2. Diversity of Life:
Introduction to
Biological
Classification
Kabwe Secondary School

3. Classification
• Classification is grouping things
together on the basis of features they
have in common
• It is a basic feature of all human
activity
• Biological classification is known as
Taxonomy
• Closely related to taxonomy is the way
organisms are named and identified

4. What is taxonomy?
Taxonomy is the branch of
biology concerned with the
grouping and naming of
organisms
Biologists who study this are
called taxonomists

5. Importance of Classification
• Makes the study of living organisms
easy
• Helps scientists to communicate
information about living organisms
clearly and unambiguously
• Helps to recognise how evolution
may have given rise to diverse but
related organisms

6. Who is Carolus Linnaeus?
• Carolus Linnaeus was a
Swedish botanist
• Developed a 7-level (taxa)
classification system based
on similarities between
organisms

7. The Seven Level System
Kingdom
Phylum
Class
Order
Family
Genus
Species
King
Phillip
Came
Over
For
Green
Soup

8. The Taxonomical groups
Kingdom largest taxon
Phylum
Class
Order
Family
Genus
Species smallest taxon

9. Linnaeus’ classification system has seven levels.
• Each level is
included in the
level above it.
• Levels get
increasingly specific
from kingdom to
species.

10. How does it work?
There are 6 broad kingdoms
Every living thing that we
know of fits into one of the
six kingdoms
Each level gets more specific
as fewer organisms fit into
any one group

11. • Physical similarities
are not always the
result of close
relationships.
• Genetic similarities
more accurately
show evolutionary
relationships.

12. KEY CONCEPT
Modern classification is based on evolutionary
relationships.

13. The 3 Domains
PROKARYOTES
organisms with no
nuclear membrane
organisms with a
nuclear membrane
EUKARYOTES

14. The 6 Kingdoms
• Kingdoms are the largest division-all
organisms are in one of the 6 kingdoms
• Animals
• Plants
• Fungi
• Protists
• Eubacteria
• Archaebacteria

15. Binomial Nomenclature
Bi means two
Nomen means name
A binomial nomenclature is a
classification system using
two names to identify an
organism

16. Binomial Nomenclature
• Each type of organism is assigned
two names:
• The first is the name of the genus
(generic name) - starts with a
capital letter
• The second is the name of the
species (starts with a small letter)
• E.g Felis domestica (domestic cat)

17. • A genus includes one or more physically similar
species.
– Species in the same genus are thought to
be closely related.
– Genus name is always capitalized.
• A species descriptor is the second part of a
scientific name.
– always lowercase
– always follows genus
name; never written alone

18. Genus…
• A genus consists of a group
of closely related species
• A species consists of animals
that can mate and produce
fertile offspring

19. • Here is the classification for a Lion
• Kingdom: Animalia (animal kingdom)
• Phylum: Chordata (Vertebrates)
• Class: Mammalia (mammals)
• Order: Carnivora (carnivores)
• Family: Felidae (cats)
• Genus: Panthera
• Species: Panthera leo

21. FUNGI
FUNGI
Fungi sometimes look like plants, but they’re not!
Fungi can’t do photosynthesis, because they don’t have chloroplasts;
they get their nutrients from the organic material they live in.
 Decomposers, like mushrooms, feed on dead organic material.
 Some fungi feed on living organisms, such as plants, animals
and even other fungi. This causes diseases and infections in these
organisms (like athlete’s foot and ringworm in humans).
 Some fungi live as symbiotic partners with algae. The result:
lichen (pronounced “like-n”). more lichen
Other differences from plants:
• fungi don’t have roots, they have a mycelium.
• fungi’s cell walls are made of chitin, not cellulose.

22. Kingdom Plantae
• Green plants with chlorophyll and other
pigments
• Photosynthetic
• Multicellular with cell walls made of
cellulose
• Large sap-filled vacuole
• Plastids and other organelles
• Reproduce asexually and sexually

23. Kingdom Protoctista (protists)
• Vary in size-from unicellular forms
(e.g. Euglena, Amoeba, Paramecium
and Plasmodium) to multicellular
forms
• DNA enclosed in a membrane-bound
nucleus
• Photosynthetic and Heterotrophic
forms exist e.g. algae and protozoa
respectively
• Reproduce asexually and sexually

24. Kingdom Animalia
• Multicellular organisms forming tissues and
organs
• Motile in nature
• Life processes controlled by nervous system in
most phyla
• Heterotrophic
• No chlorophyll, cell walls or sap-vacuole

25. ANIMALS
Invertebrates
(no backbone)
Vertebrates
(backbone)

26. Kingdom Prokaryotae
• Include bacteria and cyanobacteria
• Cytoplasm and DNA present
• No true nucleus
• No membrane-bound organelles
• Simple methods of reproducing e.g.
fission
• Several subphyla exist based on
biochemical characteristics
• Found in soil, water, air, bodies of
other organisms

27. Dichotomous keys
• What is a dichotomous key?
• A step-by-step guide to identify an organism
– Each step gives a choice of two
descriptions.
– The descriptions have to be opposites
• Ex. Leaves round vs. leaves not round
• After each description, the key directs
the user to another pair of descriptions
or identifies the organism.

28. Quick Review
• What are the seven taxa or
levels?
• Who designed the system?
• What taxa are organisms
named with?

29.  Let us now try to use the dichotomous key
provided to identify the insects shown

30. THANKYOU
 This concludes a brief review of biological
classification.