Needs of Living Things

What should need for living things? 

Sitting on the bank of the stream, you and your dog are probably not aware that you interact with everything else in the environment. However, all organisms take part in many interacting cycles with each other and with all the nonliving things around them. When an organism is part of these relationships, its needs are met. What are these needs? All organisms need energy and raw materials. The energy that you use comes from food. The main source of energy for living organisms is the sun. Green plants use the sun's energy, along with carbon dioxide, water, and minerals from the soil, to make food in the form of a sugar called glucose. The food is made in green leaves. This process also produces oxygen. Oxygen is used by most organisms to release energy from food.

Raw materials that organ-isms use are the water, oxygen, and minerals that have been used since life began. Oxygen, water, carbon dioxide, and other chemicals are used, returned to the environment, and used over again. Water is especially important. Your dog might live two or three weeks without food, but he would die in a few days without water. Living things are made up of about 70 per-cent water, and they need to maintain that level. Many substances in nature dissolve in water. Blood and the sap of trees are mostly water. Many organisms are born in or live in water all their lives. Are you and your dog different from the water and rocks? To be considered alive, an organism must have certain features. It must be made of cells, use energy, be able to move, respond, adjust, reproduce, grow and develop, and adapt. Organisms need energy, water, and oxygen. Do rocks and water have these properties?