My Science Library How Do Humans Depend on Earth by Julie K Lundgren Science Content Editor Shirley Duke Rourke Educational Media rourkeeducationalmedia com Teacher Notes available at rem4teachers com
Earth Provides 0000000000000000 People depend on plants for food clean air water fuel clothing and shelter Nearly all food webs begin with plants the primary producers During photosynthesis green plants use sunlight to change carbon dioxide from the air and water into simple sugars made of carbon hydrogen and oxygen Plants store the sugars in their roots stems and leaves As we eat plants energy and nutrition pass on to our bodies Photosynthesis Stem Glucose Release of oxygen Carbon dioxide absorption CO2 02 Absorption of Water
Plants take in carbon dioxide and give off oxygen during photosynthesis A balance of these gases in our atmosphere keeps Earth’s climate stable Carbon dioxide causes Earth to retain heat By removing carbon dioxide from the atmosphere and increasing oxygen plants cool the Earth and provide oxygen for people to breathe Since the first land plants began growing 450 to 500 million years ago Earth’s climate and landscape has changed from warm rocky and harsh to cool and green because of the exchange of carbon dioxide and oxygen during photosynthesis 5
