In biology, we just learned about the different processes and parts of plant cells, covering concepts like osmosis and the transport of molecules and ions in a cell. We started our learning around the question "how do Venus flytraps close when they are triggered by an insect?". After learning different concepts that could help explain the phenomenon, we came back to the question and tried to answer it. We made science sketches to explain our theories on the process, and this is my groups theory on how Venus flytraps are triggered and close around insects. (Be warned the drawings are not exactly Van Gogh's) Thank you!
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In Biology, we just finished our genetics and inheritance unit, which was REALLY cool. We got to learn how about DNA, the cell, and different types of inheritance. I personally thought that learning about how DNA is the code for proteins was the coolest part of our entire unit, because I had always wondered how traits were expressed in different people and I could never wrap my head around how such a small thing could hold all of the information for an entire body. We started our unit by watching Twitch, a documentary about a teenagers struggle behind wanting to know if she had Huntington's Disease, a genetic disorder, or not. It was incredibly interesting, and it sparked many questions about how genetic disorders are inherited, or what a genetic disease was in the first place. With these questions, we moved into our unit. Now that we are done with our genetics unit, we looked back to our questions and tried our best to answer them. P.S. If you want to know more about Twitch, you can scroll down to the article I wrote about it at the beginning of our genetics unit! Answers to my questions about the twitch documentary: How many mutations (or how long) is the gene that contains Huntington's Disease? The mutation for Huntington’s Disease occurs in the HTT gene, which codes for a protein called huntingtin. It’s cause is a segment of DNA, specifically CAG, repeating many times in the gene. While unaffected people typically have this segment of DNA in their HTT gene about 10-35 times, people with Huntington’s have the CAG segment 36-120 times. This results in an elongated huntingtin protein that then breaks up into smaller, toxic pieces that bind together and accumulate in neurons, disrupting their functions. How do genetic diseases first occur? A mutation occurs in an individual's gametes, and they pass down that mutation to their offspring. Mutations are errors that DNA polymerase made, affecting the tertiary structure of the proteins that it codes for. There are two different types of mutations (BASICALLY) which are point mutations, where only one nucleotide base is changed, and frameshift mutations, where extra nucleotide bases are added, causing a shift in the rest of the DNA strand. A mutation can either be dominant, meaning that it only needs one allele to be expressed, or recessive, meaning that it needs to be homozygous for an allele for it to be expressed. If the mutation is recessive, or if it only affects individuals after child rearing age, it will most likely be passed down through generations and more people will begin to suffer from it. Is it possible (or will it be possible) to cure genetic diseases with genetic modification? If so, what would those missing genes be replaced with? Most likely. Genetics and genetic engineering are fields that are exploding right now. Scientific discoveries are revealing more and more about what we can do now and what we might be able to do. As for what genes might replace genetic disorders, that’s an ethical decision that will have to be sorted out in the maybe not so distant future. Are there genetic diseases that are a dominant trait? Yep. Huntington’s is actually one of them. For a dominant genetic disorder to recur though, it has to either affect a person after they’ve had kids, or it has to be insignificant enough that it can’t prevent a person's reproduction. Dominant genetic disorders are typically rarer than recessive genetic disorders because dominant genetic disorders can’t hide in individuals, meaning everyone that gets the mutated allele will suffer from the disease, usually preventing them having offspring. Are genetic diseases usually more present in certain regions (where they probably originated)? Yes. A way that genetic disorders can be determined is looking at the history of a family and where that family originated from. A cool activity that we did this unit was when we were given a description of a disorder but we weren’t told what that disorder was. Our class had to try and figure out what the disease was, and the most helpful bit of information was that the trait was more common in eastern europe. We were able to find out that the disease was Tay-Sachs Disease, a recessive genetic disorder that results in the premature death of infants. Sources: “FAQ About Genetic Disorders.” National Human Genome Research Institute (NHGRI), USA Government, 10 Nov. 2015, www.genome.gov/19016930/faq-about-genetic-disorders/. Mayo Clinic Staff. “Huntington's Disease.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 16 May 2018, www.mayoclinic.org/diseases-conditions/huntingtons-disease/symptoms-causes/syc-20356117. “What Is a Gene Mutation and How Do Mutations Occur? - Genetics Home Reference - NIH.” Genetics Home Reference, National Institutes of Health, 29 Jan. 2019, ghr.nlm.nih.gov/primer/mutationsanddisorders/genemutation. For our genetics unit, we watched the documentary Twitch to better understand genetic diseases. The documentary Twitch follows Kristen Powers and her struggle to deal with the possibility that she has Huntington’s Disease. Huntington’s Disease, or HD, is a genetically inherited neurodegenerative brain disorder that occurs in mid-life, often after the patient has had children. HD degrades a person’s brain, slowly taking away basic motor control of the body and mind. It leaves patients helpless, unable to perform tasks like walking normally, picking up and holding items, remembering numbers and names, and much more. Kristen is a charismatic, independent, and an optimistic senior in highschool, but because her mother had and died of HD, there is a 50% chance that she has HD too. This always looms over her, constantly reminding her that the life that she loves might be taken away from her. Kristen’s mother was a lot like Kristen, independent, life-loving, and ambitious, but she had developed HD and it took her life away, leaving her helpless and completely dependent on others. Kristen had to watch and provide for her mother as she slowly lost more and more control of herself, separating with Kristen’s father, falling into depression, losing herself to HD. Throughout the documentary, she tries to cope with and discuss the reality that she might have HD. But when she turns eighteen, she decides that she wants to get tested for HD, knowing that if the test comes back positive, the rest of her life will be lived in the paranoia of knowing that her life is only a ticking clock. This documentary was extremely impactful for me. The decision and psychological impact that either outcome, testing positive or negative, would imply interested me immensely. It was hard to watch Kristen’s struggle with the practical coin toss of her life, knowing that, if the tests came back positive, she would live the rest of her life knowing she only had so much left. The most interesting part of the film for me though was thinking about if I would want to get tested or not. At first I thought about the two possibilities, testing negative or testing positive. On one hand, testing negative would mean that I could live the rest of my life to the fullest, being able to have a family knowing that they wouldn’t have the risk of HD looming over them. On the other hand, testing positive would mean living in constant paranoia. Everytime that I twitched or forgot something, I would be launched into a downward spiral that would probably lead into a depression for the rest of my life. With the knowledge that I wouldn’t be able to have a family and that my life will be slowly drained out of me, I don’t know if I would even have a will to live. And then I thought of the third possibility, which was the most interesting to me, not taking the test at all. I don’t know if I would want to change my life if I knew I had less of it. Ultimately, all I hope for is to make the world a better place, and a time limit shouldn’t affect that. The whole risk/reward scenario of the test results is a tempting gamble, but I think that I wouldn’t want it. All I want is to live my life to the fullest, and I try to do that everyday. Not by setting a destination to get to, but by making the journey as good as I can and seeing where that leads me. Even if I knew my journey was shorter than I wanted, I wouldn’t want knowing that negatively affecting the journey that I truly want to take. Five questions about genetic diseases: How many mutations (or how long) is the gene that contains Huntington's Disease? How do genetic diseases first occur? Is it possible (or will it be possible) to cure genetic diseases with genetic modification? If so, what would those missing genes be replaced with? Are there genetic diseases that are a dominant trait Are genetic diseases usually more present in certain regions (where they probably originated)? In biology class, we are learning about evolution, with a special focus on natural selection. We watched a series of videos that looked at various scientific studies done on natural selection, and we got to choose the study that we think best showcased natural selection in effect. I chose a study done on variation of color in rock pocket mice populations in New Mexico. You can click here for a link to the HHMI BioInteractive page on this study. (It's pretty darn cool, I would check it out if you have time.)
In New Mexico, there are lava flows that dot the landscape, a result of a series of volcanic explosions. Rock pocket mice, that are native in New Mexico, typically live in and around a sandy, desert environment. They are normally a tan color and blend in with the sand, letting them hide from their predators that rely mainly on their sight. However, rock pocket mice that live on the lava rocks have darker fur than the mice that live on sand. Studies were done on different rock pocket mice populations that lived on lava flows to determine if the rock pocket mice were adapting to their environment, or in other words, if natural selection was in effect. To determine that a process is natural selection, four things need to be demonstrated in a population; that there has been a change over time in the amount of individuals with a certain trait in a population, that there are variations of the trait in a population, that the trait is heritable (or able to be passed on from parents to offspring), and that the trait gives a survival or reproductive advantage to individuals with it. For rock pocket mice, there has been a change in the frequency of a dark furred trait, as rock pocket mice populations that live elsewhere are mainly, if not entirely, tan colored. There is variation in the mice populations, as there are both tan and dark colored mice. The dark fur traits are heritable, as researchers found the specific gene that causes dark fur to occur and dark furred mice had dark furred offspring. On a brief tangent about that, it was found that mice from different lava flows had different genes that made their fur darker. That means that the dark fur trait was developed separately and from different genes at different lava flows, which I thought was REALLY COOL. Lastly, having dark fur on the dark lava flows helps rock pocket mice blend into the rock, which lets them avoid predators better than tan furred mice can. This gives the dark furred mice a survival advantage over the tan furred mice on the lava flows. Natural selection of darker fur traits is occuring in rock pocket mice populations across New Mexico, as having dark fur gives the mice an advantage on lava flows and, thus, a greater chance of passing on their genes. Natural selection over time made rock pocket mice more fit to their unique and changing environment. Megaloxantha bicolor sub. mouhotiIn Biology, we had the amazing opportunity to meet with Bob Sober, who is a professional photographer and a hobby entomologist. He brought in beautiful beetle specimens, and we got the opportunity to observe and research a beetle of our choice! I chose to research Megaloxantha bicolor sub. mouhoti, which is an incredibly interesting species of beetle. Taxonomic Information Kingdom: Animalia Phylum: Arthropoda Subphylum: Hexapoda Class: Insecta Order: Coleoptera Suborder: Polyphaga Superfamily: Buprestoidea Family: Buprestidae Genus: Megaloxantha Species: bicolor Subspecies: mouhoti
During the larval stage, jewel beetles bore into mainly dead or dying wood, although some species also bore into grasses and crops. Megaloxantha bicolor sub. mouhoti is a beetle that bores into wood. This has given jewel beetles another name, flathead borers, and they can cause agricultural and economic damage. Adult Buprestidae mainly eat flowers and plants. The lifecycles of Buprestidae beetles are all rather similar, and it takes around 1 year for one complete cycle. Adult beetles lay their eggs in the crevices of a trees bark. When the eggs hatch, the larvae bore into the tree, mainly targeting dead or dying wood. The larvae are ovalish and entirely white except for maybe a few pigmented spots. The cuticle, or covering, on the jaws of Buprestidae larvae can be equivalent in hardness and stiffness to stainless steel, which helps them bore through wood easily. When the beetles reach the adult stage, they leave the tree. Megaloxantha bicolor adults are medium to large sized beetles, reaching lengths up to 75mm, and, like all members of the Buprestidae family, they are able to fly. Their head seems small, as it is somewhat retracted into their thorax, and the eyes are widely spaced from each other on both sides of their head. They are black except for two orange spots on the side of their thorax and two white spots facing up near the back of their abdomen, and of course, they have a metallic sheen on their entire body. Fun Fact! The elytra, or the covering for the wings, of Buprestidae beetles are popular among collectors, and they are traditionally used in jewelry, decorations, and shrines in Pacific Island cultures. Sources: Sober, Bob. “Megaloxantha bicolor sub. mouhoti.” 2018. Photograph Bartlett, Troy. “Family Buprestidae - Metallic Wood-Boring Beetles.” BugGuide.Net, Iowa State University: Department of Entomology, 16 Feb. 2004, bugguide.net/node/view/162. Egge, Jacob. Jewel Beetles or Metallic Wood-Boring Beetles. www.plu.edu/biology/wp-content/uploads/sites/7/2017/09/final_buprestidae_egge_20170914.pdf. Bellamy, Charles L. 1997. Buprestoidea. Version 01 January 1997 (under construction). http://tolweb.org/Buprestoidea/9082/1997.01.01 in The Tree of Life Web Project, http://tolweb.org/ Kolibac, Jiri. “Classification and Phylogeny of the Buprestoidea (Insecta: Coleoptera).” ResearchGate, Jan. 2000, www.researchgate.net/profile/Jiri_Kolibac/publication/274379176_Classification_and_phylogeny_of_the_Buprestoidea_Insecta_Coleoptera/links/551d226e0cf2000f8f938434/Classification-and-phylogeny-of-the-Buprestoidea-Insecta-Coleoptera.pdf. “Buprestidae: Jewel Beetles.” Encyclopedia of Life, Biodiversity Heritage Library, eol.org/pages/7473/details. “BUPRESTIDAE (Excluding Schizopodidae).” Wood Boring Beetle Families, 4 Feb. 2011, idtools.org/id/wbb/families/Wood_Boring_Beetle_Keys/Woodboring_Families/Media/Html/Fact_sheets/Buprestidae.html. “Jewel Beetle.” Australian Museum, NSW Government, 20 Aug. 2009, australianmuseum.net.au/jewel-beetle. For our ecology unit in Biology, we had to make a food web with the organisms in the Wichita National Wildlife Refuge. We also had to explain different concepts that we had learned about ecology like trophic levels, detritivores, the rule of tenths, and biotic and abiotic factors. While making our food webs, we learned that ecosystems that might seem relatively barren at first, like the Wichita's prairie ecosystem, actually host an abundance organisms that heavily rely on one another. If I had to think of one word that describes what I learned with the food web project and throughout the ecology unit, it would be interdependence. |