Plants grow nearly everywhere on Earth including in the water Plants are vital to life on Earth They provide food for people and animals They also make the oxygen that other living things breathe Water plants or hydrophytes are plants that have adapted to life in the water Some water plants live totally submerged while SEA PLANTS AND ALGAE Eelgrass has adapted so that it may live most of its life completely underwater 4
others live only partly in water All water plants share many similarities so scientists believe that all water plants originally came from land Still they have adapted or changed to be able to live under water Other organisms called algae live in water too Algae are very important because they make much of Earth’s oxygen which humans and other animals need to breathe Some algae such as seaweed look like plants However algae are neither plants nor animals Instead they belong to a group of living things called protists A carpet of green algae covers the rocks of this seashore Something that is submerged is completely covered with water Vocabulary 5
PHOTOSYNTHESIS Energy from sunlight fuels the process known as photosynthesis All green plants make their own food using the process called photosynthesis Photosynthesis requires sunlight water a gas called carbon dioxide and a substance in plants called chlorophyll Photosynthesis is important because it produces oxygen 6
Humans and other animals need to breathe in oxygen to survive Some living things other than plants also make their own food through photosynthesis Photosynthesis actually began with early forms of bacteria and algae The process starts when chlorophyll in plants absorbs energy from sunlight The light energy is used to change Why is it important that photosynthesis releases oxygen into the atmosphere Could you live in a world without oxygen Think About It Photosynthesis uses sunlight carbon dioxide and water to create sugars that help plants grow 7
