we Are LIVING orGaNISMS

Refresh How many living organisms did you see yesterday?

2 What are living organisms?

Living organisms are made up of cells and perform the three vital functions. They need nutrients to survive, grow and create energy. They also breathe and respire, eliminate waste and interact with their environment. Living organisms also reproduce and die. There are different types of living organisms. Examples include the plants, animals and fungi that we can observe in nature. There are also other living organisms that we can only see through a microscope, like bacteria.

Living organisms are in every habitat on the Earth and they adapt to the environment where they live.

1 Look at the photos above and answer the questions.

a) What living organisms do you see in each photo?

b) What other living organisms could exist in each environment?

2 Look at the photos and write which ones are living organisms in your notebook.

• In your notebook, make a list of the living organisms you can see in your house.

3 The three vital functions

Vital functions are the three processes that all living organisms perform to stay alive.

• Nutrition obtains nutrients to grow, get energy and eliminate waste. Heterotrophic organisms get nutrients by feeding on other living organisms. Autotrophic organisms produce their own nutrients.

• Reproduction allows living organisms to create other living organisms. Sexual reproduction requires two living organisms. Asexual reproduction requires only one living organism.

• Interaction relates to how living organisms react to changes in their environment. A living organism detects a change with its sense organs and reacts after receiving instructions from the nervous system.

3 With a classmate, decide which vital function is shown in the following photos.

• Think How would you react if...

a) ... you felt thirsty?

b) ... a tiger was running towards you?

c) ... you were under the rain?

d) ... you felt hot under the Sun?

e) ... you heard a very loud, sudden noise?

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Second Conditional

If I felt thirsty, I would drink water.