Ch: 1 The Living world

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 Ch: 1 The Living world

  • Ernst Mayr:

  1. The “Darwin of 20th century”
  2. Biological concepts of species 

Main characteristics of living:-

  1. Growth.                            (Not defining property)
  2. Reproduction                   (Not defining property)
  3. Metabolism                      (Defining property)
  4. Cellular organisation       (Defining property)
  5. Consciousness                 (Defining property)

1.Growth (irreversible,permanent)

  • Twin character (increase in mass+ increase in number)
  • Multicellular/Unicellular => Cell division ( vitro-culture )
                 1. Indeterminate (Unlimited) - Plants
                 2. Determinate (Limited) - Animals 
                 3. Intrinsic - Living 
                 4.Extrinsic- Non living   For Eg: Accretion of mountain ; Boulders ; Sand-mounds 

Note:   

1.Higher plants => [ Growth ; Reproduction ] Mutually exclusive 
2.Unicellular organisms (amoeba;Bacteria) =>[ Growth;Reproduction] synonymous 

2.Reproduction (2 Types : (i) Asexual (ii)Sexual)

Methods :

  1. Fungi & Algae - Asexual spores
  2. Yeast & Hydra - Budding 
  3. Fungi,Filamentous algae & Protonema of mosses - Fragmentation 
  4. Planaria - True Regeneration
  • Living organisms which donot reproduce:- mules; sterile worker bees ; infertile human couples

3.Metabolism ( Anabolism + catabolism) = sum total of all chemical reactions 

  1. Anabolism (eg. photosynthesis)
  2. Catabolism (eg.Respiration)

4.Cellular organisation ( cells and their products)

  • Cell —>Tissue ––> Organ —> Organ system —> Organism

5.Cosiousness ( Unexpectionally Distinguished)

  • Most obvious and technically complicated feature
  • Plant respond to external factors like organisms ,light , temperature , water & pollutants
  • Human beings self-conscious on the top level
  • Photoperiod affects reproduction in seasonal breeders (plants & animals)
Molecule —> cellular organelles—> cell —> Tissue—> organ —> organ system 

Taxonomy father : carolus Linnaeus (1.7 -1.8 million)

(I) Identification ( General characters)
(II)Nomenclature (Naming)
(III)Classification ( Grouping)

*ICBN - International code of botanical nomenclature
*ICZN - International code of Zoological nomenclature

1.Identification 
  • Systematics ( Gk. Word = “systema” means = “systematic arrangement of organism” ) given by carolus Linnaeus in his books ( 1.Book ( Animals ) = systema nature ; 2.Book (Plants) = systema plantarum)
  • Biosystematics = External and internal characters ( cytological, Histological , chemotaxonomy) . It is based on in embryo development and environment characters. It is also called neo systematics. It is given by julin huxely.
2.Nomenclature 
  • Given by carlous Linnaeus 
  • It is many types :-    1.Binomial ( two names - Genus species)               2.Trinomial ( three names - Genus species subspecies ). 
  • Eg :- Mango ( Magnifera indica linn. )

  • Universal Rules :-
  1. Biological Names => Latin ( written in italics )
  2. 1st word = Generic epithet; 2nd word = specific epithet 
  3. Handwritten = Underlined ; Print v italics 
  4. 1st word = capital ; 2nd word = small 
  5. Scientist Name = Just after specific epithet 

3.Classification 

  • Mainly two types :-
(A) Artificial 

  • Given by Linnaeus 
  • Based on mainly by their floral characters ( stamen & carpel )
(B) Natural
  • Given by  Bentham & Hooker
  • Based on compeltely on external characters and phylogenetic relationships.
Taxonomic categories :-
           Taxonomic hireachy                                  Example 
               [ Rank / Level]
  1.     Kingdom.                                                 Animalia
  2.     Phylum/ Division                                     Chordata 
  3.     Class.                                                        Mammalia
  4.      Order.                                                       Primata 
  5.       Family                                                     Hominidae 
  6.       Genus.                                                      Homo
  7.       Species.                                                    Sapines

  1. Species
  • Fundamental similarities ( interbreeding )
  • Basic unit of classification
  • Morphological differences 
   2.  Genus
     * Group of related species
     * characters agitation starts from genus

   3. Family 
      * vegetative and reproductive features in plants
   4. Order
   5. Class
   6. Phylum
    7. Kingdom 



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