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YOUR NOTES
IGCSE Biology CIE
1. Characteristics & Classification of Living Organisms
CONTENTS
1.1 Characteristics, Classification & Features of Organisms
1.1.1 Characteristics of Living Organisms
1.1.2 Concept & Uses of Classification Systems
1.1.3 Concept & Uses of Classification Systems: Extended
1.1.4 Features of Organisms
1.1.5 Features of Organisms: Extended
Page 1 of 20
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1.1 Characteristics, Classification & Features of Organisms YOUR NOTES
1.1.1 Characteristics of Living Organisms
Characteristics of Living Organisms
Movement: an action by an organism or part of an organism causing a change of
position or place
Respiration: the chemical reactions that break down nutrient molecules in living
cells to release energy for metabolism
Sensitivity: the ability to detect or sense stimuli in the internal or external
environment and to make appropriate responses
Growth: a permanent increase in size and dry mass by an increase in cell number
or cell size or both
Reproduction: the processes that make more of the same kind of organism
Excretion: the removal from organisms of toxic materials, the waste products of
metabolism (chemical reactions in cells including respiration) and substances in
excess of requirements
Nutrition: the taking in of materials for energy, growth and development; plants
require light, carbon dioxide, water and ions; animals need organic compounds,
ions and usually need water
Exam Tip
Use this mnemonic to help you remember these processes:
MRS. H. GREN
Movement
Respiration
Sensitivity
Homeostasis
Growth and development
Reproduction
Excretion
N utrition
Page 2 of 20
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1.1.2 Concept & Uses of Classification Systems YOUR NOTES
How Organisms are Classified
There are millions of species of organisms on Earth
A species is defined as a group of organisms that can reproduce to produce
fertile offspring
These species can be classified into groups by the features that they share e.g. all
mammals have bodies covered in hair, feed young from mammary glands and have
external ears (pinnas)
Page 3 of 20
© 2015-2021 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers
YOUR NOTES
IGCSE Biology CIE
1. Characteristics & Classification of Living Organisms
CONTENTS
1.1 Characteristics, Classification & Features of Organisms
1.1.1 Characteristics of Living Organisms
1.1.2 Concept & Uses of Classification Systems
1.1.3 Concept & Uses of Classification Systems: Extended
1.1.4 Features of Organisms
1.1.5 Features of Organisms: Extended
Page 1 of 20
© 2015-2021 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers
, Head to savemyexams.co.uk for more awesome resources
1.1 Characteristics, Classification & Features of Organisms YOUR NOTES
1.1.1 Characteristics of Living Organisms
Characteristics of Living Organisms
Movement: an action by an organism or part of an organism causing a change of
position or place
Respiration: the chemical reactions that break down nutrient molecules in living
cells to release energy for metabolism
Sensitivity: the ability to detect or sense stimuli in the internal or external
environment and to make appropriate responses
Growth: a permanent increase in size and dry mass by an increase in cell number
or cell size or both
Reproduction: the processes that make more of the same kind of organism
Excretion: the removal from organisms of toxic materials, the waste products of
metabolism (chemical reactions in cells including respiration) and substances in
excess of requirements
Nutrition: the taking in of materials for energy, growth and development; plants
require light, carbon dioxide, water and ions; animals need organic compounds,
ions and usually need water
Exam Tip
Use this mnemonic to help you remember these processes:
MRS. H. GREN
Movement
Respiration
Sensitivity
Homeostasis
Growth and development
Reproduction
Excretion
N utrition
Page 2 of 20
© 2015-2021 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers
, Head to savemyexams.co.uk for more awesome resources
1.1.2 Concept & Uses of Classification Systems YOUR NOTES
How Organisms are Classified
There are millions of species of organisms on Earth
A species is defined as a group of organisms that can reproduce to produce
fertile offspring
These species can be classified into groups by the features that they share e.g. all
mammals have bodies covered in hair, feed young from mammary glands and have
external ears (pinnas)
Page 3 of 20
© 2015-2021 Save My Exams, Ltd. · Revision Notes, Topic Questions, Past Papers
