Day 24-Genetics

Today we learned about genetics. We learned how genes are used to express a physical trait, which can either be dominant or recessive. There are two types of cells: a sex cell called a gamete, which is a sperm and an egg, and a somatic, which is a body cell. The two go through totally different processes to get to their chromosome. Gametes go through meiosis, where only 1 set of chromosomes is produced. Somatic go through mitosis, where an exact copy of the cell is produced.

We also learned how to solve genetics problems. Here are the steps:

1. Write down the info. For example, Dominant=A=trait.
2. Parenting genotype. Aa x Aa.
3. Law of segregation. For example, Aa splits up into A and a.
4. Punnett square. See example on the left.
5. Fill in the square. Below the empty is one that is filled in.
6. Create your ratios. For example, on the right, the phenotype ratio is 3 dominant :1recessive. The genotype ratio would be 1AA:2Aa:1aa.

Day 20-Handy Genes

Summary for Your Inner Fish CH3

Although it is interesting that we can trace homologous structure back to common ancestors, it is very interesting that we can trace back the gene frequencies, finding the small changes which result in easily visible differences between species today. Our bodies are formed from one single cell, which carries the plans for our entire body. Within this cell is all of the DNA which is passed from our parents, from their parents and so on. DNA makes up genes, which make up chromosomes, which make up cells, which turn into a body. Hands are very complex structures, which contain three different dimensions: thumb and pinky side, top and bottom, and tip and base. The million dollar question is what change in DNA causes these differences. The answer lies in the embryo, but is impossible to study this on human embryos, so the answer was chickens. A number of biologists did countless hours of work with chicken eggs to prove that each small change within the embryo causes a major difference in the mature body.

Day 19-Jump Into the Gene Pool

Survival of the Sickest Ch.6 Summary:

The first vaccines were discovered by a man named Edward Jenner, an eighteenth century doctor. A common disease was cowpox, which many milkmaids had from being around cows. He found that they were immune to smallpox so he then infected a different group of people with cowpox, and found that they were also immune to smallpox. From here, the first vaccine was born. The word vaccine comes from the Latin word vacca, meaning cow, and the Latin name vaccina, meaning cowpox.

Your body contains 46 chromosomes, 23 from your mother and 23 from your father. Within these, there are around 30,000 genes which are organized based on different traits. Although your body has so many genes, only around 3% are actually functioning. The other 97% though, contains important information about how your body works, unlike the misconception that they are "junk DNA."

A scientist named Barbara McClintock disproved another common misconception about DNA from the early 20th century. Through her research and testing on corn, she found that there are genes, which she called "jumping genes," that copy and paste themselves in different places along the chromosomes. She proved that they  were actually intentional mutations, not just random. She found this because they place themselves in certain, particular places and they are triggered by outside influences. She also found that they jump to certain places more than others and they jumped at times of stress.

Another new finding within DNA and mutations is that mutations actually occur outside the germ line all the time. We had thought previously that mutations occur inside the germ line and they affect the entire population and offspring, but this is not the case. For example, Cancer, "which is uncontrolled cell growth caused by a mutation in the gene that is supposed to control growth of cancerous cells" (Moalem, 144). Of course, some forms of cancer are hereditary, but others are caused by factors outside the germ line such as smoking. 

Day 18-DNA

1. Mendel designed an experiment involving crossbreeding pea plants. He bred different variations of the plants, such as tall and short plants. In his findings, he proved that heritable variants are not just blended randomly, but are "discreet entries passed from parents to offspring."  
2. Francis Crick and James Watson discovered the double-helix structure (see image below).
3. Variations:
• Point Mutation- Inactivates the gene, such as in whippet dog, which has a much more slender body than most other dogs.
• Insertion- A new base-pair is inserted into the gene, such as pea plants which have wrinkled skin instead of smooth skin. 
• Gene Copy Number- When entire genes are duplicated, such as in chimps, who have only 1 enzyme to digest green plants where as humans have 10.
• Duplication- Sequences containing 8 or more of the same base-pair, which can cause dark spots on the body.
• Regulatory Changes- A mutation which turns genes on and off, which can cause appearance changes.
4. Evo-devo is the study of the role that the effects of changes in important developmental genes play in evolution. 
5. If a person stops drinking milk after their infant years, they will loose the enzyme which allows them to digest lactose. Those who do not stop, though, will have an enzyme called lactase, which allows them to drink milk.

Day 17- Races

It is safe to say that different races on earth do not exist. We all originated from one continent; more specifically, one tribe of people. These people, from south-east Africa, are the origin to the human race. In this group of people, we can find features of all different races of people, all in one person. This tribe ventured out of their home to search for something new. Where they were going? They had no idea because they had never been too far away from their home. They started in south-eastern Africa, then moved through the modern Middle-East and on to Asia. After Asia, the tribe scattered out in different directions, and it is here that we find the differences that are used to characterize what modern-society defines as a race.

             

The differences in appearance and traits are caused by genetics or DNA, which are tiny variations in the genetic makeup of a person. As time went on, these variations appeared more and more often, and the gaps grew bigger and bigger between races, until finally, we get to the modern world with hundreds of different races.  All of this is an outcome of natural selection, where nature is the one who decides which traits keep reappearing, and which are not as common. For example, the original tribe of people had a dark skin color. This is because they lived in south-eastern Africa, very close to the equator, and they were hunter gatherers so they were out in the sun a lot. As time went on, though, and they moved out into cooler regions such as Asia, the need for extra protection from the sun was not needed. So the dark skin pigment trait eventually died off due to natural selection.

This happened over and over, traits came and went throughout the world as humans made their way into climates and lands which they were not used to. Eventually, each race would develop distinct adaptations for the environment they were living in, but all of these races can still trace their roots back to the same common ancestor. 

Day 15-Unit 2 Test

Today we took out test for Unit 2.

Day 14-Populaption Genetics

Today we discussed population genetics and how it relates to evolution. We reviewed that natural selection is based on being fit and able to reproduce. We learned that in genetics, there are two types of traits: dominant and recessive. In a dominant trait, there are two genes which could be an AA or Aa, but in recessive traits, the two genes are always aa. Some terms we learned are Genotype: what the genes are, Phenotype: physical traits, and Gene Frequency: the percent of A's and a's in a population. We learned the gene frequency equation, p+q=1, p being the A's and q being the a's. This equation was developed by Hardy and Weinberg, where they changed the gene frequencies into percents, and then to decimals. The fully written out equation is p²+2pq+q²=1. 

Day 13-Natural Selection

We discussed our results from the Brine Shrimp Lab in class today. We observed that most groups had the highest number of swimmers in the 2.0 concentration brine. The reason behind this is that Brine shrimp eggs wait for a specific concentration to hatch. In this batch, the eggs wanted to hatch in a higher concentration. Brine Shrimp live in saltwater lakes such as the Great Salt lake in Utah. In this lake, the concentration of salt in the water is constantly fluctuating. Mineral deposits deep in the lake cause the concentration to go up, but freshwater snow runoff causes it to go down. Due to this trend, the Brine shrimp would have to constantly be adapting if they hatched at random times, but by hatching at a specific one, they create the best chance for surviving to live to an older age.

Day 12-Brine Shrimp Lab

Today in class we began the Brine Shrimp Lab and discussed natural selection. To learn about this, we separated a bag of shells by different characteristics. We learned that nature uses these characteristics for different things, and we can tell where the shells came from by using them. For example, different colors on the shells are used as camouflage, and the texture of the shell can tell what kind of environment it was in (rocky, sandy, etc.). Later we began the lab. We prepared saltwater brines for with different molarities(0.0, 0.5, 1.0, 1.5, 2.0), and poured them into petri dishes. Then, we put some eggs on a piece of double sided tape and stuck it on a microscope slide. We used microscopes to count how many eggs were on the slide and finally put each slide in the petri dishes.

Day 11-Dangerous Foods

Today we went over Ch. 4 of Survival of the Sickest. We learned that all plants produce a toxin as a defense mechanism against predators such as insects, but not toward humans. Although the toxins are not directed toward us, they can still prove to be deadly in some cases, which could include some foods you eat in your everyday meals. For example, tapioca pudding contains a plant called cassava. When cooked and prepared the right way, it can make for a delicious snack, but in its raw form, is found to contain a precursor to deadly cyanide. Another example is a habanero pepper. If you have ever bitten into a raw habanero and felt a fiery sensation on your tongue, you are experiencing the effects of a plants toxin. This toxin can actually prove to be very harmful, by destroying neurons and can even lead to stomach cancer.

Day 10-Evidence for Evolution

1. This image shows evidence for evolution in that Whales didn't originally come from the water, they evolved from land animals into aquatic animals gradually over time. This is a great example of how evolution helps keep species alive, as the Mesonychid knew there was food in the water, but couldn't swim. So over time, evolution gave him the ability to do so.

2. e. North America.

3. A dragonfly, bird and bat are all examples of convergent evolution. This means that they have similar features but came from different common ancestors. They also have analogous structures, which means that the features which they have in common, were also not present at the last common ancestors. For example, the dragonfly and bird both have wings which serve the same purpose, to fly, although, they came from completely different lineages.

4.In the Common Decent lab, one can see ancestry as evidence for evolution through the evolution of birds. Between the Chicken, Duck and Penguin, the Penguin is the oldest. From the penguin, who has only a thin layer of feathers, to the duck who has more, and finally to the chicken who has a thick layer of feathers. We can also see the evolution of not being able to fly to being able to fly.

5. Homology is the similar bone structure in different animals. An example of this is the humorous in a human. A similar structure of this bone can be found in a bird's wing, a horse's leg, a bat's claw or a whale's fin.  

Day 9-Fossils

Today we discussed the first few chapters of Your Inner Fish. Chapter 1 discussed how fossils are formed, and found. We learned that the older fossils are found deeper in the ground and the younger ones are closer to the surface. We also discussed how the location that fossils are found today, may not have been the same millions of years ago. The example was Tiktaalik, a transitional fossil (meaning that it was a species that was evolving, and in this case from marine animals to land animals). This fossil lived somewhere below the equator, but due to continental drifts, it is found today somewhere in northern Canada. Chapter 2 talked about homologies, which are the same bones in different animals. For example, an arm bone on a human is a homology of a wing bone for a bird. To conclude class we took a trip to the museum to see the actual model of Tiktaalik.

Day 8-Test Review

We reviewed for the test and took an all chemistry quiz. (I missed this class because I was sick.)

Day 7-Macromolecules

Today we went over macromolecules. We learned about polysaccharides which are long strands of sugar, which are both storage products and structural products. We learned that lipids are fats or oils that store energy. We learned about sucrose which plants use for circulating fuel and lactose which is found in dairy products and gives them their sweet taste. We learned about starch which is used in plants to make sugars and can also store a lot of energy in a small place. We also learned about nucleic acid structures which consist of DNA, RNA and ATP.

Day 6-Cell Membranes

Today we began class by discussing cell membranes. We learned that all living organisms have cell membranes(except for viruses). They are semi-permeable based on the size of the molecule and if it is polar or non-polar. We learned that they are made up of proteins which are also known as "gate keepers" because they are where molecules cal pass through the membrane. We also learned that osmosis occurs through these proteins because they are hyper-philic or water loving. The rest of the class consisted of a short lab quiz and our first house case.

Day 5-Graphs

We began class today reviewing how to make a scatter-plot graph, as we are going to need to do this for the Osmosis Lab report. We reviewed that every little detail counts from the title to labeling the axis.We used the rest of class to finish the Osmosis lab which we started the class before.

Day 4-Diffusion and Osmosis

Today we learned about diffusion and osmosis. We learned that diffusion is the movement of molecules from a higher concentration to a lower concentration. We then concluded that osmosis is the diffusion of water. In the osmosis of water, a higher concentration of water moves through a semi-permeable membrane (meaning that it lets some particles out, but not back in) into a lower concentration. This movement is the water trying to reach equilibrium, which is when all the water molecules have the same concentration as their surrounding molecules. We spent the rest of class working on a lab, testing what we had just learned.

Day 3-Water

Today we learned about water and all of its properties. We took a written quiz on basic chemistry and an oral quiz with a partner on water. For our oral quiz about water, my partner Alvin and I answered the question: Explain why ocean temperatures fluctuate much less than temperatures on land. The reason is because water has a higher heat capacity than air, meaning that it takes a lot more heat or a lot less heat to cause a significant change in the temperature in the water. This is because water is a liquid, and its molecules are not freely moving around, like they are in the air, which is a gas. Just a little heat will cause molecular motion in the air, but it takes a lot to cause the molecules in the water to start moving.

Day 2-Worksheets and a Quiz

Today was more of a learning day. We first went over what we would be covering in Unit 1 and how grading would be done. Then, we worked on worksheets which reviewed ionic and covalent bonds, where we found the number of protons, neutrons and valence electrons there are in various elements. We also had to draw Lewis Dot structures for different elements. After we finished, we took the oral quiz which we had prepared for the night before and also took a practice written quiz. Although the day was not packed with new information, it was helpful to review things we learned last year.

Day 1-Milk in Motion Lab

Today we did a lab involving milk in motion. We first watched a video showing how to do the lab for homework: First pour some milk into a dish, then add a few drops of food coloring, finally, add one drop of dish soap and observe as the food coloring dances around the dish. In class, we got into groups and had to find out why the milk reacted this way to the dish soap. My partner, Chris Jung, and I came up with the hypothesis that the milk reacted this way because the soap's bipolar characteristics reduce the surface tension in the dish, letting the food coloring drops flow freely across the surface of the dish. Since the soap is bipolar, one end of it reacts with the fat in the milk, and one end doesn't. To test this theory, Chris and I did two tests each with Reduced Fat 2% milk and Whole Milk. Both times, the Whole Milk's reaction was much faster and more violent, which backs up our theory that the soap was in fact reacting with the fat in the milk. To make sure, we both each did two more tests but this time a little different. We each had one dish with plain black coffee, and one dish with coffee mixed with 2% Reduced fat milk. My partner and I found that in the plain coffee, there was little or no reaction, but in the coffee/milk solution, sure enough the food coloring danced around on the surface of the dish.