Biology is the scientific study of life. As a whole it comprises a vast number of ways to look at life which usually corresponds to a particular discipline within biology, some break the living world into easier to conceive parts: cells, organisms, populations, communities, ecosystems, and even the entire biosphere. Others simply classify and describe life: morphology, phylogeny, and taxonomy. Still others will look for explanations behind biological processes: genetics, proteomics, and physiology. Newer disciplines due to the advent of faster computing intend to integrate all of these different aspects or at least a subset, and combine them to create a more holistic explanation of life, systems biology for example. Bioinformatics which tries to sift out new information from vast quantities of biological data is also a discipline that has benefited and one could argue, could only be possible, due to the improvements of computer technology. There is also what can be described as "applied" biology. Applied in the scientific sense means that it has some practical benefit. It differs from "pure" science in that pure science is concerned with knowledge only, not if that knowledge can be used for any practical benefit. Examples of applied biology would be medicine, bioremediation, conservation biology and genetic engineering.
History of biology
Historically the boundaries of what people have considered "life" have shifted. Typically they have expanded, as biologists discovered that tools originally designed to help us learn about the human body and obviously "living and active" creatures turn out to be useful in studying things that were once on the other side of the definition.
Once only creatures with the "breath of life" were considered alive. Even today, opinions differ on whether viruses are a form of life.
Roman law and other local taboos forbade dissection and autopsy of the human body, which long hindered understanding the human body.
While today it is relatively easy to examine the internal features of the human body, there are still parts that are difficult to understand (such as the brain), and there are still things that living humans do (such as circadian rhythms) that are difficult to localize to a particular part of the body.