SS 1 Biology (1st, 2nd & 3rd Term)

Bacteria reproduce by binary fission in which a single cell divides into two. This process is called asexual reproduction. The time interval required for the cell to divide into two is called generation time. This time varies from one organism to another. It strongly depends upon nutrient availability, temperature, gaseous requirement and pH. There are

Sexually Transmitted Infections (STIs) (veneral diseases) are the diseases that are contacted through sexual intercourse. Examples include syphilis, gonorrhea, herpes, thrush, AIDSetc.The table below shows a list of STIs, their symptoms, transmission, etc.   DISEASE CAUSATIVE ORGANISM SYMPTOMS PREVENTION/CONTROL GONORRHOEA Bacterium (Neisseria gonorrhea) −     Burning sensation during urination in males −     A thick yellowish discharge

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

TYPES OF ASSOCIATIONS AND THEIR FEATURES SYMBIOSIS OR MUTUALISM (+  +) Definition: When both population benefit and at least one of them is so dependent upon the other for some critical resource or function that it cannot survive in the given environment without the other species is referred to as mutualism or symbiosis. Symbiosis is

Biomes are large natural terrestrial ecosystems, identified by their dominant vegetation. They are terrestrial because plants form the bulk of the community in any ecosystem e.g. a forest biome has densely packed tall trees while grasses and few scattered shrubs are found in a savanna biome. Climatic factors determine the type of vegetation in a

(1) Role of government in agricultural production
Environmental factors required for food production
3Ways of improving crop production

A pest is an organism which harbors disease organism(s) or causes damage to other organism(s). There are crop and livestock (animals) pests.

CLASSIFICATION OF PLANTS Plants exists in various forms and types hence, the need for classification.  Plants can be classified on the following bases Botanical classification Agricultural classification Classification based on life cycle Classification based on size BOTANICAL CLASSIFICATION The concept of binomial nomenclature has it that plant kingdom can be subdivided into divisions, classes, orders,

CONTROL OF HARMFUL MICRO-ORGANISMS The control of harmful microbes include removal, inhibition of growth or killing by physical agents/processes and chemical agents or antibiotics. Some common methods of controlling harmful microorganisms in order to maintain good health include High and low temperature: Boiling or heating of food, pasteurization of milk, sterilization of medical instruments and

Micro-organisms otherwise called microbes or germs can be defined as living things which cannot be seen with unaided eye but by the use of microscopes.   They exist almost everywhere, in water, air, soil, surface of objects, as well as on and within living organisms.  They are carried by air currents from the earth’s surface

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

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

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

POPULATION CHARACTERISTICS These include population size, density, frequency, percentage cover and distribution. Population size: – this is the number of organisms of the same species living together in a given area at a particular time. Population density: – this is the number of a particular species per unit area or volume of the habitat. Therefore

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