What Darwin Never Knew Video Guide

Evolution - What Darwin Never Knew As you watch the video fill in the missing blanks below with the correct information. 1. Charles Darwin was born 200 years ago and published a work 150 years ago that has become the bedrock of our understanding of life on Earth.2. Darwin's theory of evolution, his account of why species adapt and change, has been called the best idea anyone ever had.3. Charles was offered a place on the British Navy ship, The H.M.S. Beagle, whose mission was to survey the waters around South America.4. One port of call on Darwin's voyage proved more important than all the others: the Galapagos. This cluster of 13 isolated islands lies 600 miles off the coast of Ecuador, in the PacificOcean.5. Darwin learns that those birds he had collected on the Galapagos actually represented 13 differentspecies of finch. What misled Darwin was that they looked radically different: some had wide tough beaks, others had long slender ones. And these differences depended on which islandsthey lived on.6. Originally, there must have been just one type of finchon the Galapagos, but over time it had diversified into many kinds, with different beak shapes; the same for the tortoises. One type of tortoise must have turned into many kinds, with different shells depending on which island they lived on.7. Human embryos provided the most startling evidence. Under the microscope, tiny slits around the neck were clearly visible: exactly the same structures were found in fish. But in fish they turned into gills; in humans, they became the bones of our inner ear.8. Beginning with a common ancestor, over time, across generations, species could change dramatically. Some might add new body features, others might drop them. Ultimately one type of creature could be transformed into something utterly different. It's a process Darwin called descent with modification.9. Through a careful process of selection, dog breeders mixed different dogs with different physical traits to create new forms. Darwin was intrigued by what he was seeing breeders could do with domestic dogs. They could select for individual traits, such as size or shape, and they could actually change the look of their breed.10. Darwin showed that nature was a battlefield and that everything was in competition. And this brutal battle, this war of nature as Darwin described it, was actually a creative process.11. The pattern that Darwin saw was that the creatures that survived were those best adapted to the specific environmentsthey lived in.12. On a different island, where you have a different foodsource, you have a different beak shape. And this pattern was repeated across the Galapagos. It seems that the finches' beaks had altered to fit the dietof each particular island.13. Darwin realized that variation must be the starting point for change in nature. In any generation, the animals in a litter are never quite the same. And in the wild, such a tiny variation might make all the difference between life and death.14. Darwin suggested, over many, many generations, these tiny variations would allow the fit to get fitter, and the unfit would vanish. These variations accumulate and eventually new species branch off.15. This is evolution by natural selection. It is one of the keys to how new species are formed.16. Weighing just half an ounce, rock pocket mouse could never fight off large predators. Its best hope for survival is camouflage. Not surprisingly, its fur matches the color of the Pinacate rocks.17. The study of DNA is one of the great triumphs of modern science. It has taken our understanding of how creatures evolve.18. DNA is a code, and its double strand contains all the information to make living things grow and develop. Lined along each DNA molecule arranged special sequences of this code that forms our genes. Many genes get translated into proteins, and these proteins make the stuff of our bodies. One protein makes hair; another makes cartilage; others make muscle.19. Another way that DNA can change is mutation.20. A mutation is a critical ingredient in the recipe for evolution. Without mutation, everything would stay constant, generation after generation. Mutation generates variation, differences betweenindividuals.21. Mutations seems to mean that something bad has happened. Well, mutations are neither good nor bad. Whether they are favored, or whether they are rejected, or whether they're just neutral, depends upon the conditions an organism finds itself in.22. When a mouse is born with these mutations, its fur grows dark. And that means it can survive on the dark rocks when others would not. Here was a clear example of evolution and natural selection at work.23. Many of our key genes were identical to those of other animals.24. The first tantalizing clues would come from those life forms that Darwin himself had studied, embryos.25. It is almost impossibleto tell, just days after conception, which is the chicken, the turtle, the bat, the human. They look almost the same. Only as they grow, does it become clear which is which.