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Year 9 iGSCE - Biology Classification

Living organisms are classified according to their characteristic. How they look, act, what they eat and how similar they are genetically are factors affecting their classification

All living organisms on earth are made of cells. Tiny microscopic factories which create the diverse range of life you see today.

Click here for more information on cells and the characteristics of living organsisms

The first step in classifying an organism is to place them into a kingdom.

Once we have determined which kingdom the organism belongs in, we can further break it up into Phylum, Class, Order, Family, Genus and Species with increasing specificity as we go down.

Click here to lean what a species is.

The Binomial method of scientifically naming organisms uses the genus and species name.

As you can see above, humans are under the genus Homo, and out species is Sapiens. This makes our scientific name, Homo sapiens.

It is important for us to use the binomial system of naming, because it allows us to be more accurate in identifying individuals.

If we look at human evolution we have

Homo habilis, Homo erectus and Homo sapiens, and Australopithecus Afarensis (just to name a few)

Rather than just view the physical features of an organism we can analyse its DNA and RNA.

By determining the DNA or RNA sequence we can determine evolutionary relationships between species.

This method is called Cladistics.

Here are a few Mnemonics devises to help you remember the order.

Did King Phillip Cry Out “For Goodness Sakes!”?

Do Koalas Prefer Chocolate Or Fruit, Generally Speaking

Kid Play Card On Flat Gray Steps

It also allows us to accurately identify individual species wherever they are.

If we look at a robin in America it isn’t the same as a robin in the UK.

By using the binomial name Turdus migratorius (American robin) (to the left) or Erithacus rubecula (UK robin) (to the right) we limit the amount of confusion.

The 3 main reasons why binomial classification is important are:

Clear identification of species

The study and conserve species

Correctly target conservation efforts.

A dichotomous key is chart which allows you to identify a specific organism, based on its characteristics.

Click here to learn more about dichotomous keys.