-Suchismita , Subject Matter Expert at Edumarz
For some nucleus is well developed and some it is primitively developed. Hence, nucleus can be said as the distinguishing feature or the primary character for the division of the organisms.
Organisms which have primitive form of nucleus is called prokaryotes
( pro: primitive; karyon: nucleus). They don’t have any nuclear membrane surrounding the organelles. They don’t have well developed cell structure. They only have genetic material into the cell.
These organisms are generally unicellular in nature. And belongs to the lowest category of classification according to the evolution of life form. Example- amoeba, paramecium etc.
Organisms which have a well developed nucleus are called eukaryotes (eu: true karyon:nucleus). They have proper cell membranes surrounding the organelles and differentiating between them. They have the proper developed cell structure. Properly formed nuclei help them to perform all cellular functions properly.
These organisms are generally multicellular in nature. And belongs to different categories of classification as per hierarchy. Example – fungi, plants and animals.
So, the primary characteristic of classification of organisms is on the basis of the nucleus.