The Meaning Of Evolution

BioMoz — Thu, 09 Apr 2009 06:00:20 +0000

Observation unveils that the diverse types of animals bear some common characters. For example, amphibians, reptiles and mammals have limbs for locomotion on land, fishes have fins for swimming in water, birds have wings for flying. A close scrutiny reveals that the limbs, fins and wings are fonned on the same basic structural plan. All such examples can be explained if we consider that the diverse groups of organisms share a common ancestor from whom they have diverged and fonned two different species. With the passage of time a single ancestral lineage (an evolutionary sequence. arranged in linear order from an ancestral group to a descendant group) has produced two or more lineage that diverged over time. Such process of change in biological system is called evolution. The world evolution means to unfold or unroll or to reveal hidden potentialities. In its broadest sense, evolution simply means an orderly ‘change’ from one condition to another. For Instance, the planets and stars change in between their birth and death. This is stellar evolution. The matters elements -change in time. This is Inorganic evolution. The changes in the properties of population of organisms or groups of such populations over the course of generations are considered as biological or organic evolution. It is a process of cumulative change of living populations and in the descendant populations of organisms. In other words, it is descent with modifications. In general, the diversities of life, including both the differences and similarities, and the characteristics of organisms, both adaptive and non-adaptive. These are the great themes of evolutionary biology. According to Theodosius Dobzhansky (I973), nothing in biology makes sense except in the light evolution.

Ideas of evolution before Darwin

Evolution biology has a much longer and richer history than most of us realize. The contributions of ancient people are often slighted. All theories of evolution, from Darwin to the present day, are permeated with numerous earlier concepts and theories.

Ancient Indian Thoughts On Evolution

The ancient Indians succeeded in understanding the origin and evolution of life in its broad outline. The ancient Indian texts of philosophy and Ayurveda deal with the origin of life. Manu’s texts in Sanskrit, Manu Samhita or Manu-smriti (about 200 AD) mentions about evolution.

Ancient Greek Thoughts on Evolution

The first theories of evolution came about 2000 years before Darwin. According to plato (428-348 BC) each species was an unchanging ideal form. All earthly representatives are imperfect imitations of such true essence of an ideal unseen world. Since, God is perfect everything that existed on earth was his ‘Ideas’. Aristotle (384-322 BC) expanded Plato’s idealistic concepts to a chainlike series of forms- each form representing a link in the progression from most imperfect to the most perfect. He called this ladder of Nature or Scala Naturae. This is also known as the Great Chain of Being.

Evidence of Evolution

Charles Robert Darwin (1809-1882), an English naturalist was the first to resolve all the previous perplexities of evolution. Several different lines of evidence convinced Darwin and his contemporaries that modern organisms arose by evolution from more ancient forms. Darwin documented evidence of evolution mainly on the basis of geographical distribution of species and fossil record. Biological evolution has left marks in the fossil record and in the historical vestiges evident in modern life. However, with the advancement of biology, new discoveries, including the revelations of molecular biology, continue to validate the evolutionary view of life.

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The Meaning Of Evolution