Energy Flow Article.pdf

In 1868, the element helium was discovered by scientists observing the Sun with a spectroscope tool. Little did scientists know that they had stumbled upon the reaction that powers all life on Earth. In the Sun, hydrogen atoms fuse into helium atoms, producing tremendous energy. If it were not for t...

In 1868, the element helium was discovered by scientists observing the Sun with a spectroscope tool. Little did scientists know that they had stumbled upon the reaction that powers all life on Earth. In the Sun, hydrogen atoms fuse into helium atoms, producing tremendous energy. If it were not for this fusion, plants and the organisms that rely on them for food would not have enough energy to exist. Energy is defined as the power to do work. For living organisms, this work includes things like growing, moving, and responding to the environment. Every organism needs energy. Producers, also known as autotrophs, transform solar energy into food. Consumers, also known as heterotrophs, must consume other living things to obtain energy. Primary heterotrophs eat strictly plants, while secondary and tertiary heterotrophs hunt primary heterotrophs. Autotrophs, which include plants and algae, turn energy from the sun into food through the process of photosynthesis. In photosynthesis, the energy of sunlight is converted into chemical energy and stored as a simple sugar called glucose. Autotrophs break down some glucose to release the energy they need to stay alive. When heterotrophs eat autotrophs, the small amount of chemical energy that remained stored, about 10%, is passed to them. The heterotroph then breaks down some of that glucose to power their life functions, until they are consumed by another organism. Higher level heterotrophs get very little glucose from the heterotrophs below them. The flow of energy through an ecosystem can happen through many pathways. In a salt marsh ecosystem, for example, producers (autotrophs) like algae and phytoplankton both harness sunlight. Consumers (heterotrophs) like clams eat the phytoplankton, which passes the stored energy to the clams. Seagulls may eat the clams. Meanwhile, fish eat the algae, and when the fish dies, its energy goes to decomposers. Scientists use various models to show how energy passes through ecosystems. A food chain shows simple, direct connections, while food webs capture more complex paths of energy flow. Food webs show how many species connect through different feeding relationships. An energy pyramid can also represent how the energy released by the fusion of hydrogen atoms in the Sun passes from producers to consumers. © Kesler Science, 2020