Classification means forming groups. We all classify things. We classify our clothes (for example, clothes for playing outside, clothes for dirty tasks, clothes for school or work, and clothes for 'dress up' events), the foods that we eat (for example, vegetables, meat, and fruits), and most other things that we use on a regular basis.
Many things can be classified in more than one way. For instance, another way of classifying the foods that you eat would be into foods that you like and foods that you do not like, or foods that require cooking and foods that do not require cooking. Which classification is best depends on what you want to use it for.
Plants can also be classified in many different ways. For instance, they can be classified as woody or not woody. Flowering plants are often classified on the basis of their flower color.
Sometimes it is useful to have several layers in a classification. Woody plants could be divided into trees and shrubs. Trees could be divided into trees that lose their leaves into winter and those that do not.
Similarly, non-woody plants could be divided in several more ways, perhaps into plants grown for food, plants grown as ornamentals, and plants that are weeds.
Both these classifications are simple, and they are useful if you are deciding what plants to put in your garden, but their value is rather limited. For instance, is a woody vine a tree or shrub, or does there have to be another group? Should the new group include all vines, or just woody vines? How do you classify a flowering plant that does not produce obvious flowers? Some people really like the taste of young dandelion leaves. Does this make dandelions a food plant?
Botanists have found that the most generally useful way to classify plants is to consider several different characteristics, making groups of those plants that are alike in lots of characteristics. Their classification system is so useful that it is used by people in many different kinds of work.
- Classify the plants in a nearby area as woody or non-woody. Then classify the non-woody plants as trees or shrubs. Then classify the trees as ones that lose their leaves in winter or ones that keep their leaves in winter.
- Find an area with about 15 different kinds of non-woody plants. Classify the plants according to their flower color.
- How does your supermarket classify the things that it sells? How would you describe the group that includes tomatoes? apples? flour? Do all supermarkets classify things in the same way?
- Classify a mixed bunch of seeds. Be prepared to explain what characteristics the seeds in each of your groups share.