores called basidiospores are generally four in number.
They are produced exogenously on basidium. Two compatible nuclei fuse to form zygote, which undergoes meiosis and forms four basidiospores. The fruiting body containing basidia is a multicellular structure called basidiocarp. Common examples are — rusts (Puccinia), smuts (Ustilago), mushrooms (Agaricus), etc. Some mushrooms are edible and some are deadly poisonous.
Flowering Plants in India: Kingdom # 4.
Kingdom Plantae — The Kingdom of Multicellular Producers:
This kingdom contains mostly green, multicellular organisms. Their cells are of various types and form special organs. Most of these organs help in the production of food and in the reproduction of the plant. The plants are found on land, sea shores, in lakes and streams. The main groups of kingdom Plantae consist of complex red, brown and green algae, liverworts, mosses, ferns, gymnosperms and angiosperms.
The plant cells possess cellulose cell wall, and therefore, cannot contract and relax like animal cells. The plants are immobile. They are primary producers on land, and along many sea shores. Sometimes, they make dominant vegetation of lakes and ponds.
They synthesize all their organic constituents from water, carbon dioxide, and inorganic forms of essential elements, using light energy trapped by chlorophyll and accessory pigments.
This great phenomenon is photosynthesis. Certain flowering plants are parasitic and absorb their food partially or wholly from host plants. Some plants are insectivorous and absorb their nutrition by trapping and ingesting the small insects.
The main phyla of this kingdom are:
Brown algae, Red algae, Green algae, Bryophytes, and Tracheophytes (i.e., ferns, gymnosperms and angiosperms).
Brown algae:
The members of this phylum are commonly found in cool sea water They contain golden brown and green pigments that give them their brown colour. They possess stem like organs called stipes and leaf-like organs called blades.
Red algae:
The red algae are usually found in urban tropical seas. Their colour is due to a red pigment. The red pigment absorbs the blue light that penetrates deep water. They use the energy in this blue light to make food. Gelatin substitutes and other foods are obtained from them,
Green algae:
They are found both in sea and fresh water. On land, they cover most of the surfaces that receive sunlight and stay damp. They are green, store food and possess cell walls.
Bryophytes:
They are small green (e.g., liverworts and mosses) that live only in moist places.
Tracheophytes:
The members of this phylum have vessels that transport food, water and minerals to all parts of the plant body. This phylum is divided into three classes according to the kinds of seeds each plant forms. Ferns (i.e., pteridophytes) have no seeds; cone bearing plants (i.e., gymnosperms) have uncovered (naked) seeds, and flowering plants (i.e., angiosperms) possess covered seeds that are enclosed in a fruit.
Flowering Plants in India: Kingdom # 5.
Kingdom Animalia—The Kingdom of Multicellular Consumers:
The animal kingdom is the most complex of all five kingdoms. They are Multicellular holozoic eucaryotes, and also known as Metazoa. They obtain food from outside sources and move from place to place. They swallow the food, and digest it inside the body.
Ecologically they are called consumers, forming links in different food chains and complex food webs through which a part of matter and energy flows from the producer to the decomposer.
However, most living things share the following tracts:
1. They are organised as cells.
2. They are made up of complex chemical compounds.
3. They reproduce.
4. They grow and develop.
5. They respond to stimuli
6. They acquire and use energy by the process of metabolism.
The millions of kinds of organisms are grouped by most biologists into five kingdoms:
(i) Monerans
(ii) Protists
(iii) Fungi
(iv) Plants and
(v) Animals.
The merits and demerits of five kingdom classification are as follows:
Merits and Demerits:
At first biologists grouped all organisms into two kingdoms. Organisms either belonged to the plant kingdom or to the animal kingdom. Basically the plants are autotrophic and animals are heterotrophic.
Later on this was realised that some groups did not fit well into either kingdom. For example, organisms such as bread mold do not make their own food as plants do but they are not animals.
Biologists also discovered that two kinds of one-celled organisms exist. One group has a nucleus without a covering or membrane around it and the nuclear material floats freely in the cell. Such a cell is called a procaryote. Whereas organisms in the other group have an organised nucleus surrounded by a membrane and the structures inside these cells are more complex. This type of cell is called eucaryote.
As a result of these findings this was decided that other kingdoms should be added to distinguish the different kinds of organisms.
With the result, many biologists believe that a five-kingdom classification system is best.
Identification of Species and Use of Key:
A taxonomist makes it possible for other biologists to identify the species revised by him.
This can be done in three ways:
(i) By placing specimens of species classified by him (taxonomist) in a museum or herbarium,
(ii) By publishing descriptions and illustrations of the species, and
(iii) By forming taxonomic keys.
Other taxonomic aids:
(i) Monographs, which give comprehensive account of complete compilation of available information of any one family or genus at a given time.
(ii) Manuals, which contain compiled information about area covered, keys, description of families, genus and species.
(iii) Other publications, such as periodicals and dictionaries are brought out to give us information about new additions and updated information.
Utility of Systematics:
Systematics is an observational science and forms a part of natural history. This gives us an idea of organic diversity, its origin, and evolution. The role of systematics is obvious in the study of population biology, population genetics, evolutionary biochemistry, immunobiology, etc.
Systematics is of value in the identification and breeding of a number of economically important crop plants. It gives the correct identity of the plants. In our country, the epidemiological problem is important. A few species of mosquitoes transmit malaria, filaria, dengue, kala azar, etc.
The identification of these, their feeding and breeding biology and their behaviour have led to their eradication and control. Systematics provides the basic information needed in many applied disciplines and thus becomes complementary to all branches of basic and applied biology.