NCERT BIOLOGY NOTES FOR NEET

  Topic Covered  ✏ 3.1 Algae  3.2 Bryophytes  3.3 Pteridophytes  3.4 Gymnosperms  3.5 Angiosperms Introduction Artificial systems ( earliest systems)  of classification Given by Linnaeus Used only gross superficial morphological characters such as habit, colour, number and shape of leaves, etc.  They were based mainly on vegetative characters or on the androecium structure.   Limitations They separated the closely related species since they were based on a few characteristics.  Gave equal weightage to vegetative and sexual characteristics ; this is not acceptable since we know that often the vegetative characters are more easily affected by environment.  Natural classification systems Given by George Bentham and Joseph Dalton Hooker.   Based on natural affinities among the organisms  Consider,   not only the external features , but also internal features , like ultrastructure, anatomy, embryology and phytochemistr...

Topic Covered ✏ 1.1 Diversity in the Living World  1.2 Taxonomic Categories 1.1 Diversity in the Living World  Each different kind of plant, animal or organism that you see, represents a species .  The number of species that are known and described range between 1.7-1.8 million. This refers to biodiversity or the number and types of organisms present on earth.     Nomenclature Naming of living organisms such that a particular organism is known by the same name all over the world. Nomenclature or naming is only possible when the organism is described correctly and we know to what organism the name is attached to. This is identification.