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Journal #40 - Antibiotics

Submitted by robynfarrell on Mon, 05/01/2017 - 20:44

Recently I had strep, and I was in awe on how fast my antibiotics worked in order to make me feel better. Antibiotics can either be bacteriostatic or bactericidal, where static means to stop and cidal means to kill. Bacteriostatic antibiotics work by slowing the growth of bacteria by interfering with the processes that they need in order to grow and spread, such as DNA replication, metabolism, and protein production. On the other hand, bactericidal antibiotics kill the bacteria. It can do things such as prevent the cell from making a cell wall. What I was prescribed to take was amoxicillin, which is a bactericidal. A lot of antibiotics prescribed are either broad spectrum or narrow spectrum. Amoxicillin is considered broad spectrum, as it affects many different bacteria in our body, for example bacteria in our gut. This is why doctors recommend taking or eating a probiotic while on antibiotics. Narrow spectrum antibiotics only usually affect one to two different types of bacteria.

Ways of Adjusting a Family

Submitted by robynfarrell on Mon, 05/01/2017 - 17:21

Organisms have the capability of adjusting their family. Some organisms may regulate the number of offspring to maximize their fitness through miscarriages, and even cannibalism. With a miscarriage, a genetic mutation occurs in the developing fetus. This serves as a substantial penalty to the mother for carrying it, and a spontaneous death in the embryo occurs. This maintains the family size. Cannibalism occurs in a variety of species such as fish and rats. For example, in certain species of fish the male oxygenates the egg and on a certain occasion he might eat some of the eggs. This is due to the oxygen levels being too low. This condition causes the eggs to be in jeopardy, and rather than the whole clutch dying the father eats some of the eggs so others might survive. In other cases, the mother absorbs the fertilized eggs or developing embryos. If the environment gets too stressful for the mother, she has the ability to do this, and such a thing is seen in rats. This consumption of the fetus provides the mum with lots of nutrients and reduces the stress on her. She now might be more capable to reproduce again when the environment is more favorable.

 

Journal #39 - Biobag

Submitted by robynfarrell on Mon, 05/01/2017 - 15:14

Recently a sheep was developed in a plastic bag, called a “biobag.” It basically serves as a a womb outside of the body for this lamb to develop, rather than developing in the comfort of it’s mother. This biobag uses a “pumpless circulatory system” which helps connect the lamb’s umbilical cord composed of some blood vessels to an oxygenator, almost acting like a mother. This method makes it so that the blood in the lamb’s body is flowing only using their own heartbeat, almost so independent. So far this method has only been used on sheep, but scientists hope to take this to the next step eventually and help premature babies develop. It’s remarkable that people are able to even come up with solutions like this can solve such common problems that no one could have imagined to be fixable a decade ago.

Journal #38 - CloudFisher

Submitted by robynfarrell on Mon, 05/01/2017 - 13:01

A new invention called the Cloudfisher has come to help many people in need of water. This system works of a net that designed based on the structure of a spider’s web, and collects water from fog. A recent start up of this is located in Morocco. In this certain area tap water is so hard to come by, but fog is a constant. The net will collect all the moisture from the air, turn it into water, and will get collected by a gutter which drops right into a reservoir or tank. When wind hits this arid area, it helps push moisture through the netting trapping all the moisture. There were many years of experimenting done to figure out what kind of net would be the most effective in collecting the water. It was found that a monofilament that has tiny triangular openings got the job done. 

Journal #37 - Adjusting Families

Submitted by robynfarrell on Mon, 05/01/2017 - 11:27

In evolution the other day we learned how organisms can adjust their family. Some organisms may regulate the number of offspring to maximize their fitness through miscarriages, and even cannibalism. With a miscarriage, a genetic mutation occurs in the developing fetus. This serves as a substantial penalty to the mother for carrying it, and a spontaneous death in the embryo occurs. This maintains the family size. Cannibalism occurs in a variety of species such as fish and rats. For example, in certain species of fish the male oxygenates the egg and on a certain occasion he might eat some of the eggs. This is due to the oxygen levels being too low. This condition causes the eggs to be in jeopardy, and rather than the whole clutch dying the father eats some of the eggs so others might survive. In other cases, the mother absorbs the fertilized eggs or developing embryos. If the environment gets too stressful for the mother, she has the ability to do this, and such a thing is seen in rats. This consumption of the fetus provides the mum with lots of nutrients and reduces the stress on her. She now might be more capable to reproduce again when the environment is more favorable.

Organisms might also try to regulate the sex ratio to maximize fitness as well. Some organisms have the capability to change the sex ratio. In a perfect world the sex ratio would be 50:50, but that’s not always the case. In certain conditions you would benefit from one gender versus another. If there are more males than female, then it would be far more beneficial to produce more females so they would have a better chance of reproducing.

 

Extinctions

Submitted by robynfarrell on Sun, 04/30/2017 - 20:59

All extinctions are generally due to a change in atmosphere, that leads to a closing niches, which in turn leads to species dying. Volcanoes dump large amounts of carbon dioxide into the air, and that gets incorporated into oceans as carbonic acid. This changes the acidity and pH of the ocean messing with the thermal regime and amount of oxygen in the ocean. Rising acidity levels in the ocean precipitates a lot of marine invertebrates to slowly dying out. When a meteorite strikes it causes for an increase amount of iridium, which at an instant cause a radical change of a decrease in the number of species in that location.

Journal #36 - The Five Extinctions

Submitted by robynfarrell on Sun, 04/30/2017 - 18:30

Since the Earth has come to be there have been five mass extinction: Ordovician, Devonian, Permian, Triassic, and Cretaceous. The Ordovician extinction was an omega event, and occurred due to interglacial episodes and changing in marine heights. The Devonian extinction is technically not an extinction rate, it was more of a case where there were not enough new species being produced, and that was due to global cooling followed by global warming. The Permian extinction was an omega event that was caused due to volcanism. The Triassic extinction was another omega event, that was also due to volcanism and increased levels of carbon dioxide. The Cretaceous extinction was due an impact of a meteorite, and global warming followed by global cooling.

All extinctions are basically due to a change in atmosphere, that leads to a closing niches, which in turn leads to species dying. Volcanoes dump large amounts of carbon dioxide into the air, and that gets incorporated into oceans as carbonic acid. This changes the acidity and pH of the ocean which changes the thermal regime and amount of oxygen. Rising acidity levels in the ocean caused a lot of marine invertebrates to slowly die out. When a meteorite strikes it causes for an increase amount of iridium which at an instant decreases the number of species, such a radical change. 

Journal #35 - Environment Changes and Animals

Submitted by robynfarrell on Sun, 04/30/2017 - 17:02

When the environment changes it leads to rapid diversification of animals. Things such as the warming and retreating of glaciers, oxygenating of the ocean, changes of the acidity in water, and decreasing levels of carbon dioxide in the atmosphere can all have major effects on species. For example, the Cambrian radiation of animals was brought about due to an increase in oxygen availability. Species started developing genetic toolkits, body segments, and even skeletal structures. The Devonian radiation of plants happened due to the colonization of terrestrial environment. Plants started developing seeds, and vascular tissue during this time period. These are all examples of adaptive radiation, which means that a group or organisms diversify in order to fill out different ecological niches. 

Journal #34 - Bastian Mimicry

Submitted by robynfarrell on Sun, 04/30/2017 - 15:33

In one of my classes we had talked how some organisms use mimicry to help them escape predation. One form of mimicry that was discussed was Bastian mimicry. This is when one species tries to mimic a species that is distasteful and toxic. There are different results that can happen with this occurs. If a population consists of many toxic species, the species that is going to be mimicked, and few non toxic species, the species that will do the mimicking, the predator is more apt to run into a toxic organism. This is due to the chance of probability. When the predator goes to attack the toxic organism it learns that it is something that they should try to avoid and lessens the predation. So now both the toxic species and the species that is not toxic but looks like the toxic species get ignored, a stable strategy. This would go into fixation, and evolution would allow it to continue down this path.  If there is a population that consists of many mimics, an only a few toxic species the predator is more apt to run into the mimic first, eat it, and not learn that this species is something to avoid. This is an unstable strategy which is going to make the toxic species evolve into something different and get a new morphology. If a different morphology evolves in the toxic species it will be selected for. 

Bottlenecking Events

Submitted by robynfarrell on Mon, 04/24/2017 - 12:20

Bottleneck events reduce the genetic variation in a population. For example, take the species of elephant seals. Elephant seals used to be really common. They bred on islands, but have now shifted their breeding area to be shore lines. When examining their allelic composition, you would think to find a great diversity in alleles, but you find out there is a lot of homozygous diversity, which in the scientific community is not great. This is actually due to human hunting, due to them being hunted for their oils. At one point this species was down to only a few hundred, so rather than stopping hunting on them museums decided to step in. They thought that by taking dozens of these elephant seals that they would help maintain their safety. That actually drastically dropped their population in the wild to only 35. Throughout the last few decades their population has risen in the wild to around 100,000 but due to the incredible bottleneck their gene pool has dramatically shrunk. They have such a small gene pool that there are barely any mutations occurring, so their genetic diversity is slim.

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