BRAINCAKENew Evolutionary Models
Models of evolutionary relationships are not fixed. They change when new evidence is found, especially molecular evidence.
A famous example is the work of Carl Woese in the 1970s. Woese compared the base sequences of ribosomal RNA (rRNA) from many organisms. rRNA is found in all cells and changes slowly, so it is useful for comparing distantly related organisms. He found that prokaryotes, which had all been grouped together as bacteria, actually form two very different groups: Bacteria and Archaea. The Archaea were as different from Bacteria as they were from eukaryotes. This led to a new model of classification based on domains, above the level of kingdom.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
Key terms in this lesson
- peer review
- Independent assessment of a scientific paper by other experts in the field before it is published, checking that the methods and conclusions are valid.
More in Classification
- Limitations of Species Models
- Identifying a Species
- DNA Barcode
- DNA Analysis and Proteomics
- Biochemical Relationships
- More Biochemical Relationships
- Gel Electrophoresis
- Domains
All 19 lessons in Classification · All Edexcel AS-level Biology topics