biology and properties of living organisms.

living world

7. ह!रन/ व!ल* क! भ" अपन! ?तब! ह*त! ह0,
मल!ल व* कर/ ज* द+ड़ मE श!gमल नह# थ/।

8. How can we define
‘Life’?

9. What is Life?
It is unique, complex organisation of molecules that
expresses itself through chemical reactions which lead to:
Growth
Development
Responsiveness
Adaptation
Reproduction

10. Characteristics of Living Beings
Growth
Development
Responsiveness
Adaptation
Reproduction

11. Growth
This occurs by cell division
Growth is the increase in size, mass or height and number (in case of
unicellular organisms) of an individual

12. Growth
Indefinite Definite
Growth
●Indefinite growth: Growth continues throughout life
●Definite growth: Growth stops once a genetically
pre-determined structure has completely formed

13. Growth
Intrinsic Extrinsic
Growth
Intrinsic growth is the growth
that takes place inside the
body of the living organisms.
Extrinsic growth is
exhibited by non-living
matter.
Growth is a characteristic but NOT
a defining property of living beings

14. Growth V/s Development
●Permanent and irreversible
change
●May occur in a cell, an organ or a
whole organism
●Change in:
○Size
○Dry weight
○Mass
○Number
●Development is the sum total of
changes that occur in an organ or
organism during its lifetime
Growth Development

15. Growth V/s Development
●Three processes are involved in growth:
○Cell division
○Cell enlargement
○Secretion of apoplasmic substances

16. What’s common in these pictures?

17. Reproduction
●Formation of new individuals of a similar kind

●Distinguishes living from non-living

●Not essential for the survival of individuals, but
important for the continuity of the species.

18. Reproduction
Asexual Sexual
Reproduction

19. Reproduction
Asexual Sexual
Reproduction
●Does not involve fusion
of gametes
●Offspring identical to
parents
●Involves fusion of
gametes
●Offspring varies
genetically from parents

20. Do all living organisms
reproduce?

21. Reproduction
●Unicellular organisms reproduction is synonymous
with growth, i.e. increase in number of cells.
●Not very clear with the usage of terms- growth and
reproduction

22. Reproduction
Many organisms like mules, sterile worker bees,
infertile human couples do not reproduce.
Reproduction is not an all-inclusive
defining feature of life

23. Metabolism
•Metabolism is the sum total of all the biochemical reactions
occurring in our body.
Catabolism Anabolism
Metabolism is a defining property
of living beings

24. Metabolism
Anabolism
●Constructive metabolism
●Includes all the building up reactions
●Involves synthesis of complex substances
●E.g: Photosynthesis
O
2
CO
2
Water

Sugar

Chlorophyll

25. Metabolism
Catabolism
●Destructive metabolism
●Includes all the breakdown reactions
●Involves breakdown of complex substances
●E.g: Respiration, digestion

26. Cellular Organisation
●Organelles interact with each other for the
proper functioning of the cell.
●Due to presence of organellar and cellular
organisation, a living being is called organism.
●Cellular organisation is a defining property of
living beings

27. Consciousness
•Consciousness is awareness of the surroundings
and response to external stimuli.

28. Consciousness
●Stimuli are perceived by sense organs
●The visible change or reaction that an organism produces
as a result of applied stimulus is called response
Consciousness is a defining
property of living beings

29. Did You Know?
Human beings are
the only organisms
that have
self-consciousness.

30. A person in
coma is
living or
non-living?

31. Consciousness
●The patient has no self-consciousness and is
supported by machines.
● It is difficult to define the living state in such cases
as non-living or living, because they show features
of both!
Living and
non-living too!!

32. Our Living World is
Very Diverse!

33. Diversity of Living World


1.7 to 1.8 million living organisms have been
discovered so far

About 1.25 million species of animals and 0.55
million species of plants have been studied,
described and named for identification

34. Introduction to
Nomenclature

35. The process of naming of a particular
organism such that it is known by the
same name all over the world
Nomenclature

36. Monomial Nomenclature
One word to name organisms
Cons: Difficult to use unique names as more
and more organisms were discovered

37. Trinomial Nomenclature
Recognise subspecies within a species
Each name has three parts
oFirst part: Genus
oSecond part: Species
oThird part: Subspecies
Cons: Discarded for lack of justification for
sub speciation
Corvus splendens splendens
(Indian crow)

38. Polynomial Nomenclature
Example: Ranunculus calycibus
retroflexis pedunculis falcatis
caule erecto folius compositis
System of nomenclature involving more than two names
Cons:
oPolynomials were not standardized
oDifferent polynomials existed for the same plant
oCumbersome to remember

39. Binomial Nomenclature
Proposed by Carolus Linnaeus in his book Systema
Naturae and Species Plantarum
Carolus Linnaeus

40. Binomial Nomenclature
Two terms are used to name a living organism
oGeneric name
oSpecific epithet

Eg: Pisum sativum (Pea)
Generic
name
Specific
name

41. Binomial Nomenclature
Significance of Nomenclature


Ensures that each organism has only
one name
Description of any organism enables
people to arrive at the same name

42. Rules of
Nomenclature

43. Rules of Nomenclature


Generally written in Latin
First word: Represents the genus
oStarts with a capital letter
Second component: Specific epithet
oStarts with a small letter
When handwritten: Separately underlined
When printed: In italics

44. Rules of Nomenclature


Name of the author appears after the specific
epithet, i.e., and is written in an abbreviated form
E.g., Mangifera indica Linn. It indicates that this
species was first described by Linnaeus.

45. Did You Know?
Animal species having the same name for both
genus and species are known as tautonyms
Eurasian eagle owl
Bubo bubo
European grass snake
Natrix natrix

46. Various Rulebooks for
Different Organisms

47. ❑International Code for Botanical
Nomenclature (ICBN)
❑International Code of Zoological
Nomenclature (ICZN)
❑International Code of Viral
Nomenclature (ICVN)
❑International Code of Bacteriological
Nomenclature (IC Bac N)
❑International Code of Nomenclature
for Cultivated Plants (ICNCP)
Various Rulebooks for Different Organisms

49. Keep Learning!