SHOOT SYSTEM
This is the part of the plant which grows above the soil except the modified aerial roots. The shoot system consists of two main organs – the stem and the leaves. During the reproductive stage, flowers and fruits may be…
ROOT SYSTEM
The root system is the part of the plant growing in the soil. This excludes the underground stems which are organs of perennation (survival from year to year by vegetative means). There are two kinds of root systems, namely: tap…
EXTERNAL FEATURES OF FLOWERING PLANTS
The flowering plants form a group of plants known as Angiosperms. They are characterized by the possession of flowers for sexual reproduction. They bear flowers in their various breeding seasons and after pollination and fertilization, seeds are formed enclosed in…
PRIMATES
Primates are the most highly developed of all mammals with large brain, forward-facing eyes with bilocular vision, grasping fingers and toes equipped with flat nails. Characteristic features of Primates 1) Well developed arms and hands The arms and hands…
THE STRUCTURE OF MAMMALIAN GAMETES
The mammalian gametes are male gametes called sperm or spermatozoa (singular = spermato-zoon), while the female gametes are called eggs or ova (singular = ovum) The reproductive sex cells are also known as gametes. The formation of gametes or gametogenisis…
GERMINATION
Germination is a process by which the embryo of a seed grows out of its testa and develops into a seedling. In other words, Germination is the series of changes by which an embryo in a seed grows into seedling.…
PHYSICAL SETTING OF AFRICA
The physical setting of Africa is defined by its relief, drainage, climate and vegetation, among others. These factors define Africa’s physical environment and they are important influences on patterns of human activity on the continent. The physical environment affects such…
PARTURITION OR CHILD BIRTH
Parturition (labour) is the expulsion of the foetus, placenta and foetal membranes from the uterus. After about 270-280 days in the uterus, the foetus is now prepared to come to the world. The foetus at this stage has turned its…
EXTRAEMBRYONIC MEMBRANES
When the embryo has been implanted, it produces four extraembryonic membranes (membranes outside the body of the embryo namely: amnion, chorion, allantois and yolk sac). Since these membranes are located outside the body of the embryo, they are referred to…
INDUSTRIAL ENTERPRISE IN NIGERIA
Industrial enterprise in Nigeria can be broadly classified into (i) local arts and craft, and (ii) modern manufacturing. Local Arts and Craft Long before the coming of Europeans and modern manufacturing to Nigeria, the fabrication of local items, such…
IDENTIFICATION OF RELIEF FEATURES USING THEIR CONTOUR FORMS
It is possible to identify specific relief features on topographical maps by examining the way their contour forms are arranged. This post discusses specific relief features and how their contour forms are arranged, especially on topographical maps. Slopes and…
LIVER
The liver is the largest gland in the body. It is dark-red, spongy and lobed. The lobes are: caudate lobe, left lobe, right lobe and median lobe. It is hung from the posterior surface of the diaphragm by a ligament…
STOMACH
The stomach is a thick-walled large muscular sac which lies in the left portion of the abdominal cavity below the diaphragm. It is made of three layers of muscles arranged longitudinally, circularly and obliquely. The contractions of these muscles in…
EXPERIMENTS TO SHOW THE CHARACTERISTICS OF ENZYMES
Experiment 1 Aim: To demostrate the action of ptyalin (saliva) on cooked starch. Method: Some saliva is introduced into a test tube X and diluted with little amount of water. Two test tubes are labelled E and F. To test…
SEX DETERMINATION
Genetic traits are determined by genes located on the chromosomes. The sex of an organism is a genetic trait which like other traits is transmitted from parent to offspring during sexual reproduction. In all organisms with sexual reproduction there is…
POLLUTION OF WATER RESOURCES
Man cannot survive without water. The low population densities in the desert natural region is because of the water deficiency which renders vast areas of land uninhabitable. The sources of water include oceans, rivers, lakes, rainfall and groundwater. Unfortunately, man…
FRACTURE AND DISLOCATION
A fracture is any break in a bone. There are two kinds of fracture namely simple (closed) and compound (open). Simple or closed fracture If the broken bone does not come out through the skin and injury to the…
STRUCTURE AND FUNCTION OF NEURONE
Neurones are specialized cells that transmit impulses (messages) around the body in form of electrical charges. The nervous system consists of millions of neurones (nerve cell). Three main types exist in the body namely: sensory, association (intermediate) and motor neurones.…
BONE
A bone is strong, hard and tough connective tissue mainly made of calcified material. Composition of bone A fully developed bone is hard and brittle. Bones can break, and a break in a bone is called fracture. The bone…
MUSCLES
Muscles can be referred to simply as the flesh mostly associated with bones to give shape to the bodies of animals. The flesh may be red in the case of mammals. General properties of muscular system All muscular…
TRANSPIRATION
Transpiration is the loss of water vapour from different parts of the plant shoot. These parts include the stomata of leaves, the cuticle of both leaves and young stems, and the lenticels on tree trunks. Transpiration is described according to…
COASTAL FEATURES OF EROSION
1) Capes and bays: On exposed coasts, the continual action of waves on rocks of varying resistance causes the coastline to be eroded irregularly. This is particularly pronounced where hard rocks, e.g. granites and limestones, occur in alternate bands with…
THE MECHANISM OF MARINE EROSION
The most powerful agents of marine erosion are waves. Their origin is due to the sweeping of winds over the water surface, which sets a series of undulating swells surging forward. These become higher and swifter. A normal wave in…
THE ACTION OF WAVES, TIDES AND CURRENTS
The action of the wind passing over a stretch of sea causes waves to develop and when the waves reach the coast they cause erosion or deposition. Wind passing over water sets up turbulences, which causes ripples and then waves…
GILLS
Fish and tadpoles are aquatic vertebrates. They possess gills for gaseous exchange. Gills of fish Fish has four gills on each side of the head. Each gill has two rows of soft gill filaments. The filaments are tiny, long…
ALIMENTARY CANAL OF PLANARIA
Planaria is a free-living, flat, slender and small worm. The digestive tract consists of a ventrally placed mouth, muscular pharynx and intestine. The pharynx can be protruded from the mouth when attacking a prey. The pharynx leads into the intestine.…
NIGERIA’S TRADE AND COMMERCE
Trade is the selling and buying of goods and services between areas and peoples. Trade can be local, interregional or international. Nigeria is involved in all these types of trade. The term commerce” is used to cover all forms of…
RIVER REGIMES
The seasonal variation in the volume of water in a river is known as the regime. A knowledge of the regime of a river is important to man in controlling possible floods, storing up water for irrigation and human consumption,…
GREAT CIRCLE ROUTES
Since the earth is spherical in shape, the shortest distance between any two points on the globe lies along its circumference. There are an infinite number of great circles of equal length running around the globe, e.g. the circle formed…
GEOTROPISM
This is the response of plant parts to the stimulus of gravity. Plant shoots grow away from gravity of the earth and are said to be negatively geotropic. Roots grow towards gravity and are said to be positively geotropic. …
ORGAN OF SIGHT
The eyes are the organs of sight in the higher invertebrates and all vertebrates. They (eyes) are equipped with photo receptors (rods and cones) to detect light. Most of these animals have two eyes. In man, the eyes are more…
LOCATION AND POLITICAL DIVISIONS OF AFRICA
Regional Geography Regional geography is usually defined as the study of the ways in which the combinations of environmental and human factors produce territories or regions with distinctive landscapes and cultural attributes. What this means is that the general appearance…
POWER SOURCES IN AFRICA
Energy/ Power Sources Africa has various sources of energy or power distributed unevenly over Africa. The main sources of power are Hydro-Electricity Power (HEP), coal, mineral oil, thermal power and nuclear power. Africa accounts for 8% of the world’s known…
PRIMARY ECONOMIC ACTIVITIES IN AFRICA
Africa’s primary economic activities depend essentially on primary activities, which are associated with the natural resources that abound in the continent. The main primary economic activities are mining, forest exploitation/lumbering, fishing and livestock rearing. Mining Activities Africa is blessed…
EXCRETION IN PLANTS
There are no special excretory organs or systems in plants. The plants as living things do carry out excretion. Elimination of certain waste takes place through the stomata and lenticels. The main waste products of plants are water from transpiration…
OXYGEN DEBT
The oxygen needed to oxidize lactic acid to pyruvic acid and from pyruvic acid to carbon oxide, water and chemical energy is called Oxygen debt. The quick heavy breathing to take in oxygen to the muscle cells lacking oxygen in…
TRANSLOCATION
Translocation is the transport of manufactured food substances from the leaves to all parts of the plant. The movement is usually described as downwards from the leaves to the roots but it is also known to occur on the reverse…
EXPERIMENTS ON PHOTOSYNTHESIS
The occurrence of photosynthesis in plants can be shown by experiments. The easiest proof that photosynthesis has taken place is to test for the presence of starch in the green leaves. Experiments should be carried out to show the importance…
INTERNATIONAL ECONOMIC COOPERATION IN AFRICA
There are a number of international organizations in Africa formed with the aim of promoting peace, social integration, economic cooperation and development of member nation states. These include the African Union (AU), Economic Community of West African States (ECOWAS), Economic…
THE TROPICAL MONSOON AND TROPICAL MARINE LANDS
Distribution Some parts of the world experience seasonal winds like land and sea breeze but on a much larger scale. These are the tropical monsoon lands with on-shore wet monsoons in the summer and off- shore dry monsoons in the…
THE EQUATORIAL REGIONS
Distribution The equatorial, hot, wet climate is found between 5° and 10° north and south of the equator. Its greatest extent is found in the lowlands of the Amazon, the Congo, Malaysia and the East Indies. Further away from the…
PLANT NUTRITION
Photosynthesisis the process by which carbohydrates or sugars are manufactured in the green parts of the plants containing chlorophyll by combination of carbon (IV) oxide and water with the aid of radiant energy of sunlight while oxygen is given out…
THE ARCTIC OR POLAR CLIMATE
Distribution The polar type of climate and vegetation is found mainly north of the Arctic Circle in the northern hemisphere. The ice caps are confined to Greenland and to the highlands of these high-latitude regions, where the ground is permanently…
EARTH ENERGY SYSTEM
Insolation The only source of energy for the earth’s atmosphere is the sun which has a surface temperature of more than 5982°C (10 800°F). The energy travels through space for a distance of 150 million km (93 million miles) and…
PARASITIC NUTRITION
This is a type of nutrition in which one organism obtains food from another organism and during the feeding process one organism is harmed and does not benefit. The organism gaining food, protection and shelter is called parasite while the…
LANDFORMS OF GLACIATED LOWLANDS
Landforms of glaciated lowlands are mainly depositional in nature, brought about by both valley glacier and continental ice sheets. The former leave behind the eroded material in only restricted areas. The imprint of ice sheets on the landscape is far…
LANDFORMS OF HIGHLAND GLACIATION
Glaciation generally gives rise to erosional features in the highlands and depositional features on the lowlands, though these processes are not not mutually mu exclusive because a glacier plays a combined role of erosion, transport and deposition throughout its course.…
THE ICE AGE
During the earth’s history, there have been many changes in the pattern of climatic regions. The most recent change came about as a result of a fall in temperature over the whole of the earth’s surface, so that the area…
ALIMENTARY CANAL OF BIRDS
Mouth The mouth has a horny covered tongue to facilitate swallowing of food substances to the oesophagus. There are no teeth. The lower and upper lips have been modified into sharp strong beaks for picking of food substances such as…
COMPLETE METAMORPHOSIS IN MOSQUITOES
Mating and laying of eggs The adult male and female mate. The female lays fertilized eggs on the surface of a stagnant water. Eggs are laid in partially sunny but shaded places. Female Anopheles and Aedes mosquitoes lay eggs singly…
Study Guide
