Biologist today have classified and divided all living things into five groups they  Kingdoms. 

•These kingdoms are based on how living things are the same and how they are different.

Five kingdoms 

The five kingdoms currently accepted by most (but not all) scientists are the : 

•Monera 

•Protoctista

•Fungi 

•Plantae 

•Animalia  

MONERA 

• The Monera Kingdom consists of unicellular lifeforms. 

• Monera cells are far simpler and more basic than the cells of other lifeforms. 

• Are PROKARYOTES: These cells have no nucleus, and are also missing many of the organelles, or parts, commonly found in other cells. For this reason, monera are thought to be very distantly related to other lifeforms. 

Monera can be autotrophs (are able to create their own organic matter from inorganic and light, similar to plants) or heterotrophs (cannot create their own organic matter). • Monera are considered by many scientists to be the oldest life forms on Earth, and the ancestors of all the other types of life that have since evolved. 

Useful and Harmful aspects of Monera 

Some people may tend to fear bacteria, because they only imagine that bacteria cause harm. However biological studies show that bacteria can be both harmful and useful in nature. Bacteria are harmful because: 

1. They cause diseases e.g. tuberculosis and cholera in humans.

 2. Action of bacteria on food makes it rot. 

Bacteria are useful because: 

1. They help in the process of decomposition by breaking up organic wastes. 

2. They contribute to soil fertility by fixing nitrogen which is important for plant growth.

 3. Some bacteria are used in treatment of sewage. 

4. Some bacteria are used in industry e.g. in making of food like yoghurt 

PROTOCTISTA 

• The primary difference between protists and monera is that protists are more complex, having cells with a nucleus (EUKARYOTES).

• Protist can be autotrophs or heterotrophs. 

They can also be unicellular or multicellular. It is a varied group! Biologists believe that ancient protists were the ancestors of plants and animals. 

KiFUNGI

Fungi are eukaryotic organisms that include microorganisms such as yeasts, moulds and mushrooms. These organisms are classified under kingdom fungi.

The organisms found in Kingdom fungi contain a cell wall and are omnipresent. They are classified as heterotrophs among the living organisms

ngdom Fungi

BRYOPHYTA (BRYOPHYTES) 

Bryophytes are amphibians of plant kingdom as they complete their life cycle in both water and on land. These mainly grow in damp, shady places, especially in the hills. 

 They are embryophytes that do not have vascular tissues (neither xylem nor phloem), where multicellular sporophytes are always borne on the gametophytes. 

 No true leaves and roots, as their independent plant body is gametophytic (haploid). 

 Sex organs are jacketed as they are always surrounded by one or several layers of sterile cells. 

PTERIDOPHYTA

A fern plant is a pteridophyte 

Ferns are lower vascular plants. 

They contain vascular tissue. 

Which is made up of xylem and phloem and helps in conduction of water and nutrients to all parts of the plant body. 

Pteridophytes are usually found in damp, shady places or in the gardens, and on the hills where temperature is low. 

2. The main plant body represents a sporophytic (diploid) generation and has roots which penetrate the soil to absorb water, and minerals. 

3. The leaves (fronds) of sporophyte grow on thick, horizontal underground stem or rhizome which bears adventitious roots. The young leaves and the base of fronds are covered by dry brown scales (ramenta). 

Spermatophytes 

This is a group of plants that bear seeds hence seed-bearing plants. 

These include some trees, shrubs and herbs. 

They have a stem, leaves, roots and a well-developed vascular system. 

Spermatophytes are divided into two groups: 

1. Angiosperms (flowering plants) 

2. Gymnosperms 

GYMSOSPERMAE (GYMNOS; NAKED, SPERMA; SEED) 

Together with flowering plants Angiosperms, the Gymnosperms form the group Spermatophyta (sperma; seed, phyte; plant) i.e. seed-producing plants. 

The gymnospermae bear naked ovules on flat scale leaves called ovuliferous scales which are not enclosed in carpels (ovary). 

The ovuliferous scales are arranged in cones. 

Characteristics of Gymnosperms 

1. The adult plant (sporophyte) is a tall, woody, perennial tree or shrub mostly evergreen. The stem is usually branched, but rarely unbranched as in, Cycas. 

2. Leaves may be simple (as in Pinus)  or compound (as in Cycas). 

3. Leaves may be dimorphic or of one kind only. Foliage leaves are large green simple or pinnately compound, needle-like and grow on dwarf shoot as in, Pinus, or directly borne on the main trunk as in Cycas. Scale leaves are brown and simple 

Angiosperms

Flowering plants reproduce by seeds which are formed from flowers. 

The seeds are enclosed in an ovary. 

Flowering plants are divided into two: monocotyledonous and dicotyledonous plants. 

Monocotyledonous plants are flowering plants which have only one cotyledon in their seeds. Most have long, narrow leaves with parallel leaf veins. 

Their flowers have dull coloured petals in multiples of three. Examples include grasses, maize, millet, sorghum. 

Dicotyledonous plants have two cotyledons in their seeds. Their leaves are usually broad and the leaf veins form a branching network. They have four or five brightly coloured petals on each flower. Examples include; beans, peas, groundnuts. 

Activity : Sorting and identifying organisms in kingdom plantae 

What you need • 

Pictures or specimens (cycad, mango, papyrus, fern, water cabbage, cypress, eucalyptus, sugarcane, hornwort, clubmosses, wandering Jew) 

• Group names (angiosperms, pteridophytes, gymnosperms, bryophytes) •

 Characteristics of different organisms written on a chart (have roots, stems and leaves; seeds are in an ovary; have flowers; have vessels; have no flowers; have no vessels; have no roots; seeds are not in an ovary) 

What to Do 

1. Sort the organisms in the pictures according to their different groups using the common characteristics. 

2. Construct a flow chart for any four organisms based on the characteristics

KINGDOM ANIMALIA

We usually tend to limit the word ‘animal’ to a few particular organisms leaving out others. In this unit, you are going to learn what organisms are classified as animals. Animals are multicellular organisms. Their cells have no cell walls or chloroplasts therefore they cannot make their own food. Most animals ingest solid food and digest it internally. The animal kingdom can be divided into 9 main groups (Phyla); eight of these groups are animals without a backbone (Invertebrates) and the other group comprises animals that have a backbone (Vertebrates). 

Arthropods

 This is the largest phylum in the animal kingdom. They live on land, in water and in air. 

They have an exoskeleton that protects their bodies and prevents them from losing excessive water. Their bodies are segmented with pairs of jointed appendages (legs and antennae). 

The segmented body eases movement. 

Arthropods consist of four classes: 

• myriapods 

• crustaceans 

• arachnids 

• insects 

myriapods

They have an elongated body with several segments. They have one pair of antennae. They have several legs and simple eyes. Centipedes have one pair of legs on each body segment. They have a poison claw used to kill its prey. Millipedes have two pairs of legs on each body segment. They contribute to soil fertility by barrowing in soil to aerate the soil and add humus. 

crustaceans

They live in water or in damp places. They have two main body divisions i.e. fused head/thorax and abdomen. They have two pairs of antennae and two compound eyes. They have five pairs of jointed legs and in some species the front pair is modified into claws or pincers.

Arachnids 

Insects form the largest group in phylum Arthropoda. They can be found anywhere. The insect’s body is divided into three distinct body parts, namely; head, thorax and abdomen. They have three pairs of jointed legs on the thorax. They have a pair of compound eyes except the soldier termites. Most adults have one or two pairs of wings. Some insects are harmful or useful or both harmful and useful to other organisms. 

examples of arthropods include the following;

Chordates 

Members of this group are also referred to as vertebrates (have a backbone). 

They all have an endoskeleton (inner skeleton) comprising a skull, backbone, limb bones and ribs. 

They have a dorsal nerve cord (spinal cord). Most vertebrates, apart from fish, have four limbs which they use for locomotion. 

In birds and bats, the front limbs develop into wings for flying. A fish’s limbs are its fins, which vary in number. Snakes have no limbs. 

Chordates comprise five classes: 

i) Fish (Pisces) 

ii) Amphibians 

iii) Reptiles 

iv) Birds (aves) 

v) Mammals 

Class – Pisces

• These are fish. Their skin is covered with scales/plates. They lay eggs [oviporous].

• They obtain oxygen dissolved in water by using gills.

• The body is streamlined, and a muscular tail is used for movement.

• They are cold-blooded and their hearts have only two chambers, unlike the four that humans have.

• Some fish skeletons are made entirely of cartilage , such as sharks, and some with a skeleton made of both bone and cartilage .

Class – Amphibia

• As the name indicates (Gr., Amphi : dual, bios, life), amphibians can live in aquatic as well as terrestrial habitats.

• The amphibian skin is moist without scales [mucus glands in the skin]. The eyes have eyelids. A tympanum represents the ear.

• Alimentary canal, urinary and reproductive tracts open into a common chamber called cloaca which opens to the exterior.

• They have a three-chambered heart (two auricles and one ventricle). These are cold-blooded

• Respiration is through gills, lungs and through

• Respiration is by gills, lungs and through skin.

• Sexes are separate. Fertilisation is external.

• They are oviparous and development is indirect.

• Examples: Toad, Frog), Tree frog, Salamander, Limbless amphibia.

Class – Reptilia

• The class name refers to their creeping or crawling mode of locomotion (Latin, repere or reptum, to creep or crawl).

• They are mostly terrestrial animals and their body is covered by dry and cornified skin, epidermal scales or scutes. Snakes and lizards shed their scales as skin cast.

• They do not have external ear openings. Tympanum represents ear. Limbs, when present, are two pairs.

• Heart is usually three-chambered, but four-chambered in crocodiles.

• Reptiles are poikilotherms [cold-blooded animals].

• They lay eggs with tough coverings and do not need to lay their eggs in water, unlike amphibians.

• Sexes are separate.

• Fertilisation is internal.

• They are oviparous and development is direct.

• Examples: Turtle), Tortoise, Chameleon (Tree lizard), Garden lizard, Crocodile, Alligator, Wall lizard, Poisonous snakes – Naja (Cobra), Bangarus (Krait), Vipera (Viper

Class – Mammalia

• Mammals are warm-blooded animals with four-chambered hearts.

• Most mammals familiar to us produce live young ones. However, a few of them, like the Platypus and the Echidna lay eggs, and some, like kangaroos give birth to very poorly developed young ones.

• They are found in a variety of habitats – polar ice caps, deserts, mountains, forests, grasslands and dark caves. Some of them have adapted to fly or live in water.

• The most unique mammalian characteristic is the presence of milk producing glands (mammary glands) by which the young ones are nourished.

• They have two pairs of limbs, adapted for walking, running, climbing, burrowing, swimming or flying.

• The skin of mammals is unique in possessing hair. External ears or pinnae are present. Different types of teeth are present in the jaw.

• Heart is four-chambered. They are homoiothermous [warm-blooded]. Respiration is by lungs.

• Sexes are separate and fertilisation is internal.

• They are viviparous with few exceptions and development is direct.

• Examples: Oviparous – Platypus; Viviparous – Kangaroo, Flying fox), Delphinus (Common dolphin), Balaenoptera (Blue whale), etc.