The Process of Evolution Drives the Diversity and Unity of Life.

“As humanity was evolving, we probably had pretty light skin too, underneath a similar coat of coarse, dark hair. As we lost hair, the increased exposure of our skin to ultraviolet rays from the strong African sun threatened the stores of folate we need to produce healthy babies. And that created an evolutionary preference for darker skin, full of light-absorbing, folate-protecting melanin.” (Moalem 54)
As early humans lost hair, and therefore had more exposure to the sun it led to more ultraviolet (UV) exposure.

As a result skin became darker and more melanin is produced. As stated above, this melanin protected folate which is essential towards producing healthy children. Now the genetic makeup of a population (in this population in Africa) is being changed due to the strong African sun. You can see that it was only limited to central Africa because as humans began to settle in Europe, the darker skin was a disadvantaged towards them as the UV protection was not needed anymore but it affected, the human body’s ability to break down cholesterol into vitamin D which is essential to the human body.

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The benefits of vitamin D are that they: “ensure the growth of healthy bones in children and the maintenance of healthy bones in adults. It ensures that our blood has sufficient levels of calcium and phosphorus” (Moalem 50). Without this nutrients, as read in the book, it could lead to certain bone growth problems. This led to the difference in the genetic makeup of Europeans with lighter skin being able to absorb more sunlight for production of vitamin D.

This difference in genetic makeup is an example of evolution over time between different humans. The genetic makeup led to different paths of evolution. This difference in evolution promotes the diversity among human beings.
“...One generation’s evolutionary solution is another generation’s evolutionary problem, especially when people no longer live in the environment that their bodies adapted to through evolution.”
Life continues to evolve without a changing environment. There is no way to stop time. Humans are constantly changing but where they are living does not. As species grow and develop, they begin to adapt to the environment they live in. A chain of not only generations but a food chain come into play. Now there's a whole ecosystem created. But a problem is, is that these people are changing and their environment is not. Overtime, the environment may not fit their needs. What has been created is only beneficial to a certain about of time. Because evolution is about surviving in the moment, the future of the species is not taken into account.
Biological systems utilize free energy and molecular building blocks to grow, reproduce, and to maintain dynamic homeostasis.
“Diabetes is all about the body’s relationship to sugar, specifically the blood sugar known as glucose. Glucose is produced when the body breaks down carbohydrates in the food we eat. It’s essential to survival--it provides fuel for the brain; it’s required to manufacture proteins; it’s what we use to make energy when we need it. With the help of insulin, a hormone made by the pancreas, glucose is stored in your liver, muscles, and fat cells (think of them as your own internal OPEC) waiting to be converted to fuel as necessary.” (Moalem 23)
Organisms use feedback mechanisms to regulate growth and reproduction, and to maintain dynamic homeostasis.
Above, briefly demonstrates the regulation of the amount of blood sugar in humans to ensure the body is going through its correct processes to prevent any complications. When the human body receives glucose, in carb of fat form, it releases insulin in response to the glucose entering the body, to break down these sugars into fuel for your body. If the process fails, it can be very harmful to the body. People who cannot carry out this function are diagnosed with diabetes. In diabetics, the process of breaking down glucose is effected. This causes a much higher than usual concentration of glucose in the blood. “Unmanaged, these abnormal blood sugar levels can lead to rapid dehydration, coma, and death. Even when diabetes is tightly managed, its long term complications include blindness, heart disease, stroke and vascular disease that often leads to gangrene and amputation” (Moalem 24). This shows that when a singular feedback mechanism fails, the whole body can begin to crumble. This shows the importance of feedback mechanisms as they are essential to organisms not just to grow and reproduce properly, but to maintain homeostasis.
“Here’s what they uncovered: Just a few minutes after the frog’s skin senses that the temperature is dropping near freezing, it begins to move water out of its blood and organ cells, and, instead of urinating, it pools the water in its abdomen. At the same time, the frog’s liver begins to dump massive (for a frog) amounts of glucose into its bloodstream, supplemented by the release of additional sugar alcohols, pushing its blood sugar level up a hundredfold. All this sugar significantly lowers the freezing point of whatever water remains in the frog’s bloodstream, effectively turning it into a kind of sugary antifreeze.” (Moalem 43)
Enduring Understanding 2.D: Growth and dynamic homeostasis of a biological system are influenced by changes in the system’s environment.
As we learned, it shows that the wood frog’s internal environment changes once it senses a change in its external environment. Once it reaches a certain temperature (that signals winter), the growth, homeostasis and entire internal environment of the wood frog changes. The frog reduces a large amount of water from its blood and brings sugar containing molecules into the bloodstream. This allows the frog to freeze itself. We can see that the growth and homeostasis within this organism change drastically in response to their external environment changes dramatically. The frog's body adapts to its environmental conditions therefore maintaining homeostasis and a sable rat of growth.
Living systems store, retrieve, transmit, and respond to information essential to life processes.
"Instead of imagining genes as a set of discrete instructions, scientists have begun to conceive of them as an intricate network of information, with an overall regulatory structure that can react to change. Like a foreman at a construction site who directs a particularly fast welder to pick up the slack when his buddy doesn’t show up for work, the genome system can react to a knocked-out gene and get a body built the same. Except the foreman isn’t the only particular gene giving orders; rather, the whole system is interconnected and automatically.
Expression of genetic information involves cellular and molecular mechanisms.
Here we see how genetic code can cover up for itself even if certain genes are removed. As stated above, when certain genes aren’t in the genetic code that should be there, those genes are needed to be expressed, and they create a substitute for the gene that has been removed. In the contrary, earlier ideas stated that genetic sequences were motionless networks of information that had no activity but really it is one of the most active site within our body. Also to note that what was considered “junk” DNA is one of the most important parts of the DNA. It controls gene expression and can actually code for viruses. This shows how the expression of genes in DNA greatly involves cellular and molecular mechanisms that can be within the DNA itself.
“Until recently, the scientific community all but universally agreed that genetic changes were the product of accidental mutations, caused by errors that were only random and always rare. Here’s how those mutations happen. When cells are produced, DNA is copied from the “parent” cell to the “daughter” cell. This process usually produces accurate copies, but errors in production of the long string of information that composes DNA do occur. In order to protect an organism against these errors, the transcription process is complemented by a proofreading system. Those proofreaders are so good that if we cloned them for publishers, they’d put copy editors out of business. Their error rate is phenomenally low--just one out-of-place nucleotide in every billion copies. When an error does get through, the new combination of DNA sequences, however slight, is a mutation.” (Moalem 129)
The processing of genetic information is imperfect and a source of genetic variation.
The passage above references how mutations occur during the duplication of DNA. Mutations are considered the main source of genetic variation among all living organisms. They are the result of a change in nucleotide pairing by substitution, adding, deleting, etc. This genetic variation leads to evolution usually, those with the mutation will end up dominating the gene pool until another mutation comes along within a population and repeat the cycle. Mutations come from a variety of sources besides a DNA copying error. Not only do mutations come from copying errors, but they can come from radiation and powerful chemicals such as those found in cigarette smoke as previously read in the book.. Overall, the idea that the process of recreating genetic information and using it to express certain genes and that there are flaws within that system and the result of those flaws are the very source of evolution.
Biological systems interact, and these systems and their interactions possess complex properties.
“Now imagine what happens when a retrovirus or virus writes itself into the DNA of cells in the germline of an organism. That organism’s offspring is born with the virus permanently encoded in its DNA.” (Moalem 149)
Enduring Understanding 4.A: Interactions within biological systems lead to complex properties.
The following passage explains the idea of viruses encoding themselves within genetic material. Although the effects of viruses encoding themselves within DNA of germ cells is not very well known, many connections have been made. In the case of human endogenous retroviruses (HERV), the connections made. Viruses that are encoded in our DNA can have both beneficial effects such as building a healthy placenta, which is essential for a fetus to develop correctly, but can also have negative effects such as psoriasis. You consider the same type of retroviruses having two different effects with both good and bad consequences. Genetic material leads to properties that we have hardly scratched the surface of understanding. This also plays a role in the larger idea of biological systems interacting and the resulting properties and characteristics are extremely complex.
“Today many researchers believe that a genetic trait far more prevalent than sickle-cell anemia or thalassemia may also provide protection against malaria--G6PD deficiency. In two large case-controlled studies, researchers found that children with the African variant of the G6PD mutation had twice the resistance to P.falciparum, the most severe type of malaria, that children without the mutation had. Laboratory experiments confirmed this--given a choice between “normal” red blood cells or G6PD-deficient red blood cells, the malaria-causing parasites preferred the normal cells time after time.” (Moalem 90)
Naturally occurring diversity among and between components within biological systems affects interactions with the environment.
There has been a diversity of the population within Africa in the case of having a G6PD deficiency. Those with a G6PD deficiency are suffering many complications. The effects of having G6PD deficiency usually leads to the destruction of red blood cells and without any treatment, this deficiency can become fatal very fast. But people with this deficiency have a less chance of contracting malaria If one had to have contracted malaria, the G6DP deficient human would most likely to survive do to the way the red blood cells would interact. This shows why both types of people exist in the population today in large amounts. This example demonstrates how naturally occurring diversity between two humans affects both humans’ interactions with the environment.