Unit 8 Reflection

In this unit we essentially studied why a population's gene pool looks the way it does. Some factors that determine the genotypes in a gene pool include artificial selection, natural selection, evolution, and speciation. Artificial selection, or breeding, occurs when us, humans, select traits from a population's variation that we want, and only mate individuals with those traits. Traits can be selected by nature too, however, and this is known as natural selection. Charles Darwin, a famous evolutionary biologist, drew two simple conclusions from his experiments that explain the results of natural selection. Darwin said that individuals whose inherited traits help them survive better and reproduce more tend to leave more offspring than other individuals. He also concluded that this unequal ability of individuals to survive and reproduce will result in the better traits becoming more common in the population over generations. We tested these two conclusions in our bird beak lab. In Darwin's studies, natural selection caused birds to adapt to the change in their environment and, over time, their species developed new traits that helped them survive. This is known as evolution.

<http://www.yourarticlelibrary.com/evolution/notes-on-darwins-theory-of-natural-selection-of-evolution/12277/>

Natural selection is directly connected to evolution because natural selection is the mechanism of evolution which acts upon the phenotype of individuals. Based on that selection, the population is the actual thing that evolves, not the individual. We also learned about how natural selection distributes its traits in directional selection, stabilizing selection, and disruptive selection. Genetic drift, gene flow, mutations, and sexual selection, along with natural selection, are all factors that can alter the genotypes of a gene pool. Speciation is the rise of two or more species from one existing species, and this is caused by reproductive isolation. Finally we studied the history of Earth, learning about the major events in the development on life on this planet through an activity in which we created a geological timeline of Earth. 

<https://www.pinterest.com/ccoombe0014/geologic-timeline/>

I am still not confident about the concepts of RNA monomers evolving into RNA molecules and then eventually into DNA. I also still wonder: if amino acids could have been the building blocks for life, where could the amino acids come from? What created the amino acids? Or what caused the amino acids to form? 

To be more assertive, I have tried to be direct and honest with friends and classmates about my opinions and needs, trying to avoid being rude or pushy. The challenge for me is avoiding being passive completely by not talking about something I dislike about a person behind their back, but instead, directly addressing the problem by talking to them. 

Geologic Timeline Individual Reflection

In this activity, I found that three major events that changed the course of Earth's history are the Cambrian explosion, the Triassic period, and the Quaternary period. The Cambrian explosion followed the Precambrian era, during which organisms capable of undergoing photosynthesis developed, increasing the amount of oxygen in the atmosphere to be high enough to support life. The Cambrian explosion is noted by a sudden appearance in the fossil record when many organisms suddenly began to exist. This is a major event in the history of Earth because all life originated from this one geological event. The Triassic period is a pivotal period because it was during the early times of dinosaurs and the origin of mammals. Dinosaurs eventually evolved into the birds and reptiles of our current time period, making it significant in being the birthplace of many species that we know and love today. The creation of mammals was extremely significant because it was also the birth of the unique characteristics of hair, warm-blood, milk producing females, live births, and much more complex brains. This event set the stage for the population of intelligent species, humans, which drastically changed the history of Earth. Leading up to the third major event in the history of Earth: the quaternary period. This period consists of the first fossils of homeosapiens and our present day. The quaternary period significantly altered Earth's history because we quickly and immensely populated the planet, causing crucial events such as global warming. The mark on the planet that we are making now will cause future generations to look back at our accomplishments and consider them a drastic turning point in the geological timeline.

It was surprising to me that the majority of Earth's history consists of the Precambrian period, before life even existed. I was also astonished at the millimeter of space our species takes up on our 10 meter timeline. Before this activity it never really hit me how insignificant we are in the history of our planet. It's hard to wrap your head around the fact that our lives are so short and our impact on Earth is so microscopic.

I still want to know why marine life developed before land creatures?

<https://commons.wikimedia.org/wiki/File:Timeline_evolution_of_life.svg>

Hunger Games Lab Conclusion

1. In this lab we simulated the evolution of a population but having three different species, each with a unique way to collect "food" and see which population had the most allele frequency change.

2. The knucklers were the best at collecting food because they could easily collect four pieces of food at once, two in each hand. They preformed better at passing their genes on and therefore the population looked more like knucklers.

3. Yes, the population did evolve because the allele frequency changed overtime. At the start of the lab, the population consisted of 52% of the population being "A"allele, and 48% of the population being "a" allele. Halfway through the lab, during the 4th trial, 21% of the population was "A" allele and 79% was "a" allele. At the end of the lab, the "A" allele consisted of 28% of the population and the "a" allele was in 72% of the population. This drastic change in allele frequency proves that evolution did indeed occur.

4. Some random aspects of this lab included the dispersion of food, people's physical ability at moving around and collecting food, and each individual's stomach size and ability to hold the food once it was collected. The flipping of the coin during meiosis also chose random alleles to be part of the offspring. These things affected the evolution of the population because maybe all of the knucklers also had the best places to carry food as well as the people with quick physical skill. The randomness added more variables to the experiment, no longer solely testing if characteristics of each species. A few not random parts of the experiment included the mates people chose and the trait you were given at the begining of the experiment. The original traits were evenly distributed among the class, causing our first trial to have number pretty close to half of the "A" allele and half of the "a" allele. Knucklers and pinchers usually wanted to mate with pinchers, to increase the chance of having offspring that would survive. This shifted the outcome of the experiment because we could purposefully decide which alleles we wanted in the population and which ones we wanted to get rid of.

5. Yes, for example, if the food was something larger like a tennis balls or bean bags instead of corks it would have given the stumpys a huge advantage because the pinchers and knuclers don't have the right mobility to be able to pick up such large objects. Just like the potential of stumpys dominating in this population, in nature when resources change, new traits are favored and the gene pool ends up looking slightly different.

6. Knucklers were the example of incomplete dominance in this experiment because their alleles consisted of "Aa". Without the knucklers in the experiment, the "a" allele would have dominated because recessive alleles are harder to wipe out. The pinchers, with an "aa" allele, would have completely rid the gene pool of stumpys and we would find the population completely consisting of pinchers. The knucklers added that extra variable to keep the pinchers from completely dominating.

7. Natural selection filters out the less fit, leaving only the best to survive under those conditions. As species reproduce and reproduce, these traits become more and more common among a population, wiping out the unnecessary traits. This is known as evolution.

8. When the stumpys reappeared in the population, they band together, working collaboratively to try and produce offspring together, and ensure the survival of their species. This caused the "A" allele frequency to go up for a short while. In nature, organisms are given the choice with who to mate with and most are drawn to mates of the same species because to ensure the survival of that species.

9. Natural selection is the mechanism of evolution which acts upon the phenotype of individuals. Based on that selection, the population is the actual thing that evolves, not the individual. In this experiment, the population evolved from the beginning of the experiment to the end. Even though meiosis determined which genotypes would be in the offspring, the phenotypes caused the parents of the offspring to actually survive the round and be able to reproduce, therefore, the phenotypes were the aspect that determined the selection of certain traits in individual offspring.

Bird Beak Lab 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 found that Darwin's two conclusions are indeed true. Individuals whose inherited traits help them survive, tend to leave more offspring. The tweezer beaked bird's easily maneuvered beak caused it to be the best suited for picking up rubber bands, macaroni, toothpicks. It produced 21 offspring in the first part, and produced 8 offspring in the second part, more than the scissor beaked bird, the binder clip beaked bird, and the spoon billed bird. This data supports our claim because the tweezer beaked bird, who's incredibly functional beak helped it survive, produced, by far, the most offspring among the bird population. We also found that it is true that the better traits of individuals become more common in populations over generations. The tweezer beak bird's offspring became more and more abundant as the simulation went on from year 1 to year 2 to year 3. This data supports our claim because the tweezer beak bird consistently collected the most food, collecting the most food in year 3. 

While our evidence supports our claims, there could been errors due to the difference size and strength of the hands of the people participating in the experiment. Some people are better at maneuvering their hand to use their given tool to pick up the food. Another possible error that could prove our claim incorrect is the fact that food seemed to be selected to specifically customize the abilities of the scissors, tweezers, and binder clip that could all pinch the items. This caused the simulation to not be completely accurate because if an organism, such as the spoon, could not collect any food in a certain area, then realistically, they would feel the need to emigrate to an area with food that suits their ability to collect the food. Even if one of the purposes of the experiment was to eliminate the spoon species, it was very obvious even before we even started that the spoon did not have any capability of picking up food. Due to these errors, in future experiment I would recommend collecting and recording the overall class data to average out the physical skill level of individuals and get more accurate results. I would also recommend adding a food of larger size to the experiment that could give the spoon at least somewhat of a chance to at least survive the first year. This would also make the results of the simulation less obvious from the start.

This lab was done to demonstrate Darwin's two conclusions regarding natural selection. From this lab I now fully understand the ways natural selection changes the dynamics in an ecosystem, which helps me grasp the simplicity, yet brilliantness of Darwin's findings. Based on my experience from this lab, I can now interpret the reasons for the difference in species I see when I go to natural history museums or read about animals such as wholly mammoths that have evolved into elephants today. The natural environment forced these organisms to adapt or die and the ones that stayed, changed their phenotype as a result.

<http://it.pinellas.k12.fl.us/Teachers3/gurianb/files/8041AE1EF3B946ABB522A47B70C43974.pdf>