BACKGROUND:
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.
PROCEDURE:
- 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.
- Read "Growing up Ohlone" which illustrate
how the Ohlones, native people in the San Francisco Bay area used
plants in their area.
- You may want to use the Internet
to help students learn how to use a search engine. In some of the search
engines like
http://www.google.com
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.
