What is a Biological Model?

Image Credit: 
Main Image: 
Biological model.

The term “biological model” is used in many different ways. The meaning of the term is generally clear or inferred based on the context it is used in. Logically, a biological model is a mathematical model of a biological system, whereas term also refers to a specific organism which may be deliberated extensively with the aim of creating data which can be applied to other organisms. This term may also be used in reference to a meticulous theory about the genesis of mental illness and psychological distress which originated in the 19th century as perceptive of the brain advanced considerably.


What is a Biological (Medical) model?

The biological (medical) model emerged in the late nineteenth century with the discovery that brain damage could result in thought and mood disturbances and bizarre behavior. The model draws on an analogy between physical disease and mental illness. The Biological Model of Abnormality is based on the assumptions that if the brain, neuro- anatomy (the organs and processes of the nervous system) and related bio-chemicals (the study of chemical processes in living organisms) are all physical entities and work together to mediate psychological processes, then treating any mental abnormality must be physical/biological. Part of this theory stems from much research into the major neurotransmitter ( chemicals which transmit signals from a neuron to a target cell), Serotonin (contributor to feelings of well-being), which seems to show that major psychological illnesses such as bipolar disorder (is a psychiatric diagnosis that describes a category of mood disorders) and anorexia nervosa (eating disorder characterized by refusal to maintain a healthy body weight and an obsessive fear of gaining weight) are caused by abnormally reduced levels of Serotonin in the brain. The model also suggests that psychological illness could be treated like any physical illness and hence can be treated with surgery or drugs. Within medicine, each physical illness is generally characterized by a particular set of symptoms


What is a Mathematical Model?

In terms of a mathematical model, a biological model can be created to gain a deeper knowledge of an organism, an ecosystem, a genetic lineage, or a wide variety of other topics in biology. A mathematical model is a description of a system using mathematical language. The process of developing a mathematical model is termed mathematical modeling. Mathematical models are used not only in the natural sciences like physics, biology, earth science and engineering disciplines like computer science, but also in the social sciences such as economics, psychology, sociology. Mathematical model usually describes a system by a set of variables and a set of equations that establish relationships between the variables. The values of the variables can be practically anything; real or integer numbers, etc. Many physicists, engineers use mathematical models most widely. Some examples of mathematical models are as depicted below:

  • Population growth: A more practical and widely used population growth model is the logistic function, and its extensions. Logistic curve or logistic curve can model the common "S-shaped" curve of growth of some population.
  • Neighbor-sensing model: This model explains the mushroom formation from the initially chaotic fungal network.


What is a Model organism?

Model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the organism model will provide insight into the workings of other organism. In particular, model organisms are widely used to explore potential causes and treatments for human disease when human experimentation would be unfeasible or considered less ethical. Studying model organisms can be informative, but care must be taken when generalizing from one organism to another.


How Model organisms are chosen?

Frequently, model organisms are chosen on the basis that they are agreeable to experimental manipulation. This generally will include characteristics such as short life-cycle, techniques for genetic manipulation and non-specialist living requirements. Models are those organisms with a wealth of biological data that make them attractive to study as examples for other species – including humans – that are more difficult to study directly. These can be grouped as genetic models (with short generation times, such as the fruit fly).


What are the benefits of Model Organisms?

  • One of the first model systems for molecular biology was the bacterium Escherichia coli, a common constituent of the human digestive system. Several of the bacterial viruses that infect E. coli also have been very useful for the study of gene structure
  • Many yeasts, particularly ‘Saccharomyces cerevisiae’ ("budding" yeast), have been widely used in genetics and cell biology, widely as they are rapid and easy to grow. The cell cycle of a simple yeast is very similar to the cell cycle in humans.
  • The fruit fly ‘Drosophila melanogaster’ is studied, again, as it is easy to grow for an animal, has a giant chromosome in its salivary glands that can be examined under a light microscope.
External References
Related Videos: 
See video