Define the term ‘classification’
The process of placing living organisms into groups
Name the two scientists who developed classification systems
- Carl Linneaus
- Carl Woese
How did Linnaeus categorise living organisms
Traditionally living things have been classified into groups depending on their structure and characteristics
Place these groups into the correct order staring with the largest group Class Order Kingdom Species Phylum Genus Family
Kingdom → Phylum → Class → Order → Family → Genus → Species
Hint: try remembering the saying “Keep Penis Clean Or Forget Good Sex” – no offence meant here!
Give 2 reasons why some organisms have been reclassified in recent years
- Evidence of internal structures has become more developed due to improvements in microscopes
- Understanding of biochemical processes has progressed
- This has caused new models of classification to be proposed.
Explain how Carl Woese’s classification differs from Carl Linnaeus’s system
- Woese developed a 3 domain system
- This includes 3 groups which are each larger than Kingdom
Name the 3 domains used in Woese’s classification system
Describe the type of organisms that are placed in the archaea domain
- Simple prokaryotic bacteria
- Generally found in extreme habitats e.g. hot springs, salt lakes
Describe the type of organisms that are placed in the bacteria domain
- True bacteria
- They look similar to archaea but carry out different biochemical reactions
- E.g. E. coli, Staphylococcus
Describe the type of organisms that are placed in the eukaryota domain
- Broad range of organisms
- Includes animals, plants, fungi and protists
What is the term used to describe the naming system used in classification
What term terms make up the binomial name of any organism
- Genus followed by species
- E.g. Humans are correctly named as Homo sapiens
Homo = Genus
sapiens = species
How should a Scientist write the Latin Binomial name?
The genus must always have a capital letter
The species always begins with a lower case letter
Both genus and species should be typed in italics or underlined if hand written
State 4 advantages of using a Latin binomial name when talking about an organism
- The binomial name is used worldwide
- It overcomes difficulties with different Scientists using different languages
- It avoids some organisms being called different names in different countries
- It therefore makes sharing of information and data between Scientists easier as they know they are all referring to the same organism
Describe how evolutionary relationships can be shown
By the use of evolutionary trees
Where on an evolutionary tree is the most common ancestor found?
At the base of the evolutionary tree
Where on an evolutionary tree is the most recent species found?
At the tip of the longest branch = Bonobos
How are organisms that are closely related to each other shown on an evolutionary tree?
They are shown coming off one branch of the tree The closer the branching the more closely related they are
Which arrow shows speciation?
The arrow at the branching point