DIVERSITY IN LIVING WORLD POWER POINT PRESENTATIN BY HEERA KUMAR PGT BIOLOGY

LIVING ORGANISMS

WHY DO WE CLASSIFY LIVING ORGANISMS ? ANS. WE CLASSIFY LIVING ORGANISMS FOR THEIR CONVENIENT STUDY

BASIS OF CLASSIFICATION THERE ARE DIFFERENT BASIS OF CLASSIFYING LIVING ORGANISMS ON THE BASES OF THEIR HABITAT EUKARYOTIC AND PROKARYOTIC UNICELLULAR AND MULTICELLULAR PHOTOSYNTHETIC AND NON PHOTOSYNTHETIC ON THE BASIS OF FEEDING HABIT ON THE BASIS OF BODY STRUCTURE ETC.

CLASSIFICATION AND EVOLUTION CLASSIFICATION OF LIVING ORGANISMS IS RELATED TO EVOLUTION EVOLUTION : THE FAMOUS DEFINITION OF EVOLUTION GIVEN BY CHARLES DARVIN IS “ DESCENT WITH MODIFICATION “ THAT IS GRADUAL CHANGES FROM SIMPLE TO COMPLEX IN LIVING ORGANISMS

THE HIERARCHY OF CLASSIFICATION GROUPS GROUPING ORGANISMS IN DIFFERENT CATEGORIES AND SUB CATOGARIES . EACH STEP IS CALLED TAXON . AERRANGING TAXONS ON THE BASIS OF THEIR SIZE IS CALLED HIERARCHY. THESE ARE KINGDOM PHYLUM (ANIMALS) / DIVISONS(PLANTS) CLASS ORDER FAMILY GENUS SPECIES SO THE LOWERMOST OR THE BASIC UNIT OF CLASSIFICATION IS SPECIES.

WHITTAKER’S FIVE KINGDOM CLASSIFICATION IN THE PROCESS OF CLASSIFICATION OF ORGANISMS ROBERT WHITTAKER PROPOSED ORGANISMS BE CLASSIFED INTO FIVE MAJOR GROUPS KNOWN AS FIVE KINGDOM MONERA : ALL PROKARYOTIC UNICELLULAR ORGANISMS . EXAMPLE – BACTERIA PROTISTA : ALL EUKARYOTIC UNICELLULAR ORGANISMS . EXAMPLE – AMOEBA , PARAMOECIUM FUNGI : UNICELLULAR AND MULTICELLULAR NONGREEN PLANTS . EXAMPLE – YEASTS , AGARICUS PENICILLIUM ETC. PLANTAE : ALL GREEN PHOTOSYNTHETIC PLANTS . ANIMALIA : ALL MULTICELLULAR EUKARYOTIC WITHOUT CELLWALL AND HETEROTROPHS

SUB DIVISIONS OF PLANTAE AND ANIMALIA PLANTAE: FIVE DIVISIONS THALLOPHYTA BRYOPHYTA PTERIDOPHYTA GYMNOSPERMS AND ANGIOSPERM

THALLOPHYTA PLANTS WITHOUT LEAF , ROOT AND STEM . BODY HAS SIMPLE THALLUS . THE PLANTS IN THIS GROUP ARE COMMONLY CALLED ALGAE .EXAMPLES –SPIROGYEA, ULOTHRIX, CLADOPHORA ETC.

BRYOPHYTA THESE ARE CALLED AMPHIBIANS OF PLANT KINGDOM BECAUSE THEY INHABIT BOTH LAND AND WATER TO COMPLETE LIFE CYCLE. THE PLANT BODY IS COMMONLY DIFFERENTIATED TO FOR STEM AND LEAF LIKE STRUCTURES BUT THERE IS NO SPECIALISED TISSUE FOR THE CONDUCTION OF WATER AND OTHER SUBSTANCES FROM ONE PART OF PLANT BODY TO ANOTHER . EXAMPLE – FUNARIA , MARCHANTIA.

PTERIDOPHYTA THE PLANT BODY IS DIFFERENTIATED INTO ROOTS , STEM AND LEAVES AND HAS SPECIALISED TISSUE FOR THE CONDUCTION OF WATER AND OTHER SUBSTANCES FROM ONE PART OF PLANT BODY TO ANOTHER . EXAMPLE –MARSILEA , FERNS ,HORSE TAILS .

THALLOPHYTES , BRYOPHYTES AND PTERIDOPHYTES HAVE NAKED EMBRYOS THAT ARE CALLED CALLED SPORES . THE REPRODUCTIVE ORGANS OF ALL THESE GROUPS ARE VERY INCONSPICUOUS OR HIDDEN THEIRFOR CALLED CRYPTOGAMAE THE PLANTS WITH WELL DIFFERENTIATED REPRODUCTIVE TISSUES THAT ULTIMATELY MAKE SEEDS ARE CALLED PHANEROGAMS PHANEROGAMS CONSISTS OF TWO GROUPS GYMNOSPERMS AND ANGIOSPERMS

GYMNOSPERMS WORD GYMNOSPERM IS MADE FROM TWO GREEK WORDS GYMNO – MEANS NAKED SPERMA – MEANS SEED THAT IS PLANTS BEARING NAKED SEEDS THE PLANTS ARE USUALLY PERRINIAL, EVERGREEN AND WOODY . EXAMPLES – PINES LIKE CYCAS , PINUS

ANGIOSPERMS THE WORD ANGIOSPERM IS MADE FROM TWO GREEK WORDS ANGIO – MEANS COVERED SPERMA – MEANS SEED THE SEEDS DEVELOP INSIDE AN ORGAN WHICH ULTIMATELY CHANGES INTO FRUIT . ANGIOSOERMS ARE ALSO CALLED FLOWERING PLANTS THE STRUCTURE INSIDE SEED IS CALLED COTYLEDON OR SEED LEAF ANGIOSPERMS ARE DIVIDED IN TWO GROUPS ON THE BASIS OF NUMBER OF COTYLEDONS

MONOCOTYLEDONOUS OR MONOCOTS : PLANTS WITH SEEDS HAVING SINGLE COTYLEDON DICOTYLEDONOUS OR DICOTS : PLANTS WITH SEED HAVING TWO COTYLEDONS .

SUMMARY PLANTS WITHOUT DIFFERENTIATED PLANT BODY HAVE DIFFERENTIATED THALLOPHYTA WITH VASCULAR TISSUE WITHOUT SPECIALISED PRODUCE SEEDS - PHANEROGAMS DONOT PRODUCE SEEDS BEAR NAKED SEEDS BEAR SEEDS INSIDE FRUITS GYMNOSPERMS ANGIOSPERMS DICOT MONOCOT

ANABENA BACTERIA PARAMOECIUM EUGLENA AMOEBA

fungi

algae

pinus Cone of pinus Cone of cycas Stem of cycas cysas