Edexcel IGCSE Biology · Section 1
The Nature & Variety of Living Organisms
Characteristics shared by all living organisms, the main groups of living things, and the pathogens that cause disease.
What this section covers
This opening section sets up the language of Biology. Students need to recognise the shared characteristics of living organisms, understand the main groups of organisms, and describe how pathogens can cause disease.
- Use MRS GREN to describe the characteristics of living organisms.
- Compare plants, animals, fungi, protoctists, bacteria and viruses.
- Understand that pathogens include bacteria, viruses, fungi and protoctists.
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1
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Characteristics of Living Organisms
Spec 1.1
The eight life processes shared by all living organisms — the MRS GREN characteristics — and how to tell whether something is living.
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2
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Organism Groups: Required Features and Examples
Spec 1.2
Covers compare the required features of plants, animals and fungi, Recall how each group stores carbohydrate and Use named examples to identify organism groups.
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3
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Variety of Living Organisms
Spec 1.2-1.3
The main groups of living organisms — plants, animals, fungi, bacteria, protoctists and viruses — with the key features and an example of each.
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4
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Pathogens and Viruses
Spec 1.4
What a pathogen is, the four types (bacteria, fungi, protoctists and viruses), the structure of a virus, and why viruses are not truly living.
Frequently asked questions
What are the characteristics of living organisms?
All living things carry out seven life processes, remembered as MRS GREN: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion and Nutrition.
What is the difference between eukaryotic and prokaryotic organisms?
Eukaryotic organisms (plants, animals, fungi and protoctists) have cells with a nucleus. Prokaryotic organisms (bacteria) have no nucleus — their DNA floats free in the cytoplasm.
What is a pathogen?
A pathogen is a microorganism that causes disease. Pathogens can be bacteria, fungi, protoctists or viruses.
Are viruses living organisms?
No. Viruses are not made of cells and can only reproduce inside a living host cell, so they are not classed as living.
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