It is as important to their survival as it is in animals. Plants respond to a variety of stimuli in their environment. These stimuli include light, moisture, gravity and chemicals. Some plants also show response to touch. Tropisms
Plants often respond by growing in a particular direction. Such growth movements are called tropisms. They are the result of unequal growth in the part of the plant that responds. The stimulus cause unequal distribution of growth hormones (auxins) produced in the plant. One side grows more than the other resulting in a bend either towards the stimulus (positive tropism) or away from the stimulus (negative tropism). Phototropism
If seedlings are exposed to light from one direction, their shoots grow towards the light. This response is called phototropism. Shoots are said to be positively phototropic because they grow towards the light. The tip of the shoot receives the light stimulus from one direction (unilateral stimulus) but the response occurs below the tip. The response of the shoot is due to a hormone called auxin produced at the tip. It diffuses down the shoot to this zone of cell elongation where it causes the cells to elongate. Light causes auxin to migrate to the darker side. The auxin is more concentrated in the dark side than on the light side. The cells on the dark side grow faster than the ones on the light side. A growth curvature is therefore produced. Survival value:
Positive phototropism by shoots ensure that sufficient light is absorbed by leaves for photosynthesis. Geotropism
Geotropism is a growth response to gravity. Roots are positively geotropic because they grow down towards the direction of the force of gravity;
shoots are negatively geotropic because they grow away from direction of force of gravity. If a seedling is kept in the dark with its plumule and radicle in a horizontal position, the plumule will eventually grow vertically upwards while the radicle will grow vertically downwards. The effect of gravity on roots and shoots can be explained as follows:
When the seedling is placed in a horizontal position, more auxin settles on the lower side of the root and shoot due to the effect of gravity. Shoots respond to a higher concentration of auxin than roots. The lower side of the shoot grows faster than the upper side. Resulting in a growth curvature that makes the shoot grow vertically upwards. Root growth is inhibited by high concentrations of auxin.


The lower side of the shoot grows faster than the upper side. Resulting in a growth curvature that makes the shoot grow vertically upwards. Root growth is inhibited by high concentrations of auxin. Therefore, the lower side of the root grows at a slower rate than the upper side where there is less auxin concentration. This results in a growth curvature that makes the root grow vertically downwards. Survival Value:
Roots in response to gravity grow downwards where they absorb water and get anchored in the soil. This results in absorption of nutrients needed for growth. Hydrotropism
Hydrotropism is the growth of roots towards water (moisture) . Survival Value
It ensures that plant roots grow towards moisture to obtain water needed for photosynthesis and transport of mineral salts. Chemotropism
Chemotropism is the response of parts of a plant towards chemical substances,
e.g. the growth of the pollen tube towards the ovule in flowering plants is a chemotropic response. Survival Value
This ensures that fertilisation take place and the perpetuation of the species continues. Thigmotropism
Thigmotropism is a growth response to touch. e.g. tendrils of climbing plant bend around objects that they come in contact with. Survival Value
This provides support and the leaves stay in a position suitable for absorption of light and gaseous exchange for photosynthesis. Tactic Movements in Plants and other Organisms
A tactic movement is one made by a whole organism or a motile part of an organisms (e.g. a gamete) in response to a stimulus. Tactic movements are named according to the nature of the stimulus that brings about the response. Phototaxis is movement in response to direction and intensity of light. Free-swimming algae such as Chlamydomonas usually tend to concentrate where light intensity is optimum and will respond to light by swimming towards it. This is an example of phototactic response. Osmotaxis is movement in response to changes in osmotic conditions e.g. freshwater amoeba. Survival Value
Ensures favourable conditions for existence. Chemotaxis is movement in response to concentration of chemical substances. Survival Value
In bryophytes, antherozoids move towards archegonia to effect fertilisation
Survival Value of taxis:
These ensure conditions favourable for life bring maximum benefit to the organism.


Survival Value
Ensures favourable conditions for existence. Chemotaxis is movement in response to concentration of chemical substances. Survival Value
In bryophytes, antherozoids move towards archegonia to effect fertilisation
Survival Value of taxis:
These ensure conditions favourable for life bring maximum benefit to the organism. Nastic Movements
A nastic movement is one made by part of a plant in response to stimulus which is not coming from any particular direction. Nastic movements are also named according to the nature of the stimulus. Seismonasty/haptonasty - response to shock. The 'sensitive plant' Mimosa pudica responds to touch by folding up its leaves. This is an example of a seismonastic response. Production of auxins and their effects on plant growth
Auxins are produced by plant apices, i.e. root apex and shoot apex. They bring about cell elongation resulting in growth. They are diffusible substances which effect growth when in very small amounts. Roots require lower concentrations than shoots. The effect of auxins on the growth of roots and shoots has already been discussed. Auxins also exert other effects on plant growth and development. There are various other chemical substances which have been shown to influence plant growth and development. Effects of Auxin on Plant Growth
Apical Dominance
Auxins inhibit the growth of side branches. This is referred to as apical dominance. If the terminal bud is removed, side branches develop from the lateral buds. This knowledge is applied in pruning. As long as the main stem is allowed to remain intact, the development of side branches is suppressed. Pruning the terminal bud removes the main sources of auxin, thus allowing side branches to sprout. Growth of adventitious roots
Adventitious roots develop from the stem. Auxins stimulate the growth of such roots. Parthenocarpy
This refers to the formation of fruits without fertilisation. This can be induced by treating unpollinated flowers with auxin. This phenomenon is applied in the development of seedless fruit varieties. Auxins, together with other plant hormones, are involved in secondary growth, falling of leaves and ripening of fruits. Reception, Responses and Coordination in Animals
The nervous and endocrine systems (together known as the neuro-endocrine system) act as a co-ordinating system. They linking the receptors to the effectors and regulating their activities. Receptors
Receptors are cells that detect or receive stimuli.


Reception, Responses and Coordination in Animals
The nervous and endocrine systems (together known as the neuro-endocrine system) act as a co-ordinating system. They linking the receptors to the effectors and regulating their activities. Receptors
Receptors are cells that detect or receive stimuli. They may be scattered more uniformly all over the body surface
e.g. receptors for pain, touch, temperature; or they may be located in a special sense organ e.g. receptors for light, sound, taste and smell. Motor nerves link the Central Nervous System (CNS) to the effectors. Its cell body is located at one end of the axon. It transmits nerve impulses from the CNS to the effectors. Effectors
These are the cells, organs, or organelles which enable the organism to respond. They include muscles, glands, cilia and flagella. The Nervous System
Components of the nervous system in humans
Every organ is the human body is connected to nerves. The nervous system is made up of nerve cells (neurons) which transmit impulses from one part of the body to another. It consists of the following:
The Central Nervous System (CNS) is a concentrated mass of interconnected nerve cells which make up the brain and the spinal cord. The peripheral nervous system is made up of nerves which link the CNS to the receptors and the effectors. Sensory nerves link the sensory cells (receptors) to the central nervous system and transmit nerve impulses from a sense organ to the CNS. Structure and Functions of Neurons
A nerve cell consists of a cell body (centron) where the nucleus is located, and projections called dendrites arise. One of the projections is drawn out into an axon i.e. the longest process. Each axon contains axoplasm which is continuous with the cytoplasm in the cell body. The axon is enclosed in a fatty myelin sheath which is secreted by Schwarm cell. The myelin sheath is interrupted at approximately 1 mm intervals by constrictions known as nodes of Ranvier. The myelin sheath is enclosed by a thin membrane called the neurilemma, which is part of the Schwann cell in contact with axon. The myelin sheath and nodes of Ranvier enhance transmission of the impulse. There are three types of neurons:
Sensory neurone
Also known as afferent neurone.


The myelin sheath is enclosed by a thin membrane called the neurilemma, which is part of the Schwann cell in contact with axon. The myelin sheath and nodes of Ranvier enhance transmission of the impulse. There are three types of neurons:
Sensory neurone
Also known as afferent neurone. Transmits impulses from sensory cells to the CNS. The cell body of a sensory nerve cell is located at some distance along the length of the axon outside the CNS. Motor neurone
Known as efferent or effector neurone
Transmit impulses from the CNS to the effectors(muscles and glands)
Its cell body is located inside the CNS. Intermediate or connector neurone
Also called relay neurone
Found inside the CNS. The connect sensory and motor neurons with each other and with other nerve cells in the CNS. Functions of the neurone
The nerve impulse is electrical in nature. Its transmission depends on differences in electrical potential between the inside and the outside of the axion. The outside is positive while the inside is negative. The stimulus triggers a change that affects the permeability of neurone membrane. The result is a change in the composition of ions on either side of the membrane. The outside becomes negative as the inside becomes positive due to sodium ions rushing in. The above constitutes a nervous impulse which is transmitted along the sensory neurone to the CNS. The speed of transmission is very high. Certain mammalian axions transmit impulses at the rate of 100m/s. The dendrites of neurons do not connect directly to each other, but they leave a small gap called synapse. The transmission of an impulse from one cell to the next takes place through synapse. Synaptic knobs are structures found at the ends of dendrites. Thus the dendrites of one nerve cell make contact with the dendrites of the adjacent nerve cell through the synapses. Impulses are transmitted in the form of a chemical transmitter substance which crosses the gap between one dendrite and the next. The transmitter substance is found within synaptic vesicles. The chemical substance is either acetylcholine or noradrnaline. The synaptic vesicles burst and release the transmitter substance when an impulse arrives at the synaptic knob. Impulses in motor neurone s are trans mitted to effectors. The space between motor end dendrite and muscle is known as neuro-muscular Junction. Synaptic vesicles in the ends of the dendrites release the transmitter substance across the neural muscular junction.


Impulses in motor neurone s are trans mitted to effectors. The space between motor end dendrite and muscle is known as neuro-muscular Junction. Synaptic vesicles in the ends of the dendrites release the transmitter substance across the neural muscular junction. Functions of Major Parts of the Human Brain
The Central Nervous System (CNS) consists of the brain and the spinal cord. The CNS co-ordinates body activities by receiving impulses from sensory cells from different parts of the body. It then sends the impulses to the appropriate effectors. The brain is enclosed within the cranium or braincase. It is covered and protected by membranes known as meninges. When meninges are infected by bacterial or fungi they cause meningitis. The brain consist of the following parts:
Cerebrum. This is the largest part of the brain. It consists of two cerebral hemispheres. It is highly folded in order to increase the surface area. The cerebrum controls learning, intelligence, thought, imagination and reasoning. The medulla oblongata (brain stem). The medulla oblongata has centres which control breathing (ventilation) rate,
heart beat rate (cardiac frequency),
swallowing, salivation, blood pressure
temperature regulation, hearing, taste and touch. The cerebellum
Is located in front of the medulla and is a folded dorsal expansion of the hindbrain. It controls posture movement and balance. The hypothalamus
Controls functions such as body temperature and osmoregulation. The pituitary gland
Is an endocrine organ that secretes a number of hormones which control osmoregulation, growth, metabolism and sexual development. Optic lobes -control the sense of sight. Olfactory lobes -control the sense of smell. Spinal Cord
The spinal cord is located within the vertebral column and consist of the following:
The grey matter forms the central part of the spinal cord. It consists of nervecell bodies and intermediate nerve fibres. The white matter of the spinal cord carries sensory nerve fibers while the ventral root carries motor nerve fibers. Simple And Conditioned Reflex Actions
Simple Reflex Action
A simple reflex action is an automatic response to a stimulus. The route that is followed by impulses during a reflex action is called a reflex arc. A reflex action follows the following sequence:
A receptor is stimulated and an impulse is transmitted along a sensory nerve fibre to the spinal cord.


Simple And Conditioned Reflex Actions
Simple Reflex Action
A simple reflex action is an automatic response to a stimulus. The route that is followed by impulses during a reflex action is called a reflex arc. A reflex action follows the following sequence:
A receptor is stimulated and an impulse is transmitted along a sensory nerve fibre to the spinal cord. The impulse is picked up by an intermediate neurone within the CNS. The intermediate nerve fibre transmit the impulse to a motor nerve fibre which is connected to an effector. The effector responds. Examples of reflex action include:
Pulling the hand away from a hot object. The knee jerk. Sneezing. Conditioned Reflexes
These are learned responses. When two or more stimuli are presented to an animal at the same time and repeatedly, the animal eventually responds to either stimulus. For example, if a hungry animal is presented with food, it will respond by salivating. If a bell is rung at the same time as the food is presented to the animal, the animal will learn to associate the sound of the bell with food. Eventually, the animal can be made to salivate at the sound of the bell alone. This response is called conditioned reflex and is one of the ways by which animals learn. The Role of Endocrine System in Human Beings
Endocrine system consists of glands that secrete hormones. The glands have no ducts and are known as endocrine glands. Other glands are known as exocrine glands because they have ducts. The pancreas has an outer exocrine portion and an inner endocrine portion. Hormones are chemical substances, protein in nature which are secreted at one part of the body and have effects on other parts not necessarily near the point of secretion. They are secreted directly into blood and transported by blood. Each hormone either has a generalised co-ordinating effect on the body or brings about a specific response in a particular target organ. Hormones produced in humans and the in effects on the body. Adrenaline
Enhance activity of sympathetic nervous system. Over secretion
Increased heartbeat
High blood pressure
Thin toneless muscles. Under secretion
Low blood pressure
Inability to withstand stress
Muscular weakness
Thyroxine
Over secretion is termed hyperthyroidism this causes:
Increased Basal Metabolic Rate (BMR) hence increased temperature. Person becomes very angry, nervous and hands may shake. Increased heartbeat which lead to cardiac failure.


Under secretion
Low blood pressure
Inability to withstand stress
Muscular weakness
Thyroxine
Over secretion is termed hyperthyroidism this causes:
Increased Basal Metabolic Rate (BMR) hence increased temperature. Person becomes very angry, nervous and hands may shake. Increased heartbeat which lead to cardiac failure. Under secretion is termed hypothyroidism:
Poor growth and mental retardation (cretinism). Reduced metabolic rate hence decreased temperature. Person becomes inactive and slothful. Eyes and face become puffy as fluid gets stored under skin. In extreme cases the tongue is swollen and skin becomes rough. Enlarged thyroid gland. Comparison between endocrine and nervous system
Similarities
Both endocrine and nervous system are involved in the coordination of body functions. Both have target organs. Both are controlled via a negative feedback mechanism, i.e too high production results in a reduced production. Effects of drugs abuse on the human health. Drug abuse can be defined as misuse of drugs. Drugs are chemical compounds that affect the working of body or kill disease causing microorganisms. Prescription drugs
Are drugs prescribed by a doctor. Prescribed drugs can be abused through taking overdose which may cause death. Over the counter drugs(OCD)
Are self prescribed drugs. These have harmful effects and may lead to tolerance such that higher doses are needed. Below is a list of effects of hard drugs on human health
Lung cancer caused by nicotine. Emphysema. Liver cirrhosis -caused by alcohol. Interferes with vision - alcohol. Sterility - khat (rniraa). Sleeplessness - insomnia - khat (miraa). Hallucinations - Canabis sativa (Bang i). Digestive system is upset, nausea. Diarrhoea and vomiting. Headache and double vision. Skin tone changes - e.g. too dark. Appetite is extreme - very poor or very great. Weight loss. Personality changes e.g. irritable and confused. Convulsions, lethargy and depressions due to inhalation of solvents e.g. glue. Structure and Function of Parts of the Human Eye
Structure
The human eye is spherical in shape and situated within a socket or orbit in the skull. It is attached to the skull by three pairs of muscle, which also control its movement. It is made up of three main layers; sclerotic layer, choroid and the light sensitive retina.


Structure and Function of Parts of the Human Eye
Structure
The human eye is spherical in shape and situated within a socket or orbit in the skull. It is attached to the skull by three pairs of muscle, which also control its movement. It is made up of three main layers; sclerotic layer, choroid and the light sensitive retina. Sclerotic layer
Outermost white part situated at the sides and back of the eye. Made up of collagen fibres. It protects the eye and gives its shape. Cornea
This is the transparent front part of the sclera that allows light to pass through. It is curved, bulging at the front. It thus reflects light rays hence helps to focus light rays onto the retina. Choroid
The second or middle layer. It has many blood vessels that supply nutrients to the eye and remove metabolic wastes from the eye. It has dark pigments to absorb stray light and prevent its reflection inside the eye. Ciliary body
Is glandular and secretes aqueous humour. It has blood vessels for supplying of nutrients excretion and gaseous exchange. It has ciliary muscles - which contract and relax to change the shape of lens during accommodation. Suspensory ligaments
Are inelastic and attach the lens onto the cilliary body holding it in position. Lens
Biconvex in shape, to refract light. Crystalline and transparent to allow light to pass through and focus it on to the retina. Aqueous humour
Found between lens and the cornea. Transparent to allow light to pass through it. It is watery thus helping in focusing. Helps maintain shape of eye ball. To convey nutrients and oxygen to cornea, and remove waste products. Iris
The coloured part of the eye has an opening - the pupil at the centre. Iris has circular and radial muscles which controls size of the pupil, hence the amount of light entering the eye through the pupil. Vitreous humour
It is a fluid. Found between lens and retina. Is viscous and gives eye the shape. It is transparent and refracts light. Retina
Retina contains light sensitive cells and is situated at the back of the eye. There are two types of light sensitive cells in the retina:
Rods - are sensitive to low-intensity light and detect black and white. Nocturnal mammals have more rods. Cones - are sensitive to high intensity of light;
They detect bright colour.


There are two types of light sensitive cells in the retina:
Rods - are sensitive to low-intensity light and detect black and white. Nocturnal mammals have more rods. Cones - are sensitive to high intensity of light;
They detect bright colour. Diurnal mammals have more cones. Fovea centralis
Fovea centralis (yellow spot) is the most sensitive part of the retina. Consists mainly of cones for accurate vision (visual acuity). Optic nerve
Optic nerve, has neurons for transmission of impulse to the brain for interpretation. Blind spot
Blind spot is located at the point where the optic nerve leaves the eye on its way to the brain. It is not sensitive to light it has no rods or cones. Eye lid
Eye lid is a loose skin that covers the eye. It closes by reflex action. Protects it from mechanical damage and from too much light. Eyelashes
Prevent dust and other particles from entering eye. Conjuctiva
It is transparent and thin and allows light to pass through. It is a tough layer that is continuous with the epithelium of the eye lids. It protects the cornea. Accommodation
Accommodation refers to the change in the shape of the lens in order to focus images. Rays from a distant object would be focused at a point behind the retina if the lens were not adjusted appropriately. When the eye is focusing at a distant object, the cilliary muscles are relaxed and the suspensory ligament are stretched tight. The lens is pulled thin, thus allowing light rays from a distant object to be properly focused on to the retina. When the eye is looking at near object, the ciliary muscles contract and the suspensory ligament become slack. The lens becomes more convex. This allows light rays from near object to be focused onto the retina. Control of light intensity entering the eye
In bright light (high intensity) the circular muscles of the iris contract. The diameter of the pupil decreases and less light enters. This protects retina from damage by too much light. In dim light circular muscles of iris relax (radial ones contract). Pupil's size (diameter) increases, more light enters the eye. Image formation and Interpretation
Light rays from an object enter the cornea and are directed onto the lens through the pupil. They are refracted by the cornea and the lens. The latter brings the rays into fine focus.


Image formation and Interpretation
Light rays from an object enter the cornea and are directed onto the lens through the pupil. They are refracted by the cornea and the lens. The latter brings the rays into fine focus. It makes the light rays converge so that an image is focused at a point on the retina. The image on the retina is inverted. This stimulate, the rods and cones on the retina and impulses generated are transmitted through the optic nerve to the brain. The brain interprets the image as upright. Common Eye Defects and their Correction
Short-sightedness (Myopia)
A shortsighted person cannot focus distant objects properly. Light rays from a distant object fall at a point in front of the retina. This may be due to the eyeball being too long. This defect can be corrected using spectacles with concave lenses. The lenses make the light rays diverge before they reach the eye. Long-sightedness (Hypermetropia)
A long-sighted person cannot focus near objects properly. Light rays from the object are not focused on the retina. This may be due to the eyeball being too short. This defect may be corrected by using spectacles with convex lenses which make light rays converge before they reach the eye. Astigmatism
Astigmatism refers to a condition in which the cornea or the lens is uneven, so that images are not focused properly on the retina. This defect can be corrected by wearing spectacles with special cylindrical lenses. Presbyopia is a condition in which light rays from a near object are not focused on the retina. This is caused by hardening or loss of elasticity of lense due to old age. This defect is corrected by wearing convex (converging) lenses. Structure and Functions of Parts of Human Ear
The Mammalian Ear
The mammalian ear performs two major functions:
hearing and detecting changes in the positions of the body to bring about balance and posture. The ear is divided into three sections. The Outer Ear
This consists of:
An outer flap, the pinna which is made up of cartilage. The function of the pinna is to catch and direct sounds. The external auditory canal is a tube through which sound travel. The lining of the tube secretes wax, which traps dust particles and microorganisms. The tympanum is a membrane stretching across the inner end of the external auditory canal. The tympanum vibrates when it is hit by sound waves.


The lining of the tube secretes wax, which traps dust particles and microorganisms. The tympanum is a membrane stretching across the inner end of the external auditory canal. The tympanum vibrates when it is hit by sound waves. The Middle Ear
This is a chamber containing three small bones called the ear ossic1es, the malleus, incus and stapes. The three ossic1es articulate with one another to amplify vibrations. The vibrations are transmitted from the tympanum to the oval window. At the end of the chamber is a membrane called the oval window. When the tympanum vibrates, it causes the ear ossic1es to move forwards and backwards. This causes the oval window to vibrate. The Eustachian tube connects the middle ear to the pharynx. It allows air to get in and out of the middle ear, thus equalising the pressure between the inside and the outside of the tympanum. The Inner Ear
This consists of a series of chambers filled with fluid. It comprises the cochlea and semicircular canals. Cochlea is a coiled tube that occupies a small space and accommodates a large number of sensory cells. The cells are connected to the brain through the auditory nerve. They detect vibrations which lead to hearing. Hearing
The sound waves set the tympanum vibrating and are transformed into vibrations. The vibrations are transmitted to the oval window by the three ossicles. Vibrations of the oval window cause the fluids inside the cochlea tube to vibrate. The membranes inside the cochlea have sensory cells which change the sound vibrations to nerve impulses. These are transmitted to the brain through the auditory nerve. Hearing is perceived in the brain. Balance and posture
The semi-circular canals
There are three semi-circular canals in each ear. They are situated at right angles to each other and each one is sensitive to movement in a different plane. They are filled with fluid and each has a swelling called the ampulla at one end. Inside the ampulla are sensory cells. Balance and posture are detected by these cells. Movement of the head in a given direction causes the fluid to move the hairs on sensory cells. This transmit impulses to the brain through the auditory nerve so that the movement is registered. Defects of the ear
Acute labyrinthitis
This is an inflammation of the middle ear and cochlea. It may lead to deafness.


This transmit impulses to the brain through the auditory nerve so that the movement is registered. Defects of the ear
Acute labyrinthitis
This is an inflammation of the middle ear and cochlea. It may lead to deafness. It can be treated by using certain drugs but sometimes an operation may be necessary. Tinnitis:
This is a sensation of noises in the ear. It is caused among others by accumulation of wax in the ear or use of certain drugs e.g. quinine. Treatment is by removal of wax, stopping use of the causative drug. Vertigo - Giddiness
This is disorientation of body in space - one of the causes is dilation of endolymph. Corrections: Use of appropriate drugs. Deafness. This is inability to hear. It is presented in various degrees in various individuals, some have partial hearing, others are completely deaf. This may be as a result of:
Chronic infection of cochlea. Lack of sensory cells. Excess wax in external auditory canal. Fusion of ear ossicles. Otitis Media
This is the inflammation of middle ear due to build-up of fluid. It is marked by the swelling of tissues surrounding the Eustachian tube due to infection or severe congestion. A strong negative pressure creates a vacuum in the middle ear. Treatment - use of antibiotics or surgery. Practical Activities
To investigate tactic response
Tactic response in fly maggots are investigated using choice chambers(s). Responses to various stimuli are observed e.g. to chemical substances - chemotaxis. On one side of choice chambers is placed beef/fish that has been dried in the sun. On the opposite chambers is placed rotting meat/fish. Ten maggots are placed at the center and choice chamber is covered. After 10 minutes the number of maggots at each end is counted. Most of the maggots have moved to the chamber with rotting meat. Tropisms
Maize or been seeds are soaked and germinated, to the stage when radical and coleoptile/plumule just appear . (about 5 days for beans and seven days for maize). Seedlings with straight radic1es and plumules are used .. Geotropism
The seedlings are placed horizontally on the medium (Soil or vermiculite or saw dust or sand). Observations are done after three days and results recorded.


Seedlings with straight radic1es and plumules are used .. Geotropism
The seedlings are placed horizontally on the medium (Soil or vermiculite or saw dust or sand). Observations are done after three days and results recorded. Phototropism
A potted plant or a young seedling planted in a beaker is kept next to a window which is the only source of light in the laboratory. Alternatively, a dark box may be used. Observations are made after 3-5 days and results recorded. The shoots grow bending towards the same light. Etiolation
Young seedlings are placed in a dark box. It is kept moist but not exposed to light. After two weeks the seedlings are removed and observations made to note the following:
Colour of leaves is yellow. Size of leaves is small
Length of internodes is long
Length of stem elongated long and thin. Other seedlings that were grown in light are observed (as control) and similar measurements taken. They are green in colour with larger leaves, shorter internodes and the stem is shorter and thicker. Those in the dark have smaller yellow leaves, long thing stems with long internodes. (etiolated). Experiment to Determine Distance of the Blind Spot
Students should work in pairs so that one takes measurements while the other observes. A cross and a dot are marked on a white paper . The two points are 6-9 cm apart. The paper is held 50 cm away from the face. Closing the left eye, the paper is slowly moved towards the face as the right eye is fixed on the cross. At 50 cm distance the cross and the dot are seen clearly. As-the paper is moved closer to the face, the dot disappears. The distance at which the dot disappears is measured. This is the distance of the blind spot. When the light rays from the dot are focused on the blind spot it disappears hence the dot is not seen. The Knee Jerk Experiment
Students work in pairs, one student sits on the table, high stool or bench with one leg crossed over the other. The other student chops the crossed knee just below the knee cap with the edge of palm or wooden ruler. It is observed that the crossed knee jerks. This is a spinal reflex. END
Support and Movement in Plants and Animals
Necessity for support and movement
Movement is a characteristic of all living organisms. It enables animals and plants to adjust to their environment.


This is a spinal reflex. END
Support and Movement in Plants and Animals
Necessity for support and movement
Movement is a characteristic of all living organisms. It enables animals and plants to adjust to their environment. Most animals move from place to place but some are sessile (i.e. fixed to the substratum). Majority of plants move only certain parts. However, though not easily observed all living protoplasm shows movement of one type or another. Necessity for support and movement in plants
They enable plants to be held upright to trap maximum light for photosynthesis and gaseous exchange. To hold flowers and fruits in appropriate position for pollination and dispersal respectively. To enable plants to grow to great heights and withstand forces of environment e.g. strong winds. Movement of male gametes to effect fertilisation and ensure perpetuation of a species. Plant parts move in response to certain stimuli in the environment of tropisms. Tissue distribution in Monocotyledonous and Dicotyledonous plants
Vascular bundles are the main support tissues in plants. In monocotyledonous stem they are scattered all over the stem. while in dicotyledonous stem they are found in a ring or rings. In monocots the xylem and phloem alternate around with pith in the centre. In dicots of the xylem forms a star in the centre - there is no pith. Phloem is found in between the arms of xylem. Dicotyledonous plants have cambium which brings about secondary growth resulting in thickening of the stem and root hence providing support. Secondary xylem becomes wood, providing more support to the plant. Role of support tissues in young and old plant
Plants are held upright by strengthening tissues ;
parenchyma,
collenchyma,
sclerenchyma
xylem tissue. Parenchyma and collenchyma are the main support tissues in young plants. Parenchyma –
They are found below the epidermis. They form the bulk of packing tissue within the plant between other tissues . They are tightly packed and turgid they provide support. Collenchyma –
Their cell walls have additional cellulose deposited in the corners. This provides them with extra mechanical strength. Sclerenchyma –
Their cells are dead due to large deposits of lignin on the primary cell wall.


Collenchyma –
Their cell walls have additional cellulose deposited in the corners. This provides them with extra mechanical strength. Sclerenchyma –
Their cells are dead due to large deposits of lignin on the primary cell wall. The lignified wall is thick and inner lumen is small, hence provide support. Sclerenchyma fibres are arranged in elongated and in longitudinal sheets giving extra support. They are found in mature plants. Xylem –
Has two types of specialised cells. Vessels and tracheids. Vessels are thick-walled tubes with lignin deposited in them. They give support and strength to the plant. Tracheids are spindle-shaped cells arranged with ends overlapping. Their walls are lignified. They help to support and strengthen the plant. Plants with weak stems obtain their support in the following ways. Some use thorn or spines to adhere to other plants or objects. Some have twinning stems which grow around objects which they come into contact with. Others use tendrils for support. Tendrils are parts of a stem or leaf that have become modified for twinning around objects when they gain support. In passion fruit and pumpkin, parts of lateral branches are modified to form tendrils. In the morning glory, the leaf is modified into a tendril. Support and Movement in Animals
Necessity for support and movement in animals. Animals move from place to place:
In search of food. To escape from predators. To escape from hostile environment. To look for mates and breeding grounds. The skeleton, which is a support structure helps to maintain the shape of the body. Movement is effected by action of muscles that are attached to the skeleton. Types and Functions of Skeletons
Two main types will be considered. These are exoskeleton and endoskeleton. Exoskeleton
Exoskeleton is hard outer covering of arthropods made up of mainly chitin. Which is secreted by epidermal cells and hardens on secretion. It is strengthened by addition of other substances e.g. tannins and proteins to become hard and rigid. On the joints such as those in the legs the exoskeleton is thin and flexible to allow for movement. Functions of Exoskeleton
Provide support. Attachment of muscles for movement. Protection of delicate organs and tissues. Prevention of water loss. Endoskeleton:
It forms an internal body framework. This is a type of skeleton characteristic of all vertebrates.


Prevention of water loss. Endoskeleton:
It forms an internal body framework. This is a type of skeleton characteristic of all vertebrates. The endoskeleton is made of cartilage, bone or both. It is made up of living tissues and grows steadily as animal grows. Muscles are attached on the skeleton. The muscles are connected to bones by ligaments. Functions
The functions of endoskeleton include support, protection and movement. Locomotion in a finned fish e.g. tilapia. Most of the fishes are streamlined and have backward directed fins to reduce resistance due to water. External features-of Tilapia
Scales tapers towards the back and overlap forwards to provide a smooth surface for a streamlined body. The head is not flexible. This helps the fish to maintain forward thrust. Slimy mucous enables the fish to escape predators and protects the scales from getting wet. The pectoral and pelvic fins are used mainly for steering, ensuring that the fish is balanced. They assist the fish to change direction. The dorsal and anal fins keep the fish upright preventing it from rolling sideways. The caudal or tail fin has a large surface area, and displaces a lot of water when moved sideways creating forward movement of the fish. In order to change position in water the fish uses the swim bladder. When filled with air the relative density of the body is lowered and the fish moves up in the water. When air is expelled, the relative density rises and the fish sinks to a lower level. Swimming action in fish is brought about by contraction of muscle blocks (myotomes). These muscles are antagonistic when those on the left contract, those on the right relax. The muscles are attached to the transverse processes on the vertebra. The vertebra are flexible to allow sideways movement. Mammalian skeleton
The mammalian skeleton is divided into two:
Axial and appendicular. Axial skeleton is made up of the skull and the vertebral column. Appendicular skeleton is made up of the pelvic and pectoral girdles and limbs (hind limb and forelimbs). The Axial Skeleton
This consists of the ;
skull,
the sternum,
ribs,
the vertebral column. The Skull
The skull is made up of cranium and facial bones. The cranium; encloses and protects the brain. It is made up of many bones joined together by immovable joints. The facial bones consists of the upper and lower jaws.


The cranium; encloses and protects the brain. It is made up of many bones joined together by immovable joints. The facial bones consists of the upper and lower jaws. At the posterior end of the cranium are two smooth rounded protuberances, the occipital condyles. These condyles articulate with the atlas vertebra to form a hinge joint, which permits the nodding of the head. Sternum and ribs –
They form the rib-cage. The rib-cage encloses the thoracic cavity protecting delicate organs such as the heart and lungs. The ribs articulate with the vertebral column at the back and the sternum at the front. The Vertebral Column
The vertebral column is made up of bones called vertebrae placed end to end. The vertebrae articulate with one another at the articulating facets. In between one vertebra and another is the cartilaginous material called intervertebal disc. The discs act as shock absorbers and allow for slight movement. Each vertebra consists of a centrum and a neural arch which projects into a neural spine. The neural canal is the cavity enclosed by the centrum and the neural arch. The spinal cord is located inside the canal. The neural spine and other projections e.g. transverse processes serve as points of attachment of muscles. Type and number of vertebrae in human and rabbit
Cervical Vertebrae
These are found in the neck region of a mammal. The distinguishing feature is a pair of verte-braterial canals in the neural arch, through which the blood vessels of the neck pass. Another feature is the structure of the transverse processes. They are flattened out and are known as cervical ribs. The fIrst cervical vertebra is known as the Atlas. It has a large neural canal and no centrum. The second cervical vertebra, is called axis. The other five cervical vertebrae have no specific names. They have the same structure. The cervical vertebrae possess numerous processes for muscle attachment. Thoracic Vertebrae
Each thoracic vertebra has a large centrum ,a large neural canal, neural arch and a long neural spine that projects upwards and backward. There is a pair of prezygapophyses and postzygapophyses for articulation with other vertebra . They have a pair of short transverse process. The thoracic vertebra also articulates with pair of ribs at tubercular and capitular facets.


There is a pair of prezygapophyses and postzygapophyses for articulation with other vertebra . They have a pair of short transverse process. The thoracic vertebra also articulates with pair of ribs at tubercular and capitular facets. Lumbar Vertebrae
Each lumbar vertebra has a large, thick centrum for support of the body. It has a neural spine that projects upwards and forwards. There is a pair of large transverse process that are directed forwards. Above the prezygapophyses lies a pair of processes called metapophyses,
Below postzygapophyses lies the anapophyses. Metapophyses and anapophysis serve for attachment pf muscles of the abdomen. In some mammals, there may be another process on lower side of centrum called hypapophysis also for muscle attachment. Sacral Vertebrae
The sacral vertebrae are fused together to form a rigid bony structure, the sacrum. The centrum of each vertebra is large, but the neural canal is narrow. The neural spine is reduced to a small notch. The transverse processes of the first sacral vertebra are large and wing-like
They are firmly attached to the upper part of the pelvic girdle. Caudal Vertebrae
Human beings have only four of these vertebrae which are fused together to form coccyx. Animals with long tails have many caudal vertebrae. A typical caudal vertebra appears as a solid rectangular mass of bone. The entire bone consists of the centrum only. Appendicular Skeleton
The appendicular skeleton consist of the limbs and their girdles. Bones of Fore-limbs
Pectoral girdle
Pectoral girdle is made of scapula, coracoid and clavicle. A cavity known as glenoid cavity occurs at the apex of the scapula. The humerus of the fore limb fits into this cavity. The clavice is a curved bone connecting the scapular to the sternum. Humerus
Humerus is found in the upper arm. It articulates with the scapula at the glenoid cavity of the pectoral girdle and forms a ball and socket joint. Ulna and radius
These are two bones found in the forearm.


Humerus
Humerus is found in the upper arm. It articulates with the scapula at the glenoid cavity of the pectoral girdle and forms a ball and socket joint. Ulna and radius
These are two bones found in the forearm. The ulna has a projection called olecranon process and a sigmoid notch which articulates with the humerus. Bones of hind limb
Pelvic Girdle
The pelvic girdle consists of two halves fused at the pubic symphysis. Each half is made up of three fused bones:
the ilium,
ischium
pubis. Each half has cup-shaped cavity for the acetabulum for articulation with the head of the femur. Between the ischium and pubis is an opening obturator foramen where spinal nerves, blood vessels and a tough inflexible connective tissues pass. The ilium, ischium and pubis are fused to form the innominate bone. The Femur
The femur is the long bone joining the pelvic girdle and the knee. The head of the femur articulates with acetabulum forming the ball and socket joint at the hip. The femur has a long shaft. At the distal end it has condyles that articulate with the tibia to form a hinge joint at the knee. The patella covers the knee joint and prevents the upward movement of the lower leg. Tibia and Fibula
The tibia is a large bone, and the fibula a smaller bone is fused to it on the distal part. In humans the tibia and fibula are clearly distinguishable. Joints and Movement
Ajoint is a connection between two or more bones. Joints provide articulation between bones making movement possible. However some joints do not allow any movement e.g. the joints, between bones of the skull. Movable joints are of three main types:
Gliding joint
e.g., joints which occur between the vertebrae wrists and ankles. The ends of the bones that make the joint are covered with cartilage. The bones are held together by tough ligaments. Synovial joint
The joint is enclosed by fibrous capsule lined by synovial membrane which secretes synovial fluid into the synovial cavity. The synovial fluid lubricates the joint. They are called synovial joints. They include hinge joint and ball and socket joint. Hinge joint
e.g.


They are called synovial joints. They include hinge joint and ball and socket joint. Hinge joint
e.g. knee joint. The joint allows movement in one plane. Ball and socket joint. e.g., hip joint. The joint allows rotation in all directions. Types, Locations and Function of Muscles
There are three types of muscles, located at various parts of the body. In order to function all use energy in form of ATP. These include smooth, skeletal and cardiac muscles. Smooth Muscle (Involuntary Muscles)
These are spindle-shaped and contain filaments with myofibrils. Each muscle is bound by plasma membrane. They are found lining internal organs such as alimentary canal, bladder, and blood vessels. They are controlled by involuntary part of the nervous system. They are concerned with movement of materials along the organs and tubes. They contract slowly and fatigue slowly . Skeletal Muscle (striated or voluntary muscle)
Skeletal muscles are striated and have several nuclei. They are long fibres each containing myofibrils and many mitochondria. They have cross-striations or stripes. They are also called voluntary muscles because the contraction is controlled by voluntary nervous system. They are surrounded by connective tissue and are attached to bones by tendons. Their contraction brings about movement of bone, resulting in locomotion. They contract quickly and fatigue quickly. Cardiac Muscle
Consist of a network of striated muscle fibres connected by bridges. Are short cells with numerous mitochondria and uninucleate. They are found exclusively in the heart. Contractions of cardiac muscles are generated from within the muscles and are rhythmic and continuous hence they are myogenic. They do not tire or fatigue. The rate can be modified by involuntary nervous system. Their contractions result in the heart pumping blood. Role of muscles in movement of the human arm
Muscles that bring about movement are antagonistic, i.e. when one set contracts the other relaxes. Antagonistic muscles of human forelimb
The biceps muscles of the forelimb act as flexors while the triceps muscles act as extensors. The biceps has its point of origin on the scapula and the point of insertion on the radius. The triceps has its points of origin on the scapula and humerus and is inserted on the ulna. When the muscles contract, the limb acts as a lever with the pivot at the joint.


The biceps has its point of origin on the scapula and the point of insertion on the radius. The triceps has its points of origin on the scapula and humerus and is inserted on the ulna. When the muscles contract, the limb acts as a lever with the pivot at the joint. Contraction of biceps muscles bends (flexes) the arm while contractions of triceps extends the arm. Practical Activities
To observe prepared slides of transverse section of stems of herbaceous and woody plants. Permanent slides of transverse sections of:
Herbaceous plant and Woody plant are obtained. The permanent slide of a herbaceous plant is placed onto the stage of the microscope. Observations under the low power and medium power objective is made. A plan diagram is drawn and labelled. The permanent slide of a woody plant is placed on the stage of the microscope. Observations under the low power and medium power objectives are made. A plan diagram is drawn and labelled. In both cases, support tissues such as parenchyma, collenchyma, sc1erenchyma and xylem are observed. To observe wilting in young herbaceous plants. A herbaceous potted plant e.g. bean plant is obtained. The plant is placed on the bench near a window and left for 3 days without watering on the third and subsequent day. The shoot droops due to fall in turgor pressure; caused by water loss. To examine the exoskeleton in an arthropod. Obtain a beetle and observe the external structure. The exoskeleton is on the outer surface with muscles attached on inner side. The exoskeleton is hardened by chitin. Movement is due to joints on the limbs. Also examine various shed cocoons of insects e.g., butterfly. To observe the external features of a finned fish. Fresh Tilapia is obtained and placed on a tray. Observations are made on the external features of the fish. A labelled drawing is made. Features like scales, fins a streamlined body and an operculum are seen. Opened operculum reveals the gills. To examine bones of the axial skeleton of a rabbit. Bones of the vertebra column are obtained. These are cervical, thoracic, lumbar and sacral. For each of the bones the distinguishing features are listed down. Labelled drawings of the anterior and lateral views is made. To observe bones of appendicular skeleton.


For each of the bones the distinguishing features are listed down.

Labelled drawings of the anterior and lateral views is made.

To observe bones of appendicular skeleton.

Bones of pectoral girdle and fore limb are obtained i.e., scapula, humerus, ulna and radius.

Labelled drawing of each bone is made.

Observations on how the bones articulate with one another is made.

Bones of pelvic girdle and hind limbs are obtained i.e., pelvic girdle, femur, tibia and fibula.

Labelled drawings of each, bone is made.

The distinguishing features of each bone is noted.

Observations on how the bones articulate with one another is made.

END
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FORM THREE BIOLOGY
By the end of form three work, the learner should be able to:
Classify common organisms into their main taxonomic units
Write scientific names of organisms correctly
List the kingdoms of organisms
Describe the general characteristics of Kingdom monera
Describe the general characteristics of Kingdom protoctista
Observe, draw and name parts of spirogyra, amoeba, paramecium and euglena
Describe the general characteristics of Kingdom fungi
List down all the members of kingdom fungi
Draw and name parts of bread mold (mucor), yeast and mushrooms
Describe the main characteristics of kingdom plantae
Describe the main characteristics of bryophyta
Identify examples of hyophyta
Observe draw and name parts of liverworts and moss plants
Identify examples of pleridophyta
Observe draw and name parts of fern plant
Identify examples of division spermatophyta
Identify major sub-division of spermatophyta
List main characteristics of angiospermae
Differentiate between angiospermae and gymnospermae
State the characteristics of angiospermapyta
Identify and state major characteristics of classes of angiospermapytaegdicotyledonae&monocotyledonoe
describe the general characteristics of kingdom animalia
describe the general characteristics of Phylum arthropoda
list down the classes of the Phylum arthropoda
describe the general characteristics of Class crustacean
describe the general characteristics of Class insect
describe the general characteristics of Class arachnida
list down the members of class arachnida and insect
Describe the general characteristics of Classeschilopoda and diplopoda
List down the members of class chilopoda and diplopoda
Describe the general characteristics of Phylum chordate
describe the general characteristics of Pisces and amphibian
describe the general characteristics of reptilian
describe the general characteristics of Class aves
Describe the general characteristics of Class Mammalia
Identify different types of members of Class Mammalia
Construct a simple dichotomous to identify given organisms
Use an already constructed dichotomous key to identify given organisms
Use an already constructed dichotomous key to identify given organisms
draw and label organisms correctly
Define the term ecology and identify terms used in ecology
Define the term ecology and identify terms used in ecology
Identify the types of ecosystems
State and explain how light determines distribution of organisms in an ecosystem
Identify and describe how temperature determines distribution of organisms in an ecosystem
Identify and describe how Rainfall and humidity determines distribution of organisms in an ecosystem
describe how Wind and atmospheric pressure determines distribution of organisms in an ecosystem
Write down correct answers to questions asked in the test
describe how salinity affects the distribution of organisms in aquatic ecosystems
describe how waves, currents and tides affects the distribution of organisms in aquatic ecosystem
Describe how Edaphic factors affects the distribution of organisms in an ecosystem
Measure certain factors in samples of different soils
Describe how Geological factors affect the distribution of organisms in an ecosystem
Describe how Abiotic factors affect the distribution of organisms in an ecosystem
Describe how competition affects the distribution of organisms in an ecosystem
Describe how Predation and Symbiosis affects the distribution of organisms in an ecosystem
Differentiate between Parasitism and saprophytism
Describe how Parasitism and saprophytism influence the distribution of organisms in an ecosystem e.g.


FORM THREE BIOLOGY
By the end of form three work, the learner should be able to:
Classify common organisms into their main taxonomic units
Write scientific names of organisms correctly
List the kingdoms of organisms
Describe the general characteristics of Kingdom monera
Describe the general characteristics of Kingdom protoctista
Observe, draw and name parts of spirogyra, amoeba, paramecium and euglena
Describe the general characteristics of Kingdom fungi
List down all the members of kingdom fungi
Draw and name parts of bread mold (mucor), yeast and mushrooms
Describe the main characteristics of kingdom plantae
Describe the main characteristics of bryophyta
Identify examples of hyophyta
Observe draw and name parts of liverworts and moss plants
Identify examples of pleridophyta
Observe draw and name parts of fern plant
Identify examples of division spermatophyta
Identify major sub-division of spermatophyta
List main characteristics of angiospermae
Differentiate between angiospermae and gymnospermae
State the characteristics of angiospermapyta
Identify and state major characteristics of classes of angiospermapytaegdicotyledonae&monocotyledonoe
describe the general characteristics of kingdom animalia
describe the general characteristics of Phylum arthropoda
list down the classes of the Phylum arthropoda
describe the general characteristics of Class crustacean
describe the general characteristics of Class insect
describe the general characteristics of Class arachnida
list down the members of class arachnida and insect
Describe the general characteristics of Classeschilopoda and diplopoda
List down the members of class chilopoda and diplopoda
Describe the general characteristics of Phylum chordate
describe the general characteristics of Pisces and amphibian
describe the general characteristics of reptilian
describe the general characteristics of Class aves
Describe the general characteristics of Class Mammalia
Identify different types of members of Class Mammalia
Construct a simple dichotomous to identify given organisms
Use an already constructed dichotomous key to identify given organisms
Use an already constructed dichotomous key to identify given organisms
draw and label organisms correctly
Define the term ecology and identify terms used in ecology
Define the term ecology and identify terms used in ecology
Identify the types of ecosystems
State and explain how light determines distribution of organisms in an ecosystem
Identify and describe how temperature determines distribution of organisms in an ecosystem
Identify and describe how Rainfall and humidity determines distribution of organisms in an ecosystem
describe how Wind and atmospheric pressure determines distribution of organisms in an ecosystem
Write down correct answers to questions asked in the test
describe how salinity affects the distribution of organisms in aquatic ecosystems
describe how waves, currents and tides affects the distribution of organisms in aquatic ecosystem
Describe how Edaphic factors affects the distribution of organisms in an ecosystem
Measure certain factors in samples of different soils
Describe how Geological factors affect the distribution of organisms in an ecosystem
Describe how Abiotic factors affect the distribution of organisms in an ecosystem
Describe how competition affects the distribution of organisms in an ecosystem
Describe how Predation and Symbiosis affects the distribution of organisms in an ecosystem
Differentiate between Parasitism and saprophytism
Describe how Parasitism and saprophytism influence the distribution of organisms in an ecosystem e.g. Tick and cattle
Describe the interaction between organisms in an ecosystem
Describe the role of decomposers in Nitrogen cycle & carbon cycle
Define the terms food chain and food web
Construct food chains and food webs
Describe energy flow in a local ecosystem and Construct food chains and food webs
Define population
List down the characteristics of population
Explain the use of quadrants and transects as methods of Population estimation
Explain the capture –recapture method of population estimation
Use quadrant method to estimate population of named organisms within the compound
Describe total count, aerial count and aerial photography and other methods of population estimation
Relate to the adaptations of xerophytes to their habitats
Relate to the adaptations of mesophytes to their habitats
Relate to the adaptations of hydrophytes to their habitats
Observe, draw and label parts of named hydrophytes, mesophytes and xerophyte plants
Relate to the adaptations of halophytes to their habitats
Explain pollution and give examples of pollutants
Describe the various air pollutants
Discuss the effects of air pollution on the environment
Suggest methods of controlling air pollution
Describe various causes of Land/ soil pollution
Discuss the effects of Land/ soil pollution and human health in rural and urban centers
Suggest methods of controlling Land/ soil pollution
Describe the causes of Water pollution
Identify other causes of environmental pollution in rural and urban centers
Discuss the effects of water pollution on human health in rural and urban centers and other organisms
Suggest methods of controlling water pollution
Identify symptoms of cholera and typhoid fever
State methods of transmission
Suggest control measures
Identify the causes, symptoms and methods of transmission and control of malaria
Identify the causes, symptoms and methods of transmission of amoebic dysentery
Suggest control methods of amoebic dysentery
Identify the causes, symptoms and methods of transmission of ascariosis
Identify the causes, symptoms and methods of transmission and control of schistomiasis
Define reproduction and state its importance
Differentiate between asexual and sexual reproduction
Describe the appearance and location of chromosomes
Define mitosis
Describe chromosomicmovement during mitosis
Describe e the movement of chromosomes in mitosis
Identify stages of mitosis
Identify and describe stages of mitosis
State the significance of mitosis in reproduction
Define meiosis
State the stages of meiosis
Describe the chromosome movement during meiosis
Observe the stages of meiosis
Describe the movement of chromosomes during meiosis
State the significance of meiosis in reproduction
Differentiate between mitosis and meiosis
State and describe the importance of Binary fission
Observe spore formation in bread mould (mucor) and binary fission in paramecium
State and describing the importance of budding in reproduction
Observing drawing and budding cells of yeast
Describe the external structure of a typical flower
Describe the internal structure of a typical flower
Observe, describe and draw different types of pollen grains
Describe the structure of ovules
Describe other characteristics of flowers
Describe and compare adaptations of wind and insect pollinated flowers
Describe the features and mechanisms that hinder self-pollination and self-fertilization
Describe the process of fertilization in flowering plants
Describe and explain how embryo and seeds are formed in flowering plants
Describe how fruits are formed in flowering plants
Differentiate between a fruit and a seed
Describe and explain how different seeds and fruits are dispersed
Classifying various types of fruits and describe their placentation
Differentiate between internal and external fertilization
Describe external fertilization in amphibians
Relate the structure of mammalian male reproductive system to its functions
Relate the structure of mammalian male reproductive organ and spermatozoa to its function
Relate the structure of mammalian female reproductive system to its function
Relate the structure of mammalian ovum to its function
Describe internal fertilization in mammals
Describe the fertilization process
Describe implantation and the role of the placenta in mammals
Define gestation in mammals
Identify different gestation periods in different mammals
Describe birth and explain parental care
Describe the role of hormones in reproduction of humans
Describe the role of hormones in the menstrual cycle
Identify symptoms and explain the methods of transmission and prevention of gonorrhea and herpes simplex
Identify symptoms and explain the methods of transmission and prevention of syphilis and trichomoniasis
Identify symptoms and explain the methods of transmission and prevention of candidiasis and hepatitis
Identify the causes and modes of transmission of HIV/AIDS and prevention of HIV and AIDS
Identify effects of HIV/AIDS in human economy
Identify the symptoms of HIV/AIDS and stages of HIV and AIDS
Explain ways of preventing and controlling the spread of HIV/AIDS
Discuss the social effects of HIV/AIDS
Explain the advantages and disadvantages of sexual and asexual reproduction
Define the terms growth and development
Describe the sigmoid growth curve
Describe the phases of sigmoid curve
Describe the intermittent growth curve
Analyze data on growth rate
Draw growth curves
Define seed dormancy
Identify factors affecting viability and dormancy of seeds
Identify factors affecting seed dormancy
Define seed germination
Differentiate between types of seed germination
Identifying Conditions necessary for germination - oxygen
Investigate the necessity of water and warmth
Describe the region of growth in seedlings
Identify the regions of growth
Determine the regions of growth in seedlings
Measure the aspect of growth in a given seedling
Describe growth in plants I.e.


FORM THREE BIOLOGY
By the end of form three work, the learner should be able to:
Classify common organisms into their main taxonomic units
Write scientific names of organisms correctly
List the kingdoms of organisms
Describe the general characteristics of Kingdom monera
Describe the general characteristics of Kingdom protoctista
Observe, draw and name parts of spirogyra, amoeba, paramecium and euglena
Describe the general characteristics of Kingdom fungi
List down all the members of kingdom fungi
Draw and name parts of bread mold (mucor), yeast and mushrooms
Describe the main characteristics of kingdom plantae
Describe the main characteristics of bryophyta
Identify examples of hyophyta
Observe draw and name parts of liverworts and moss plants
Identify examples of pleridophyta
Observe draw and name parts of fern plant
Identify examples of division spermatophyta
Identify major sub-division of spermatophyta
List main characteristics of angiospermae
Differentiate between angiospermae and gymnospermae
State the characteristics of angiospermapyta
Identify and state major characteristics of classes of angiospermapytaegdicotyledonae&monocotyledonoe
describe the general characteristics of kingdom animalia
describe the general characteristics of Phylum arthropoda
list down the classes of the Phylum arthropoda
describe the general characteristics of Class crustacean
describe the general characteristics of Class insect
describe the general characteristics of Class arachnida
list down the members of class arachnida and insect
Describe the general characteristics of Classeschilopoda and diplopoda
List down the members of class chilopoda and diplopoda
Describe the general characteristics of Phylum chordate
describe the general characteristics of Pisces and amphibian
describe the general characteristics of reptilian
describe the general characteristics of Class aves
Describe the general characteristics of Class Mammalia
Identify different types of members of Class Mammalia
Construct a simple dichotomous to identify given organisms
Use an already constructed dichotomous key to identify given organisms
Use an already constructed dichotomous key to identify given organisms
draw and label organisms correctly
Define the term ecology and identify terms used in ecology
Define the term ecology and identify terms used in ecology
Identify the types of ecosystems
State and explain how light determines distribution of organisms in an ecosystem
Identify and describe how temperature determines distribution of organisms in an ecosystem
Identify and describe how Rainfall and humidity determines distribution of organisms in an ecosystem
describe how Wind and atmospheric pressure determines distribution of organisms in an ecosystem
Write down correct answers to questions asked in the test
describe how salinity affects the distribution of organisms in aquatic ecosystems
describe how waves, currents and tides affects the distribution of organisms in aquatic ecosystem
Describe how Edaphic factors affects the distribution of organisms in an ecosystem
Measure certain factors in samples of different soils
Describe how Geological factors affect the distribution of organisms in an ecosystem
Describe how Abiotic factors affect the distribution of organisms in an ecosystem
Describe how competition affects the distribution of organisms in an ecosystem
Describe how Predation and Symbiosis affects the distribution of organisms in an ecosystem
Differentiate between Parasitism and saprophytism
Describe how Parasitism and saprophytism influence the distribution of organisms in an ecosystem e.g. Tick and cattle
Describe the interaction between organisms in an ecosystem
Describe the role of decomposers in Nitrogen cycle & carbon cycle
Define the terms food chain and food web
Construct food chains and food webs
Describe energy flow in a local ecosystem and Construct food chains and food webs
Define population
List down the characteristics of population
Explain the use of quadrants and transects as methods of Population estimation
Explain the capture –recapture method of population estimation
Use quadrant method to estimate population of named organisms within the compound
Describe total count, aerial count and aerial photography and other methods of population estimation
Relate to the adaptations of xerophytes to their habitats
Relate to the adaptations of mesophytes to their habitats
Relate to the adaptations of hydrophytes to their habitats
Observe, draw and label parts of named hydrophytes, mesophytes and xerophyte plants
Relate to the adaptations of halophytes to their habitats
Explain pollution and give examples of pollutants
Describe the various air pollutants
Discuss the effects of air pollution on the environment
Suggest methods of controlling air pollution
Describe various causes of Land/ soil pollution
Discuss the effects of Land/ soil pollution and human health in rural and urban centers
Suggest methods of controlling Land/ soil pollution
Describe the causes of Water pollution
Identify other causes of environmental pollution in rural and urban centers
Discuss the effects of water pollution on human health in rural and urban centers and other organisms
Suggest methods of controlling water pollution
Identify symptoms of cholera and typhoid fever
State methods of transmission
Suggest control measures
Identify the causes, symptoms and methods of transmission and control of malaria
Identify the causes, symptoms and methods of transmission of amoebic dysentery
Suggest control methods of amoebic dysentery
Identify the causes, symptoms and methods of transmission of ascariosis
Identify the causes, symptoms and methods of transmission and control of schistomiasis
Define reproduction and state its importance
Differentiate between asexual and sexual reproduction
Describe the appearance and location of chromosomes
Define mitosis
Describe chromosomicmovement during mitosis
Describe e the movement of chromosomes in mitosis
Identify stages of mitosis
Identify and describe stages of mitosis
State the significance of mitosis in reproduction
Define meiosis
State the stages of meiosis
Describe the chromosome movement during meiosis
Observe the stages of meiosis
Describe the movement of chromosomes during meiosis
State the significance of meiosis in reproduction
Differentiate between mitosis and meiosis
State and describe the importance of Binary fission
Observe spore formation in bread mould (mucor) and binary fission in paramecium
State and describing the importance of budding in reproduction
Observing drawing and budding cells of yeast
Describe the external structure of a typical flower
Describe the internal structure of a typical flower
Observe, describe and draw different types of pollen grains
Describe the structure of ovules
Describe other characteristics of flowers
Describe and compare adaptations of wind and insect pollinated flowers
Describe the features and mechanisms that hinder self-pollination and self-fertilization
Describe the process of fertilization in flowering plants
Describe and explain how embryo and seeds are formed in flowering plants
Describe how fruits are formed in flowering plants
Differentiate between a fruit and a seed
Describe and explain how different seeds and fruits are dispersed
Classifying various types of fruits and describe their placentation
Differentiate between internal and external fertilization
Describe external fertilization in amphibians
Relate the structure of mammalian male reproductive system to its functions
Relate the structure of mammalian male reproductive organ and spermatozoa to its function
Relate the structure of mammalian female reproductive system to its function
Relate the structure of mammalian ovum to its function
Describe internal fertilization in mammals
Describe the fertilization process
Describe implantation and the role of the placenta in mammals
Define gestation in mammals
Identify different gestation periods in different mammals
Describe birth and explain parental care
Describe the role of hormones in reproduction of humans
Describe the role of hormones in the menstrual cycle
Identify symptoms and explain the methods of transmission and prevention of gonorrhea and herpes simplex
Identify symptoms and explain the methods of transmission and prevention of syphilis and trichomoniasis
Identify symptoms and explain the methods of transmission and prevention of candidiasis and hepatitis
Identify the causes and modes of transmission of HIV/AIDS and prevention of HIV and AIDS
Identify effects of HIV/AIDS in human economy
Identify the symptoms of HIV/AIDS and stages of HIV and AIDS
Explain ways of preventing and controlling the spread of HIV/AIDS
Discuss the social effects of HIV/AIDS
Explain the advantages and disadvantages of sexual and asexual reproduction
Define the terms growth and development
Describe the sigmoid growth curve
Describe the phases of sigmoid curve
Describe the intermittent growth curve
Analyze data on growth rate
Draw growth curves
Define seed dormancy
Identify factors affecting viability and dormancy of seeds
Identify factors affecting seed dormancy
Define seed germination
Differentiate between types of seed germination
Identifying Conditions necessary for germination - oxygen
Investigate the necessity of water and warmth
Describe the region of growth in seedlings
Identify the regions of growth
Determine the regions of growth in seedlings
Measure the aspect of growth in a given seedling
Describe growth in plants I.e. Primary and secondary growths
investigate primary and secondary growth in a seedling
Explain the role of hormones in regulation of growth and development in plants
Explain Apical dominance in plants
Define metamorphosis
Distinguish between complete and incomplete metamorphosis
Describe complete metamorphosis in housefly and anopheles mosquito
Describe incomplete metamorphosis in a cockroach
Describe and explain the Role of growth hormones in metamorphosis in insects
Observe metamorphosis in some insects
Classification II
General Principles of Classification
Classification is the science that puts organisms into distinct groups to make their study easy and systematic.


FORM THREE BIOLOGY
By the end of form three work, the learner should be able to:
Classify common organisms into their main taxonomic units
Write scientific names of organisms correctly
List the kingdoms of organisms
Describe the general characteristics of Kingdom monera
Describe the general characteristics of Kingdom protoctista
Observe, draw and name parts of spirogyra, amoeba, paramecium and euglena
Describe the general characteristics of Kingdom fungi
List down all the members of kingdom fungi
Draw and name parts of bread mold (mucor), yeast and mushrooms
Describe the main characteristics of kingdom plantae
Describe the main characteristics of bryophyta
Identify examples of hyophyta
Observe draw and name parts of liverworts and moss plants
Identify examples of pleridophyta
Observe draw and name parts of fern plant
Identify examples of division spermatophyta
Identify major sub-division of spermatophyta
List main characteristics of angiospermae
Differentiate between angiospermae and gymnospermae
State the characteristics of angiospermapyta
Identify and state major characteristics of classes of angiospermapytaegdicotyledonae&monocotyledonoe
describe the general characteristics of kingdom animalia
describe the general characteristics of Phylum arthropoda
list down the classes of the Phylum arthropoda
describe the general characteristics of Class crustacean
describe the general characteristics of Class insect
describe the general characteristics of Class arachnida
list down the members of class arachnida and insect
Describe the general characteristics of Classeschilopoda and diplopoda
List down the members of class chilopoda and diplopoda
Describe the general characteristics of Phylum chordate
describe the general characteristics of Pisces and amphibian
describe the general characteristics of reptilian
describe the general characteristics of Class aves
Describe the general characteristics of Class Mammalia
Identify different types of members of Class Mammalia
Construct a simple dichotomous to identify given organisms
Use an already constructed dichotomous key to identify given organisms
Use an already constructed dichotomous key to identify given organisms
draw and label organisms correctly
Define the term ecology and identify terms used in ecology
Define the term ecology and identify terms used in ecology
Identify the types of ecosystems
State and explain how light determines distribution of organisms in an ecosystem
Identify and describe how temperature determines distribution of organisms in an ecosystem
Identify and describe how Rainfall and humidity determines distribution of organisms in an ecosystem
describe how Wind and atmospheric pressure determines distribution of organisms in an ecosystem
Write down correct answers to questions asked in the test
describe how salinity affects the distribution of organisms in aquatic ecosystems
describe how waves, currents and tides affects the distribution of organisms in aquatic ecosystem
Describe how Edaphic factors affects the distribution of organisms in an ecosystem
Measure certain factors in samples of different soils
Describe how Geological factors affect the distribution of organisms in an ecosystem
Describe how Abiotic factors affect the distribution of organisms in an ecosystem
Describe how competition affects the distribution of organisms in an ecosystem
Describe how Predation and Symbiosis affects the distribution of organisms in an ecosystem
Differentiate between Parasitism and saprophytism
Describe how Parasitism and saprophytism influence the distribution of organisms in an ecosystem e.g. Tick and cattle
Describe the interaction between organisms in an ecosystem
Describe the role of decomposers in Nitrogen cycle & carbon cycle
Define the terms food chain and food web
Construct food chains and food webs
Describe energy flow in a local ecosystem and Construct food chains and food webs
Define population
List down the characteristics of population
Explain the use of quadrants and transects as methods of Population estimation
Explain the capture –recapture method of population estimation
Use quadrant method to estimate population of named organisms within the compound
Describe total count, aerial count and aerial photography and other methods of population estimation
Relate to the adaptations of xerophytes to their habitats
Relate to the adaptations of mesophytes to their habitats
Relate to the adaptations of hydrophytes to their habitats
Observe, draw and label parts of named hydrophytes, mesophytes and xerophyte plants
Relate to the adaptations of halophytes to their habitats
Explain pollution and give examples of pollutants
Describe the various air pollutants
Discuss the effects of air pollution on the environment
Suggest methods of controlling air pollution
Describe various causes of Land/ soil pollution
Discuss the effects of Land/ soil pollution and human health in rural and urban centers
Suggest methods of controlling Land/ soil pollution
Describe the causes of Water pollution
Identify other causes of environmental pollution in rural and urban centers
Discuss the effects of water pollution on human health in rural and urban centers and other organisms
Suggest methods of controlling water pollution
Identify symptoms of cholera and typhoid fever
State methods of transmission
Suggest control measures
Identify the causes, symptoms and methods of transmission and control of malaria
Identify the causes, symptoms and methods of transmission of amoebic dysentery
Suggest control methods of amoebic dysentery
Identify the causes, symptoms and methods of transmission of ascariosis
Identify the causes, symptoms and methods of transmission and control of schistomiasis
Define reproduction and state its importance
Differentiate between asexual and sexual reproduction
Describe the appearance and location of chromosomes
Define mitosis
Describe chromosomicmovement during mitosis
Describe e the movement of chromosomes in mitosis
Identify stages of mitosis
Identify and describe stages of mitosis
State the significance of mitosis in reproduction
Define meiosis
State the stages of meiosis
Describe the chromosome movement during meiosis
Observe the stages of meiosis
Describe the movement of chromosomes during meiosis
State the significance of meiosis in reproduction
Differentiate between mitosis and meiosis
State and describe the importance of Binary fission
Observe spore formation in bread mould (mucor) and binary fission in paramecium
State and describing the importance of budding in reproduction
Observing drawing and budding cells of yeast
Describe the external structure of a typical flower
Describe the internal structure of a typical flower
Observe, describe and draw different types of pollen grains
Describe the structure of ovules
Describe other characteristics of flowers
Describe and compare adaptations of wind and insect pollinated flowers
Describe the features and mechanisms that hinder self-pollination and self-fertilization
Describe the process of fertilization in flowering plants
Describe and explain how embryo and seeds are formed in flowering plants
Describe how fruits are formed in flowering plants
Differentiate between a fruit and a seed
Describe and explain how different seeds and fruits are dispersed
Classifying various types of fruits and describe their placentation
Differentiate between internal and external fertilization
Describe external fertilization in amphibians
Relate the structure of mammalian male reproductive system to its functions
Relate the structure of mammalian male reproductive organ and spermatozoa to its function
Relate the structure of mammalian female reproductive system to its function
Relate the structure of mammalian ovum to its function
Describe internal fertilization in mammals
Describe the fertilization process
Describe implantation and the role of the placenta in mammals
Define gestation in mammals
Identify different gestation periods in different mammals
Describe birth and explain parental care
Describe the role of hormones in reproduction of humans
Describe the role of hormones in the menstrual cycle
Identify symptoms and explain the methods of transmission and prevention of gonorrhea and herpes simplex
Identify symptoms and explain the methods of transmission and prevention of syphilis and trichomoniasis
Identify symptoms and explain the methods of transmission and prevention of candidiasis and hepatitis
Identify the causes and modes of transmission of HIV/AIDS and prevention of HIV and AIDS
Identify effects of HIV/AIDS in human economy
Identify the symptoms of HIV/AIDS and stages of HIV and AIDS
Explain ways of preventing and controlling the spread of HIV/AIDS
Discuss the social effects of HIV/AIDS
Explain the advantages and disadvantages of sexual and asexual reproduction
Define the terms growth and development
Describe the sigmoid growth curve
Describe the phases of sigmoid curve
Describe the intermittent growth curve
Analyze data on growth rate
Draw growth curves
Define seed dormancy
Identify factors affecting viability and dormancy of seeds
Identify factors affecting seed dormancy
Define seed germination
Differentiate between types of seed germination
Identifying Conditions necessary for germination - oxygen
Investigate the necessity of water and warmth
Describe the region of growth in seedlings
Identify the regions of growth
Determine the regions of growth in seedlings
Measure the aspect of growth in a given seedling
Describe growth in plants I.e. Primary and secondary growths
investigate primary and secondary growth in a seedling
Explain the role of hormones in regulation of growth and development in plants
Explain Apical dominance in plants
Define metamorphosis
Distinguish between complete and incomplete metamorphosis
Describe complete metamorphosis in housefly and anopheles mosquito
Describe incomplete metamorphosis in a cockroach
Describe and explain the Role of growth hormones in metamorphosis in insects
Observe metamorphosis in some insects
Classification II
General Principles of Classification
Classification is the science that puts organisms into distinct groups to make their study easy and systematic. Modern scientific classification is based on structure and functions.


Tick and cattle
Describe the interaction between organisms in an ecosystem
Describe the role of decomposers in Nitrogen cycle & carbon cycle
Define the terms food chain and food web
Construct food chains and food webs
Describe energy flow in a local ecosystem and Construct food chains and food webs
Define population
List down the characteristics of population
Explain the use of quadrants and transects as methods of Population estimation
Explain the capture –recapture method of population estimation
Use quadrant method to estimate population of named organisms within the compound
Describe total count, aerial count and aerial photography and other methods of population estimation
Relate to the adaptations of xerophytes to their habitats
Relate to the adaptations of mesophytes to their habitats
Relate to the adaptations of hydrophytes to their habitats
Observe, draw and label parts of named hydrophytes, mesophytes and xerophyte plants
Relate to the adaptations of halophytes to their habitats
Explain pollution and give examples of pollutants
Describe the various air pollutants
Discuss the effects of air pollution on the environment
Suggest methods of controlling air pollution
Describe various causes of Land/ soil pollution
Discuss the effects of Land/ soil pollution and human health in rural and urban centers
Suggest methods of controlling Land/ soil pollution
Describe the causes of Water pollution
Identify other causes of environmental pollution in rural and urban centers
Discuss the effects of water pollution on human health in rural and urban centers and other organisms
Suggest methods of controlling water pollution
Identify symptoms of cholera and typhoid fever
State methods of transmission
Suggest control measures
Identify the causes, symptoms and methods of transmission and control of malaria
Identify the causes, symptoms and methods of transmission of amoebic dysentery
Suggest control methods of amoebic dysentery
Identify the causes, symptoms and methods of transmission of ascariosis
Identify the causes, symptoms and methods of transmission and control of schistomiasis
Define reproduction and state its importance
Differentiate between asexual and sexual reproduction
Describe the appearance and location of chromosomes
Define mitosis
Describe chromosomicmovement during mitosis
Describe e the movement of chromosomes in mitosis
Identify stages of mitosis
Identify and describe stages of mitosis
State the significance of mitosis in reproduction
Define meiosis
State the stages of meiosis
Describe the chromosome movement during meiosis
Observe the stages of meiosis
Describe the movement of chromosomes during meiosis
State the significance of meiosis in reproduction
Differentiate between mitosis and meiosis
State and describe the importance of Binary fission
Observe spore formation in bread mould (mucor) and binary fission in paramecium
State and describing the importance of budding in reproduction
Observing drawing and budding cells of yeast
Describe the external structure of a typical flower
Describe the internal structure of a typical flower
Observe, describe and draw different types of pollen grains
Describe the structure of ovules
Describe other characteristics of flowers
Describe and compare adaptations of wind and insect pollinated flowers
Describe the features and mechanisms that hinder self-pollination and self-fertilization
Describe the process of fertilization in flowering plants
Describe and explain how embryo and seeds are formed in flowering plants
Describe how fruits are formed in flowering plants
Differentiate between a fruit and a seed
Describe and explain how different seeds and fruits are dispersed
Classifying various types of fruits and describe their placentation
Differentiate between internal and external fertilization
Describe external fertilization in amphibians
Relate the structure of mammalian male reproductive system to its functions
Relate the structure of mammalian male reproductive organ and spermatozoa to its function
Relate the structure of mammalian female reproductive system to its function
Relate the structure of mammalian ovum to its function
Describe internal fertilization in mammals
Describe the fertilization process
Describe implantation and the role of the placenta in mammals
Define gestation in mammals
Identify different gestation periods in different mammals
Describe birth and explain parental care
Describe the role of hormones in reproduction of humans
Describe the role of hormones in the menstrual cycle
Identify symptoms and explain the methods of transmission and prevention of gonorrhea and herpes simplex
Identify symptoms and explain the methods of transmission and prevention of syphilis and trichomoniasis
Identify symptoms and explain the methods of transmission and prevention of candidiasis and hepatitis
Identify the causes and modes of transmission of HIV/AIDS and prevention of HIV and AIDS
Identify effects of HIV/AIDS in human economy
Identify the symptoms of HIV/AIDS and stages of HIV and AIDS
Explain ways of preventing and controlling the spread of HIV/AIDS
Discuss the social effects of HIV/AIDS
Explain the advantages and disadvantages of sexual and asexual reproduction
Define the terms growth and development
Describe the sigmoid growth curve
Describe the phases of sigmoid curve
Describe the intermittent growth curve
Analyze data on growth rate
Draw growth curves
Define seed dormancy
Identify factors affecting viability and dormancy of seeds
Identify factors affecting seed dormancy
Define seed germination
Differentiate between types of seed germination
Identifying Conditions necessary for germination - oxygen
Investigate the necessity of water and warmth
Describe the region of growth in seedlings
Identify the regions of growth
Determine the regions of growth in seedlings
Measure the aspect of growth in a given seedling
Describe growth in plants I.e. Primary and secondary growths
investigate primary and secondary growth in a seedling
Explain the role of hormones in regulation of growth and development in plants
Explain Apical dominance in plants
Define metamorphosis
Distinguish between complete and incomplete metamorphosis
Describe complete metamorphosis in housefly and anopheles mosquito
Describe incomplete metamorphosis in a cockroach
Describe and explain the Role of growth hormones in metamorphosis in insects
Observe metamorphosis in some insects
Classification II
General Principles of Classification
Classification is the science that puts organisms into distinct groups to make their study easy and systematic. Modern scientific classification is based on structure and functions. Organisms with similar anatomical and morphological characteristics are placed in one group while those with different structures are grouped separately.


Primary and secondary growths
investigate primary and secondary growth in a seedling
Explain the role of hormones in regulation of growth and development in plants
Explain Apical dominance in plants
Define metamorphosis
Distinguish between complete and incomplete metamorphosis
Describe complete metamorphosis in housefly and anopheles mosquito
Describe incomplete metamorphosis in a cockroach
Describe and explain the Role of growth hormones in metamorphosis in insects
Observe metamorphosis in some insects
Classification II
General Principles of Classification
Classification is the science that puts organisms into distinct groups to make their study easy and systematic. Modern scientific classification is based on structure and functions. Organisms with similar anatomical and morphological characteristics are placed in one group while those with different structures are grouped separately. Modern studies in genetics and cell biochemistry are used to give additional help in classifying organisms. There are seven major taxonomic groups. The kingdom is the largest group. Others are phylum (division for plants) class, order, family, genus and species, the smallest. Binomial Nomenclature
Living organisms are named using Latin or Latinised names. Every organism has two names. This double naming is called binomial nomenclature. This system of naming was devised by Carolus Linnaeus in the 18th Century. The first name is the generic name - the name of the genus. The second name is the name of the species. The generic name starts with a capital letter while that of the species starts with a small letter. The names are written in italics or are underlined in manuscripts. Examples:
Bean =Phaseolus vulgaris. Phaseolus is the generic name,
vulgaris is specific name. Dog =Canis familiaris. Canis is the generic name
,familiaris the specific name. General Characteristics of Kingdoms
Organisms are classified into five kingdoms. Monera,
Protoctista,
Fungi,
Plantae
Animalia. Viruses do not fit neatly into any of the above kingdoms. They are simple and not cellular. They are metabolically inactive outside the host cell. Most of them can be crystallised like chemical molecules. Therefore they do not exhibit the characteristics of living organisms.


They are metabolically inactive outside the host cell. Most of them can be crystallised like chemical molecules. Therefore they do not exhibit the characteristics of living organisms. Examples of Organisms in Each Kingdom and Their Economic Importance
Kingdom Monera
General Characteristics
Unicellular and microscopic
Some single cells ,others colonial
Nuclear material not enclosed within nuclear membrane-prokaryotic
Have cell wall but not of cellulose. Have few organelles which are not membrane bound
Mitochondria absent
Mostly heterotrophic, feeding saprotrophically or parasitically,some are autotrophic. Reproduction mostly asexual through binary fission
Most of them are anaerobes but others are aerobes
Most move by flagella
Examples include Escherichia coli, Vibrio cholerae and Clostridium tetani. Spherical known as Cocci. Rod shaped - e.g. Clostridium tetani
Spiral shaped e.g. sprilla
Coma shaped- Vibrios -e.g., Vibrio cholerae. Economic importance of bacteria Benefits to man include:
They are used in food processing e.g., Lactobacillus used in processing of cheese, yoghurt. Involved in synthesis of vitamin Band K, in humans and breakdown of cellulose in herbivores. Genetic Engineering
Bacteria are easily cultured and are being used for making antibiotics, aminoacids and enzymes e.g. amylase, and invertase e.g., Escherichia coli. Nutrient cycling:
Saprophytes
They are involved in decomposition of dead organic matter. They are useful in the nitrogen cycle. Nitrogen fixing and nitrifying bacteria. They increase soil fertility. Modem sewage works use bacteria in treatment of sewage. Cleaning oil spills in oceans and lakes. Harmful Effects
Bacteria cause disease:
To humans (e.g. Cholera). To animals (e.g. Anthrax). Bacteria cause food spoilage. Others cause food poisoning e.g. Salmonella. Denitrifying bacteria reduce soil fertility e.g., Pseudomonas denitrificans. Kingdom Protoctista
Examples include ;
Algae such as spirogyra, Chlamydomonas, euglena, Sargassum
And protozoa such as amoeba, paramecium and Trypanosoma.


Salmonella. Denitrifying bacteria reduce soil fertility e.g., Pseudomonas denitrificans. Kingdom Protoctista
Examples include ;
Algae such as spirogyra, Chlamydomonas, euglena, Sargassum
And protozoa such as amoeba, paramecium and Trypanosoma. General Characteristics
They are said to be eukaryotic since their nucleus is bound by a membrane
Most are mobile, and use flagella, cilia and pseudopodia. Some are sessile. They reproduce mainly asexually, by binary fission, fragmentation and sporulation. Some reproduce sexually by conjugation. Some are heterotrophic e.g. paramecium. Others are autotrophic e.g. spirogyra. Economic importance of protoctista
Algae are the primary producers in aquatic food chains. They release a lot of oxygen to the atmosphere. Some cause human diseases like malaria and amoebic dysentry ,sleeping sickness
Some are source of food for humans e.g. sargassum is a source of iodine
Skeletons of diatoms used in paint making. Spirogyra: They have spiral chloroplast. They are green, thread-like filaments
Chlamydomonas:
This is a unicellular green algae and has a cup shaped chloroplast. They move towards light using the flagella
Cilia assist the organism to move. The shape is due to the presence of a thin flexible pellicle. Kingdom Fungi
Multicellular fungi are made of thread-like structures called hyphae (singular hyphae) that form a mycelium. .e.g.Saccharomyces cereviseae(bread yeast). Others include Penicillium, Rhizopus, and edible mushroom
Economic Importance of Fungi
Beneficial Effects
Some fungi are used as food e.g. mushrooms. Some are decomposers which enhance decay to improve soil fertility - recycling of nutrients e.g., toadstools. Some are useful in brewing and bread making e.g., yeast. Yeast is used as food - a rich source of Vitamin B. Some are useful in production of antibiotics e.g., Penicillium griseofulvin. Used in sewage treatment e.g., Fusarium spp. Harmful Effects
Some cause food poisoning by producing toxic compounds e.g.