- Slides: 8
Identifying organisms using Keys
Keys • Most people do not know what the identity or name of organisms are. • But with a few identifiable features organisms can be identified and named. • There are 2 types of biological key that will help do this. • In this lesson you will be learning about paired statement keys • By the end you should: be able to use and construct a paired statement key to identify organisms
Paired Statement Keys These keys are based on pairs of statements. The information will either allow the organism to be identified OR will lead to another pair of statements which should be read. The easiest way to get used to them is to follow through on a few examples. It would be best to have a genuine specimen to work on but sometimes only pictures are available Lets start with something relatively familiar
This key leads only to class level of identification of vertebrates. 1. A vertebrate is an animal with a backbone. 2. Vertebrates can have hair, feathers, and fins. 3. Vertebrates can have bone, cartilage, and fish scales both cycloid and placoid. You the user of this and any other key starts at the first feature described. Where necessary the second and subsequent pairs of statements are consulted. Have a look at the picture sheet to put some vertebrates into their class using their features.
This is the paired statement Key to the classes of the Vertebrates or Chordata (animals with backbones) 1 a hair present……. . Class Mammals 1 b hair absent………. Go to 2 2 a feathers present…. Class Birds 2 b feathers absent……Go to 3 3 a Dry scaly skin……. Class Reptiles 3 b Other type of skin……Go to 4 4 a Four limbs, moist scaly less skin…. . Class Amphibians 4 b Limbless…………Go to 5 5 a Fins, cycloid scales and bony skeleton……Class Fish (bony) 5 b Fins, placoid scales and cartilage skeleton…. . Class Fish (cartilage)
Try this paired statement key to identify some trees from their leaves Follow the link to key powerpoint. Can_You_Name_the_Tree_from_the_Leaf. ppt Pupils can come out and use the interactive board.
Now compete the sheet of questions on Keys. It has an activity that your group can do to construct a key for yourselves. Try the Buttercup key if you have time.
Keys Paired statement keys What are they used for? Can you use them? Could you complete one with missing information?