Five Kingdom Classification
Important terms:
▪ Species – A species is an organism of a particular kind whose members can interbreed among themselves
to produce fertile young ones. It is the basic unit of classification.
▪ Classification – the process of grouping similar things into groups or categories on the basis of
similarities and differences.
Grouping of Organisms:
Organisms are grouped from less complex to more complex and from less similarity to increasing similarity.
All individuals of a species can interbreed. Offspring obtained by breeding individuals of different species
have been found to be sterile e.g. mule is the sterile offspring of donkey and horse.
Kingdom classification:
According to Linnaeus, all organisms were classified into 2 categories: Animals and Plants. This
classification was discarded because:
Bacteria and fungi are not true plants but were classified with plants.
Euglena, Chlamydomonas have chloroplasts and some animal’s features also.
Porifera:
▪ Simplest multicellular animals with perforated bodies.
▪ The body consists of a tube or tubular structures.
▪ Cannot move- attached to the spot.
▪ Holes all over body leading into canal system.
▪ Canal system circulates water throughout body and brings in food and oxygen.
▪ Hard exoskeleton.
▪ Minimal differentiation into tissues.
▪ Mainly found in marine habitat.
▪ E.g. Sycon.
Coelenterate (Cnidaria):
▪ Aquatic animals with body cavity filled with mesoglea.
▪ Radial symmetry.
Important terms:
▪ Species – A species is an organism of a particular kind whose members can interbreed among themselves
to produce fertile young ones. It is the basic unit of classification.
▪ Classification – the process of grouping similar things into groups or categories on the basis of
similarities and differences.
Grouping of Organisms:
Organisms are grouped from less complex to more complex and from less similarity to increasing similarity.
All individuals of a species can interbreed. Offspring obtained by breeding individuals of different species
have been found to be sterile e.g. mule is the sterile offspring of donkey and horse.
Kingdom classification:
According to Linnaeus, all organisms were classified into 2 categories: Animals and Plants. This
classification was discarded because:
Bacteria and fungi are not true plants but were classified with plants.
Euglena, Chlamydomonas have chloroplasts and some animal’s features also.
Porifera:
▪ Simplest multicellular animals with perforated bodies.
▪ The body consists of a tube or tubular structures.
▪ Cannot move- attached to the spot.
▪ Holes all over body leading into canal system.
▪ Canal system circulates water throughout body and brings in food and oxygen.
▪ Hard exoskeleton.
▪ Minimal differentiation into tissues.
▪ Mainly found in marine habitat.
▪ E.g. Sycon.
Coelenterate (Cnidaria):
▪ Aquatic animals with body cavity filled with mesoglea.
▪ Radial symmetry.
