What is pollution? This is the introduction of foreign material, poisonous compounds and excess nutrients or energy to the environment in harmful proportions. Any such substance is called a pollutant. Effects of Pollution on Human Beings and other Organisms Effects and Control of causes of Pollutants in Air, Water and Soil Industrialisation and urbanisation are […]
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Ascaris lumbricoides Ascaris lumbricoides lives in the intestines of a man or pig, feeding on the digested food of the host. The body of the worm is tapered at both ends. The female is longer than the male. Mode of transmission The host eats food contaminated with the eggs, the embryo worms hatch out in
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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
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What is Asexual reproduction? Asexual reproduction is the formation of offspring from a single parent. The offspring are identical to the parent. Types of asexual reproduction. Binary fission in amoeba. Spore formation in Rhizopus. Budding in yeast. Binary fission This involves the division of the parent organism into two daughter cells. The nucleus first divides
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What is pollination? This is the transfer of pollen grains from the anther to the stigma. Types of pollination Self pollination is the transfer of pollen grains from the anther of one flower to the stigma of the same flower. Cross-pollination is the transfer of pollen grains from the anther of one flower to the
What is sexual reproduction in plants? In flowering plants, the flower is the reproductive organ which is a specialised shoot consisting of a modified stem and leaves. The stem-like part is the pedicel and receptacle, while modified leaves form corolla and calyx. Structure of a flower A typical flower consists of the following parts: Calyx
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The process by which mature individuals produce offspring is called reproduction. Reproduction is a characteristic of all living organisms and prevents extinction of a species. There are two types of reproduction: sexual and asexual reproduction. Sexual reproduction involves the fusion of male and female gametes to form a zygote. Asexual reproduction does not involve gametes.
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AUTOTROPHIC NUTRITION Plants are referred to as autotrophs, i.e. being able to manufacture their food (Organic compound from inorganic materials such as water, carbon dioxide) Autotrophs generally have two modes of nutrition which are chemosynthesis and photosynthesis (holophytic). HETEROTROPHIC NUTRITION This is a type of nutrition in which organisms depend directly or indirectly on autotrophs
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MODERN CLASSIFICATION OF LIVING ORGANISMS All organisms cannot be suitably classified as either plants or animals based on CarolusLinneaus classification. Therefore five kingdoms have been generally accepted for all living organisms, these include Monera, Protista, fungi, plantae and animalia. KINGDOM MONERA (Prokaryotes) This group consists of simplest living organisms (bacteria, blue-green anabaena). They are microscopic
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DEFINITION AND FORMS OF CELLULAR EXISTENCE The cell is the simplest, smallest, basic, structural and functional unit of life. The cell can carry out all life activities such as growth, respiration e. t. c. Cells can exist in various forms which include As a single cell (unicellular forms) g. Amoeba, Chlamydomonas, Chlorella, Euglena Chlamydomonas(Chlamydomonas rivalries)
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What is growth? Growth is the irreversible increase in dry mass, size and complexity of an organism brought about by the synthesis of new protoplasm. For growth to be effective, building up of materials (anabolism) must exceed the rate of breaking down (catabolism). In plants, growth is indefinite and apical while it is definite and
CELLULAR (INTERNAL/TISSUE) RESPIRATION The oxidation of glucose in the cell to release energy is known as cellular respiration and it occurs in the mitochondria of all living cells. There are two types of cellular respiration i.e. aerobic and anaerobic respiration AEROBIC RESPIRATION When cellular respiration takes place in the presence of oxygen is known as
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Bees are important in pollination i.e. in production of honey Members of the phylum have a notochord in early stages of development. They have visceral clefts – which are slits perforating the body wall at the pharynx. In fish these slits become gills while in higher chordates these slits are only present in embryo. They
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All living organisms can be generally classified as plants or animals. However, plants can be distinguished from animals in the following ways: PLANTS ANIMALS 1. Undergo passive movement. Undergo free or active movement with well developed organs of locomotion. 2. Gaseous exchange takes place through the entire body. Gaseous exchange is through special organs. 3.
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THE VERTEBRATES (PHYLUM CHORDATA) All vertebrates have the following features: A bilaterally symmetrical body which is divided into a head, trunk and a tail with a neck joining the head to the trunk in most vertebrates. An internal skeleton (endoskeleton) Well developed central nervous system and sense organs. A closed blood system Skin covered with
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BIOLOGY AS AN INQUIRY IN SCIENCE Science is the study of nature (living and non-living things). Biology is a science that studies living things in nature. Biology was formed from the Greek words “Bio” (meaning life) and “logos” (meaning, study of). The organisms studied in biology are generally classified into plants and animals. Therefore, biology
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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
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Leaves Type of leaf (a) Compound leaves. (b) Type of venation. Simple leaf Trifoliate Pinnate Type of leaf margin. Type of leaf arrangement on stem. The colour of leaf. The texture ofleaf; whether hairy or smooth. Shape of the leaf e.g. palmate. Stem Type of stem – woody or herbaceous. Shape of stem – cylindrical
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Oxygen is required by plants for the production of energy for cellular activities. Carbon (IV) oxide is required as a raw material for the synthesis of complex organic substances. Oxygen and carbon (IV) oxide are obtained from the atmosphere in the case of terrestrial plants and from the surrounding water in the case of aquatic
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Living organisms require energy to perform cellular activities. The energy comes from breakdown of food in respiration. Carbon (IV) oxide is a by-product of respiration and its accumulation in cells is harmful which has to be removed. Most organisms use oxygen for respiration which is obtained from the environment. Photosynthetic cells of green plants use
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