Part III – Big Idea #1 Meets Survival of the Sickest on the NHS AP Biology Blog (40 points)
Read Chapters 1-4 of Survival of the Sickest
- Charles Darwin"Nothing in biology makes sense except in the light of evolution." - Theodosius Dobzhansky
“Evolution is no linear family tree, but change in the single multidimensional being that has grown to cover the entire surface of Earth.”
- Lynn Margulis
I would like you to write a brief essay that explains Big Idea #1 in your own words. To adequately touch upon this concept you will likely need to write about 2 pages. I know this is a vast topic. You may write more than 2 pages, but don’t feel the need to compose a chapter on evolution. Please keep in mind that I may run this writing assignment or any other that you post to this blog through plagiarism detection software. I always want to see your own work. Be proud of it. You are kind of awesome. Respect.
In your analysis of Big Idea 1 and the quotes above I would like you to incorporate themes, ideas, and examples throughout chapters 1-4 of Survival of the Sickest. Relate the book to these quotes and Big Idea 1. Include a personal reflection on the book that includes your favorite or most interesting bits of information, such as something you may have told your friends or family about after reading it. Be sure to include specific examples that demonstrate that you have read the book and show that you have done research. Reading this book will help you think outside the box! A topic does not have to specifically be in the evolution chapter to summarize the Big Idea!
Hang on to your copies of Survival of the Sickest. We will be revisiting the last 4 chapters over February vacation during the Evolution Unit and may have a quiz on the first four chapters the first week of school.
The assignment is not due for a while (Sunday, August 25th), but I would advise you to at least get started by jotting down some notes or drafting an outline on the computer to come back to sometime over the next week. You will submit the assignment by posting a comment to this blog post. I would suggest first writing your paper in Microsoft Word and then copy/paste it into the comment box. Make sure you save your own copies of everything just in case. Don’t trust computers! If you submit your assignment as a comment before the due date and it does not show up don’t freak out! It will be sent to me first and I will post all of the essays at once on the due date. If you do freak out: 1) Don’t panic 2) Breathe 3) Always feel free to email me with questions comments or concerns- I am here to help.
Big Idea 1 – The process of evolution drives the diversity and unity of life.
“It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change.”
- Charles Darwin"Nothing in biology makes sense except in the light of evolution." - Theodosius Dobzhansky
“Evolution is no linear family tree, but change in the single multidimensional being that has grown to cover the entire surface of Earth.”
- Lynn Margulis
I have included the above quotes from three famous scientists to help you get started. Think about what is meant by these quotes by recalling what you have learned about in past life science courses and by doing some research on the subject. What do you think is meant by Big Idea # 1?
Be sure to include specific examples that show that you have done research. Think outside the box! A topic does not have to specifically be in the evolution chapter to help summarize the Big Idea!
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Big Idea #1 Meets Survival of the Sickest Essay (Part 1)
By: Corina Jurczyk
Big Idea #1 is a very important concept that can be witnessed every day in every aspect of biology. It states that evolution drives both the survival and unity of life. In Survival of the Sickest¸ Dr. Sharon Moalem delves into the reasoning behind why diseases not only exist in today’s society but also why they are so common. To do this, Moalem shows how these diseases once helped people to survive and how through natural selection they became common. The quote by Charles Darwin declares “the one that is most adaptable to change” is the one that will survive. This statement suggests that adapting quickly is the only way one can survive, a claim that supports the research of Dr. Moalem and Big Idea #1. “The light of evolution” (Dobzhansky) has helped answered the ‘whys’ biologists have been asking for centuries.
Big Idea #1: “The process of evolution drives the diversity and unity of life.” This statement is twofold and seemingly contradictory. First, let us look at how evolution drives diversity. Charles Darwin’s famous finches are a perfect example of huge diversity in even closely related organisms. In order for the finches to survive, each one had to adapt to their surroundings. Evolutionary adaptations of the finch were caused by the food sources and plant life on each island. Beak shape, feather coloration, and body size, to name a few, are differentiations between various species of finch on the Galapagos Islands that all derived from the same common ancestor.
The common ancestor came from the South American mainland. This ancestor already contained diversity within its own species, and upon arrival to the islands, the birds that were able to get food were those that survived. On one of the islands, large seeds may be the most abundant food source. Finches on this island with small beaks cannot eat these seeds and will therefore perish. The finches with large enough beaks will survive and pass on that trait, a process known as natural selection. This bird, however, did not have to be the strongest; it was just the most adaptable to the diet change.
Dr. Moalem’s research can be linked to this phenomenon. In Chapter 1 of Survival of the Sickest, Dr. Moalem looks into a disease called hemochromatosis. This disease, which inhibits the regulation of iron in the bloodstream, is deadly. However, it is very common; a surprising 1 in every 200 people of European descent are affected by this disease, and 1 in every 9 is a carrier of it. Moalem shows how during the fourteenth century, the bubonic plague was sweeping across the continent, killing half of its population. Inside the body, the virus is taken by white blood cells called macrophages to the lymph nodes. In normal people, the macrophages carry lots of iron, which during that trip to the lymph nodes the virus will feed on and become stronger. In people with hemachromatosis, macrophages are deprived of iron despite the large amounts everywhere else in the blood. Because of this, the virus does not grow stronger and can be defeated. Survivors of the plague with this disease, like large-beaked finches, passed it on to their offspring and made hemachromatosis a common disease in modern society. They were not the strongest, since the disease can poison the blood and kill later in life, but they could fend off the plague.
Chapter 3 of Moalem’s book focuses more on the diversity of life. In this chapter, Moalem discusses skin color and its effects on cholesterol. He talks about how all people came from a common ancestor, but as they spread out around the world, they adapted to change in sun exposure to maintain proper levels of cholesterol and vitamin D. Humans evolved to either block UV rays with darker skin or to absorb them better with lighter skin depending on their location.
Big Idea #1 Meets Survival of the Sickest Essay(Part 2)
Even though this physical variation and all variations show how diverse humans as a species are, we must remember everything stems from a single ancestor. This ancestor looked very different from the modern human, but it just goes to show how much we had to adapt and evolve to become the dominant species on Earth. Our single ancestor is not the only common thread between humans. Most people of European descent are connected to the group of people that survived the bubonic plague because of hemachromatosis. People with diabetes are connected to people who may have survived the Younger Dryas because sugar in their blood kept them from freezing. People with the same skin color are connected to each other and a global location. People with favism, and therefore a better resistance to malaria, are connected to the Mediterranean area and to each other. These traits show just how similar we are because despite all our differences, humans still share over 99 percent of DNA.
Now let’s look into the unity evolution brings. Diseases and physical traits connect us as a species, but we are also connected to every species. According to evolution, all life on Earth stemmed from one single ancestor. This can be seen in the homologous structures many organisms share. Bats have wings they use for flight, but the bone structure of those wings mirrors the bone structure of the human arm. Although they have very different usages, these limbs show a common ancestry between bats and humans. This arm structure is also found in whales, horses, and many other animal species that on the outside, look nothing alike. Evolution “has grown to cover the entire surface of the earth” (Margulis), but it all stemmed from that single ancestor.
All life on Earth is connected through evolution, but it is also the reason Earth is so diverse. From jellyfish to elephants, butterflies to polar bears, all animals are made with the same animal cells just as all plants are composed of the same plant cells. Those two types of cells share much of the same structure and organelles. Even though evolution shows all life is connected to that single ancestor, Earth is filled with extreme diversity no other known planet contains. Although millions of separate species do exist and flourish on this earth, that common ancestor has drawn an infinite amount of connections that form the ever-expanding web of life.
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