Biology

A Computer and a Tree

The biggest difference between a computer and a tree is that a tree is a living organism, while a computer may seem alive at some times, but it is really an inanimate object. It does not reproduce, and it does not go dormant in the fall, as many deciduous trees do. Trees also support other life, such as birds, insects, plants or fungus (like mistletoe), and create an ecosystem around them that is disturbed if the tree disappears. Trees might not seem as complex as computers, but they are made up of millions of cells and fibers that create a hard bark on the outside, and a fibrous interior that draws in water and nutrients and sends them out to all parts of the tree, including the branches and leaves. It is a pretty complex organism, and we as humans would be hard pressed to create such a complex "machine" with such a pleasing exterior. Computers are extremely complex, and are probably more complex than trees, but they are manufactured complexity by humans, not natural, and so they differ from the complex and sometimes mysterious complexity of the natural world. Computers do not have any of the five levels of organization of life, so they cannot be "alive" even though they react to our input.

There are five levels in the organization of life. The first is cells, which are the basic structural unit in all living things. Cells can be very different, such as blood cells, bone cells, skin cells, etc. Next is tissue and all living things have tissue, too. Tissue is made up of cells that are alike, like bone tissue and muscle tissue. Third are organs, and they are a vital part of the organization of life. They give life to many objects, and are made up of groups of tissues that work together, like the heart, the lungs, the liver, and so on. Fourth are organ systems, which are made up of groups of two or more tissues. Examples of these include digestive, circulatory, skeletal, reproductive, etc. Finally are the organisms. These are fully alive and can grow, reproduce, take in food and excrete it, etc. They are usually made up of organ systems, but they can be single celled.