This document discusses classification and kingdoms. It explains that classification is used to organize living organisms into a hierarchy with five kingdoms. The kingdoms are defined by characteristics of cells and include Animalia, Plantae, Fungi, Protista, and Prokaryotae. Within these kingdoms, organisms are further classified into domains, kingdoms, phyla, classes, orders, families, genera, and ultimately species using their binomial scientific name.

1. Classification and Kingdoms
Classification is the method used by scientists to order living organisms. All species
have a unique classification that results in a binomial name. Vertebrates are an
example of a classification group. Keys can be used to help to identify individual
organisms.
Kingdom to species
Classification
You will remember from your Key Stage 3 studies that species with similar characteristics are put
into groups, and that this is called classification. Remind yourself of the basics of classification.
Kingdoms
The first rank in this system is called a kingdom. There are five kingdoms, based upon what
an organism's cells are like:
1. animalia (all multicellular animals)
2. plantae (all green plants)
3. fungi (moulds, mushrooms, yeast)
4. prokaryotae (bacteria, blue-green algae)
5. protoctista (Amoeba, Paramecium).
Further divisions
There are several further ranks before we reach a particular species. In order, these
are:
• kingdom
• phylum
• class
• order
• family
• genus
• species.
For example, lions have the following classification:
• kingdom - animal
• phylum - vertebrate
• class - mammal
• order - carnivorous
• family - cat
• genus - big cat

2. • species - lion.
One way to remember this is by using a daft sentence like this one:
"Kevin plays clarinet or flute - grotty sound!"
All organisms are known by their binomial name which is the genus and species eg
Homo sapiens – modern humans
Classification - Higher tier
Being able to classify species is important to scientists as it allows them to
accurately identify individual species wherever they are. For example - a robin in
America isn’t the same as a robin in the UK so by using the binomial name
Turdusmigratorius (American robin) or Erithacusrubecula (UK robin) then there is no
confusion.
Binomial classification is important because it can:
• clearly identify species
• study and conserve species
• target conservation efforts.
Kingdom characteristics
The first big division of living things in the classification system is to put them into
one of five kingdoms. These are based on what an organism's cells are like. This
table shows the names of the kingdoms, the characteristics and examples of the sort
of organisms they contain:
Kingdoms
Kingdom Characteristics and Examples
Animalia
Multicellular, no cell wall or chlorophyll, heterotrophic
feeders. Examples: all multicellular animals, including:
jellyfish, worms, arthropods, molluscs, echinoderms, fish,
amphibia, reptiles, birds and mammals
Plantae
Multicellular, have cell walls and chlorophyll, autotrophic
feeders. Examples: all green plants, including: algae, ferns
and mosses (plants that do not produce seeds), conifers
and flowering plants (plants that do produce seeds)
Fungi
Multicellular, have cell walls, do not have chlorophyll,
saprophytic feeders. Examples: moulds, mushrooms, yeast
Protoctista
Usually unicellular, with a nucleus eg amoeba. Examples:
amoeba and paramecium

3. Kingdom Characteristics and Examples
Prokaryotes
Unicellular, with no nucleus eg bacteria. Examples:
bacteria and blue-green algae
Classification examples
It can be easy to classify a species. For example, we are Homo sapiens.
Classification of species
Rank
Classificati
on
Notes
kingdom animalia
phylum chordates
animals with a supporting rod running the length of the body eg
backbone
class mammals
animals that are warm-blooded, have lungs and body hair,
produce milk and give birth to live young
order primates ape-like animals
family hominids human-like animals
genus homo humans
species sapiens modern humans
It can also be difficult to classify a certain organism. For example, the single-celled
organism called Euglena has some confusing characteristics. It has:
• chloroplasts, like a plant
• no cell wall, like an animal
• a flagellum to swim with, like some bacteria.
A fifth kingdom, called the protoctista, was made for organisms like Euglena.
Viruses
Scientists do not classify a virus as a living thing. This is because:
• it does not show all seven processes for life
• when it enters a cell it changes the way a cell works so it can make copies of
the virus.
Vertebrates
The vertebrates are animals with a backbone. Scientists separate this group into
smaller groups because of their features:
• how the animal takes in oxygen – lungs, gills or through the skin
• thermoregulation – maintains own temperature (homeotherms) or

4. temperature varies with surroundings (poikilotherms)
• reproduction – internal or external fertilisation, lay eggs (oviparous) or give
birth to live young (viviparous).
Vertebrates
Group Characteristics
Fish Gills, external fertilisation
Oviparous, poikilotherm
Amphibian
Some lungs or gills, external
fertilisation
Oviparous, poikilotherm
Reptile Lungs, internal fertilisation
Oviparous, poikilotherm
Bird Lungs, internal fertilisation
Oviparous, homeotherm
Mammal Lungs, internal fertilisation
Vivaparous, homeotherm
Assigning vertebrates to different groups can be difficult as some fall into many categories:
for example, sharks are fish but give birth to live young and use internal fertilisation.
What is a species?
Organisms of the same species:
• have more characteristics in common than they do with organisms of a different
species
• can interbreed to produce fertile offspring.
Sometimes a species may have different kinds or breeds that show great variation but the
individuals still belong to the same species. Different breeds of pedigree dog are like this.
From left to right - Beagle, Wheaten Terrier, Rhodesian Ridgeback, Red Siberian Husky,
Irish Setter, Golden Retriever, Boxer, Sheltie
Similar species tend to live in similar habitats, and are closely related in evolutionary
terms. They are likely to share a relatively recent ancestor. Closely related species living in

5. different types of habitat may have different characteristics. You can use keys to identify
organisms according to their features.
A species is defined as organisms that produce fertile offspring but this is sometimes
limited as some organisms do not always reproduce sexually, and some hybrids are fertile.
Sometimes classification can be complicated by:
• variation within a species
• hybridisation (closely related species breed to produce offspring that have
characteristics of both – the hybrids are often infertile)
• ring species – neighbouring populations of species may have slightly different
characteristics but can still interbreed as part of a chain but the two ends of the
chain can’t interbreed.
Keys
Keys are used to help identify a species. Keys can either be branching or a series of paired
statements and are based on the physical characteristics of the species.

6. different types of habitat may have different characteristics. You can use keys to identify
organisms according to their features.
A species is defined as organisms that produce fertile offspring but this is sometimes
limited as some organisms do not always reproduce sexually, and some hybrids are fertile.
Sometimes classification can be complicated by:
• variation within a species
• hybridisation (closely related species breed to produce offspring that have
characteristics of both – the hybrids are often infertile)
• ring species – neighbouring populations of species may have slightly different
characteristics but can still interbreed as part of a chain but the two ends of the
chain can’t interbreed.
Keys
Keys are used to help identify a species. Keys can either be branching or a series of paired
statements and are based on the physical characteristics of the species.