Classification SNAB Notes



Taxonomy = science of classification

  • Involves naming and organising organisms into groups based on similarities and differences, making them easier to study
  • Eight taxonomic groups used in classification
  • Similar organisms are first sorted into one of three domains

Eight taxonomic groups:









  • As you move down the hierarchy, there are more groups with fewer organisms in them
  • Hierarchy ends with species, containing only one type of organism
  • Species in the same genus can be similar (phenotypes and genotypes) but are separated as they cannot breed to produce fertile offspring (the species concept)

All species are given a Latin name to distinguish them. It is a binomal system where the first word is the genus, and the second word is the species (i.e. humans = homo sapiens). All scientists around the world use the same name. 

  • Classification of organisms is based on phenotype, genotype and how related they are. 

Early Classification:

  • Early systems only used observable phenotypes to group organisms, such as their ability to fly or lay eggs. Scientists don't always agree on the relative importance of different features and groups based solely on physical features. 
    • E.G. Sharks and whales live in the ocean but are in no way related - whales are mammals and sharks are cartilaginous fish; two different classes. 
  • New technologies that…


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