Numerous species exist on Earth and for the ease of study and identification of organisms, they have been classified into different groups based on different criteria like body design. Basic body design forms basis of every classification.
Earlier, only a single body design existed, but it changed with time.
Such organisms having new body design may have been more advanced.
Numerous species exist on Earth and for the ease of study and identification of organisms, they have been classified into different groups based on different criteria like body design. Basic body design forms basis of every classification.
Earlier, only a single body design existed, but it changed with time.
Such organisms having new body design may have been more advanced.
According to theories of evolution, the life-forms that exist today are better forms of early life-forms.
In 1859, ‘The Origin of Species’ by Charles Darwin introduced the term evolution.
According to Darwin theory, the organisms which existed years ago had undergone certain changes for better survival and the new life forms have arisen from them.
Evolutions formed basis for classification.
Evolution was continuous even at the time of classification, some sort of species retained their ancestry body designs and did not change totally known as ‘primitive or lower’ organisms.
But another set of organisms developed new advanced body design different from their ancestor and are called ‘advanced or higher’ organisms.
However evolutionary differences are not justified.
Primitive ones may be called ‘older organisms’ and advanced ones as ‘young organisms’.
Thus, older organisms would have simple body designs while young organisms would have complex body designs.
In other words, evolution has taken place in simple older organisms to form complex young organisms.
