Evolutionary biology

The Dodo is dead. The passenger pigeon has passed on. But Lonesome George, the iconic Galapagos tortoise whose death marked the end of his species, is in post-mortem luck. A scientific expedition has discovered some of his close blood relations alive and well. With careful breeding, biologists now hope to revive George's species. Originally there were at least eight species of Galapagos tortoise, scientists now believe. At least three species are now extinct, including tortoises on Pinta Island. The last one, George, was discovered wandering alone in 1972 and taken into loving custody. His death, in 2012 at more than 100 years old, was a powerful reminder of the havoc unleashed by humans on delicate ecosystems worldwide over the last two centuries. But, now the story of extinct Galapagos tortoise has taken a hopeful twist. More than a century ago, it turns out, sailors dumped saddlebacked tortoises they did not need into Banks Bay, near Wolf Volcano on Isabela Island. Luckily, tortoises can extend their necks above water and float on their backs. Many of them made it to shore, lumbered across the lava fields and interbred with Isabela's native domed tortoises. In 2008, scientists tagged and collected blood samples from more than 1,600 tortoises living on the flanks of the volcano. Back in the laboratory, there was a genetic eureka: Eighty-nine of the animals were part Floreana - whose full genetic Profile DNA had been obtained from museum samples. Some had genes indicating their parents were living purebred Floreana tortoises, hinting that the species may not be extinct. Seventeen tortoises were shown to have high levels of Pinta DNA. Tortoises can live for more than 150 years, so some of them may well be George's immediate next of kin. Last month, scientists went back to find them. Their plan was to capture and separate tortoises with high levels of Pinta and Floreana DNA, and then breed animals that are genetically closest to the original species. In a few generations, it should be possible to obtain tortoises with 95 percent of their "lost" ancestral genes, the scientists said.

the human species. Our closest relatives are Chimpanzee, Gorilla and Orang-utan. Similarities between man and other animal forms were identified by Linnaeus who grouped man, the great ape and monkey in a single order, primates. The three main theories of evolution are Lamarckism, Darwinism and Synthetic theory. Lamarck is chiefly remembered for his belief in the inheritability of acquired characters which is disputed. But he is credited in the history of evolutionary thought for recognizing and stating for the first time that evolution is a universal truth covering all forms of life and it is a gradual and an incessant process. The scientific propagation of the theory of evolution was mainly the work of Charles Darwin. He said, that human evolution occurs through the process of natural selection. The main points of this theory are struggle for existence, variation, survival of the fittest and natural selection. Darwins natural selection serves as the corner stone of the modern synthesis but the mutation theory, mendelian genetics and the statistics of population dynamics are also very important components of its foundation. The basic postulate of the synthetic theory is that evolution proceeds principally as a result of the interaction between five indispensable processes mutation, change in the chromosome number and structure, genetic recombination, natural selection and reproductive isolation. This is also called Neo Darwinism.

the human species. Our closest relatives are Chimpanzee, Gorilla and Orang-utan. Similarities between man and other animal forms were identified by Linnaeus who grouped man, the great ape and monkey in a single order, primates. The three main theories of evolution are Lamarckism, Darwinism and Synthetic theory. Lamarck is chiefly remembered for his belief in the inheritability of acquired characters which is disputed. But he is credited in the history of evolutionary thought for recognizing and stating for the first time that evolution is a universal truth covering all forms of life and it is a gradual and an incessant process. The scientific propagation of the theory of evolution was mainly the work of Charles Darwin. He said, that human evolution occurs through the process of natural selection. The main points of this theory are struggle for existence, variation, survival of the fittest and natural selection. Darwins natural selection serves as the corner stone of the modern synthesis but the mutation theory, mendelian genetics and the statistics of population dynamics are also very important components of its foundation. The basic postulate of the synthetic theory is that evolution proceeds principally as a result of the interaction between five indispensable processes mutation, change in the chromosome number and structure, genetic recombination, natural selection and reproductive isolation. This is also called Neo Darwinism.