Harnessing the Sun All living things need sun water air and food A food chain links living things each eaten by the one that follows it Food chains begin with sunlight shining on green plants Through photosynthesis green plants transform the Sun’s energy into food for living and growing This food energy passes on to animals when the plants are eaten and again when the animals are eaten Because each living thing plays a role in many food chains scientists call all of the food chains in an area a food web The animals and plants in a food web depend on each other for survival 4 During the brief days of moisture after a rare rainfall North America’s Sonoran Desert explodes with flowers Desert plants jump into action when water is available on This Chew Chlorophyll spurs the chemical reaction trans forming light energy into food during photosynthesis It colors the plants green too
This diagram shows the flow of a simple food chain beginning with the Sun’s energy and ending with an animal 5
Weaving a Desert Web A community of plants and animals and the ways they interact with each other and their surroundings form an ecosystem Desert ecosystems cover a third of Earth’s land Hot or cold hilly or flat sandy or rocky they all have one thing in common deserts receive 10 inches 25 centimeters or less of rain each year Plants and animals must have adaptations to make their home in this parched habitat They must have special ways to survive Although South America’s Atacama a cold winter desert sits next to the Pacific Ocean it receives the least amount of moisture of any place on Earth 6
The Arctic and Antarctic form vast frozen polar deserts The ice there has stockpiled over thousands of years Most people know about hot deserts like the Sahara in northern Africa Arctic Ocean NORTH AMERICA Atlantic Ocean EUROPE ASIA Pacific Ocean SOUTH AMERICA AFRICA Indian Ocean Southern Ocean ANTARCTICA Hot deserts circle Earth near its middle while cold deserts are found in regions away from the equator Pacific Ocean Equator AUSTRALIA 7
