Characteristic of living being:
๐Growth is fundamental characteristic of all living organisms.
๐It is regarded as an intrinsic property of living organism through which they can increase both in mass and in number of cells in their body.
๐ All living organism whether unicellular or multicellular grows by cell division.
๐ The pattern and duration of growth is distinct in different organisms.
๐ In unicellular organism like bacteria, amoeba, growth, occurs by cell division also leads to the growth of their population.
๐Growth and reproduction are mutually inclusive event in unicellular organisms.
๐In higher animals and plants growth and reproduction are linked but are mutually exclusive events.
๐Also during maintenance to replace lost cells due to some injury etc from the body.
๐To maintain original size shape and structure of a body new cells are formed by division in various living beings.
๐Growth involves both increase in mass and number of cells which take place from inside the body of living organism and is irreversible.
๐On the other hand non-living object can also be seen growing link snow mountain grow by addition of snow them, crystal increase in size by addition of molecule.
๐Non- living objects growth is extrinsic as compared to intrinsic growth in living organism.
๐Non- living objects can increase their mass by accumulation of material on surface by any external agency which can be reserved.
๐Growth, therefore cannot be taken has defining property of living organisms through it takes place in all living organism and is absent in dead organisms.
Reproduction
reproduction is one of the fundamental characteristics living organisms.
It can be defined as the production of new individuals of same kind by the grown up individuals.
It is the characteristic exhibits the living organisms which can produce new young ones of their own kind.
They are two modes of reproduction.
(1) Asexual reproduction
(2) Sexual reproduction
Asexual reproduction:-
๐ In asexual mode, new individuals are produced from specialised or any unispecialised part of single parent (therefore with or without the involvement of gamete formation)
๐ For instance, unicellular organism like bacteria, algae and amoeba divide by fission to produce new individuals.
๐ In such processes parent body undergoes division to from two or more individuals that is number of cells increases.
๐ Unicellular organisms reproduction is synonymous with growth.
๐ These buds first grows on parent's body and then separates from it, to rise arise new individuals.
๐ It is also quite common in filamentous alagae, fungus, bryophytes ( at protonema stage which occurs during life cycle in Moses.)
๐ Planaria (flatworm)exhibits an extraordinary ability to regenerate it's lost body parts completely (which is known as true regeneration.)
๐ This is a method of reproduction as new Planarians develop by splitting of parent Planarian body either lengthwise or transversely.
Sexual reproduction
๐ In higher organism like plant, animals sexual mode of reproduction is quite common which involves formation of gametes (that is sex cells) from two parents of opposite sex but same species.
๐ This gametes that fuse to form zygote (2n) which developes to form a new origin of same kind.
๐ Reproduction is shown by all living organism except a few which are either sterile aur infertile like mules, work-bees infertile human couples, etc do not reproduce at all.
๐ Reproduction can be regarded as characteristic of living organisms but it is not their exclusive defining characteristic.
Metabolism:-
๐ The sum total of all the chemical reactions occurring in the body of living organism is known as metabolism.
Anabolism
๐ The metabolic processes which involves the synthesis molecules are called anabolism.
๐ Example:- synthesis of protein from amino acid.
Catabolism
๐ Large molecules are broken down into small are known as catabolism.
๐ Example:- sugar broken down into molecules of water and carbon dioxide to liberate energy that is ATP( Adenosine triphosphate).
Metabolism
๐ On the other hand non- living objects do not show metabolism so metabolism can be regarded as defining feature of all living organisms.
๐ The way cell performs on its functions or process to organise or constitute the body of an organism ( cellular organisation) is unique and that can be regarded as defining feature of all life forms.
