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Characteristics of Living Organisms

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CHARACTERSTICS  OF  LIVING  ORGANISMS

The living things show a number of characteristic by which they can be recognized easily. The properties shown by living organisms are grouped into two categories, general properties and the defining properties. The general characters mean they may be shown by non living things also. The defining property means it is exhibited by living beings only.

Following are major characteristics of living organisms:-

DEFINITE SHAPE AND SIZE: Every living being has a definite shape and size. eg .man, dog, fish, mango tree, maize, all have a definite shape.

GROWTH: All living beings grow. It is defined as irreversible increase in mass and volume.It is internal in organisms. Non living things also grow but their growth is external and not metabolic.

CELLULAR ORGANIZATION: All living things are made up of cells. They may be single cellular or multicellular but cell is the structural and functional unit of life.

METABOLISM: It is the defining property of all the living organisms. The sum total of the biological reactions occurring in the body of living beings is called metabolism. It may be anabolic,(constructive), or catabolic, (Destructive).
Metabolism= Anabolism + catabolism.

CONSCIOUSNESS: It is the ability of living organisms to sense their environment. They react to physical, chemical or biological changes. These changes which force living things to respond, are called stimuli and the reaction of the organism is called response. The whole  phenomenon is called responsiveness.

HOMEOSTASIS: All living organisms have the ability to maintain a favourable internal environment in spite of the changes in their outside environment. This property is called homeostasis. It is the defining property of living beings.

PROTOPLASM: It is the semitransparent jelly like, viscous, semi fluid organic material present in all living components of organisms.

REPRODUCTION: It is the ability of all living organisms to produce new young ones of their own kind. It is called reproduction. But it can’t be the defining property of organisms as there are some organisms which are infertile and can’t reproduce.

LIFE SPAN: The period from the formation (birth, germination, origin etc.) of living organisms till their natural death or end is called life span. Every living organism has a definite life span.

GENETIC MATERIAL: All living things have genetic material (RNA or DNA) by which they transmit their characteristics to their offspring.


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