Charles Darwin's The Voyage Of The Beagle

Andrew Day
Bio Extra Credit

Two weeks before Charles Darwin died he wrote a short paper about a clam clamped to a water beetle in a pond in the English Midlands. The man's son that sent him the beetle worked together with his son and discovered that what Darwin said about evolution was correct. The vindication came from a book that said every organism has a certain chemical code called DNA. Darwin surmised that all Galapagos finches were close cousins and he explained this in his book The Voyage of the Beagle. Scientist today can confirm that his thoughts were correct and they can prove that with their DNA findings. Darwins greatest idea was that natural selection is largely responsible for the variety of traits one sees among related
He wrote to the American botanist Asa Gray that "The sight of a feather in a peacock's tail, whenever i gaze at it, makes me sick!" Even biologists became obsessed with arguing that traits evolve to suit the species, rather the individual. Darwin did not speculate much on why a female would choose any certain male. It is a question that still excites biologists, because they have two equally good answers to it. One example is fashion such as when females are choosing males, other females must follow suit or risk having sons that do not attract females. The other is more subtle. The tail of a peacock is an exhausting and dangerous thing for the bird to grow. It can only be done well by the healthiest males: parasites, starvation, and careless preening will result in duller plumage. So bright plumage constitutes what evolutionary biologists call an "honest indicator of fitness." Substandard peacocks cannot fake it. And peahens, by instinctively picking the best males, thereby unknowingly pass on the best genes to their offspring. Darwin aslo said that sexual selection might account for human racial
Intriguingly, the spelling change that causes blue eyes is not in the pigment gene itself, but in a nearby snippet of DNA scripture that controls the gene's expression. This lends support to an idea that is rushing through genetics and evolutionary biology. Evolution works not just by changing genes, but by modifying the way those genes are switched on and off. According to Sean Carroll of the University of Wisconsin at Madison, "The primary fuel for the evolution of anatomy turns out not to be gene changes, but changes in the regulation of genes that control development." In other words, a giraffe doesnt ave special genes for a long neck. Its neck-growing genes are the same as a mouse's; they may just be switched on for a longer time, so the giraffe ends up with a longer neck. And the discovery of a primitive bony fish called a paddlefish found that the pattern of gene expresion builds the bones in its fins is much the same as the one that assembles the limb in the embryo of a bird, a mammal, or any other land-living animal. The difference is only that it is swithed on for a shorter time in fish. The discovery