Taxonomy

• Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
• Classification can be artificial meaning based on observable differences
• Classification can be phylogenetic meaning based on evolutionary relationships and homologous characteristics in heirachy
• Hierarchy is where groups are ordered with no overlap
• Homologous characteristics are where characteristics originate from the same source but have different functions
• The three domains are Archaea, Bacteria and Eukarya
• A taxon is where similar organisms are grouped at the same level
• Organisms can be grouped based off of fossils, behaviour, sequence of DNA and proteins and visible features
• Phylogeny is the evolutionary relationship between organisms and their common ancestors
• Evidence for evolutionary relationships include comparing base DNA sequences, amino acid sequences, MRNA and courtship behaviour
• DNA sequences are the hardest to compare as a sample has to be taken from the nucleus
• MRNA sequencing involves taking spliced MRNA from the cytoplasm, creating cDNA to produce the original template strand and comparing its sequence to that of another organisms MRNA coding for the same protein
• Protein sequencing is the most simple as you can compare amino acid sequences, however, these evolve slowly and may not give accurate results
• To compare species evolutionary relationships, we can inject a species antigens into another, allowing it to produce antibodies, then, the antibodies are isolated with the other species antigens, the more precipitate formed, the closer the species are