Life: Eating and Being
Life forms can be found that are made up of only one cell or millions of cells. Millions of years ago, life consisted mostly of one-celled organisms, but over time a myriad of bigger and more complex organisms emerged.
Single-cell organisms like bacteria are very efficient at surviving in very specific environments and sometimes even very harsh environments! More complex organisms need more energy but are also more able to move and interact with their environment and seek food and comfort, with more specialized ways of protecting themselves or muscles and legs that allow them to move greater distances with greater control.
Life has evolved over millions of years, taking a myriad of shapes and forms, from one-cell organisms like bacteria to organisms with millions and millions of cells, like human beings! But in every size, shape and form, Life is always in a constant balancing act of getting food for energy and protecting ourselves from things that might disrupt and infect our bodies. These basic needs give rise to the most fundamental processes in our bodies: metabolism and the immune system!
All organisms, no matter how big or small, and all the cells that compose them, need energy to survive. Metabolism is the process through which a life form gets energy from its environment and uses it to live. Metabolism includes eating food, breaking it down into nutrients, getting the nutrients to each cell of the body and each cell’s processes that utilizes this food energy.
The immune system is not a simple organ or a simple function. It is a constellation of cells and tissues that work together in the challenging task of identifying what belongs to the body (the self) from those that may be harmful- like old, dead cells or outsider particles like some kinds of bacteria, viruses. Our immune systems have to be very intelligent to deal with the magnificent variety of unknowns in the world.
Metabolism and the immune system share a common purpose, somehow they must swallow other particles, one for energy, one to stop a harmful invader. Discover the role of the swallowing cells in both >>