1.2) Concept and use of classification system
- Species: is a group of organisms that can reproduce to produce fertile offspring.
- Binomial system: is an internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and the species.
- It is important to classify organisms:
- Possible to identify those most at risk of extinction.
- Understand evolutionary relationships. (by studying the anatomy of different groups of vertebrates)
- Morphology: the study of the form, or outward appearance, of organisms.
- Anatomy: the study of their internal structure, as revealed by dissection.
- The use of DNA has revolutionised the process of classification.
- Eukaryotic organisms contain chromosomes made up of strings of genes.
- DNA is made up of a sequence of bases, coding for amino acids and proteins.
- Each species has a distinct number of chromosomes and a unique sequence of bases in it DNA, making it identifiable and distinguishable from other species.
- This helps when different species are very similar morphologically and anatomically.
- Cladistics: the process of biological classification.
- Organisms which share a more recent ancestor (more closely related) have DNA base sequences that are more similar than those that share only a distant ancestor.