General introduction to Biology for learners

Some things on earth are living and some non-living.  It is easy to figure out that the living things are plants and animals and therefore non- living things are the rest. Things like the sun, soil, rocks and water.

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There are certain things that we need to know when classifying something as a living being.  

The following aspects are called "life processes".  For something to be living it must possess the following

• It must have the ability to move
• It must get its energy from food
• It must be able to grow
• It must reproduce and deliver offspring
• It must be able to get rid of waste
• It must take in and use food
• It must be sensitive to changes taking place around it

Now think of a human - we can move from one place to another, we eat food and that gives us energy, we grow from a baby to an adult, humans can reproduce and have babies, we are sensitive to certain stimuli like if it gets colder or hotter and we get rid of the waste in our bodies through exhaling, urinating and sweating.  

We possess all 7 life processes and therefore we are living organisms.

Imagine a river.  It flows from one area to another which means it moves (one of the life processes).  Does this now mean that the water in a river is living?  

No, it is very important to understand that only once it possesses ALL 7 life processes it is classified as living.

• A plant is living - look at the 7 life processes again and say how a plant does each of these.

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An animal is also called a consumer and a plant is called a producer.  

If you consume something it means you use it or take it up, we are animals and we eat food which means we consume it, hence we are consumers.

A plant makes its own food which means it produces food hence all green plants are producers.

• You can play the game on producers and consumers here

The process through which a plant produces its own food is called photosynthesis.  For this process it will use sunlight, water and carbon dioxide to produce sugars and store is as starch and in turn it will give off oxygen (a good reason why plants are very important to us besides from being used as food).  

This whole process takes place in the chlorophyll inside the chloroplast that is found inside the leave.

Living things consist of millions of cells

If you could be able to break down any living organism into the smallest part, you will see that it all starts with a cell.

We get two different types of cells - plant cells and animal cells.  They are almost the same but there are a few differences.

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• Watch the video and see if you can identify the different organelles that are mentioned in the table.  You must also do research and find a picture of each organelle and one function.

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Cells are so small they need to be looked at through a microscope. 

How does a microscope work?

You need to decide what cell or object you want to look at through the microscope.  You will have to put it on a glass slide on the stage of the microscope.  The light shines through the slide and you have a look at it through the lenses.  You can adjust the lenses to get better focus and to magnify it more, to make it bigger and see more in detail.

A microscope has a lot of different parts and each one has a specific function.

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One of the best cells to look at is an onion cell.  If you want to look at an onion cell, you must peel a thin layer from the inside of the onion and then spread it out on the glass slide.  You will have to color it with iodine in order for you to see the cells better.

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