Could this extraordinary variety really be explained by the idea that God had created all the species on Earth in six days? Could the variations he saw on the Galapagos have anything to do with the huge scale of geological time he had learnt about from geologists such as Sedgwick? In a tentative way, Darwin argued about these issues with Captain Fitzroy, whose dogmatic religious belief acted as a useful stimulant, though neither knew it at the time. Darwin thought that the unique species of the Galapagos could not have been specially created for each island, but must have evolved from similar ancestors carried from the mainland and washed up on the islands.
But how had this evolution occurred? Read more. It truly is amazing that Charles Darwin put together the pieces, and his ideas have changed human history and our perceptions of our place both in nature and the history of the world.
Your email address will not be published. This site uses Akismet to reduce spam. Learn how your comment data is processed. But conversations are dynamic and text is not. I i disagree that here rested easy, Since his wife was a Christain who wanted him to hold back his theory for fear he would not be in haven with her. He was wondering if he had made a mess in the world, What if he was wrong?
His theory said it was the best explanation of what he came up with explaining changes and diversity in life. His daughter died at the young age of 10 and he would be wondering if he would he her. Would he and his works be a cause or support of Atheism and therefore not be able to enter the New Jerusalem?
These doubts may have accused him or challenged him worry and he left the world in a great controversy that probably will not be out done. Religious believers of most persuasions and many secularists do not see life as a struggle with no purpose but survival; and Darwinian fitness is frequently a euphemism for brute strength.
But the world is not a fundamentally nasty place and people are fine — given a chance. That is natural selection. Just look around. Resources are not and never have been scarce; rather, they are abundant; so species do not have to compete to the death to survive. This is all thanks to the sun, which constantly showers the earth with an almost infinite supply of energy. Over billions of years life evolved into a wealth of forms, many of which are alive today.
As the sun never sets, so life never stops happening, evolving, changing and dying. That abundance of energy allows the evolution of a multitude of species, each adapted to a selection of the earth and its resources called an eco-system. The individuals of all species come into the world equipped to survive and reproduce but they are already being limited in how to do this by their species history, their anatomy the nipple count and reproductivity; by climate, geography, altitude etc and chance.
They are further constrained by the other individuals in their eco-system, all of which are also establishing territories and behaviours to maximise their survival. Inevitably, they limit one another in configuration and behaviour. Viable webs of life are created, in — and perhaps by — the eco-system with everything getting its due bite of the apple and no more. Evolution is a communal process, not the individualist endeavour of Victorian capitalism and Charles Darwin; nor its modern development in social gene theory.
The prime objective of eco-systems is, after survival, stability, which is an emergent property essential for the evolution of characteristics and behaviour: nothing can evolve if its environment is in a state of flux. Similarly, and to retain stability over time, populations are limited and stablised by their evolution, by the checks imposed on individuals by eco-systemic interactions and by natural hazards.
All life kills or otherwise exploits others to survive: sheep eat grass; leopards eat gazelles; but such behaviours have evolved and are necessary, not vindictive.
Struggle also occurs between individuals for mating; between individuals and groups for territory, and against the many hazards of life.
Useful variations lurk unexpressed in the genome until environmental events make them valuable and the phenotype to which they give rise is selected. Natural selection operates slowly in stable environments: the great white shark has hardly changed in million years; more rapidly on species cut off from their mainstream by earth movement, climate change or some other barrier; and dramatically after major disturbances like earthquakes, disease, an asteroid hits, etc.
New and newly denuded environments provide opportunities for the selection of useful variations leading to dramatic speciation such as produced and later killed off the dinosaurs.
The theory is sometimes described as "survival of the fittest," but that characterization can be misleading, Pobiner said. Here, "fitness" refers not to an organism's strength or athleticism but rather its ability to survive and reproduce. It is one of the best-substantiated theories in the history of science, supported by evidence from a wide variety of scientific disciplines, including not just genetics which shows that different species have similarities in their DNA but also paleontology and geology through the fossil record, which shows how that species that existed in the past are different from those present today , and developmental biology species that seem very different as adults pass through similar stages of embryological development, suggesting a shared evolutionary past.
See the open-access textbook Concepts of Biology for more information about these lines of evidence. In the first edition of "On the Origin of Species," published in , Darwin speculated about how natural selection could cause a land mammal to turn into a whale. As a hypothetical example, Darwin used North American black bears Ursus americanus , which were known to catch insects by swimming in the water with their mouths open.
The idea didn't go over very well with the public or with other scientists. Darwin was so embarrassed by the ridicule he received that the swimming-bear passage was removed from later editions of the book. Scientists now know that Darwin had the right idea but the wrong animal.
Instead of looking at bears, he should have been looking at cows and hippopotamuses. The story of the origin of whales is one of evolution's most fascinating tales and one of the best examples scientists have of natural selection. To understand the origin of whales, you need a basic understanding of how natural selection works. Natural selection can alter a species in small ways, causing a population to change color or size over the course of several generations.
When this process happens over a relatively short period of time and in a species or small group of organisms, scientists call it "microevolution. But when given enough time and accumulated changes, natural selection can create entirely new species, a process known as "macroevolution.
Take the example of whales: By using evolution as a guide and understanding how natural selection works, biologists knew that the transition of early whales from land to water occurred in a series of predictable steps. The evolution of the blowhole, for example, might have started with random genetic changes that resulted in at least one whale having its nostrils farther back on its head. The whales with this adaptation would have been better suited to a marine lifestyle, since they would not have had to completely surface to breathe.
Such individuals were more successful and had more offspring. In later generations, more genetic changes occurred, moving the nose farther back on the head. Other body parts of early whales also changed. Front legs became flippers. Back legs disappeared. Their bodies became more streamlined, and they developed tail flukes to better propel themselves through water. The Natural History Museum hosts the biggest ever Darwin exhibition until April ; moves are afoot to have his home and living laboratory of forty years, Downe, declared a World Heritage Site by Unesco; celebrations will take place across the country on 12 February, his birthday, or "Darwin Day".
Even Hollywood has taken note of the romance of his marriage and tragedy of the death of three of his children, and a movie starring Paul Bettany will appear later this year. But any complacency about his place in history should be tempered by an awareness that his significance could easily be forgotten. In , a public poll conducted by the BBC judged him the fourth greatest Briton of all time — one place behind Diana, Princess of Wales.
If that's not worth celebrating, what is? Join thought-provoking conversations, follow other Independent readers and see their replies. Want to bookmark your favourite articles and stories to read or reference later? Start your Independent Premium subscription today.
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