For IGCSE O-Level biology students chapter 1

1. Classification
of living things

2. Why do we need to classify
living things?
 There are over 1.4 million different species
of discovered organisms on earth. We
classify them to make studying them
easier.
 Organisms are divided into five large
groups called kingdoms.

3. kingdoms
animals plants Bacteria fungi protoctists

4. Animals

5. Plants

6. Bacteria

7. Fungi

8. Protoctists

9.  We still find that in each group there may be
organisms that are very different such as ants and
giraffes in the animal kingdom.
 That is why each kingdom is divides into smaller groups
called phyla (singular: phylum).
 Each phylum is divided into several classes, then a
class is divide into orders, then family, then genus and
finally the smallest group is called species.
 Kingdom>phylum>class>order>family>genus>species.
 Try to remember them using this sentence:
 King Philip cut oranges for good students.

10. Animal kingdom
 Animals are either vertebrates (have a
back bone) or invertebrate (without a
back bone).
 Vertebrates are divided into five classes.

11. vertebrates
Fish Amphibians
Reptiles Birds
Mammals

12. Fish Amphibians Reptiles Birds Mammals
Body covering
Limbs
Ears
Eggs
Other
features

15. Insects Arachnids Crustaceans Myriapods
Body segments
Number of legs
Antenna
Other features
Common features They all have: 1. Segmented bodies 2. Jointed legs 3. A hard exoskeleton

18. Molting in insects

19. Other invertebrates
 Annelids
 Nematodes
 Molluscs

20. Annelids

21. nematodes

22. Molluscs

23. Molluscs
tentacles

24. Flowering plants
 Monocotyledons
 Dicotyledons

25. monocotyledons

26. Dicotyledons