Special tribute to Charles Darwin:

"The origin of species"

by Dr. P. Nilanthie DASANAYAKA

November 24 marked the 150th anniversary of "The origin of species" publication (1859) which is one of the most famous and influential books of all time. It has caused to change development of human thoughts over since. February 12 of this year celebrated the 200th birthday of the writer of this book: Charles Darwin, throughout the world. Many other events have been organized throughout this year to celebrate both anniversaries. Therefore it was thought to keep a special note here to pay special tribute to this great scientist in celebration of his life and work especially as the founder of modern evolutionary biology.

Charles Robert Darwin was an English naturalist who was born on February 9, 1809 in Shrewsbury, England. His father Robert Waring Darwin, was a successful and wealthy physician who sent Charles to medical school in Edinburgh, Scotland in 1825. But after attending two surgeries he decided not to be a doctor, as surgeries were performed without anesthesia or pain killers at that time. Then his father was worried and sent him to Cambridge University with the aim of being a minister of the Church of England. Charles enjoyed Science and Nature best of all there with his favourite hobby of collecting beetles. His favourite professor at Cambridge was John Steven Henslow who taught Botany. This friendship could change Charles's life.

The story of Charles Darwin and his theory began in 1831, when he was 22 years old. On the recommendation of Professor John Steven Henslow he was selected to serve as naturalist on a five-year navigational mapping expedition around the coasts of South America, aboard HMS Beagle. During this long voyage, Charles had a chance to study a wide variety of plants and animals on continents and in distant seas.He was able to explore the biological richness of tropical forests, examine the extraordinary fossils of huge extinct mammals in Patagonia and observe a remarkable series of related but distinct forms of life on the Galapagos Islands. This opportunity clearly played an important role in the development of his thoughts about the nature of life on earth. At the beginning of the voyage Charles believed that species were unchanging and immutable. But he observed that living and fossil organisms are directly related to one another in the same area. Further he saw the characteristics of closely related organisms that convinced him that a process of evolution had taken place.

Combining observations with what he had seen on the voyage as well as with his own experience in breeding domestic animals, Charles made an important association. The individual with superior physical and behaviourial characteristics are more likely to survive than individuals that are not so well endowed. These individuals with more suitable characteristics tended to leave more offspring and so become more common in future generations. Charles called this as natural selection. On the 24th of November 1859, Charles Darwin published "The origin of species" in which he proposed that the mechanism of evolution was natural selection. The first small edition of this book, 1,250 copies was sold on the day of publication, and a second edition of 3,000 copies soon afterwards. Sixteen thousand copies have been sold only up to 1876 indicating how stiff a book it is. It is still considered as one of the most important books on science ever written.

This theory: Natural selection marked out for controversy from birth.

Darwin's claim was that natural selection could explain the diversity or all life on earth, from bacteria to barnacles, orchids, fish, lizards, mushrooms, pine tree, elephants, bananas, insects and bonobos. According to Darwin, the varieties of forms that are observed arose because "as many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle inheritance, any selected variety will tend to propagate its new and modified form". The theory's application has not been limited to biology. In the past few decades, it has jumped to many other disciplines, with papers on natural selection appearing in the scientific journals of, among others, anthropologists, sociologists, philosophers, economists, mathematicians and statisticians, demographers, physicists and even surgeons, yielding a wide distribution.

As evolutionary studies enter the genomic era, biologists are finding out more and more about how genes combine with a surprisingly large range of genetic regulatory mechanisms to produce complex systems that are the phenotypes of organisms such as us. Human genome project has been completed and it has revealed that the variation is less than 1% of the population.

That means all the variations like health, personality, intelligence, beauty among human beings are regulated by less than of the genome. It is believed that it might have a regulatory role in human society not unlike that of gene regulation and this may have enhanced human survival.The ability of natural selection to keep up with the times as more and more questions are asked, shows that far from being old at 150, Darwin's theory still has a spring in its step.

The writer is a Senior Lecturer, Department of Botany University of Sri Jayewardenepura.