Life Cycle - Plants (3B)
 Post Lab 

  • Exploring the uses of plants.
  • Investigating the importance of plants.


  • photosynthesis
  • soil conservation
  • wood pulp

Students use the Internet to find Information.



Plants form the basic food staple for all life forms. They are the major source of food and oxygen on earth, since no animal can supply these necessary components without plants. The cattle we eat as beef, feed on grasses and the fish we eat, consume algae and are therefore dependent on plants for well being. Other important uses of plants include, providing shelter for animals, providing materials for clothing (cotton fibers), paper products, medicines and other chemicals, producing coal from once living plant material, reducing wind speed and noise levels, and reducing soil erosion and water runoff.

There are many different types of cash crops that produce money for farmers. Olive oil comes from olives, corn oil comes from corn, and peanut oil comes from peanuts. Typical agricultural products like corn, wheat, rye, and rice are all considered cash crops. Coffee plants produce beans that are used to make coffee; coca plants give us chocolate; vanilla plants grow long thin beans that are used to produce vanilla flavoring. Many drinks and beverages, like cola and tea, come from plants. Rubber from trees is also a cash crop, as is lumber, fruit, vegetables, and cotton.

Plants were very important to early native peoples who used plants for food, medicine, transportation, and shelter. Plants are also used in agriculture to help reduce wind speed. Planting trees in a row prevents the wind from blowing away the valuable topsoil. In the forest, trees act as shelter for many organisms.

Plants are also important for the overall ecology of an area. Roots help to stabilize soil and prevent erosion by water run off (soil conservation). Plants are also important in our atmosphere because they use carbon dioxide and give off oxygen while they undergo photosynthesis.

Plants are also used in the urban setting to reduce noise, produce shade, and to beautify an area. Trees add value to homes and communities.


  1. Ask students if they know why plants are important. Review the information provided in the "Background" section. Discuss the worksheet before they start writing, especially if you want them to use the Internet or school library to do their work.

  2. Read "Growing up Ohlone" which illustrate how the Ohlones, native people in the San Francisco Bay area used plants in their area.
  3. You may want to use the Internet to help students learn how to use a search engine. In some of the search engines like go over some of the key words that might help them to search more successfully.

    Words like: paper products, agriculture, fabrics, medicine, and food may produce a long list of sites students can investigate.

 [Back to Life Cycle Grid]  [Back to Plants (3)]