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How Many Kingdoms Are There?

Classification, like almost everything in science, is continually changing. You may be familiar with the modern classification system. This system arranges organisms into kingdom, phylum, lass, order, family, genus, and species. This system has not always existed. It was developed by Carolus Linnaeus in the 1700s.

How many kingdoms of living things are there? You may have read in a textbook that there are six: archaebacteria, eubacteria, protists, fungi, plants, and animals. If you look at a textbook from ten years ago or so, you will likely only find five kingdoms. This method was used earlier in Sci-ber text in Unlocking The Mysteries!If you look at an even older textbook, you will only find two kingdoms, plants and animals. What if you look at a textbook ten years from now? You may see even more kingdoms! Some scientists argue that viruses should be included with living things and that they should have their own kingdom. This would bring the number of kingdoms to seven. Perhaps it will increase with new scientific discoveries.

Let’s back up more than 2000 years to the time of Aristotle. He was the first person we know about to come up with a classification system. His system was very simple compared with the one we currently use. He divided living things into plants and animals. The plants were then divided into three groups: herbs, bushes, and trees. Animals were also divided into three groups: land, water, and air animals. We now know that this classification system is too simple. It, however, was a good way to start the process of classification.

Why so much change over time? Well, as we learn more and more about organisms, we have to adapt the classification systems to better fit the new information. Will the classification system change again? Several years from now you are likely to see more changes. DNA research is providing new information about living things. Based on the new information, scientists may change how organisms are classified.

When do you think that classification will stop changing? When we know everything! Actually, we will probably never be able to know everything, because as plants and animals evolve and change, there will be new things to learn. We may also find new living things to study as we continue to explore space and discover new planets. Who knows, you may become famous by discovering a new species!

Congratulations, you have reached the end of Sci-ber text! You may review any part of Sci-ber text by using the links at the bottom of this page. Look forward to using Sci-ber text next year as part of your studies in Eighth Grade.

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Updated October 24, 2008 by: Glen Westbroek

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