First Milestone

 25%-ish Complete Already?

    A break-through that I think I  had was probably over last week's material, or more specifically, finding and witnessing examples of natural selection occurring without evolution taking place. It still surprises me that it's a thing that can happen, since I've always been taught the blanket idea that natural selection leads to evolution. I was never told anything to the contrary and I never looked into it further, it never interested me enough. Not until last week, anyway. 

    Honestly, I don't think I'd change how I phrased it. Could I expand on it more? Sure, probably. I could probably provide better examples and articulate myself more goodly, but I don't think there's anything wrong with my definition as it currently stands.

    I wouldn't say that I'm struggling with anything right now. I do occasionally have trouble on R, but I've found the discussion board and the Almighty Google™ to be exceedingly helpful in amending these issues. That being said, if there are concepts I don't understand, there's a multitude of resources to explore, including the Evolution team and my peers.

    This is going to be a terrible answer, but I'm curious about all of it. I don't have one particular subject that just jumps out at me, flailing its arms excitedly for attention. They're all interesting in their own way, and I'd like to see how each one unfolds and works out.

Obligatory memes, but they're random and only one is related to evolution.

I'm still not sorry.

Mutations

 Mutations Everywhere

    Darwin's Postulates are the following:
1) Individuals within species are variable; 

2) Some of these variations are passed on to offspring; 

3) In every generation, more offspring are produced than can survive; and

4) The survival and reproduction of individuals are not random; the individuals who survive and go on to reproduce the most are those with the most favorable variation, and they are naturally selected. It follows logically from these that the characteristics of the population will change with each subsequent generation until the population becomes distinctly different from the original.

    Keeping those in mind, I do think that mutation rates can evolve. The genetic makeup of an organism, environmental impacts, diet, or other mutations could very will effect how that particular mutation behaves. We already know that mutations are random and what can help guide an organism or species into evolution, so I find it unlikely that mutations would not also evolve as, say, a species does. 

    An example would be a study conducted by Kelly Harris and Jonathan Pritchard in 2017 at Stanford University, titled "Rapid evolution of the human mutation spectrum." They found that the mutational spectra was substantially different among species, human continental groups, and some more closely-related populations. They closely examined an increased TCC --> TTC signal's mutation rate found in Europeans, and suggested that it indicates a "burst of mutations from about 15,000 to 2000 years ago," possibly due to the appearance, drifts, and "ultimate elimination of a genetic modifier of mutation rate." They concluded that their results would suggest that mutation rates can evolve "markedly over short evolutionary timescales and suggest the possibility of mapping mutational modifiers." 

    I think that mutation rates could be adaptive similarly to how an organism is adaptive. Outside stressors could impact how the mutation behaves, similarly to, say, Darwin's Finches. Their environmental stresses forced them to adapt so that they could survive. I think that mutations would do the same thing if the right stressors were pushed onto them.

Obligatory memes, as usual.

Sources:

Barnes-Sarvney, P., & Sarvney, T. E. (2014). What are the Four Postulates presented in Charles Darwin's on the origin of Species? - the Handy Biology answer book. Retrieved February 26, 2021, from https://www.papertrell.com/apps/preview/The-Handy-Biology-Answer-Book/Handy%20Answer%20book/What-are-the-four-postulates-presented-in-Charles-Darwin-s-O/001137031/content/SC/52cb02a282fad14abfa5c2e0_default.html

Harris, K., & Pritchard, J. K. (2017). Rapid evolution of the human mutation spectrum. ELife. doi:10.7554/elife.24284.001

Natural Selection and Evolutionary Change

 Can One Work Without the Other?

    I honestly wasn't sure how to answer these questions. I had to wrack my brain and go surfing through Google's resources to try and see actual, verifiable examples of natural selection working without leading to evolution. Natural selection is a mechanism that leads to evolution, but I don't think it's the only one. Genetic mutations are also a key part of the change. 

    In the first chapter of the book, when it talks about evolution and what it is, one of the passages on page 4 reads:  Natural selection is one process that can cause evolutionary change, but natural selection can occur without producing evolutionary change. Conversely, processes other than natural selection can lead to evolution.

    It follows after with an example: Natural selection within populations refers to the situation in which individuals with one variant of a trait (say, blue eyes) tend to leave more offspring that are healthy and fertile in the next generation than do individuals with an alternative variant of the trait.

    It goes on with how it can impact it by making that organism more desirable, increase of lifespan, or even increased offspring production. The catch to all of this, however, is that the differences among the individuals in the population are not genetically based. That is what can lead to natural selection without evolution. If variation in a population isn't genetically based, then it doesn't lead to evolution. 

    If we flip it and question if evolution can happen without natural selection, then it can happen through these means: mutation, genetic drift, and immigration of individuals with different genetic makeup. As the book says, "Natural selection can cause adaptive evolutionary change, but not all evolution is adaptive."

Obligatory memes to make up for the dryness.

Fitness

What is Fitness?

    

    As I understand it, fitness refers to how well an organism (or organisms) survive and reproduce. More specifically, how many healthy offspring that organism produces relative to others in the population. The reproduction part is very important since they're passing on their genetic code and trying to keep their line going strong, to keep that species going strong. The more healthy offspring an organism can produce, the better for them (and their species). That being said, I think that one of the easiest ways to measure fitness would probably be the checking the average lifespan of that organism, and checking how many offspring the average organism produces in its lifetime. 

    The best example I can think of would be the tree beetles. One variant was brown, and the other was white. On standard brown tree bark, the brown beetle is going to be camouflaged and have a higher survival rate. It will, in turn, also have a better (and higher) reproduction rate compared to that of the white beetle. Since the white beetle will stick out like a sore thumb, they're going to get picked off more quickly and have a lower population count, which will also impact their ability to reproduce.

Have some memes to offset the dryness.

Lamarck on Evolution

 What He Got Right and What He Got Wrong

    While Lamarck did help bring evolution to light and supported it so thoroughly, I believe he was wrong in how he addressed it. Lamarck seemed to believe the spontaneous generation theory, wherein organisms can develop from essentially nothing. He also believed that anything an organism used a lot would get bigger or used more often, whereas things that were used less often (or not at all) would eventually phase out of existence from that organism. 

    Furthermore, he also seemed to believe that all organisms were evolving to become these complex, perfect versions of themselves, which implies that all simple organisms would eventually cease to exist, which is simply not the case. He also seemed to think that any traits that a parent organism possessed would be passed onto its offspring, which is also not entirely correct.

   While we can see that some traits do get passed off to their offspring, it's more genetic variation and can be randomized what they actually get, assuming the offspring are healthy. Not all mutations that one organism develops will be passed onto its offspring, nor are all mutations necessarily good or bad. Furthermore, we have plenty of species on the planet that are simple in nature and still exist. For instance, things like algae, bacteria, or even fungi such as mushrooms. All of these are considered simple organisms and they've been around for an insanely long time. 

    What's more, while things that we use less will start to disappear, it doesn't mean that they're gone for good. For example: our appendix. It's incredibly useless for our species these days and no longer helps out in digestion like it used to for our ancestors. At this point in our existence, it's just a ticking time bomb in our bodies.

    Some of the giraffes would - through microevolution - develop slightly longer necks that could enable them to reach higher sources of food, so that when food became scarce on the lower levels, they had increased overall fitness because they could reach the other food sources. So the idea "If a giraffe stretched its neck for leaves, for example, a "nervous fluid" would flow into its neck and make it longer. Its offspring would inherit the longer neck, and continued stretching would make it longer still over several generations," seems wholly incorrect. 

(There is no escape. The giraffe is inevitable.)

(Again, have more memes to make it less dry.)

Game of Evolution

  Hopefully Not Like Game of Thrones 

    For the game presented to us for module two, I wanted to look at examples of microevolution, as it's one of my favorites (thanks, microbiology). There are various strains of bacteria that are resistant to a lot of treatments today. One particular type that I want to talk about it Pseudomonas aeruginosa. Anyone who has taken microbiology or dealt with bacteria is probably familiar with this species, since it's super common. 

     P. aeruginosa is known as an opportunistic pathogen that can target humans and plants. That means it goes for the people or plants who already have something wrong with them, something that broke down their defenses enough for them to break through and spread. Typically, you can find it in soil, vegetation, and in water. In more rare cases, you can find it in a human's throat, or in human fecal matter. It's predominantly found in hospitals and spreads through human contact, surfaces, being carried over by patients from other hospitals, and on produce. It has the biggest effect on people with preexisting conditions and has a 50% mortality rate on those who are already sick (if they have cancer, severe burns, or cystic fibrosis (CF), to name a few -- the more immunocompromised the patient is, the higher the risk). 

 

    What makes P. aeruginosa a great example of microevolution that we can witness is its resistance to antibiotics. In Microbiology, we ran an antibiotic resistance test called the Kirby-Bauer Method that tests for resistances and zones of inhibition for bacteria (tests to see how effective an antibiotic is on a bacteria type). This was done on P. aeruginosa, Staphylococcus aureus and Enterococcus faecalis. S. aureus and E. faecalis were shown to be susceptible to antibiotics - namely Vancomycin, Penicillin, Erythromycin, and Tetracycline. However, when looking at P. aeruginosa, we saw that only Tetracycline was effective against it, and it was able to resist all of the others. What's more, P. aeruginosa can develop resistances through chromosomal mutations and acquire antibiotic resistant genes. It's both an amazing, ever-evolving bacteria, and also terrifying because it's the cause of severe infections and death in hospitalized people.

Another example for it is from the article titled, "Pseudomonas aeruginosa Evolutionary Adaptation and Diversification in Cystic Fibrosis Chronic Lung Infections," written by Craig Winstanley, Siobhan O’Brien, and Michael Brockhurst for Science Direct in 2016: "Populations of P. aeruginosa in chronic CF lung infections typically exhibit high phenotypic diversity, including for clinically important traits such as antibiotic resistance and toxin production, and this diversity is dynamic over time, making accurate diagnosis and treatment challenging."

(Here's some memes to make it seem less dry.)

Sources:

Microbiology Laboratory Manual, Biology 455, Chapter 6: Sensitivity to Antibiotics, 2019
Antibiotic resistance in Pseudomonas aeruginosa – Mechanisms, epidemiology and evolution

Medical Microbiology, 4th Edition -- Chapter 27, Pseudomonas

Pseudomonas aeruginosa Evolutionary Adaptation and Diversification in Cystic Fibrosis Chronic Lung Infections
Picture Source

Evolution Discussion 1

 Week 1: Fact Or Theory?

    Evolution is the steady change over time in all organisms and it also suggests that we are all somehow related/come from the same original source of life. We don't know what that origin of all life is, but we're able to assume that it exists, given that we have seen examples that we're connected, that we came from one common ancestor. For instance, we can see that humans, dogs, cats (any vertebrate like us that has four legs/limbs), birds (or any flying vertebrate), whales, and so on all share similarly structure forelimbs (can't call them forearms since they don't technically have arms, right?). It's an everyday example - called a homologous structure - that many of us have in common, and it also ties back into the tetrapod, Ichthyostega, whose fossil indicates that this four-legged animal (basically a four-legged fish) was the first one to actually drag itself onto land. It's one of my more favorite examples for evolution and how we're connected (it's pretty easy to remember).

    That being said, I don't think we can call it a fact. Evolution is only a theory because we can't prove (beyond the shadow of a doubt) that it's true. Like someone mentioned in one of the discussion posts, we know for a fact that all life is evolving because we can witness it on a microevolutionary level as well. For example, bacteria's ability to evolve in order to resist antibiotics. Bacteria has been around for millions (billions?) of years, evolving with us and other organisms. Antibiotics weren't discovered nor distributed for use until the early-mid 1900s, so in that short time since antibiotics were developed, bacteria has adapted and evolved to become resistant to it.

Hi, My Name is Cristina and I Have a Nuka Cola Addiction

Also, I Have a Cheese Wheel Hoarding Problem

    Hi! I'm just now starting up my blog because yay procrastination. I've been playing through Fallout 4 again and I've sank so many hours into it (I'm not sorry... okay, maybe a tiny bit sorry).

    Like my title says, my name's Cristina. I'm from Alaska originally, I came to Kansas back in 2015 when I got stationed at good ol' Fort Riley. I've been attending K-State since Fall of 2018, and I'm projected to finish my degree in Medical Biology in Fall of 2021 (fingers crossed). I've got an almost unhealthy passion (read: obsession) with video games. I love first-person shooters (FPS) and roleplaying games (RPGs), especially combinations of the two. I like well-developed stories and character development as you progress. I'm a huge fan of the Mass Effect trilogy and the Fallout series, so I play those a lot. I also like going back into Skyrim to dominate everyone and hoard all of the cheese wheels and mead.

    I find evolution and biology fascinating because there's so many things we still don't know or fully understand yet about who/what we are, our ancestors, where we come from, the sources of all life, if we have any actual religiously-based maker(s), etc. It's all very interesting to me.

    I think that evolution plays a big part in everyday life since we can see it in action. For instance, our hands. We've developed these wonderful, grabby things that can do more than any other species (that I know of, anyway) on Earth. We can build so many things, destroy things, articulate our thoughts in writing/typing, we use them for human connection, for eating, for so many things. Hands are f***ing neat.

(Futurama is amazing.)

    I would like to get a better understanding of evolution, and to read/hear other people's opinions and outlooks on evolution. I like diversity in many things, and I think it's important to consider a lot of other perspectives and to keep an open mind.