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CHAPTER-1, LIVING WORLD, ,  Life can be defined as unique complex organization of molecules expressing itself through, chemical reactions which lead to growth, development, responsiveness, adaptation and, reproduction,  Viruses are nonliving lifeless particle outside the living organism but become active (living), inside the cells of living beings ., CHARACTERISTICS OF LIVING BEINGS, 1.GROWTH, ,  Increase in mass and increase in number of individuals are twin characteristics of growth.,  In plants, this growth n occurs continuously throughout their life span.,  In animals, this growth is seen only up to a certain age. However, cell division occurs in, certain tissues to replace lost cells.,  Unicellular organisms also grow by cell division (increase in number).,  Increase in body mass is considered as growth.,  Non-living objects also grow if we take increase in body mass as a criterion for growth.,  Mountains, boulders and sand mounds do grow.,  Growth, therefore, cannot be taken as a defining property of living organisms.,  A dead organism does not grow., 2. REPRODUCTION, ,  Reproduction refers to the production of progeny possessing features more or less similar to, those of parents.,  Fungi multiply and spread easily due to the millions of asexual spores they produce.,  In lower organisms like yeast and hydra, we observe budding.,  In Planaria (flat worms), we observe true regeneration, i.e., a fragmented organism, regenerates the lost part of its body and becomes, a new organism.,  The fungi, the filamentous algae, the protonema of mosses, all easily multiply by, fragmentation.,  There are many organisms which do not reproduce (mules, sterile worker bees, infertile, human couples, etc).,  Hence, reproduction also cannot be a defining characteristic of living organisms.

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 No non-living object is capable of reproducing or replicating by itself, 3.METABOLISM, ,  The sum total of all the chemical reactions occurring in our body is metabolism No nonliving object exhibits metabolism,  Metabolisms is a defining feature of all living organism .,  It consists of anabolism and catabolism., ANABOLISM, , CATABOLISM, , Synthesis process, , Breakdown process, , Energy consumed, , Energy released, , 4. CELLULAR ORGANIZATION, ,  All organisms consist of one or more cells.,  Cells-tissues-organs-organ system-organism,  It is a defining property., 5. CONSCIOUSNESS, ,  All organism from prokaryote to eukaryotes can sense and respond to environmental, changes.,  Human being is the only organism who is aware of himself ie: Self Consciousness.,  We sense our environment through sense organs.,  All organisms therefore, are ‘aware’ of their surroundings.,  It is a defining property., 6.ADAPTATION, ,  It is the ability to adjust(adapt) with our surroundings.,  It is a defining property., There for Defining property of living organisms are Metabolism, cellular organization of the, body, Consciousness