Kingdom Monera 

kingdom consists of bacteria and blue-green algae. The scientific study of bacteria is called Bacteriology

Characteristics of bacteria

(a) They are prokaryotic. Their cells lack a well-defined nucleus, since they have no nuclear membrane. They also lack other membrane bound organelles.

(b) They are small unicellular organisms. Some bacteria stick together to form chains or clusters called colonies.

(c) Some are free-living while others are parasites or saprophytes. Free- living bacteria means that they exist on their own, for example in sewage or soil. These bacteria do not need to form relationship to other organisms in order to survive. Parasitic bacteria depend on other organisms known as hosts for their needs. Example of hosts are human beings and other animals. Saprophytic bacteria get their food from dead organic matter.

(d) Free-living bacteria have flagella for movement.

(e) Bacteria have a slimy outer layer. This layer helps to protect them from parasites like viruses and predators such as protozoa.

(f) They reproduce asexually by binary fission or through spores.

(g) They occur in various shapes. There are five known shapes of bacteria. These are spherical or cocci (singular: coccus), rod or bacilli (singular: bacillus), spiral or spirilla (singular: spirillum), comma or vibrio (singular: vibrion) and corkscrew or spirochaetes (singular: spirochaete). 

Activity 11.1: Observation of features of bacteria

Materials: Microscope and prepared microscope slides of bacteria

Procedure

1. Observe prepared slides of bacteria using the microscope. What shapes of bacteria do you see?

2. Draw what you have observed.

3. Compare your drawings with diagrams in the textbooks in the figure below

Advantages of bacteria

(a) Some non-pathogenic bacteria feed on substances that are harmful to the environment, and in the process neutralize them. For example, they neutralize petroleum waste from petroleum industries, dyes and pesticides, thereby making the environment clean.

(b) Bacteria in the stomach of ruminant animals such as goats and cows secrete cellulase enzyme. Cellulase enzyme helps in the digestion of cellulose which forms a large part of the diet of ruminants.

(c) Nitrogen-fixing bacteria lives in the root nodules of leguminous plants. They converte nitrogen in the air to nitrates in soil which can be used by plants to make proteins.

(d) Vitamins produced by bacteria are important for the health ofmanimals, including human.

(e) Many bacteria are decomposers. They break down the dead bodies of plants and animals to release important elements such as nitrogen, carbon, and phosphorus which can be recycled.

(f) Some bacteria produce lactic acid as a result of fermentation of carbohydrates. This is important in the production of cheese, yoghurt, vinegar, and alcohol.

(g) Controlled fermentation is used in the curing of tea and tobacco and retting of flax. Curing helps to treat and preserve these products. Retting of flax is important in the production of linen.

(h) Some bacteria are used to produce antibiotics, which are used to treat bacterial infections.

(i) Bacteria are used in genetic engineering to produce hormones such as insulin and human growth hormone.

(j) Autotrophic bacteria undergo photosynthesis to release oxygen into the atmosphere. Oxygen is important for respiration.

(k) Bacteria in the human gut manufacture vitamins K and B12, for example Escherichia coli.

Disadvantages of bacteria

(a) Some bacteria cause infections and diseases in animals. Some of the common bacterial diseases of animals are typhoid fever caused by Salmonella typhi, Tuberculosis (TB) caused by Mycobacterium tuberculosis and gonorrhoea caused by Neisseria gonorrhoeae.

(b) Some bacteria cause diseases in crops. Examples of these diseases are fireblight on pea and apple caused by Erwinia amylovora and leaf spot in cotton caused by Xanthomonas campestris. Bacterial diseases in crops cause reduction in yield hence loss to farmers.

Kingdom Protoctista

Members of this kingdom include Amoeba sp., Euglena sp., Plasmodium sp., Paramecium sp., and Trypanosoma sp.

Characteristics of protoctists

(a) They are eukaryotic.

(b) Most are unicellular organisms, only a few are multicellular.

(c) Most live in or near water, or in moist places. Others are parasitic.

(d) Some are autotrophic (they manufacture their own food) while others are heterotrophic (obtain nutrients from other organisms).

(e) Some are mobile while others are sessile.

(f) Some reproduce sexually and others asexually. Others reproduce both sexually and assexually.

(g) Many protoctists have locomotory structures such as cilia, flagella or pseudopodia

Activity 11.2: Observing different protoctists

Materials: Specimen bottles, microscope, microscope slides and cover slips, pond water, a notebook, and a pencil

Procedure

1. Go to a pond or any other place with stagnant water.

2. Fetch water from the pond using specimen bottles.

3. In the Biology laboratory, put a drop of the pond water on a microscope slide, add stain and cover it with a cover slip.

4. Observe the slide under the microscope. Can you identify any organisms? Name them.

5. Draw what you see under the microscope.

Kingdom Fungi 

Kingdom fungi include mushrooms, yeast and moulds. Some fungi grow in wood and soil, and develop from tiny spores. Fungi have a nucleus and their cells have a cell wall made up of a substance known as chitin. They do not make their own food; instead feed on the decomposing organic matter of animals and plants. You may already be aware that some types of fungi like mushrooms are grown and eaten while others like puff balls are poisonous. This informs you that fungi can be useful or harmful in nature. 

Useful Aspects of Fungi 

1. Fungi keep soil fertile by recycling organic material through decomposition. 2. Some fungi are food for humans, for example, mushrooms. 3. Manufacture of medicine, for example, antibiotic Penicillin Yeast is a type of fungus used in baking of bread and brewing of beer in industries. 

Harmful Aspects of Fungi 

1. They cause diseases e.g. ringworm, candida, athletes’ foot (in animals), potato blight and leaf rust in coffee. 2. Fungi like moulds when they grow on food they cause food spoilage. 

Plant Kingdom – Plantae

Kingdom Plantae includes all the plants. They are eukaryotic, multicellular and autotrophic organisms. The plant cell contains a rigid cell wall. Plants have chloroplast and chlorophyll pigment, which is required for photosynthesis.

Characteristics of Kingdom Plantae

The plant kingdom has the following characteristic features:

1. They are non-motile.

2. They make their own food and hence are called autotrophs.

3. They reproduce asexually by vegetative propagation or sexually.

4. These are multicellular eukaryotes. The plant cell contains the outer cell wall and a large central vacuole.

5. Plants contain photosynthetic pigments called chlorophyll present in the plastids.

6. They have different organelles for anchorage, reproduction, support and photosynthesis.

Classification of Kingdom Plantae

A plant kingdom is further classified into subgroups. Classification is based on the following criteria:

1. Plant body: Presence or absence of a well-differentiated plant body. E.g. Root, Stem and Leaves.

2. Vascular system: Presence or absence of a vascular system for the transportation of water and other substances. E.g. Phloem and Xylem.

3. Seed formation: Presence or absence of flowers and seeds and if the seeds are naked or enclosed in a fruit.

The plant kingdom has been classified into five subgroups according to the above-mentioned criteria: 

1. Bryophyta

2. Pteridophyta

3. Gymnosperms

4. Angiosperms

Bryophyta

Bryophytes do not have vascular tissues. The plant body has root-like, stem-like and leaf-like structures. Bryophytes are terrestrial plants but are known as “amphibians of the plant kingdom” as they require water for sexual reproduction. They are present in moist and shady places. Bryophyta includes mosses, hornworts and liverworts 

Pteridophyta

Pteridophytes have a well-differentiated plant body into root, stem and leaves. They have a vascular system for the conduction of water and other substances.

Gymnosperms

Gymnosperms have a well-differentiated plant body and vascular tissues. They bear naked seeds, that is, seeds are not enclosed within a fruit. Some of the common examples of gymnosperms are Cycas, Pinus 

Angiosperms

Angiosperms are seed-bearing vascular plants with a well-differentiated plant body. The seeds of angiosperms are enclosed within the fruits. Angiosperms are widely distributed and vary greatly in size, for example. Wolffia is small measuring about 0.1 cm and Eucalyptus trees are around 100 m tall. Angiosperms are further divided into monocotyledons and dicotyledons according to the number of cotyledons present in the seeds. Some of the common examples are mango, rose, tomato, onion, wheat, maize, 

Kingdom Animalia

Kingdom Animalia constitutes all animals. Amongst the five kingdoms, the largest kingdom is the animal kingdom. Animals are multicellular eukaryotes. However, like plants, they do not possess chlorophyll or a cell wall. Therefore, members of the animal kingdom exhibit a heterotrophic mode of nutrition. Kingdom Animalia has been classified into different subphyla based on their body design or differentiation.

The different phylum of the animal kingdom are as follows:

1. Porifera

2. Coelenterata (Cnidaria)

3. Platyhelminthes

4. Nematoda

5. Annelida

6. Arthropoda

7. Mollusca

8. Echinodermata

9. Chordata

Phylum Porifera

Porifera means organisms with holes. They are commonly known as Sponges. Features of the poriferan are:

1. Non-motile, multicellular organisms with a hard outer skeleton.

2. Have a porous body.

3. Pores on the bodies create a canal system which helps in the circulation of substances.

4. Not differentiated into head and tail; do not have a well-developed organ or organ system.

5. Include marine habitat.

Phylum Coelenterata (Cnidaria)

The term Coelenterata is derived from the Greek word “kilos” which means hollow-bellied. Their features are:

1. Have a hollow body cavity.

2. The body is differentiated into two ends.

3. Includes all aquatic animals.

4. The body is made of two layers of cells: inner and outer linings.

5. Live in colonies (corals) as well as solitary (Sea anemone).

Phylum Platyhelminthes

Platyhelminthes are commonly known as flatworms. Their features are:

1. Dorsoventrally flattened body.

2. Complex and have differentiated body structure.

3. Tissues are differentiated from three layers of cells.

4. Have bilateral symmetry.

5. Either free-living (Planaria) or parasitic (liver flukes).

Phylum Nematoda

Phylum Nematoda consists of nematodes or roundworms. Their features are:

1. Nematodes have a cylindrical body.

2. Bilaterally symmetrical.

3. Parasitic and causes diseases such as elephantiasis, ascariasis.

Phylum Annelida

Annelids are commonly known as segmented or ringed worms. They have the following features:

1. Have a segmented cylindrical body.

2. The body is differentiated into head and tail.

3. Bilaterally symmetrical..

4. Habitat: marine, freshwater and land.

Phylum Arthropoda

Arthropod means jointed legs. Animals which have jointed appendages belong to this phylum. This is the largest phylum in the animal kingdom. Other features are:

1. They are bilaterally symmetrical.

2. Have jointed appendages, exoskeleton and a segmented body.

3. Have well-differentiated organ and organ system.

4. Have an open circulatory system, but do not have differentiated blood vessels.

Phylum Mollusca

Phylum Mollusca consists of a large group of animals. Features are:

1. Bilaterally symmetrical.

2. Less segmented body.

3. Well-developed organ and organ system.

4. Typically, open circulatory system.

5. Limbs are present.

Phylum Echinodermata

The term Echinodermata is derived from the Greek words, echinos meaning hedgehog and derma meaning skin. Thus, echinoderms are spiny-skinned animals.

1. Radial symmetry 

2. Have hard calcium carbonate skeleton structure.

3. Free-living marine animals.

Phylum Chordata

The Chordates possess the following characteristics:

1. They are bilaterally symmetrical with an organ-system level of classification.

2. They possess a notochord and a nerve cord.

3. The circulatory system is closed type.