7.4
The classification system continues to change In this topic, you will learn that:
• Carolus Linnaeus was the first scientist to use a dichotomous key to classify every living thing • scientific names are binomial (two names), the genus and the species • the Linnaean taxonomy system is still used today.
Giving organisms a precise name
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When trying fi nd your house on Google Earth, you fi rst fi nd Australia and then the state you live in. Each time you narrow your search closer to your town, your suburb, your street until you fi nally fi nd your house.
double names are given to every living thing using the Linnaean classification system. Our homes can easily be found by using only the two smallest groups in an address – the street and the suburb. The information about the bigger groups, such as the Earth and the country, is not really necessary.
KINGDOM: Animalia e.g. insect, ÿsh, bird, lizard, kangaroo, fox, lion, jungle cat, domestic cat
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PHYLUM: Chordata e.g. ÿsh, bird, lizard, kangaroo, fox, lion, jungle cat
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Figure 1 How do you find your house on Google Earth?
Linnaean taxonomy a hierarchical system of classification developed by Linnaeus in which all organisms are grouped into kingdom, phylum, class, order, genus and species, with each individual organism known by its genus and species names kingdom the highest category in taxonomic classification
The Linnaean taxonomy for classifying living things works in a similar way. It starts with large groups called kingdoms and then divides into smaller groups called phyla. Each phylum has several classes. The classes have orders and so on. There are seven different levels to get to the final name of each organism: kingdom, phylum, class, order, family, genus and species. (Tip: Some people use the following mnemonic to remember the Linnaean system: ‘K ing Phillip Crawled Over Four Gooey Snails’.)
ORDER: Carnivora e.g. fox, lion, jungle cat, domestic cat FAMILY: Felidae e.g. lion, jungle cat, domestic cat GENUS: Felis e.g. jungle cat, domestic cat SPECIES: catus domestic cat
Linnaeus’s double-name system Have you eaten a Musa sapientum lately or have they been too expensive to buy? And did you pat your Canis familiaris is this morning? These
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CLASS: Mammalia e.g. kangaroo, fox, lion, jungle cat, domestic cat
Figure 2 The Linnaean classification system uses seven different levels. It is used to give names to living things such as the domestic cat, Felis catus.
OXFORD UNIVERSITY PRESS OXFORD SCIENCE 7: VICTORIAN CURRICULUM No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means.
