I. Photosynthetic organisms are those that convert the sun's energy through a process called photosynthesis. They are also called autotrophs. These organisms include plants, algae, and some bacteria. These organisms absorb energy from the sun and water. They then complete the stages of photosynthesis and produce oxygen and glucose. All living organisms on earth require oxygen to survive. Plants provide a continuous supply of oxygen to these organisms. Without plants, there would be fewer oxygen molecules present in the atmosphere, creating a potential threat to organisms that require oxygen.a. Photosynthetic organisms use their internal composition to carry out the process of photosynthesis. Their composition is different from that of organisms such as animals. Plant and algae cells contain chloroplasts where photosynthesis occurs. The light reactions of photosynthesis drive the transformation of solar energy into ATP. The chloroplasts of plants contain pigment molecules (chlorophyll) which have the task of capturing light from algae. The way to get the most energy from algae would be to eat it directly. If the algae had been given to the cow first, the energy would have also been consumed by the cow. The energy produced by the algae would then be used directly by the cow's cells. It would use energy to carry out its daily functions just like a human would. This means that when humans were to consume the cow, there would be no energy left from the algae. When referring to the pyramid of life, you can see that the sun has more energy. This is why photosynthetic organisms are next in the pyramid. They get energy directly from the sun while other organisms have to get energy from other resources. If instead man ate algae, he would obtain a greater quantity of energy. This is because, according to the pyramid, plants have a greater amount of stored energy than cows, also called cows