INTRODUCTION TO BIOLOGY

Biology is the science of life.

WHAT IS LIFE?

Life is an emergent property of matter.

This requires a little more elaboration. Defining life in a scientific and objective way has always been a great challenge for biologists. It is very easy for us to distinguish the living from the non living on the basis of certain characteristics but when it comes to defining life, the exceptions ruin every such attempt. What is life? Even a small child realizes that a dog or a plant is alive, while a rock or a lawn mower is not. Yet the phenomenon we call life defies a simple, one-sentence definition. We recognize life by what living things do.

Currently the most uncontroversial and most widely accepted definition of life comes from the discipline of systems biology.

Systems biology is the science of study of biological systems. In the 20th century the discovery of DNA and the beginning of the era of molecular biology made 'zooming in' to a cell the paradigm of biological sciences. Any and every research in branch of biology now mandated an explanation at the molecular level. In the midst of the volumes of data thus generated, some new disciplines arose. The discipline of bioinformatics involved the usage of computer algorithms for storing, processing and interpreting all the data thus generated. At the same time the discipline of systems biology followed a direction of inquiry exactly opposite to that of molecular biology, i.e. rather than zooming into the single biological system of the cell, systems biologists 'zoomed out' and took a look at how biological systems performed in their totality and how they interacted with other biological systems and used mathematical modeling to scientifically study such patterns.

Systems biology is an approach that attempts to model the dynamic behavior of whole biological systems based on a study of the interactions among the system’s parts. Successful models enable biologists to predict how a change in one or more variables will affect other components and the whole system.

The "grades of organization" is an age old concept in biology but systems biology gave it an impetus and elaboration that it truly deserves. The combinations of laws of physics and mathematics with the biological phenomena made systems biologists see life from a very different perspective. In mathematics "the chaos theory" deals studies the behavior of dynamic systems that are very sensitive to initial conditions (a response popularly referred to as "the butterfly effect”; you can watch the Hollywood movie with the same name; good movie!) In layman's terms, the theory states inter se that beginning with existence of a single entity, qualitative or quantitative multiplicity follows it. This multiplicity eventually leads to a chaotic situation in which, with passage of time, self organization emerges. This self organization thus creates a new system that becomes a singularity for the next level of self organization and the process keeps repeating.

Perhaps one of the best examples of this can be found in the originally biological idea of the grades of organization. As a student of biology you must be aware that cell is the basic structural and functional unit of life. Many cells of the same type become a tissue, many tissues form an organ, different organs together form an organ system and various organ systems work together to form an organism or a living individual. One can go further ahead "up" this ladder and say, many individuals of the same species in a given geographical area form a population, many different populations of the area together constitute a biotic community, Biotic communities coupled with environmental conditions become an ecosystem, many ecosystems become a biome and many biomes become the biosphere.

NEW PROPERTIES EMERGE AT EACH LEVEL OF BIOLOGICAL ORGANIZATION

However, it should be noted here that every entity, each rung of this ladder, is an independent self sustaining system in itself; cells, tissues, organs, organ systems, individuals, populations, communities, etc. another noticeable point here is that at every level, there are new properties acquired that emerge only when the components of the systems come together. Systems biology mandates that whenever a system is born its properties would be more than the arithmetic sum of the properties of its individual components, i.e. NEW properties would EMERGE that only the system would be having as a whole while any of its individual components would lack that property.

Life is today considered to be one such emergent property that arises when matter, as macromolecules, organizes itself as a system, a living system, a cell.