Saturday, August 20, 2011

DIFFERENCE BETWEEN TWO CATEGORIES LIVING OBJECTS [ANIMALS vsPLANTS]

Most living object can be assigned  to one of the  two great  categories  of plants  and animals  but some microscopically  small living objects  have characteristics of both .Plants and animals have common ,to a greater or lesser extent  almost all character of the living  objects  but there  are some fundamental differences  between them .These  include the following ;                                                                                                                         [1] Method of feeding ; Animals take food in   that is chemically complex [i.e., composed of macro molecules ]. It consists  either of plant  products  or of animals  that feed  on plants .Thus , they are hetrotrophs . The complex food is reduced  to simpler  material by the process  of digestion , and in this form it  is taken  up by the body .On the   contrary , plants  take in  very simple  substances as food which  consists of simple  molecules ,namelyCO2, from the air ,and water  and mineral from the soil .In their leaves ,they combine CO2,and water to form a simple sugar , the glucose using energy of the sun  to affect the change ,a process called photosynthesis .From the glucose so formed and mineral salts  absorbed from the soil  ,green plants  make any  of the substances  needed for their existence .Obviosly plants are  autotrophs  and they  do not  depend on any source  for their  food .                                                                                                        [2] Chlorophyll .The green color  of the plants is due to the presence of compound  called chlorophyll ,which is not present in animals .The chlorophyll is important   in absorption of the  solar energy , and its presence  in animals  .The chlorophyll  is important  in absorption  of the solar energy, and its presence  indicates fundamental  difference between  nourishing process of plant and animals  .However ,fungi and most bacteria  lack chlorophyll  and therefore , must obtain both  their  nourishment and their energy  from the food they consume , much as animals do .[3] Cellulose.A considerable proportion of the plant body   is composed of a complex  polysaccharide  called cellulse .It is not present in animals .                                                           [4] Movement .Most of the  animalos  can move their whole body ,and are able to change place .On the contrary ,most plants  cannot move their whole body , for example ,opening and closing of    petals   of certain flowers  ,and movement   of parts due to the growth .However ,microscopic plants move as  freely as microscopic animals .[5] Growth .The animals  grow  only upto a certain  age  after which they donot grow till  death.Their body  body parts  proportionately  in all directions .On the  contrary ,plants grow  through out life and their growth is   terminal ,i.e.,  they grow more along their length  than width .                                                [6] Organisation of body .In animals , parts are  mostly  placed in the body  , whereas  in plants , the parts are  mostly placed  on the surface of the body .                                                                                             [7] Receptors . The receptors are unique  to animals ; they recieve stimuli  and keep animals  informed about the environmental  changes , but  in contrast with the animals ,the  plants lack receptors .                              [8]  Excretion . Animals  remove out  toxic wastes of their body  but this doesnot takes place  plants .                                                                                                          

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