BIOLOGY FORM 1: TOPIC ONE

1. 1.INTRODUCTION TO BIOLOGY

Is a scientific study which deals with living things or organisms. Living things or organisms mean:

1. Animals.
2. Plants.

Biology is derived from two Greek words:

Bios- Life.

Logos- Study.

Note:All living things are made up of cells. Unicellular organisms -> Single celled e.g. Amoeba are multicellular organisms with many cells.

A cell: Is a single unit of life.

Cell -> tissue -> organ -> system -> organism.

Characteristics of living things.

1. Movement: change of position or posture.
2. Nutrition: food for growth and energy.
3. Sensibility and irritability: response towards or against a stimulus.
4. Respiration: break down of food in order to release energy.
5. Excretion: removing waste products from the body.
6. Growth and life cycle: the increase of size and shape and finally death.
7. Reproduction: the increase in number.

Note the following:

1. Zoology- study of animals.
2. Botany- study of plants.
3. Mycology- study of fungi.
4. Bacteriology- study of bacteria.
5. Anatomy- study of the structure of an organism internally.
6. Physiology- study of how the living matter functions.
7. Taxonomy- study of scientific classification.
8. Parasitology- Study of parasites or parasitism.

Simple structure of animal and plant cell.

Animal cell

Plant cell

Functions of cell parts.

1. Nucleus- Controls all the activities of the cell.
2. Cytoplasm- Is a cavity in which all the organelles part.
3. Cell membrane- Protects or covers the cell, also allows the material in and out of the cell.
4. Cell wall- It is made of cellulose which protects and gives shape to a plant.
5. Chloroplast- Is a greenish part of a cell which contains a pigment called chlorophyll which traps solar energy and makes use of it in manufacturing of its own food, a process known as photosynthesis.
6. Vacuole- Is filled by a liquid called cell sap which exerts a pressure on the cytoplasm to make a cell wall firm and strong.

Plant cell	Animal cell
1. Has definite shape.	Has no shape (irregular)
2. Has a cell wall made up of cellulite.	Has no cell wall.
3. Has a large permanent vacuole.	Has a small and temporary vacuole.
4. Has chlorophyll.	No chlorophyll.

The importance of studying biology.

1. Man is a living organism so studying biology helps him to understand himself better.
2. We have to learn how animals and plants grow, because they provide us with food, clothes, and shelter.
3. The knowledge of this subject enables man to conserve his environment, because man has been so distinctive to life than any other creature.
4. We care for animals and plants by treating their diseases by observing at their causes, symptoms and mode of transmissions.
5. We become more curious by asking questions like when did life originate, how do plants feed? Etc. We get employed e.g. Doctor e.t.c.

The relationship between Biology and other related science subjects.

1.  Biology and Chemistry.

Biology tells us about living things and Chemistry tells us about the composition of living things.

2. Biology and Physics.

In Biology we learn names and shapes of different organisms and in physics we describe the quantity of matter in organisms.

3. Biology and Mathematics.

An organism can be measured to check body temperature, blood sugar, obesity, blood pressure etc. All these are done due to mathematical skills.

4. Biology and Geography.

Geography provides the information about the home of living things.