Basic characteristics of life and living things


Living organisms exhibit cellular organization. They can grow, utilize energy, reproduce, pass traits to offspring's, evolve, adapt and respond to environment. Check out this article to know the basic characteristics of a life which helps to differentiate living organisms from non-living ones.

Introduction

Life itself is that one entity that separates or distinguishes living organisms from non-living ones. If something is said to be alive then it is self sustaining in nature. Living things include all those living organisms irrespective of whether they are present in visible world or in an invisible world. For example, humans, plants, animals and all those organisms seen by naked eyes, viruses, bacteria and other pathogens that cannot be seen by naked eyes etc are known to possess life.

Characteristics of life

It is not easy to differentiate living from dead or non-living things. There are certain rules which can be termed as characteristics which help greatly to differentiate life from other matter. An object cannot display just one characteristic to exhibit that it is living. To be considered alive, it needs to exhibit most of the characteristics of living things. All living things exhibit basic characteristics. Apart from basic characteristics, even many other characteristics are present which are actually species specific.

Some basic characteristics of life and living organisms

  • Living organisms exhibit cellular organization : Living organisms are composed of cells which are actually basic units of structure and function of all living forms. All living entities are composed of one or more cells. Organisms in which single cell is present are known as single-cell organisms and this single cell has capacity to carry out all the functions. Organisms in which many cells are present are called as multi-cellular organisms. In them, different groups of cells are assigned to carry out different functions. Living organisms organize cells at tissue and organ level. Cells which are alike combine and forms tissues which then form organs. A group of organs together performing common function forms organ system and in this way living organisms are formed. In absence of cells, living organisms will not be able to carry out basic functions necessary for sustaining life
  • Exhibit growth : Living organisms grow in size by using the energy present in organic molecules. Over time, they turn into more complex beings. Rate of anabolism is higher in their body when compared to catabolism. They simply do not keep on accumulating matter. Growth that takes place in them is even in all the parts of their body. All living organisms grow and develop i.e., over a period of time they seem to become bigger in size, shape and matter
  • Life reproduces : All living entities reproduce and give birth to offspring. Process of reproduction can be asexual or sexual. Asexual reproduction only requires a single parent to give birth to offspring and sexual reproduction is a process in which both parents need to copulate. This will combine male and female sex cells giving birth to young ones. There are many unicellular organisms which too undergoes the process of reproduction. In them, asexual reproduction takes place i.e., single cell present in them divides to form a daughter cell. Hereditary information is passed on to offspring. Only living organisms has this ability to give birth or reproduce and this trait is not displayed by non-living matter. Life creates more life i.e., more organisms like themselves. If a specie cannot reproduce then it is likely to become extinct in the coming years
  • Utilize energy : Living organisms make use of energy to grow and develop as well as for maintenance. They need energy to carry out their life functioning. No function can be carried out in absence of energy whether it is respiration, digestion, growth, repair or reproduction. Each and every living creature consumes energy in one or the other form from the environment. This energy which is absorbed from environment in the form of food gets metabolized which sustains survival. Metabolism allows living entities to maintain life. Anabolism converts chemicals into molecules whereas catabolism breaks molecules from organic matter into energy. Animals, plants, humans and all other living organisms undergo the process of metabolism on daily basis to utilize energy. Plants by the process of photosynthesis in the presence of sunlight convert the energy to derive all the essential nutrients. Animals and humans depend on other living organisms to derive the same energy
  • Homeostasis : All living organisms are required to maintain a stable internal environment inside body. This process itself is called as homeostasis which is essential to sustain life as it promotes cell metabolism. Stable internal environment means normal body functions and if by any chance disruption is caused in the internal environment then normal processes too get disrupted. Body itself maintains its homeostasis in a proper manner. Internal environment always remains stable despite of changing outer environment. For example, body maintains temperature of 37 degree Celsius. When temperature in outer environment drops or in case of sickness, body shivers. Movement in arms and legs create warmth and this increases internal temperature. During summers, body sweats to decrease body temperature. In this way, body maintains homeostasis
  • Living organisms evolve and adapt : All living organisms are able to evolve and adapt to the environment to sustain life. Non living entities do not display characteristics like evolution and adaptation. Process of adaptation allows living organisms to suit themselves in the prevailing environment. This sort of adaptation over a period of time will help them to evolve consequently. Evolution is nothing but a genetic change that can be minor or major, inherited over several generations. Adaptation is a process which helps a living organisms to adjust or adapt to the existing environment. Adaptations can be of any sort like bodily adaptation, mental adaptation or changes in the behavioral pattern. Adapting means to increase chances of surviving in the prevailing environment
  • Response to environment : Another important characteristic of life and living organism is that they respond to various stimuli in the environment. Response will surely get generated irrespective of whether stimuli may be heat, light, sound, cold, high temperature etc. This is not the case in non-living entities. For example, when we step on a stone, it does not respond but just imagine, stepping on a living creature. A living entity will respond to us in one or the other way as living organisms know what changes are taking place around them. Usually response is exhibited by some kind of movement. Response can be either a reaction to an internal stimuli or to an external stimuli. Trees shedding their leaves in the season of fall and sunflower tilting towards sun are both examples of response to stimuli. In case of unicellular organisms, response is displayed in the form of contraction that takes place. In case of multi-cellular organisms, complex reactions take place which usually involve all the senses
  • Living beings pass traits to offspring's : All living organisms pass hereditary traits to their offspring in the form of their genes. Genes contain DNA and these DNA are a bundle of information. We can often see living organisms exhibit certain characteristics or show certain behavioral patterns when disposed to certain situations and all this work is done by the genes which predispose organisms to behave in that manner. Heredity is a very important characteristic of living organisms because it helps them to evolve over a period of time as they possess sets of different characteristic from their parents. Genes are located on chromosomes and gene transmission form one generation to another itself will make sure that traits get inherited


Conclusion

Life is a complex process seen in living organisms. Non-living entity can simply be defined as a substance. However, life cannot be defined as a substance. It is difficult to define life because any definition made should be general enough to include all the lives existing on earth and thus life is considered to be a characteristic of something. An entity is considered to be living and can be different from those other non-living ones if it exhibits all or at least most of the characteristics like growth, adaptation, evolution, reproduction, maintaining homeostasis, cellular organization, utilizing energy in the form of metabolism etc. These characteristics together define life and living things as these physiological functions itself maintain and sustain life. They have underlying bases which are physical as well as chemical. Non-living organisms do not have such functions either because they never had them or else because such functions have stopped past death. Whatever may be the case, presence of these characteristics in organisms itself will clearly help to differentiate living from non-living organisms.


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