Extinctions No Comebacks

Email

Whatsapp

Facebook

Pinterest

Twitter

Copy link

Earth has witnessed five major mass extinctions. During these extinctions large numbers of species died out simultaneously or within short periods of time. Those extinctions led to the major changes in the biodiversity of Earth. The book explores the history of life on Earth and various factors that resulted in mass extinctions. Even today, several plant and animal species are on the verge of extinction. Scientists believe that the rate of modern-day extinctions is faster than the earlier ones due to human activities like illegal trade of endangered species, habitat destruction and pollution among others. The book looks into the impact of extinctions on Earth's biodiversity and gives some idea about measures that need to be taken to save Earth from further degeneration.

Dr. M.A. Haque has a doctorate in Environmental Science from Jawaharlal Nehru University, New Delhi and worked as Scientist at Central Pollution Control Board and Ministry of Environment, Forest and Climate Change, Government of India. He has represented Govt. of India in various international meetings, conferences, etc. including those organised by the UN. He was UNDP Adviser in Afghanistan from 2007-08. He has authored five popular science books and contributed more than 800 papers and articles particularly on environment. He was also the Editor of the magazine Paryavaran for fourteen years. Besides, he has also conceptualized/scripted documentaries and participated in a number of programmes of Doordarshan/AIR. He was also associated with Iraq TV and BBC. He has been regularly teaching as guest faculty in various universities and educational institutions. Dr. Haque has an interest in photography as well. He has a large collection of visuals from India and abroad on different subjects.

Estimates suggest that Earth has been in existence for about four billion years and life as such has been present on Earth for about 600 million years. This kind of estimate is based on the fossil records. But the existence of life even before 600 million years cannot be completely ruled out. Since the time organisms appeared on Earth, they have also been disappearing. Scientists use the term extinction for such disappearances. This term is applied when an organism or a group of organisms is finished from the Earth, i.e. death of the last individual of the species takes place. Scientists explain that more than 99 per cent of all species which were ever present on the Earth are now extinct. Also, they suggest that at times the existing organisms disappear and parallel to the same new organisms appear and occupy the space. But it is not always so. Therefore, the Biodiversity present on the Earth has been fluctuating.

Generally, the process of extinction is very slow and for a casual observer it is not easy to conclude if there was any extinction. But at times in the history of Earth there were sudden disappearances of very large number of organisms due to external factors. These incidences are called Mass Extinctions and we have evidences for several of them. One such extinction is well-known as the same resulted in disappearance of the Dinosaurs.

Scientists say that a typical species has been going extinct within 10 million years of its appearance. But certain species continue to live even after that.