By the end of the topic, the learner should be able to:
INTRODUCTION (5 LESSONS)
Introduction to Biology
Biology derived from Greek words
Biology is therefore the study of living things/organisms.
Branches of Biology
Importance of Biology
Characteristics of Living Things
Life defined through observations of activities carried out by living things;
Nutrition is the processes by which food/nutrients are acquired/made and utilized by living organisms.
Green plants and certain bacteria make their own food.
All other organisms feed on complex organic materials.
This is the breakdown of food to provide energy.
The energy released is used for various activities in the organism.
Process through which respiratory gases (CO2 & O2) are taken in and out through a respiratory surface.
Excretion is the removal of metabolic wastes from the body.
Substances like urea, carbon dioxide (Carbon (IV) oxide).
These substances are poisonous if allowed to accumulate in the body.
Growth and Development
Growth means irreversible change in size.
All organisms increase in size that is, they grow.
Development is irreversible change in complexity.
As they do so, they also become differentiated in form.
Reproduction is the formation of new individuals of a species to ensure continued existence of a species and growth of its population.
The ability of organisms to detect and respond to changes in the environment. This is of great survival value to the organism.
This the progressive change in position from one place to another.
Some organisms are sessile (i.e. fixed to the substratum).
The majority of plants move only certain parts.
Collection and Observation of Organisms
Biology as a practical subject is learnt through humane handling of organisms.
Materials needed for collection of organisms include:-
Observation of Organisms
Presenting the Results of Observations
Organisms are observed and important features noted down: colour, texture hard or soft; if hairy or not. Size is measured or estimated.
Biological DrawingsIt is necessary to draw some of the organisms.
In making a biological drawing, magnification (enlargement) is noted.
Indicate the magnification of your drawing, i.e. how many times the drawing is larger/smaller than the actual specimen MG=length of drawing/length specimen
How to Draw
Collection, Observation and Recording of Organisms
Plants and animals collected from the environment, near school or within school compound using nets, bottles and gloves.
Animals collected include:-
arthropods, earthworms and small vertebrates like lizards/chameleons/ rodents.
Place in polythene bags and take to the laboratory.
Stinging/poisonous insects killed using ether.
Other animals are observed live and returned to their natural habitat.
Plant specimen collected include: -
leaves, flowers and whole plants.
Observations are made to show the following:-
The differences between animals and plants collected.
COMPARISON BETWEEN PLANTS AND ANIMALS