Biology

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. Adaptive colouration may be grouped into Concealing (cryptic) colouration to help organisms blend with their background and remain unnoticed by predators Colour blending with the […]

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, space, nutrient and water while animals complete for food, space or mate. Competition finally results in survival of the fittest and elimination of the unfit.

STRUCTURE OF A FRUIT What is 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 formation of their fruit. Such fruits are called parthenocarpic fruits e.g. banana and pineapple. Such fruits are seedless. A typical fruit

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 an herbaceous plant is placed onto the stage of the microscope. Observations under the low power and medium power objective are made. A plan

What is a joint?  A joint 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

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.

MAMMALIAN SKELETON – AXIAL SKELETON, SKULL, RIBS, VERTEBRAL COLUMN & BONES 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

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

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

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

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

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 There 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

WHAT IS ENDOCRINE? 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

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 nerve¬cell 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

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

What is the nervous system? The nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body Components of the nervous system in humans Every organ is the human body is connected to nerves. The nervous system is made

The nervous and endocrine systems (together known as the neuro-endocrine system) act as a co-coordinating 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

The structures involved in detecting the changes may be located far away from the ones that respond. There is need for a communication system within the body. The nervous system and the endocrine system perform this function, i.e. linking the parts of the body that detect changes to those that respond to them. Irritability Living

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

EVOLUTION Meaning of Evolution and Current Concepts Evolution is the development of organisms from pre-existing simple organisms over a long period of time. It is based on the similarities in structure and function that is observed in all organisms. All are made up of cells, and similar chemical compounds are present. This indicates that all