The Newbie Science Guide to Taxonomy

Biology can be a complicated world, and the names of species can be even more confusing. Canis familiaris a.k.a. the domestic dog, is a pretty easy example, as is Escherichia coli (E.coli) – a microbe commonly known to cause food poisoning. But have you ever been to a garden centre and wondered what the fancy Latin names actually means? Well here is the Newbie Science guide to taxonomy!

Why hello there little E.coli (you can get your own from giantmicrobes.com)
Why hello there little E.coli
(you can get your own from giantmicrobes.com)

Taxonomy (from the Greek taxis “arrangement” and nomos “law” – thank you Britannica Encyclopedia!) is a formal classification system for all living and extinct organisms, it aims to group related organisms together, whilst also identifying them as individuals (species).  This ‘kinship’ is generally based on what common and defining features that organism has, e.g. members of the big cat family all have whiskers and paws, but only tigers have stripes! Taxonomy is also highly useful in studying evolutionary relationships, creating what is essentially a large, prehistoric family tree.

Now remember this phrase: King Prawn Curry Or Fat Greasy Sausage. Not sure what this means? Well its the easier method of remembering 7 taxonomic ranks. Here are the actual names, and I’ll use the example of  where humans lie within each group to make it even easier:

Kingdom (king)

This is where taxonomy starts and all (well nearly all) organisms are placed into one of five kingdoms, which are prokaryota (sometimes called monera), protoctista, animalia, plantae and fungi. This order is based on a cellular level, for example, plantae and animalia differ in several different ways – animal cells are only surrounded by a membrane and are circular in shape, whereas plant cells also contain a cell wall and tend to be rectangular. Most important of all is the presence of chloroplasts in plant cells, green pigments that are responsible for photosynthesis, something that no animal cell is capable of.

Humans are part of the animalia kingdom.

five_kingdoms

Phylum (prawn)

Following on from kingdom, phylum further classifies groups based on their characteristics, a prime example of this is the Chordata phylum, a group which includes humans.

Class (curry)

Following phylum comes class, as with all the taxonomic ranks, common features create the group, and class is the level whereby the differences can be seen by both scientists and non-scientists. The class Mammalia includes us, our dogs and cats, cows, whales and thousands of other species. Animals within the Mammalia class share the features of hair follicles, mammary glands and most importantly, giving birth to live young as opposed to laying eggs.

Fun fact: did you know that reptiles and birds are both members of the class Sauropsida?

The blue whale: the largest animal to have ever existed is actually a mammal.
The blue whale: the largest animal to have ever existed is actually a mammal.

Order (or)

Next up, we have order. Humans are part of the primate order, and primates are well known for having large eyes at the front of the skull, allowing for a good sense of vision, albeit at the expense of a sense of smell. Primates also have their own way of getting around, whether it be bipedal motion, knuckle walking or jumping from tree to tree. Most importantly, most primates have opposable thumbs, meaning that object can be manipulated, and they also have a complex social structure.

Primates tend to be subdivided into prosimians and simians (the greater apes) – the latter of which make up our next example of taxonomic rank.

Family (fat)

As previously mentioned, primates are usually divided. One of these division are the greater apes, which is classified as the family Hominidae. Within this group, we have humans, chimpanzees, gorillas and orangutans. An interesting point about this family is that newborns are relatively helpless (for example, an antelope walks very soon after it’s born, but a newborn ape will cling to its mother and will be need to be carried and fed). In terms of diet, the great apes are omnivores, with all the species except humans preferring mostly fruit based diets.

An orangutan at the San Diego Zoo
An orangutan at the San Diego Zoo. We’re all family!  (Photo credit: Wikipedia)

Genus (greasy)

This is the first taxonomic rank that people will regularly come across, such as in garden centres (the most common example I can think of). For humans, we are a member of the genus Homo, which comes from the Latin word for human or man. Human beings are the only surviving member of the Homo genus, with other extinct members being Homo erectus, Homo habilis and Homo neanderthalensis.

Members of the Homo genus have large cranial cavities and large brains, allowing for higher brain functions and most importantly, the manipulation and creation of tools. The remains of the different specials within this genus have been found in far apart areas such including Africa, western Europe, eastern Europe and the far east of Asia.

Species (sausage)

This is the most important order of taxonomy, and is usually defined as a group of organisms that are capable of interbreeding (i.e. lion + tiger = liger/tion). As there are no longer any other Homo species, humans are incapable of interbreeding, though there is the theory that early humans in Europe did possibly breed with the neanderthals (see The Caveman In All of Us). Another good example of interspecies breeding is wolves and domestic dogs, I myself have met the result of this interbreeding, Ziggy. She is incapable of barking (unlike domestic dogs) and instead howls like a wolf, especially when the ice cream van drives by.

Ziggy the half wolf half dog - aged six months when this photo was taken, she's now about twice this size.
Ziggy the half wolf half dog – aged six months when this photo was taken, she’s now about twice this size.

Why is it all in Latin?

Latin is the language of science, this is because it can be universally understood, and doesn’t lead to the misunderstandings that using a modern language could lead to. So don’t be freaked out too much by the fancy Latin names, it’s just the universal name for something. The latin names should also be italisised, as you’re using a foreign language. Also, if you have to ever do a biology exam using species names and it’s handwritten (making italicising much harder), you should underline the names instead, with the genus always having a capital letter, and the species being in lower case.

Recap

Where do humans stand in taxonomic classification?

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Primate

Family: Hominidae

Genus: Homo

Species: sapiens

(Side note: Wikipedia will class humans as being Homo h.sapiens, however this is not entirely accurate. They’ve accidentally added the h onto sapiens when they don’t need to).

Well I hope that this explained a bit to you about biological classification. Remember to like Newbie Science on Facebook! https://www.facebook.com/NewbieScience

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