BIOLOGY
SALIVARY GLANDS
Three pairs of salivary glands exist in man while in rabbit they are four pairs. In man, the three pairs are parotid, submaxillary and sublingual glands. They all have ducts leading to the mouth cavity. They secrete digestive juice called…
SKELETON
Skeleton is therefore, the hard framework on which the body is built. This hard framework may be made up of sand particles as in Arcellar (a shelled Amoeba), exoskeleton as in insects and snails, cartilage as in the cartilaginous fish,…
RHESUS FACTOR
Rhesus factor in some red blood cells in some human beings was named after the rhesus monkey in which it was first discovered. Rhesus factor is an antigen present on the cell membrane of some red blood cells. The people…
CHITIN
Chitin is non living and non-cellular and is secreted by the underlying epidermis. It is a protein-carbohydrate compound. It is composed of several different substances. It is really made up of an outer waxy layer, a middle horny layer and…
GROWTH
Growth is defined as an irreversible or permanent increase in size, dry mass or weight due to the addition of living protoplasmic materials in organism. In other words, Growth is defined as an irreversible increase in size and complexity of…
FEEDING MECHANISMS IN HOLOZOIC ORGANISMS
There are five modifications and mechanisms of feeding associated with someorganisms. These feeding mechanisms include: 1) Absorbing mechanisms, e.g. tapeworm The tapeworm is an endoparasite which carries out parasitic feeding on its host i.e ., the man. It has no…
ASEXUAL REPRODUCTION
Asexual is the type of reproduction in which new organisms are produced from a single parent without the production of gametes. The offspring called the clones are the same in all respects to each other and to the parent organisms…
REPRODUCTION
Reproduction is the ability of living organisms to give rise to new individuals of the same species. The purpose of reproduction is to ensure the continuity of life. Types of Reproduction There are two main types of reproduction. These…
THE ALIMENTARY CANAL AND DIGESTION OF FOOD IN MAN
The alimentary canal of man includes the mouth, oesophagus, stomach, duodenum, small intestine or ileum, caecum, appendix, large intestine or colon, rectum and anus. The description and importance of the parts are as follows: Mouth: The alimentary canal of man…
BALANCE IN NATURE
FACTORS AFFECTING A POPULATION A number of factors referred to as environmental resistance control the population of organisms in a particular habitat. These factors are classified as abiotic and biotic factors. Abiotic Factors Affecting a Population Heat: The degree…
ECOLOGY OF POPULATION
ECOLOGICAL SUCCESSION Ecological succession is defined as the orderly series of changes occuring in plants and animals or microbial communities over a period of time, resulting in the establishment of a final, stable and climax community. In other words, this…
AQUATIC HABITATS
Aquatic habitat is a body of water in which certain organisms live naturally. In other words, aquatic habitats are habitats or places that relates to lives in water. Organisms that live in water are called aquatic organisms. Examples of aquatic…
CLASSIFICATION OF PLANTS
Plants are generally classified based on three major criteria. These are: Botanical classification. Agricultural classification. Classification based on life cycle. BOTANICAL CLASSIFICATION OF PLANTS Plants are generally classified through the botanical method and the use of binomial system. The…
SUPPORTING TISSUES IN PLANTS
Plants generally are known to possess supporting tissues which give them definite shape, strength, rigidity and resistance against external forces such as wind and water to which they are continuously subjected. Types of Supporting Tissues in Plant The main…
NUTRITION
Nutrition is the process by which food is taken in by living organisms in order to supply the nutrients required for the continuous metabolic reactions going on in the body. Food is the source of nutrients. Usefulness of Food…
MICRO-ORGANISMS IN ACTION
GROWTH OF MICRO-ORGANISMS Micro-organisms, like all living things, do increase in size and multiply in number of cells using either the culture medium provided or any suitable surface such as moist bread as source of food. Microorganisms can also increase…
MICRO-ORGANISMS AROUND US
Micro-organisms are tiny organisms which cannot be seen with the naked eye except with the aid of microscopes. The branch of biology which involves the study of organisms that are microscopic in sizes is called microbiology. Micro-organisms are found everywhere…
THE CELL AND ITS ENVIRONMENT
DIFFUSION Diffusion is defined as the process by which molecules or ions of a substance (i.e. gases and liquids) move from a region of high concentration to a region of low concentration until they are evenly distributed. The substance involved…
EVOLUTION
Organic evolution is defined as the sum total of adaptive changes from pre-existing or old form that have taken place over a long time, resulting in diversity of forms, structures and functions among organisms. The concept behind organic evolution is…
CELL AS A LIVING UNIT OF AN ORGANISM
The cell is defined as the structural and functional unit of a living organism. In other words, the cell is the simplest, the smallest and basic unit of life. All living things (plants and animals) are made of cells. The…
ORGANISATION OF LIFE
All living things are highly organised. This organisation occurs in levels. The simplest structures are found at the lowest levels and they interact to build up more complex structures at the next level and so on. Levels of Organisation…
BIOLOGY AS AN INQUIRY IN SCIENCE
Definition of Science and Biology Science is defined as a systematic process of making enquiry about the living and non-living things in our environment. Human beings have always been so curious to know more about the existence of things around…
