ANIMAL NUTRITION Animals generally cannot manufacture their food. Rather, they depend directly or indirectly on plants for their food. Hence they are called heterotrophs. Based on their food types, animals are grouped into three: Carnivores which feed on flesh or other animals e.g. lion. Herbivores which feed on plants e.g goat. Omnivores, which feed on […]
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IRRITABILITY AND TYPES OF RESPONSES Irritability is the ability of organisms to respond to stimuli. A stimulus is any change in external or internal environmental condition which can bring about a change in the activity of the whole or part of the organism. Response is the term used for the change in activity of the
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REPRODUCTION IN AMOEBA Amoeba reproduces asexually by binary fission and multiple fission (sporulation) during adverse condition. In binary fission when an amoeba reaches full size, it stops moving and divides into two equal parts starting from the nucleus. This is followed by the division of the cytoplasm, after which two daughter amoebae are formed. In
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There are two types of sexual reproduction, this includes conjugation and fusion of gametes. Conjugation: the simplest form of sexual reproduction, as contrasted with asexual reproduction. This is observed in some unicellular organisms e. g. paramecium, fungi e. g. rhizopus, algae e. g. spirogyra. Two similar organisms (conjugants) join together and exchange genetic material contained
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MEANING AND TYPES OF REPRODUCTION Reproduction is the ability of an organism to give rise to new individuals of the same species in order to ensure continuity of life. There are two types of reproduction asexual reproduction sexual reproduction Asexual Reproduction: is the process whereby an organism produces an offspring by itself. I.e. only one
RESPIRATORY SYSTEM IN MAMMALS The respiratory system of mammals is the most complex of all respiratory systems. It comprises a pair of lungs enclosed in the thorax and connected to the outside by a series of branched air tubes. In human beings, air can be drawn in through the mouth or nose. Both lead into
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DEFINITION/PHASES OF 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 therefore be defined
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In simple unicellular plant materials are exchanged by simple diffusion process between the plants and its aquatic environment. Hence there is no need for elaborate transport system. However, in higher plant such as ferns and the flowering plants. There is a need for elaborate transport system for transporting water and mineral salts from the soil
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PROTECTIVE FUNCTION OF BLOOD The blood performs two basic functions in mammals and these are: (1) Transportation of various substances and (2) Protection of the body against diseases The blood defends the body in major ways Antibody production (Clumping): The lymphocytes produce antibodies which are any of a large variety of proteins normally present in
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Transport system is the movement of metabolic materials from various parts of an organism where they are produced and transported to other parts where such are used, stored or removed from the body. Need For Transport System All living organisms (plants and animals) need transport system for the following reasons To obtain essential materials such
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INVERTEBRATES Feeding in Hydra Digestion in Planaria Digestion in Earthworms Digestion in insects (Grasshopper) VERTEBRATES Digestion in Birds Digestion in Rabbits FEEDING IN HYDRA Hydra feeds on small aquatic organisms e.g. crustaceans. It captures its food through its structure called nematocysts found on its tentacles. The food is then passed into the mouth while the
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TYPES OF TEETH Human beings have two sets of teeth in their lifetime. The first set is called the milk teeth that grow when the child is few months old. They are about twenty (20) in numbers. These include only three types of teeth i.e. Incisors, canine and premolars. They later fall off to be
To carry out life processes, all organisms (plants and animals) need tissues. Tissues are group of similar cells that carry out specific functions. Skeleton is the framework of the body which provides support, shape and protection to the soft tissues and organs in animals. It forms the central core of human body and it is
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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 pairs known as homologous chromosomes. Each chromosome is made up of two threads called chromatids joined at a point called centromere. Each human somatic cell
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Genetics is the scientific study of heredity and variation in all living things. The word genetics was coined by Dilliam Bateson (1906
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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 and functions among organism. The basis of evolution is that all organisms have pre–existing ancestors. Evidences of evolution Fossil record: A fossil is an
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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 blendingwith the environment
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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.
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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 exist between individuals of the same species Types of variations Morphological variation Physiological variation. Morphological variation is the noticeable physical appearance of individuals
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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 formation of their fruit. Such fruits are called parthenocarpic fruits e.g. banana and pineapple. Such fruits are seedless. A typical fruit has the following parts