LOCATION AND STRUCTURE OF CHROMOSOMES Chromatin granules (thread – like structures) found in the nucleus of eucaryotic cells are the precursors or raw materials of chromosomes. Chromosomes occur in… Read More »CHROMOSOME | THE BASIS OF HEREDITARY
Genetics is the scientific study of heredity and variation in all living things. The word genetics was coined by Dilliam Bateson (1906
ORGANIC EVOLUTION Organic evolution is the sum total of adaptive changes from pre–existing or old forms that has taken place over a long time resulting in diversity of forms, structures… Read More »THEORIES OF EVOLUTION
ADAPTIVE COLOURATION This is the possession by an organism of a colour which enables it to catch its prey, avoid its predators or enemies, secure mates and ensure their survival.… Read More »ADAPTIVE COLOURATION AND BEHAVIOURAL ADAPTATION
COMPETITION Competition is the process by which living organisms in the habitat struggle with one another for limited essential needs in the environment. Such scarce resources in plants include; light,… Read More »ADAPTATION FOR SURVIVAL
VARIATION IN POPULATION Population is a group of organisms of the same specie living in a specified area within a given period of time. Variation refers to the differences which… Read More »VARIATION IN POPULATION
STRUCTURE OF A FRUIT A fruit is a matured fertilized ovary of a flower containing one or more seeds. Contrary to this, some plants do not undergo fertilization for the… Read More »FRUIT
DEVELOPMENT OF ZYGOTE IN FLOWERING PLANTS, GERMINATION OF SEEDS, ADAPTIVE FEATURES IN A DEVELOPING ANIMAL DEVELOPMENT OF ZYGOTE IN PLANTS Pollination is followed by fertilization and the development of zygote… Read More »DEVELOPMENT OF ZYGOTE IN FLOWERING PLANTS
COURTSHIP BEHAVIOURS IN ANIMALS Courtship is a reproductive communication between males and females of a species that ends in sexual union. Courtship behaviours in animals include PAIRING: – A form… Read More »DEVELOPMENT OF NEW ORGANISMS
THE ORGAN OF HEARING Mammals have two ears on each side of the head. The greater part of it is enclosed in the skull for protection. The ear is for… Read More »ORGAN OF HEARING, SMELL AND TASTE
SENSORY RECEPTORS All living organisms respond to changes in their environment (stimuli). These changes can be mechanical, electromagnetic, chemical or thermal. Though most cells in the bodies of organisms are… Read More »SENSE ORGANS
REFLEX AND VOLUNTARY ACTIONS Actions are responses to stimuli. These actions are grouped into two: involuntary (reflex) and voluntary actions. REFLEX ACTIONS Reflex actions are automatic responses to stimuli… Read More »REFLEX, VOLUNTARY ACTIONS AND CONDITIONAL REFLEXES
THE PERIPHERAL NERVOUS SYSTEM These include the sensory system (receptor and nerves leading from all parts of the body to the CNS) and the motor system (nerves running from the… Read More »THE PERIPHERAL NERVOUS SYSTEM
THE NERVOUS SYSTEM The nervous and hormonal systems co-ordinate various biological activities in the body of multicellular animals, the basic structural unit of nervous system is the nerve cell called… Read More »NERVOUS CO-ORDINATION
HORMONES AND ENDOCRINE GLANDS Hormones are chemical substances produced or secreted by endocrine glands (ductless glands) in response to various stimuli. Hormones are secreted into the bloodstream and circulated to… Read More »HORMONAL CO-ORDINATION
STRUCTURE OF THE LIVER The liver is the largest organ in the body of a mammal with a weight of about 1.25kg. It is reddish brown, soft with two lobes… Read More »LIVER AND SKIN: STRUCTURE, FUNCTIONS, DISEASES AND CARE
HOMEOSTASIS Homeostasis is the process by which a fairly constant internal environment is maintained in an organism. The internal environment of an organism is made up of the body fluid… Read More »REGULATION OF INTERNAL ENVIRONMENT