This document discusses the key characteristics of living organisms and methods of biological classification. It describes the characteristics of movement, respiration, sensitivity, growth, reproduction, excretion and nutrition that define life. It also explains the concepts of classification, putting organisms into groups based on similarities, and the binomial naming system. Specific phyla and classes within the animal and plant kingdoms are outlined, along with the distinctive features of fungi, protoctista, prokaryotes, viruses and different types of plants and animals.

1. Cambridge IGCSE Biology
1- Characteristics and
classification of living organisms
Biology
Cambridge IGCSE Biology

3. 1.1 characteristics of living organisms
Movement : an action by an organism or part of an
organism causing change of position

4. 1.1 characteristics of living organisms
Respiration : the chemical reaction in cells that
break down nutrients molecules to
release energy for metabolism

5. 1.1 characteristics of living organisms
Sensitivity : the ability to detect and respond to
change in the environment
Extended the ability to detect or sense stimuli in
internal or external environment and
make appropriate responses

6. 1.1 characteristics of living organisms
Growth : a permanent increase in Size
Extended: a permanent increase in Size and
dry mass by an increase in cell number or
cell size or both

7. 1.1 characteristics of living organisms
Reproduction : the process that make more of the
same kind of organism

8. 1.1 characteristics of living organisms
Execration : removal from organisms of toxic
material or substances in excessive of
requirements
Extended: removal from organisms the waste
products of Metabolism which is toxic
material and substances in excessive of
requirements

9. Nutrition : taking in of material for energy ,
growth and development
Extended: taking in of material for energy ,
growth and development ;
plants need ( light – water – CO2 – ions )
Animal need ( organic compounds – ions – water)
1.1 characteristics of living organisms

10. 1.2 concept and use of Classification
classification : putting living organisms in groups
referring to common similarities
e.g: mammals have hair / breasts to feed babies so
Human , horses , dogs belong to one group
All of them are descended from the same ancestor
Distant ancestor
species as a group of organisms that can reproduce to produce fertile offspring
binomial system of naming species as an internationally agreed
system in which the scientific name of an organism is made up of two parts
showing genus and species

11. 1.2 Classification
classification : putting living organisms in groups
Extended: 1- depending on morphology
2- depending on anatomy

12. classification : putting living organisms in groups
Extended: 3- DNA ( genetic material )
Animal with more similar base of DNA they are more
close and that means they have
recent ancestor

13. DNA and base pairs
Base pairs hold the two strands of the DNA helix together.
The rules for base pairing are…
There are millions of base pairs in a DNA molecule that always follow these
rules.
A always pairs with T
C always pairs with G
Amazingly, it is the sequence of bases along a DNA molecule that forms the
genetic code – it’s that simple!

14. classification : putting living organisms in groups
Extended: 3- DNA ( genetic material )
Animal with more similar base of DNA they are more
close and that means they have
recent ancestor

15. 1.3 features of living organisms
Plant features Animal features
Movement Fixed ,
stay in one place
Move actively
Nutrition photosynthesis
( autotrophic )
Hunting for food
( heterotrophic )
Cell structure (Cell wall – cell membrane –
cytoplasm – nucleus -
chloroplast )
(cell membrane –
cytoplasm – nucleus)
All living organisms body made of cells contain
( cell membrane – cytoplasm – DNA genetic material )
Extended:
all living organisms cells contain ribosome for making
protein and enzymes for respiration

16. Animals features
1- Multicellular
2- cells have no cell wall and chloroplasts
3- feed on organic substance made by other living organisms
Plant features
1- Multicellular
2- cells have cell wall (made of cellulose) and chloroplasts
3- feed by photosynthesis
4- may have roots , stems and leaves
1.3 features of living organisms

17. Extended: Fungi Kingdom
1- usually multicellular
2- have nuclei ( singular : nucleus )
3- have cell wall made of chitin
( not cellulose )
4- have no chloroplasts
5- feed by saprophytic or parasitic nutrition
1.3 features of living organisms

18. Extended: protoctista Kingdom
1- multicellular – unicellular
2- have nuclei ( singular : nucleus )
3- may have cell wall and chloroplast
4- some feed by photosynthesis
( Autotrophic)
some feed on organic substance made by
other organisms ( heterotrophic )
1.3 features of living organisms

19. Extended: prokaryotic Kingdom
1- unicellular
2- have no nuclei ( singular : nucleus )
3- may have cell wall made of cellulose
4- have no mitochondria
1.3 features of living organisms

20. Animal kingdom
Phylum vertebrate : all animals have backbone called vertebrates
class fish : all live in water - scaly skin – have gills – have fins
cold blooded
class amphibians : moist scale less skin – cold blooded
tadpoles have gills – adults have lungs
class reptiles : dry scaly skin – lay eggs with water proof shells
cold blooded
class birds : covered with feathers –
lay eggs with water proof shells – have beak
have wings - warm blooded
1.3 features of living organisms

21. class mammals : body covered with hair – have placenta –
young feed on milk from breast
warm blooded – have diaphragm
have different types of teeth
1.3 features of living organisms

22. animal Kingdom
Phylum : arthropods
1- several pairs of jointed legs
2- exoskeleton
3- segmented body
1.3 features of living organisms

23. animal Kingdom
Phylum : arthropods
insects
1- 3 pairs of jointed legs
2- breath through trachea
3- body divided into 3 parts
( head - thorax - abdomen )
1.3 features of living organisms

24. animal Kingdom
Phylum : arthropods
Crustaceans
1- more than 4 pairs of jointed legs
2- breath through gills
3- segmented body
1.3 features of living organisms

25. animal Kingdom
Phylum : arthropods
Archnids
1- 4 pairs of jointed legs
2- breath through book lungs
3- segmented body
1.3 features of living organisms

26. animal Kingdom
Phylum : arthropods
Myriapods
1- each segment has pairs of jointed legs
2- exoskeleton
3- many segments in body
1.3 features of living organisms

27. Extended:
plant kingdom
Ferns
1- plants with roots ,stems and leaves
2- have leaves called fronds
3- do not produce flowers
4- reproduce by spores
1.3 features of living organisms

28. Extended:
plant kingdom
Flowering plants
1- plants with roots ,stems and leaves
2- reproduce sexually by flower and seeds
3- seeds produced inside the ovary
1.3 features of living organisms

29. Extended: viruses features
1- all of them pathogen ( cause diseases )
Common cold / influenza / AIDS
2- the can not conceder as living organism – outside
cells found as crystals
3- they are not cells and have protein coat
4- genetic material may be DNA or RNA
5- they are smaller than Bacteria
1.3 features of living organisms

30. 1.4 Dichotomous keys