4.6.4 Classification

Question 1

Classification:

Answer 1

involves putting organisms into groups depending on their structure and characteristics

Question 2

What have traditionally living things been classified into and by who?

Answer 2

traditionally living things have been classified into groups depending on their structure and characteristics in a system developed by Carl Linnaeus - called the Linnaean system

Question 3

How did Linnaeus classify living things?

Answer 3

kingdom → phylum → class → order → family → genus → species

Question 4

How are organisms named?

Answer 4

• organisms are names by the binomial of genus and species
• the first part is their genus and the second part is their species - used worldwide + overcomes language barriers

Question 5

Why did new classification systems develop?

Answer 5

• due to developments in science e.g. improvements in microscopes + understanding of biochemical processes progressed (found that some species were more distantly related than first thought
• this led to evidence of internal structures becoming more developed
• so new models of classification were proposed

Question 6

Why did the ‘three domain system’ develop?

Answer 6

due to evidence available from chemical analysis

Question 7

Who developed the ‘three domain system’?

Answer 7

Carl Woese

Question 8

How are organisms divided/classified in the ‘three domain system’?

Answer 8

• archaea - primitive bacteria usually living in extreme environments e.g. hot springs
• bacteria - true bacteria (despite having similar features to archaea
• eukaryota - organisms which have a nucleus enclosed in membranes, which includes the kingdoms, protists, fungi, plants and animals

Question 9

Evolutionary trees:

Answer 9

• a method used by scientists to show how they believe organisms are related
• use current classification data for living organisms and fossil data for extinct organisms