BIOLOGY PRACTICAL ACTIVITIES Ecology is best studied outdoors. Students identify a habitat within or near the school compound, e.g. a flower bed. The quadrat method is used. Observation and recording of the various animals as well as their feeding habits is done. Birds that feed on the plants or arthropods in the area studied are […]
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HUMAN DISEASES (PARASITIC DISEASES) 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
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HUMAN DISEASES – BACTERIAL DISEASES The term disease denotes any condition or disorder that disrupts the steady state of wellbeing of the body. Health is a state of physical, mental and emotional wellbeing in the internal environment of the body. Some of the causes of diseases are due to entry of pathogens and parasites. Pathogens
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POLLUTION: DEFINITION. EFFECTS, CAUSES, SOURCES AND CONTROLS 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
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HYDROPHYTES (WATER PLANTS) What is hydrophytes (water plants)? Water plants are submerged, emergent or floating. Submerged Plants The leaves have an epidermis with very thin walls and a delicate cuticle. They have no stomata. Water is excreted from special glands and pores at the tips. Other adaptations include the following: Presence of large air spaces
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POPULATION ESTIMATION METHODS What is population estimation methods? It is important to find or estimate the sizes of the different populations in a habitat. Direct counting or head count which involves the counting of every individual is not always applicable for all organisms. e.g., it is impossible to count directly the numbers of grasshoppers in
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FOOD CHAINS What is a food chain? A food chain is a linear relationship between producers and consumers. It represents the transfer of food energy from green plants through repeated stages of eating and being eaten. Types of Food Chain Grazing food chain – starts with green plants. Detritus food chain – starts with dead
INTER-RELATIONSHIPS BETWEEN ORGANISMS The relationships between organisms in a given ecosystem is primarily a feeding one. Organisms in a particular habitat have different feeding levels referred to as trophic levels. There are two main trophic levels: Producers: These organisms that occupy the first trophic level. They manufacture their own food hence are autotrophic. Consumers: These
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THE ECOSYSTEM What is Ecosystem? The community and the abiotic or non-living environment together make up an ecosystem or ecological system. In this system energy flow is clearly defined from producers to consumers and nutrient cycling takes place in paths that links all the organisms and the non-living environment. Biomass: This is the mass of
BIOLOGY PRACTICAL ACTIVITIES To examine Bryophyta A mature moss plant is obtained. The specimen is observed using a hand -lens. A labelled drawing showing structures is made: rhizoids, set a capsule, gametophyte, sporophyte. To examine Pteridophyta A mature fern plant is obtained. It is observed using a hand lens. Sori can be seen on the
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Introduction to Ecology:
Ecology is the study of organisms and their environment.
All organisms show interdependence on one another.
Organisms are affected by their environment, and they in turn affect the environment.
Green plants manufacture food by photosynthesis which other organisms obtain directly or indirectly.
CHARACTERISTICS OF VERTEBRATES 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
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FEATURES USED FOR IDENTIFICATION IN PLANTS 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
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KINGDOM ANIMALIA Most animals move from place to place in search of food. Major phyla are: Platyhelminthes (Tapeworm). Nematoda (Ascaris). Annelida (Earthworm). Mollusca (Snails). Arthropoda Chordata KINGDOM PLANTAE Phylum Arthropoda Distinguishing Characteristics of Phylum Arthropoda They have jointed appendages, which are specialised for various functions. Their body is covered by a hardened exoskeleton made
KINGDOM PLANTAE General Characteristics of Kingdom Plantae They are multicellular and eukaryotic. They are photosynthetic and have pigment chlorophyll. Their cells have cellulose cell walls. They reproduce sexually, others asexually. Kingdom Plantae has three major divisions: Bryophyta, Pteridophyta Division Bryophyta These include mosses and liverworts. Plant body is not differentiated into root, stem and
KINGDOM FUNGI Multicellular fungi are made of thread-like structures called hyphae (singular hyphae) that form a mycelium. e.g. Saccharomyces cereviseae (bread yeast). Others include Penicillium, Rhizopus, and edible mushroom KINGDOM PROTOCTISTA Economic Importance of Fungi Beneficial Effects of Fungi Some fungi are used as food e.g. mushrooms. Some are decomposers which enhance decay to improve
KINGDOM PROTOCTISTA Examples include; Algae such as spirogyra, Chlamydomonas, euglena, Sargassum And protozoa such as amoeba, paramecium and Trypanosoma. KINGDOM MONERA General Characteristics They are said to be eukaryotic since their nucleus is bound by a membrane Most are mobile, and use flagella, cilia and pseudopodia. Some are sessile. They reproduce mainly asexually, by binary
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KINGDOM MONERA General Characteristics Unicellular and microscopic Some single cells ,others colonial Nuclear material not enclosed within nuclear membrane-prokaryotic Have cell wall but not of cellulose. Have few organelles which are not membrane bound Mitochondria absent Mostly heterotrophic, feeding saprotrophically or parasitically,some are autotrophic. Reproduction mostly asexual through binary fission Most of them are anaerobes
GENERAL PRINCIPLES OF CLASSIFICATION Classification is the science that puts organisms into distinct groups to make their study easy and systematic. Modern scientific classification is based on structure and functions. Organisms with similar anatomical and morphological characteristics are placed in one group while those with different structures are grouped separately. Modern studies in genetics and
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GROWTH 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