Creating the Questionnaire

In the past two weeks, I've started creating my questionnaire for my 20-time project. I finished reading The South Asian Health Solution and I am much better educated about my topic now. I will be doing a study that will look at how South Asians are at high risk for diabetes and heart disease. Using the study to determine what each individual's risk factors are, I would like to help people who are at risk for diabetes and heart disease make lifestyle changes so that they can prevent this from happening.

My questionnaire so far has tried to address people's family history, amount of exercise, diet, amount of sleep per night, and certain levels, such as triglycerides, HDL, blood pressure, that should ideally be around a certain number.

My next steps are to continue writing my questionnaire, and I will start surveying people as soon as possible.

Unit 8 Reflection

This unit was about evolution; we looked at how populations evolve and how life on Earth originated. Evolution happens because genetic variation exists in populations. Variation is due to sexual reproduction, meiosis, and crossing over which happens during meiosis. Humans breed animals for both work purposes and for food, and this is called artificial selection. They select individuals with the trait they want and only mate individuals with this trait. A selection process also occurs in nature, natural selection. Nature favors certain phenotypes which are advantageous for survival and these individuals have a better chance of surviving, reproducing, and passing on their genes. The population evolves to look like these "winners", which was one of Darwin's conclusion about the evolution of populations. This principle was illustrated in The Hunger Games Lab where each there were three phenotypes, and the ones that were better for picking up enough food survived, and those who couldn't gather sufficient food fast enough died and didn't pass on their genes. The initial population in this lab did evolve, as we could see by the change in allele frequency.

Allele frequency change in the Hunger Games Lab

We can tell if a population evolved by looking at if the allele frequency has changed. Allele frequency is how common an allele is in a population. Natural selection can favor one extreme phenotype, in which case the normal distribution bell curve will shift towards that extreme. This is called directional selection. In stabilizing selection, nature favors the intermediate phenotype, and in disruptive selection, nature favors both extreme phenotypes. Disruptive selection can lead to speciation, where two new species arise from one. They are considered two new species if they can no longer mate with each other. Speciation occurs when groups are reproductively isolated, either geographically, behaviorally, or temporally.

http://www.bio.miami.edu/dana/pix/selection_modes.jpg

Evidence of evolution can be seen in many ways, from the analogous and homologous structures in organisms to embryology to vestigial structures, which are evolutionary left-overs. These all indicate a common ancestry. Scientists use fossils as evolutionary evidence as well, although fossil evidence can be biased because organisms which have shells or bones fossilize the best. Earth's history, which is 4.6 billion years long, is divided into 4 eras (precambrian, paleozoic, mesozoic, and cenozoic), which are further divided into periods.

I am curious to learn more about the ways that current populations in the world are changing now.
I am working to become more assertive in group settings (rather than passive or aggressive). I am doing this by voicing my opinions, but also coming up with compromises and incorporating others' opinions as well.

Geologic Timeline Reflection

In this assignment, we made a timeline of Earth's history to better understand when and how some major events happened on our planet. We used a strip 10 meters long to represent the 4.6 billion years of Earth's history, where 1 million years was represented by 2 mm. One very significant major event is the creation of Earth itself, which happened 4.6 billion years ago. Nothing as we know it would exist if this collision did not happen to form our planet. The increase of oxygen in the atmosphere and organisms which use oxygen for life processes which happened in the Ordovician is an important event in Earth's history. This laid the foundation for processes such as photosynthesis and respiration, which are essential. The majority of organisms today are descended from these first organisms. The extinction of the dinosaurs was a very significant event in Earth's history as well. It happened during the Mesozoic Era and gave way for mammals to dominate. This paved a path for humans and other mammals to come into existence because the dinosaurs were very dominant at the time and the smaller mammals stood no chance.

In our scale, 1 million years was represented by 2 mm. It was surprising for how much of Earth's history there was no life. Being able to see this visually represented really put so much of history into perspective for me. Before doing this timeline, I knew that the Precambrian Era was 88% of Earth's history but when we scaled our timeline accordingly, I began to really understand how significant a part of history this is.

Humans have made up such a small part of Earth's history, and it is surprising how much they have changed the planet in such an relatively insignificant amount of time. Humans are now the dominant species, but have been around for not even a speck in terms of geologic time.

One question I have is, how significantly have humans changed the planet in relatively small time that they have occupied it?

Hunger Games Lab Analysis

1. In this lab, we simulated a population of organisms competing for survival. We wanted to model the process of natural selection. There were 3 phenotypes for picking up food in our environment: stumpys (AA), knucklers (Aa), and pinchers (aa). Corks represented food, and the food was scattered around a field. The organisms had 30 seconds to gather as much food as they could, and they had to get a certain amount in order to mate and reproduce.

2. Pinchers were the best phenotype at gathering food, because they got to pick up food with their thumb and their index finger, which was the easiest to get as much food as possible.

3. We found that the population did evolve, and the changed allele frequency is evidence for that. In the initial population, the frequency of the "A" allele was 52% and the frequency of the "a" allele was 48%. After 8 generations, the "A" allele frequency was 41% and the "a" allele frequency was 59%.

4. The genotypes and phenotypes that each organism was "born with" was completely random, the scattering of food throughout the field was random.

5. If the food supply was smaller than it was, there would have been more competition within the population for food. In this situation, the more aggressive organisms would have obtained more food regardless of their food-gathering phenotype. If there was a larger food supply, those organisms who weren't as aggressive would have a more equal chance. This parallels what happens in nature when food is scarce.

6. The results would probably have been significantly different if there was no incomplete dominance with the knucklers. The "A" allele would probably have been completely wiped out, because the stumpys' phenotype was the most difficult for gathering food.

7. In natural selection, nature "favors" individuals who have the best traits. The population evolves to look like these individuals.

8. At times when the food supply was clumped, some individuals developed aggressiveness in order to gather enough food and survive. There are many behaviors similar to this in nature, when an animal is more skilled at gathering food fast, or running from a predator. Individuals needed a place to store their food after they picked it up, and those with bigger pockets often had an advantage. In nature, certain animals will have certain genetic advantages like this over other organisms. The individuals with these strategies' phenotypes would have been more common in the population, which affects the allele frequency.

9. In nature, natural selection acts on and favors certain phenotypes, not genotypes. Populations as a whole will evolve, but not individuals.

10. One question I still have from this lab is: in nature, how much of an organism's chance of survival has to do with it's genes and how much has to do with it's learned skill set?

Beginning Research

During the past two weeks, I have begun to research my topic, which centers around risk factors for diabetes and heart disease in South Asians. I am currently reading a book for my research called The South Asian Health Solution. It is written by Ronesh Sinha M.D., an internal medicine specialist, who has noticed that South Asians are one of the groups that are at highest risk for diabetes and heart disease, and he states that overall, this is due to a set of high-risk genes coupled with poor lifestyle choices.

I read about the processes of inflammation and insulin resistance. Insulin is a hormone that carries glucose to your cells. The author likens insulin resistance to a train station, where insulin is the train ticket, glucose molecules are the passengers, the conductor is the insulin receptor, and and the train represents a muscle cell. Insulin resistance happens when the insulin receptors won't let in the glucose molecules, and therefore they remain in the bloodstream, increasing a person's blood sugar levels.

This is one of the key topics in the book, and I think the rest of the research will progress much faster now that I have the basics down. With a little bit more research, I think I will soon be ready to start creating my questionnaire.

Bird Beak Lab

Part 1: Analysis
In the bird beak lab, we came to the same conclusion as Darwin did: individuals who have "better" traits, or traits that are more suited to the environment, leave behind more offspring. We simulated 4 different types of birds' beaks with a spoon, a binder clip, a pair of tweezers, and a pair of scissors. The goal was for each bird to pick up as many pieces of "food" (rubber bands, macaroni, toothpicks, paper clips). We saw evidence that individuals with better traits leave more offspring when the tweezers-beaked bird had a total of 18 chicks, the highest among all other birds. A possible explanation for this could be that their beaks were more adept at picking up food. Another of Darwin's conclusions was shown true in our lab: the fact that populations gradually start to look more like the "winners", or individuals with the better traits. The tweezers chicks made up 37% of the population. An explanation for this is that the tweezers chicks collected more food and had more offspring.


Conclusion:
In this lab, we asked the question: if natural selection occurs in a population, how do changes in selective pressures affect the evolution of that species?  We also simulated a drought in this lab, where the drought wiped out all the seed pods (toothpicks). The toothpicks were removed from the birds' supply of food. Theoretically, this would affect only the birds who relied on the seed pods as a source of food. We found an increase in the tweezers chicks' population and the spoon chicks' population, who did not rely on the seed pods as a staple source of food. The scissors chicks' population stayed constant. This data support our claim because the birds did not rely much on the toothpicks for food, therefore the drought did not affect them much.

When we simulated the seed pod drought, our data somewhat contradicted the expected results. We hypothesized that the binder clip chicks' population would increase or stay constant, since it was the only type of bird that had never consumed the seed pods. Instead, the binder clip chicks' population decreased. This was probably due to an error. The binder clip required the user to apply a decent amount of pressure in order to operate it and pick up the food. When doing the back to back trials, using the binder clip became tiring. This error caused the population to decrease, instead of staying the same or increasing. In the lab as a whole, each bird beak was operated by a different student, and each student would have a different skill level in terms of picking up the food. This might have caused certain populations to be too high or too low. Due to these errors, in future experiments I would recommend students switching "bird beaks" in order to make the lab more objective and maybe finding an alternative for the binder clip, because of the finger pressure that is needed to use it.

This lab was done to demonstrate the concept of natural selection, and how every population will have winners and losers. From this lab I learned how natural selection would works in an ecosystem, and I now understand the concept better. Based on my experience from this lab, I can better understand why certain traits are more dominant in certain populations.