Diversity in Living Organism

3225 Words Nov 11th, 2012 13 Pages
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Classification And Evolution
Classification refers to the identification, naming, and grouping of organisms into a formal system based on similarities in their internal and external structure or evolutionary history. It determines the methods of organizing diversity of life on earth. Therefore, classification helps in understanding millions of life forms in detail.
Who started the classification of organisms? Let us explore the history of classification.
History of classification
One of the earliest schemes of classification was given by the Greek thinker, Aristotle, around 300 BC. He classified animals according to their habitat – land, air, or water.
However, this classification
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This slow change in the body design of an organism over a long period of time is termed as evolution. It helps an organism to survive in its surroundings.
Classification allows things to be identified and categorized on the basis of structure and function of an organism, and accordingly, we can refer to them as primitive or advanced organisms. This helps in predicting the line of evolution.
Which characteristic do you consider basic – the one that came into existence earlier or later?
The characteristic that came into existence earlier is basic because they are independent of other characteristics, in terms of their effects on the structure and function of an organism.
For example, cell structure is the basic characteristic that decides the cellularity of an organism that is to be classified.
Primitive and advanced organisms
A primitive or a lower organism has a simple body structure and an ancient body design or features, which have not changed much over time.
An advanced organism or a higher organism has a complex body structure and organization.
Thus, we can conclude that unicellular or simple organisms gave rise to multicellular or complex organisms.
It means that the existing animals and plants have developed by a process of gradual and continuous change in primitive or simple organisms. This is known as evolution.
Which of the following two organisms do you consider primitive?