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BIOLOGY LESSON NOTE ON CROP PROPAGATION

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Topic: Crop Propagation Class: Senior Secondary School 2 (SS2) Subject: Biology Specific Objectives By the end of this lesson, students should be able to: Define crop propagation. Differentiate between sexual and asexual propagation. Identify and explain various methods of crop propagation. Highlight the advantages and disadvantages of each method. Recognize common examples of crops propagated using each method. Lesson Content 1. Meaning of Crop Propagation Crop propagation refers to the process by which plants reproduce or are reproduced to give rise to new plants. This can occur naturally or be carried out artificially by farmers or agricultural scientists. It is a vital practice in agriculture that ensures the continuous production of food and other plant-based resources. 2. Types of Crop Propagation Crop propagation is broadly categorized into two main types: Sexual Propagation (Seed Propagation) Asexual Propagation (Vegetative Propagation) 3. Sexual Propa...
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Respiratory Structures

 Th is varies from organism to organism depending on their type, complexity, size and habitat in which they can be found. The table below shows various organisms and the respiratory structures related to them. Organisms Respiratory Structures Unicellular organisms e.g. amoeba and paramecium Body surface Earthworms Wet skin or body surface Hydra and tapeworm Cell membrane  Amphibians e.g. toads Mouth, skin and lungs Fishes e.g. tilapia  Gills Mammals Lungs Tadpoles Gills Anthropods e.g. insects Tracheal system Flowering plants Stomata and lenticels Arachnids e.g. spiders Book-lungs and tracheal Reptiles e.g. lizards Lungs
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Respiratory Surface

R espiratory surface refers to the definite surface of the body such as the surface of the lungs or a gill where gaseous exchange takes place. Characteristics of Respiratory Surfaces   It must be moist because gases diffuse in solution through them. It must be permeable to allow gas to pass in and out of them. It must be thin-walled to make diffusion easier and faster. It must have an adequate supply of transport medium. The surface must be large to aid easy diffusion of gases. It must be highly vascularized i.e. it must have lots of capillaries or a similar network to bring in and take away gases.
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RESPIRATION

  The process of respiration involves the taking in of oxygen, its transport within the body of the organism, its exchange in the cells, and the eventual release of energy in form of ATP, water and carbon(iv)oxide. The energy is utilized by the cells for their daily activities. Respiration can be defined as a biochemical activity of the cell, in which glucose is broken down in a series of reaction controlled by enzymes in order to release energy. Phases/Stages of Respiration External Respiration:  This simply involves the breathing in of air or oxygen into the respiratory organs such as lungs or gills otherwise called inspiration or inhalation and the breathing out of carbon dioxide and water vapour into the atmosphere otherwise called expiration or exhalation. It is the exchange of gases between the environment and the respiratory organs of living organisms. Internal Respiration:   This is the oxidation of food substances within the cells, leading to the releas...
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Conditions Necessary for Respiration

  Conditions Necessary for Respiration For effective exchange of gases to take place, the following conditions must be met: Respiratory medium:  This refers to the environment from which the organism inhales oxygen. Examples include air and water. Respiratory organ:  This refers to the organ possessed by the organism needed to inhale oxygen from the environment and exhale CO 2  and water vapour. Examples of such organs are lungs in mammals and gills in fishes. Transport medium:  This is needed to transport the dissolved oxygen to the various cells of the body which in turn picks up CO 2  and other waste products for the elimination process. An example is blood in mammals. Ventilation:  This is the movement of air in the direction over the respiratory surface. This ensures the replacement of used oxygen and the elimination of waste products. An increase in the rate of gaseous exchange is facilitated by a ventilation mechanism. An example is breathing in...
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