Evolution+Letter

=//S.W.A.K.// =

//23 Trilobite Rd// //Cave Creek, Arizona, 98765-4321// //Sunday, June 3, 2012//

//Dear Mom,//

 //I have had a blast with all of my friends, here at Dad’s expedition cite. We have found many small fossils of past mammals, and even some from larger animals that once lived on Earth! The first fossil that we found was of a Megazostrodon, which, by our research, lived about 220 million years ago. When Dad and I found this fossil, there were many other organisms around it, but not mammals. There were “small” dinosaurs around it! This explained why the Megazostrodon was sized like a shrew. Dad told me that the mammals living around the beginning of mammals did not live long enough to grow larger and develop mutations because of many of the dinosaurs diets. Through previous knowledge, though, I know that when the dinosaurs became extinct, during the Mesozoic and Cenozoic eras, the mammals finally had the chance to adapt to the changing climate, and they were able to create variety.//  //Dad, my friends, and I were so interested on the evolution of mammals, that we went to a lab, about 5 mile south of us. We met Dr. Springer in one of the labs and he showed us a bunch of fossils of very different mammals. Dr, Springer told us that three groups of mammals evolved and adapted from one single, small mammal, hundreds of millions of years ago. The three groups are monotremes, such as a duck-billed platypus, Marsupials, such as kangaroos, and placentals, such as humans. The Doctor said that the placentals are the most successful, but he also made it very clear, that for the different types of conditions that they lived in. For this group of mammals, all of the young are well developed before being introduced to the world. This allows the offspring to have a large advantage for its first months because they can do many of the basic activities that can be done by adults. Also, the offspring of placentals are and were fed by their mother and will have sophisticated teeth when they get older. We all saw that all of these characteristics were still found today, and that is what connected the present day mammals with the past.//  //Dr. Springer also told us that one of the reasons that the mammals of the Cenozoic Era, or modern times, is because of the variety of them. I recalled, at that moment, what I had learned in science class. I remembered Charles Darwin’s theory of Natural Selection and that it stated that only the favorable traits gets past down from generation to generation. The process of natural selection allowed only the best of the traits to go on to the offspring and this allowed different traits to move on from different type of animals. Also, the thought of different characteristics from different animals, but still of the same species being past down, allowed an species to mate and to then pass down multiple traits that were favorable at that time. For example, the favorable traits that have been past down to the Megatherium were a set of sharp teeth for grinding vegetables, like those of an elephant’s, and the large claws that it had on its hands, used for grabbing and gripping the branches. Both of these traits were the most useful of the parents and thanks o that, their offspring had an easier time living in the environment that it was in.//  //So far I have had so much fun with a lot of my friends and Dad at the expedition cite. I will be home in a few weeks to finally have our vacation that I have promised. See you soon!//  //Miss you lots!//  //Rach P :) <3// //P.S. I know I promised to go to Paris with you, but I have already gone with my class and it’s a little too city for me. I hope you understand, and I hope we can figure something out that is a little more country than urban.//

=// S.W.A.K. // =

// "I have called this principle, by which each slight variation, if useful, is preserved, by the term Natural Selection." - Charles Darwin // Evolution Poem Evolution Comic Strip