living world

• Growth

  Increase in the number of cells in a living organism (by cell division)
• Types of growth

  • Intrinsic Growth (Internal)
  • Extensive Growth (External)
• Examples of extensive growth

  • Mountain
  • Boulders
  • Sand
  • Mounds
• Extensive growth

  Growth by deposition & substances from outside
• Reproduction


  Production of progeny with features similar to parents
• Asexual reproduction


  Reproduction involving only one parent
• Sexual reproduction


  Reproduction involving fusion of gametes
• Somatic cell


  A cell that is not a gamete
• Zygote


  A fertilized egg cell
• characteristic:

  a character found in living organisms
• defining : a character found in all living organisms without an exception
• twin characters of growth are Increase in number and Increase in mass
• • living organisms are intrinsic growth
  • non living things are extrinsic growth
• vegetative propagation is asexual reproduction in plants

  examples : spore , fragmentation- fungi and lower plants

  budding in yeast and hydra

  true regeneration in planaria
• reproduction is synonymous with growth in unicellular organisms
• many organisma don't reproduce

  example- worker bee, infertile human couples
• • metabolism is sum total of all chemical reactions taking place in organism
  • it is defining property
  • all living organisms exhibit metabolism
• • cellular organization is defining property
  • isolated metabolic reactions in-vitro are not living things but surely living reactions
• consciousness:

  • defining property
  • it is the ability to sense their surroundings or environment and respond
  • both plant and animals - photoperiod ( duration of light) affects reproduction in seasonal breeds
  • human have self consciousness
• biodiversity:

  • 1.7 - 1.8 million species
  • binomial nomenclature given by carolus linnaeus in his book systema naturae
• ICBN = international code for botanical nomenclature
• ICZN = international code of zoological nomenclature
• identification :

  recognisation to identify of organism or essential characters of an organism
• classification :

  arrangement into family or group
• nomenclature:

  assignment of scientific names
• nomenclature rules :

  1. name has 2 components - genus first with capital letter and second species with small letter ; example : Magnifera indica linn
  2. written in Latin and printed in italics or separately underlined when hand written
  3. name of author at the end in abbreviation form
• systematic = taxonomy + phylogeny

  ( comparison between species their relationship)
• species :

  • concept of species given by Ernst mayer
  • group of potentially interbreeding population that are reproductively isolated from other such species
• Taxonomic Categories

  • Kingdom
  • Phylum/Division
  • Class
  • Order
  • Family
  • Genus
  • Species
• Taxonomic categories are arranged in a hierarchical structure from broad to specific