1.1 Introduction to Energy and Matter

We live on a planet bathed in sunlight, our primary source of energy. From this source, all of life has arisen. The cells that make up all organisms from single-celled bacteria to meter tall trees and blue whales require two fundamental things in order to make up the diversity of life all around us, energy and matter.

Figure 1.1. An energy pyramid is a presentation of the trophic levels in an ecosystem. Energy from the sun is transferred through the ecosystem by passing through various trophic levels. Roughly 10% of the energy ass transferred from one trophic level to the next, thus preventing a large amounts of trophic levels. There must be higher amounts of biomass at the bottom of the pyramid to support the energy and biomass requirements of the higher trophic levels. [Image description]

Organisms need to acquire new matter if they are to grow and reproduce. Matter comes in the form of nutrients that make up all of the molecules that are required for life. These nutrients can be found in the atmosphere, in the soil and in other organisms. They in turn are made up of the fundamental elements of life, which are transformed from one form to another through chemical reactions. In the following chapters, you will learn about these fundamental elements, how they are taken up by cells and organisms, and where we can find them in the molecules of life. You will also explore how the availability of these elements and their ability to move from one organism to another can shape the populations of animals, plants, fungi and bacteria that make up life on this planet. Importantly, matter is recycled from inorganic forms, to organic forms, and back again.

Organisms also need energy for maintenance, growth and reproduction. Energy too undergoes many transformations. These transformations require a coordinated dance between matter and energy. Sunlight can be captured into the chemical bonds of a sugar molecule. The energy held in a sugar molecule can be extracted to power much of the work of cells and organisms. Unlike matter, however, energy is not completely recycled. Much is lost as heat to the universe.

Underneath this process that dictates the composition of organisms in vastly different ecosystems across the planet, there are fundamental chemical, cellular and organismal processes that guide and control these transformations of energy and matter. We will explore these throughout BIOL1A and in the first 12 chapters of this book ever mindful that what happens at a small scale has impacts on the larger scales.

Figure Descriptions

Figure 1.1. The image depicts an energy pyramid illustrating the flow of energy in an ecosystem. The pyramid has multiple levels, each representing a different trophic level. At the base is the “Primary Producers” level labeled 100%, shown in light blue; these organisms capture the Sun’s energy. Above them are the “Primary Consumers” labeled 10% in a darker blue, followed by “Secondary Consumers” at 1% and “Third Level Consumers” at 0.1%, each in progressively darker shades of blue. At the top of the pyramid are “Apex Predators” at 0.01%, in the darkest blue. To the right of the pyramid, green arrows labeled “Energy Lost As Heat” indicate energy loss at each level. To the left, an orange arrow leads to a hexagon labeled “Decomposers,” which arrows connect to each pyramid level, illustrating their role in breaking down materials. At the bottom right is a yellow circle symbolizing the “Sun’s Energy” with an arrow pointing to the base of the pyramid. [Return to Figure 1]