Biology

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 […]

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

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

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

hen population-influenced factors (abiotic and biotic) are favourable, growth is promoted but when they are unfavourable growth is retarded.

The orderly change in the inhabitants of an area over time is called succession. It can also be defined as the step by step orderly and gradual replacement of communities of organisms that leads to a climax community. An illustration of succession is that of a pond. Rain carries sediment from surrounding land into the

This is the transfer of mature pollen grains from the anther of one flower to the mature stigma of the same or another flower of the same plant or another plant of closely related species. Pollination usually precedes fertilization. There are two types of pollination namely, self-pollination and cross-pollination. SELF POLLINATION This is the transfer

STRUCTURES AND FUNCTIONS OF THE REPRODUCTIVE ORGANS IN PLANTS The flower is the reproductive structure of a flowering plant. It has both male and female sex organs hence it can carry out sexual reproduction. After fertilization has taken place in flowers, seeds are produced. A flower has two major parts: The floral part (whorls) The

REPRODUCTIVE SYSTEM Most multicellular animals and plants undergo a complex form of sexual reproduction in which especially differentiated male and female reproductive cells (gametes) unite to form a single cell, known as a zygote, which later undergoes successive divisions to form a new organism. The process takes place with the help of the system known

Excretion is the process by which metabolic waste products are removed from the body of all living things. Excretion is different from egestion which is the removal of solid waste (undigested food substances i.e.faeces) through the anus. Excretion is necessary for the following reasons: To avoid or prevent any harm that would be caused by

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

FEEDING RELATIONSHIPS Since all living organisms must obtain energy and nutrients from the environment in order to remain alive, they are into feeding relationships. This makes an ecosystem a functional unit. All organisms fall into one of the three major groups of biotic community, namely: producers (autotrophs), consumer (heterotrophs) and decomposers The autotrophs provide food

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

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

DEFINITION OF ECOLOGY Ecology is the study of plant and animals (as well as microorganism) in relation to their environment. As a practical science, ecological studies involve:- Studying the distribution of living organisms Finding out how living organisms depend on themselves and their non-living environment for survival. Measuring factors affecting the environment. BRANCHES OF ECOLOGY

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

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

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

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

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