New News Biology #61

Classification

We used to classify species by what they looked like, but this presented a problem, which is different countries around the world had different names for the same thing. Also, these names don’t tell us much about how different organisms are related (e.g. panda bears and grizzly bears and koala bears aren’t really related although they are all called ‘bears’).

In the 1700’s, Carl Linnaeus came along, and attempted to fix these problems. He proposed a new type of classification, the Linnaean System, which classifies according to characteristics and bone structure. This new system grouped organisms into kingdom -> phylum -> class -> order -> family -> genus -> species.

To make this system usable by all countries, and because it was created hundreds of years ago, the names were written in Latin. For example, humans are animalia chordata mammalia primates homindae homo sapiens.

Then the binomial naming system was proposed on the basis of the Linnaean system, and proposed that a organism be named by its genus species. This meant that humans are known as Homo sapiens.

This system worked well, and is still used to this day. As biology advanced through the centuries, many newer models of the system were proposed. However, they didn’t get to replace the Linnaean system. Instead, these proposed models were sort of merged with the original system.

In the 1990’s, Carl Woese proposed the three domain system (bacteria, eukaryota, archaea). With evidence gathered from new techniques like analysis of RNA sequences, he discovered that some species were less related than we thought. He modeled a new system where organisms were based on domains. This system later was merged with the Linnaean system, with domains above kingdoms.

Here’s a tip on how to remember the order: Dear Kate Please Come Over For Great Spaghetti