• Developed by `color{Green}"Carl Linnaeus"` (1758). He is regarded as the `color{Green}"Father of Classification"` .
• Divided organisms into `color{Brown}"Plantae and Animalia kingdoms"` that included all plants and animals respectively.
• This system was used till very recently.
• Eventually, the two kingdom classification used for a long time was found `color{Green}"inadequate"`.
• A need was also felt for including, besides gross morphology, other characteristics like cell structure, nature of wall, mode of nutrition, habitat, methods of reproduction, evolutionary relationships, etc.
`color{purple}♣ color{Violet} "CRITERIA"`
• Based on `color{Green}"gross morphology"`. The classification was carried out based on some functional and structural characteristics such as `color{Brown}"mode of nutrition, response to external stimuli, conductile and contractile system, locomotion and cell wall"`.
• So plants were organisms (which had cell wall, were autotrophs and did not move) and animals were organisms (which did not have a cell wall, were heterotrophs and could move).
`color{purple}♣ color{Violet} "MERITS"`
• Classification of organisms into plants and animals was easily done easily done and was `color{Green}"easy to understand"`.
• The classification was not done abruptly but `color{Green}"scientifically"`, based on but based upon `color{Green}"distinctive characters"`.
• It gave rise to the process of classification using `color{Green}"systematic methods"`. Later, for development of better methods, more and more characters were taken into consideration to classify the living organisms.
`color{purple}♣ color{Violet} "DEMERITS"`
• This system did not distinguish between the `color{Green}"eukaryotes and prokaryotes ,
unicellular and multicellular organisms and
photosynthetic (green algae) and non-photosynthetic (fungi) organisms"`.
• A large number of organisms did not fall into either category like `color{Green}"microorganisms"` such as bacteria, micro algae and micro fungi .The reason could be because the organisms were not properly known by that time.
• This placed together groups which widely `color{Green}"differed"` in other characterstics.
• Organisms like bacteria, blue green algae, fungi, mosses, ferns, gymnosperms and the angiosperms were grouped under ‘Plants’ due to the presence of a cell wall in their cells.
• It brought together the prokaryotic bacteria and the blue green algae with other groups which were eukaryotic.
• It also grouped together the unicellular organisms and the multicellular ones, say, for example, Chlamydomonas and Spirogyra were placed together under algae.
• The classification did not differentiate between the heterotrophic group – fungi, and the autotrophic green plants, though they also showed a characteristic difference in their walls composition – the fungi had `color{Green}"chitin"` in their walls while the green plants had a `color{Green}"cellulosic"` cell wall.
`color{purple}♣ color{Violet} "Just for Curiousity"`
• Around 1800, during the earlist attempts, as more minute organisms were discovered, micro-fungi and multicellular microalgae, which were immotile and in some cases `color{Green}"plant-like"` in form, were naturally positioned in the plant kingdom.
• Other motile, microscopic forms like unicellular protozoa, multicellular invertebrates and bacteria were grouped together as a single group, the `color{Green}"infusoria"`, within the animal kingdom.
• Eventually, the biologists realized that infusoria was a `color{Green}"heterogenous group"` and transferred bacteria from it to plant kingdom. Thus, kingdom plantae included the bryophytes, pteridophytes, angiosperms, gymnosperms, fungi (macro and micro), algae (macro and micro) and bacteria; and all animals including unicellular protozoa, multicellular invertebrates were grouped in kingdom Animalia.
• Developed by `color{Green}"Carl Linnaeus"` (1758). He is regarded as the `color{Green}"Father of Classification"` .
• Divided organisms into `color{Brown}"Plantae and Animalia kingdoms"` that included all plants and animals respectively.
• This system was used till very recently.
• Eventually, the two kingdom classification used for a long time was found `color{Green}"inadequate"`.
• A need was also felt for including, besides gross morphology, other characteristics like cell structure, nature of wall, mode of nutrition, habitat, methods of reproduction, evolutionary relationships, etc.
`color{purple}♣ color{Violet} "CRITERIA"`
• Based on `color{Green}"gross morphology"`. The classification was carried out based on some functional and structural characteristics such as `color{Brown}"mode of nutrition, response to external stimuli, conductile and contractile system, locomotion and cell wall"`.
• So plants were organisms (which had cell wall, were autotrophs and did not move) and animals were organisms (which did not have a cell wall, were heterotrophs and could move).
`color{purple}♣ color{Violet} "MERITS"`
• Classification of organisms into plants and animals was easily done easily done and was `color{Green}"easy to understand"`.
• The classification was not done abruptly but `color{Green}"scientifically"`, based on but based upon `color{Green}"distinctive characters"`.
• It gave rise to the process of classification using `color{Green}"systematic methods"`. Later, for development of better methods, more and more characters were taken into consideration to classify the living organisms.
`color{purple}♣ color{Violet} "DEMERITS"`
• This system did not distinguish between the `color{Green}"eukaryotes and prokaryotes ,
unicellular and multicellular organisms and
photosynthetic (green algae) and non-photosynthetic (fungi) organisms"`.
• A large number of organisms did not fall into either category like `color{Green}"microorganisms"` such as bacteria, micro algae and micro fungi .The reason could be because the organisms were not properly known by that time.
• This placed together groups which widely `color{Green}"differed"` in other characterstics.
• Organisms like bacteria, blue green algae, fungi, mosses, ferns, gymnosperms and the angiosperms were grouped under ‘Plants’ due to the presence of a cell wall in their cells.
• It brought together the prokaryotic bacteria and the blue green algae with other groups which were eukaryotic.
• It also grouped together the unicellular organisms and the multicellular ones, say, for example, Chlamydomonas and Spirogyra were placed together under algae.
• The classification did not differentiate between the heterotrophic group – fungi, and the autotrophic green plants, though they also showed a characteristic difference in their walls composition – the fungi had `color{Green}"chitin"` in their walls while the green plants had a `color{Green}"cellulosic"` cell wall.
`color{purple}♣ color{Violet} "Just for Curiousity"`
• Around 1800, during the earlist attempts, as more minute organisms were discovered, micro-fungi and multicellular microalgae, which were immotile and in some cases `color{Green}"plant-like"` in form, were naturally positioned in the plant kingdom.
• Other motile, microscopic forms like unicellular protozoa, multicellular invertebrates and bacteria were grouped together as a single group, the `color{Green}"infusoria"`, within the animal kingdom.
• Eventually, the biologists realized that infusoria was a `color{Green}"heterogenous group"` and transferred bacteria from it to plant kingdom. Thus, kingdom plantae included the bryophytes, pteridophytes, angiosperms, gymnosperms, fungi (macro and micro), algae (macro and micro) and bacteria; and all animals including unicellular protozoa, multicellular invertebrates were grouped in kingdom Animalia.
