Classification

Classification:

Sea sponges used to be thought of as plants. This was due to Aristotle who sorted organisms into groups based on
their characteristics. This was called Classification. Aristotle thought any organism that didn't move was a plant.

Organisms with many characterisitics in common are all together grouped as a species. Species that share many
characteristics are together grouped as a genus. Genus that share many characteristics are together grouped as
a family. And so on untill Kingdom is reached.

The order is:
Kingdom      Phylum       Class      Order     Family       Genus        Species

To help remember them use:
Keep         Plates       Clean      Or        Family       Gets         Sick


Organisms can be classified into one of five Kingdoms according to some characteristics. Some organisms are unicellular
(Single cells) others are multicellular (Made of many cells). Many organisms have cells that contain a nucleus. But bacteria doesn't have a nucleus.

Another characteristic is how an organism gets its food.

Plants make their food autotrophically using Photosynthesis- Making food from molecules using a energy source.
Animals feed heterotrophically- Getting food by eating a digesting other organisms.
Fungi feed saprophytically- Digesting organisms outside the body and absorbing the digested food.


Kingdom:                        Main characteristics:
Animalia                        Multicellular; heterotrophic feeders so no chlorophyll; no cell walls; complex cell
                                structure with nucleus.

Plantae:                        Multicellular; autotrophic feeders using chlorophyll; cell walls made of cellulose;
                                complex cell structure with nucleus.

Fungi:                          Multicellular; cell walls not made of cellulose; saprophytic feeders so no chlorophyll;
                                complex cell structure with nucleus.

Protoctista:                    Mostly unicellular; complex cell structure with nucleus.

Prokaryotae:                    Unicellular; simple cell structure with no nucleus.



Remember: There is no Kingdom for Viruses because most scientists don't think of them as being alive. This is because they don't
show all seven life processes and had to live inside a living cell.


Key words to remember: 

• Characteristics
• Classification
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species
• Multicellular
• Unicellular
• Nuclus
• Bacteria
• Autotrophically
• Photosynthesis
• Heterotrophically
• Saprophytically
• Animalia
• Plantae
• Fungi
• Protctista
• Prokaryotae
• Virus

Define these words in your revision notes.

Questions:

1. Why did Aristotle think sponges were plants?
2. What is Classification?
3. Seaweeds don't have cellulose cell walls but do photosynthesise. Suggest why seaweeds were thought of as plants?
4. Why do you think seaweed is no longer classified as plants?
5. Viruses don't have a nucleus but nor do bacteria. Why are viruses not classified as Prokaryotae with bacteria?


What you should've learnt:

Demonstrate an understanding of how biologists classify organisms according to how closely they're related to one another including
a. Species  b. Genus  c. Family  d. Order  e. Class  f. Phylum  g. The Five Kingdoms

Describe the main characteristics of the five kingdoms including a. Animalia b. Plantae c. Fungi d. Protoctista e. Prokaryotae

Explain why scientists don't classify viruses in any of the Five Kingdoms and regard them as non-living.