History Weblecture for Unit 12
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Last week we concentrated on the general problems of classification, and Aristotle's position as one of the first recorded scientists to try to classify organisms. This week we look briefly at Aristotle's overall scheme, and then at a sample of his observations. Most of our effort, however, will be spent on the modern classification of invertebrates.
Aristotle proposed a "ladder of nature", which organized matter from simplest to most complex forms. His ladder included all matter, both non-living (the basic elements) and living organisms.
|Reptiles & Fish|
|Octopuses & Squids|
|Jointed Shell Fish|
|Jelly Fish ----------- Sponges|
|Inanimate Matter: Earth, Fire, Water, Air|
Our modern schema includes microscopic organisms Aristotle couldn't see, and many plants and animals that he could not observe in Mediterranean Greece. But two concepts are at the basis of both Aristotle's scheme and the modern one:
Aristotle based his classifications on the close observation of over 500 species of animals. His work in marine biology is still considered among the best and most reliable set of observations available for species of the Aegean.
Read an example of Aristotle's observation and description of the Crustaceans and Cephalopods from On the Parts of Animals, Book IV Part 5 (you'll need to click on book IV then scroll down to part 5).
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