4.2.2: Classification And Evolution Flashcards
What has improved the accuracy of classification systems?
Advances in technology
Particularly through immunology and genome sequencing.
What were traditional methods of classification based on?
Observable characteristics
This method can be misleading due to variations in environmental conditions.
What can cause members of the same species to look very different?
Different habitats with very different environmental conditions
What can cause members of different species to look similar?
Similar habitats and environmental conditions
How is the closeness of relatedness among organisms now measured?
DNA base sequence comparison
What happens to DNA base sequences of distantly related organisms?
Fewer similarities due to accumulated mutations
What is the significance of mutations in classification?
They accumulate over time, indicating how long ago species evolved from a common ancestor
What can be compared to determine the relatedness of species?
Amino acid sequence of proteins
Who proposed a change to the classification system in 1977?
Carl Woese
What new taxon did Carl Woese introduce?
Domain
What are the three domains added to the classification system?
- Archaea
- Bacteria
- Eukaryota
What are organisms classified based on in the domain system?
Type of rRNA, ribosomes, and cell membrane structures
How many kingdoms are there under the new classification system?
Six kingdoms
What is the prokaryotae kingdom divided into?
- Eubacteria (true bacteria)
- Archaebacteria
Where are eubacteria typically found?
Everywhere
Where do archaebacteria live?
Extreme environments, such as thermal hot springs and anaerobic environments
