Not All Living Things Show Characteristics of Life

No general full fledged definition for life has been articulated since time, but lists of properties have been suggested to discern ‘the inert/non-living’ from ‘the living’ of which a an organism has to posses in order for it to be considered as a living being. These include self organization or movement, growth, reproduction, inheritance, feeding, excretion, sensitivity and adaptation. Moreover, the question of what life is takes us back to evolution, that is, for an organism to be considered living, it has to be part of the fossil record. Even so, there are living organisms which do not show some of these characteristics of life.

According to Dirk and Irwin(2004), life qualifies by a collective presence of all the above stated set of characteristics. This is not necessarily correct because there are organisms which have characteristics substantial enough to qualify them as living organisms although they may lack one or two of the latter stated characteristics, hence it would be irrational to categorise them as non-living.

All living organisms are able to move in one way or another (Cole M. 2008). Living things move in a directed and controlled way, they move of their own accord as compared to the inert which move only when pushed by external forces. Animals have special organs for movement e.g legs, wings, head etc known as locomotory organs. Plants on the other hand do not show obvious signs of voluntary movement as animals do, but as a matter of fact they do move physically and voluntarily through the different types of tropisms which result from the action of auxins in response to stimuli. The point made by Cole M. (2008) that all living things move one way or another, is not entirely correct because there are living organisms which can not move, for example, bacteria without flagella. These types of bacteria have no means of movement other than those induced onto them by external forces. Other examples of a living organism which does not experience physical movement is a chorals and moulds. Chorals do not move for the rest of their lives, they develop from where their spores were dropped and grow without moving, moulds also don’t move, they simply replicate on their host as they feed on it.

According to Andrew P. and McCay J. (2005) ,from the theory of evolution, all living organisms at the present time are descendents of historic organisms which started off as unicellular organisms and evolved with time to those we see today. This shows that all living organisms posses the characteristic of adaptation through which they have managed to survive changing climatic conditions through time. All living things therefore respond and adapt to changes in their environment, plants and animals end up developing certain characteristics which fortify them against any changes which pose danger to their lives such that they end up managing to survive in that particular environment.

Another characteristic which not all living things undergo or portray is reproduction. This is the procreation of offspring. It is a fundamental law of nature that living things can only be reproduced by other living things. Sterile organisms (those that can not reproduce) and plant seeds with completely dormant metabolism are included in the class of living organisms. Mules are a hybrids off springs of donkeys and horses. They can not reproduce nor do they have gender because of their genetic makeup. This is because they have peculiar numbers of chromosomes which make it impossible for them to reproduce, this however does not classify them as non living simply because they possess other vital characteristics of life and have a fossil record (Erasmus D. 2000).

All living things feed, that is they ingest material from which they obtain energy for growth, reproduction, respiration and movement. Plants devise their own food using chlorophyll in their leaves,hence are referred to as autotrophs. Animals are heterotrophic because they depend on plants for food. All organisms also undergo chemical changes within their bodies which are vital for sustaining their life, the same goes for homeostasis which refers to the ability to maintain a constant internal environment for succession of life. Growth is another characteristic which all living things undergo. Animals usually grow until they reach maturity while most plants continue to grow infinitely throughout their life span (Cole M. 2008). Additionally, all organisms excrete, that is they remove unused substances from their bodies or those that may be toxic to their bodies. This is ensured for example through egestion, respiration(release of carbondioxide), urination and sweating.

Finally, it can be concluded that indeed there are living things which do not show some of the characteristics of life, but still have to be categorized as living things for the logic reason that they exude many other obvious characteristics of life.

REFERENCES

Andrew P., McCay J.(2005), New directions in ecology and ecological anthropology, Rutgers ltd. Publishers, New Jersey

Cole M. (2008),Explore science 2nd edition, Pearson publishers, South Asia

Dirk S. and Irwin L(2004), life in the universe, Volume 3, Springer publishers, pg 33

Erasmus D. (2000),Controversies, USA,Volume 77, pg 470

References: Andrew P., McCay J.(2005), New directions in ecology and ecological anthropology, Rutgers ltd. Publishers, New Jersey Cole M. (2008),Explore science 2nd edition, Pearson publishers, South Asia Dirk S. and Irwin L(2004), life in the universe, Volume 3, Springer publishers, pg 33 Erasmus D. (2000),Controversies, USA,Volume 77, pg 470