Biology - What is Life?

EncycloZine.com Life Biology : Biochemistry, Bioinformatics, Biophysics, Biotechnology, Cells, Human, Microbiology, Paleontology • Books, Posters

The science and study of life and of plant, animal, and other types of organisms. The science of life and living organisms, biology studies the form, structure, function, growth and development, behavior and interaction of all living things. Biologists study the characteristics of life forms, such as their cellular organization and development, how they respond to stimulation, the chemical processes of their growth and production of energy (metabolism) and how they reproduce. But the underlying question all biologists try to answer is, What is life?

Life is divided into levels of organization that help biologists see the big picture within the study of each organism. The organization goes from the tiniest part of the life form that can be studied, to the largest:

• Molecules, the smallest portion of compounded atoms or elements that carries the form's characteristics;
• Cells, the smallest unit of living tissue that can function as an independent entity (form of life);
• Tissues, which are made up of cells and other matter, are what animal and plant organ are made of;
• Organs, a structure of a plant or animal which performs a specific and essential function;
• Organ systems, a group of organs that work together to perform a function, such as the digestive system;
• Organisms, a living thing and/or its structure - a human being is a complex organism, so is a dog, a cat and a tree;
• Populations, the organisms living in a certain group or area, such as a city, a forest or a test tube. The basic disciplines of biology study life at one or more of these levels.

While people have always been interested in the study of life and used what they learned in their attempts at healing and in their religious rites (like the Egyptians' practice of embalming or trying to preserve the bodies of the dead), biology was confused with a lot of superstition and was sometimes considered magical. The study of biology as a science wasn’t really developed until the last few centuries BC.

During this time, Aristotle established the basic tools of biology, which are observation and analysis. Aristotle was responsible for the concept of classification, which separated the life forms and made it easier to study a certain branch or level of a life form. Still, his knowledge of all the different classifications of life was limited. From about the third century BC until the second century AD, biological studies were most concerned with agriculture and medicine and how biological discoveries could benefit the human condition.

In the 15th and 16th centuries, the European Renaissance brought rapid advancement in biology, as artists and scientists like Leonardo da Vinci and Andreas Vesalius studied human anatomy through cutting apart and studying dead bodies. Their studies resulted in improvements in medicine and marked the beginnings of the study of physiology, which concentrates on the functions of an organism.

The recognition of cells and molecules did not begin until years after the invention of the microscope, credited to Galileo Galilei around the year 1610. From explorations with the microscope came the discovery of bacteria and germs. Additional study led to the germ theory of disease in the late 1800s and the development of vaccines and antibiotics to control the spread of disease in the early 1900s.

Jan Ingenhousz, a Dutch-born British physician and scientist, is credited with the discovery of photosynthesis. Expanding upon the work of the English chemist Joseph Priestley, Ingenhousz found that light was necessary for plants to restore oxgyen to the air. He lived from 1730 to 1799.

Although the question, “What is life?” may never be fully answered, the study of biology has made many significant improvements to human life. The complexity of biology and its interconnection with other sciences will probably keep humans forever fascinated with the study of life.

Branches of Biology

Because there is such a huge variety of living things on the earth, the science of biology has many different branches and areas of study. Depending on their discipline, biologists usually research one or more of the following categories:

• Microbiology, a study dealing with the structure and existence of microorganisms, which are tiny life forms such as a bacteria or a virus;
• Zoology, which is the study of animal life;
• Botany, which is focused on plant life;
• And physical anthropology, where scientists study human life, such as our existence and how we interact with other life forms.

Biologists also use other sciences to research life. Without chemistry and physics, much of the knowledge we have gathered about life would have been impossible to collect.

In an effort to answer the “what is life” question, much of the history of biological study has been focused on trying to classify and define life forms. The four categories above led to the development of many subcategories as biologists learn more about the depth and complexity of living things. Some of the other subdivisions of biology are:-

Physiology

Study of the vital functions and basic activities of living organisms - cells, tissues, organs, and organ systems - and their parts, in relation to the whole.

Embryology

Study of the formation and development of organisms from the zygote, or fertilised egg. Confined mainly to multi-celled organisms.

Taxonomy

Hierarchical classification of natural organisms indicative of their structures and differences.

Genetics

Study of inheritance and variation in organisms, and mechanisms by which these operate; causes of similarities and differences among related individuals.

Ecology

Study of relationships between organisms and their environment; the interactions of individuals within groups and with their suroundings.

Morphology

The study of the shapes of plants and animals.

Molecular Biology

Study of chemical processes at the level of large organic molecules such as proteins and nucleic acids.

Biochemistry

Study of the chemical processes within living systems as a whole.

Microbiology

The study of micro-organisms - their structure, function, and significance.