The Evolution of Rock Pocket Mice Introduction- People sometimes wonder how organisms get so different from their ancestors. The answer is through their genes. Organisms over generations are always adapting to the environment. They are becoming better fit for survival to reproduce and live. The rock pocket mice were tested under different gene traits and environmental conditions to see what rock pocket mice would survive and reproduce more offspring. The different environments the mice were measured under are the ice age or desert and the different alleles that were tested were color, thickness of fur, and strength of jaw. Brown is dominant to white, normal fur is dominant to thick, and normal strength is dominant to strong. Of course through …show more content…
natural selection, the environment would chose one of these traits over the others in the rock pocket mice population. Either it be brown or white, thick or normal, strong or normal, the environment would chose one over the other to survive and be carried down to most of the offspring. The brown, normal thickness would survive better in a desert than the ice age. The white, thick fur would survive better in the ice age. In comparison, mutations in the rock pocket mice population can be harmful or helpful to them. One can survive over another depending on the environment in which the mice live in. Gene flow would bring organisms in and out of an environment to reproduce with the mice. Genetic drift is another way the mice population overtime can occur in evolution. Something can happen whether environmental or not, to the mice population that causes them not reproduce which means soon those mice would die without offspring with their genes. Either order of them can most likely make a population evolve and hopefully create two different species. By observing the rock pocket mice over many generations and recording the allele frequencies of the population after each generation, evolution can be determined as well as if speciation has occurred between two populations. Materials and Methods- Trial 1- A population of mice were observed over a given time period. They were monitored through different habitats, with different gene alleles to see how they would survive. Within the first events, they were tested with mutations and random-mating. The first population of mice went through a mutation that replaced ⅓ of a population of 30 with white fur. Then the mice underwent a mutation with ⅓ of the population being strong jaws so we got the population of 15 brown normal mice, 5 white normal, 5 white jaws, and 5 brown jaws due to randomly taking the mice out. Then, those mice were tested with random-mating. A flood caused a river to split the population of mice into two groups. That meant overtime they will get their own genetic differences and soon become a different species. After the split, the first group was, 5 brown fur, normal, normal, 5 brown, normal, hetero normal, 1 brown, normal, strong,1 brown normal hetero normal, 1 hetero brown, normal, normal. The other group was 4 brown normal normal, 1 brown, normal, hetero normal, 6 hetero brown, normal, normal, 4 heterbrown, normal, hetero normal, 1 brown, normal, strong, 1 white normal, strong, 1 white, normal, hetero normal. Then we randomly picked one of the populations, which was the first and it went under a mutation of ⅓ of the population being thick coat. The population then turned into 5 brown, normal, normal, 4 brown, normal, hetero normal, 1 brown, thick, hetero normal, 1 brown, thick, strong 1 brown, thick, hetero strong, 1 hetero brown, thick, normal. After predation though, from the first group, a BBttJj was eaten and from group two, 1 BbTTjj, 1 BbTTJj, 1 bbTTJj was eaten due to predation. Predation would happen after every two evolution events due to others higher up on the food chain eating the mice. Predation is calculated due to the environment. If the mice did not blend in with the desert, it would be 30% of the population was randomly would die, but if it did blend in, it would only be 10%. In resemblance, if it was an ice age, it would work the same way. Then the population was calculated in reproduction to get a new population of offspring. Reproduction was calculated by the carry capacity and the alleles of the population. Trial 2- Another population of mice were being tested under different conditions to see if they would change.
The population was tested under natural selection, genetic drift, and gene flow. The first population started out as 1 BBTTJj, 1 BBTtJJ, 2 BBTtJj, 1 BBTtjj, 1 BBttJj, 1 BbTTJJ, 2 BbTTJj, 1 BbTTjj, 2 BbTtJJ,4 BbTtJj, 2 BbTtjj, 1 BbttJJ, 2 BbttJj, 1 Bbttjj, 1 bbTTJj, 1 bbTtJJ, 2 bbTtJj, 1 bbTtjj, 1 bbttJj. The population then went through an ice age. This means that the brown mice have a greater chance of being spotted and killed. The white mice would have a greater chance of survival because they blend in. Next we had to kill of ½ of our population without thick coat because of natural selection. Now the population was 1 BbttJJ, 1 BbTTjj, 2 BbTtjj, 1 BBTTJj, 1 BbTtJj,1 BBTtjj, 1 bbttJj, 1 BBTtJJ, 1 bbTtjj, 1 bbTtJj, 1 BbTtJJ, 2 BbttJj, 1 Bbttjj, 1 bbTtJJ, 1 BBttJj. Then the population went through predation and they got a new population to start with. The population was 1 BBTtJj, 1 BBTtjj, 1 BBttJj, 1 BBttjj, 1 BbTTJj, 1 BbTTjj,1 BbTtJJ, 3 BbTtJj, 2 BbTtjj, 1 BbttJJ,3 BbttJj, 2 Bbttjj, 1 bbTtJJ, 2 bbTtJj, 1 bbTtjj, 1 bbttJJ, 2 bbttJj, 1 bbttjj. That population then underwent a forest fire that randomly killed off half of the population. The population after the fire was 2 BbTtJj, 1 bbTtjj, 1 bbttjj, 1 BbttJj, 2 bbttJj,2 BbTtjj, 2 Bbttjj, 2 bbTtjj. That population went through 10% of all organisms leaving due to greener pastures. The population then turned out to be 2 Bbttjj, 1 bbttjj, 1 bbTtjj, 2 BbTtjj, 2 bbttJj, 1 BbttJj, 1 bbTtJj. Next, after predation happened, a few more organisms died but then we got a new population through the carrying capacity calculations that brought it back up to 30 mice. The new population then went through a few more obstacles like no rain, a hot summer and organisms coming in to end with the population, 3 BbTtjj, 1 Bbttjj, 3 bbTTjj, 1 bbTtJj, 9 bbTtjj, 8 bbttjj, 1 BbttJJ, 1 BBTtJj, 1 BBTTJJ, 1
BBTTjj. Results- Color- Figure 1- This graph shows the allele B going down and the allele b going up. Figure 2- This graph shows the allele B going up and the allele b going down. Fur thickness- Figure 3- This graph shows the allele T going down and back up and the allele t going up and then back down. Figure 4- This graph shows allele T going up and then down. Also allele t going down, then back up. Jaw Strength- Figure 5- This graph shows allele j going up and allele J going down. Figure 6- This graph shows allele J going up then down and allele j down and then up. Chi Square: With Hannah's Group B b T t J j Observed 25.5 4.5 15 15 12.9 17.1 Expected 5.7 24.3 12.3 17.7 2.7 27.3 o - e 19.8 -19.8 2.7 -2.7 10.2 -10.2 (o - e)2 392.04 392.04 7.29 7.29 104.04 104.04 (o - e)2 / e 68.78 16.13 0.59 0.41 38.53 3.81 Total Partial Value: 128.25 Figure 7- This table shows the observed data of the mice to the expected. Discussion- Overtime, the mice population did achieve evolution and speciation. The hypothesis of observing the rock pocket mice over many generations and recording the allele frequencies of the population after each generation, evolution can be determined as well as if speciation has occurred between two populations was accepted. This can be proven by looking at the graphs between two populations that started at the same alleles to see where they finished and what happened to them at different events. All graphs started at even numbers between the whole population or at .5. In figure 1, compared to figure 2, the allele B went down and on figure 2, allele B went up. In addition, allele b on figure 1, went up and the allele b on figure 2 went down. The allele B ended at 19% of the population for figure 1 and for figure 2, 85% of the population. For allele b, it ended at 81% of the population for figure 1 and for figure 2, only 15% of the population. Evolution occurred by both colors starting at 50% but then either went up or down from that number. On the other hand, the thick fur on figure 3 went up then back down and normal fur went down but then back up. The thick fur on figure 4 went down but back up and the normal fur went up but then down. Both alleles went back down to 50% of the entire population for figure 4. For figure 3 though, allele T turned out to be 41% of the entire population while allele t being 59%. Lastly, figure 5 shows the allele j going up and allele J going down. Allele j ended at 91% of the population well normal jaws ended at only 9 %. In figure 6, strong jaws went down but then back up and normal jaws is the opposite. Normal jaws ended at 43% and strong jaws at 58% of the mice population. These numbers were caused by the different events happening to the rock pocket mice in random orders. Evolution occurred by the numbers of the population being different than the beginning of the test and unlike another population that started with the same ancestors. Every time new genes were brought in, they mated with different ones causing a diversity of organisms. Also figure 7 shows the expected number of organisms to the the ones there are actually. The total partial value is 128.25 and it is supposed to be 11.07. This means that the two populations are different species and that speciation has occurred. This information is important to tell whether the two populations have evolved over time. In general, it is important to study evolution for many reasons. Evolution teaches us about where organisms come from and which one of them shares a common ancestor to another. It helps endangered species survive and it teaches people what they need to do to stop a disease from spreading. Scientists study disease-causing organisms to try and stop them from spreading a disease. Evolution helps many people discover things about agriculture, medicine, and much more to help prevent diseases and to learn how to make the world safer for different organisms.
1These two populations are different species because they have different capabilities of performing in nature. For example there is behavioral isolation. My evidence for that is that in the data, it states that the average time spent in courtship display for the St. Kitts rodent is 12.6 seconds. While the courtship display for the Nevis Rodent is 21.3. You can see that there is a major difference in the way that they behave. Also there is another type of isolation which is gametic isolation. There is gametic isolation because the average gestation time for St. Kitts rodent is 29.3 days. The average gestation for the Nevis rodent is 42.7 days. Therefore a sperm from St. Kitts rodent wouldn’t survive in the reproductive tract of the Nevis rodent. It wouldn’t survive because it wouldn’t develop properly and is not accustomed to its environment. There is also another type of isolation happening with the rodents of St. Kitts. This type of isolation is called temporal isolation. There is temporal isolation because the article states, “the reproductive seasons are being delayed by up to one year.” This is talking about that the rodents are having a hard time finding mates therefore, their reproductive season is being delayed. Also in the article it states, “In the 240 attempts to bring a Nevis animal into the St. Kitts population, you are unable to observe a single successful reproductive event.” The rodents are mechanically isolated, because if you can’t have a reproductive event, there reproductive organs might not be matching with one another. Their appearance might look identical but they are genetically different.
The second condition of natural selection evolution involves the Honey Badgers heritability of its complex traits (Phelan, 2010). Honey Badgers have been able to maintain their presence and dominant nature within their habitats as a result of successfully transmitting traits from parent to child. As can seen from Honey Badgers consistent size and cognitive abilities, the animal is capable of genetically passing it successful traits.
Have you ever heard of a British scientist named Charles Darwin? He is the one who developed the theory of evolution. He also had a little motto, “survival of the fittest”, which means that natural selection chooses those best adapted to their environment to live. Those who survive reproduce and have new babies with the gene to survive in the environment, unless something changes. With that mentioned, certain traits are more common in a population because the traits increase an individual’s probability of surviving and reproducing in its environment. Evidence includes male peacocks with their colorful tails, Hawaii climbing gobies, and rock pocket mice.
Biological evolution is a change in the characteristics of living organisms over generations (Scott, 2017). A basic mechanism of evolution, the genetic drift, and mutation is natural selection. According to Darwin's theory of evolution, natural selection is a process in nature in which only the organisms best adapted to their environmental surroundings have a higher chance of surviving and transmitting their genetic characters in increasing numbers to succeeding generations while those less adapted tend to be eliminated. There has been many experimental research projects that relate to the topic of natural selection and evolution.
According to Klug, &Ward (2009), members of a certain population from another are distinguished by the presence of unique genetic characteristics. It is believed that large populations have greater diversity of alleles, compared to the small populations. In most cases, the diversity of alleles designates a greater potential for any evolution of new genes combination. This also shows greater capacity for evolution in adapting different environmental condition. On the other hand, individuals in small populations are possible to be hereditarily, anatomically as well physiologically more consistently than in large populations.
Natural selection is associated with the phrase “survival of the fittest.” This basically means that the fittest individuals can not only survive, but are also able to leave the most offspring. The selection of phenotypes affects the genotypes. For example, if tall pea plants are favored in the environment, then the tall pea plants would leave more offspring behind, meaning that the offspring will carry tall alleles. Phenotypes that are successful have the best adaptations (characteristics that help an individual to survive and reproduce) to their environment. These adaptation arise from the interactions with living and nonliving aspects of the environment. Some nonliving aspects of the environment are climate, water availability, and concentration of mineral sin the
The second of Tinbergen’s questions Phylogeny looks at the evolutionary explanations of development, as opposed to just how behaviour has adapted, including mutations in response to environmental changes. Some of these mutations remain in species even after necessity has gone, and can influence future characteristics of that species. The third of Tinbergen’s questions looks at Causation,...
Evolution in general, is a hard concept to grasp. There are multiple factors that effect the outcome a species, for example: genetics, nurture, nature, and the environment all play an important role. It was once said that species do not survive due to the fact that they are the strongest or the most intelligent, but because that species is the most responsive to change.
According to Darwin and his theory on evolution, organisms are presented with nature’s challenge of environmental change. Those that possess the characteristics of adapting to such challenges are successful in leaving their genes behind and ensuring that their lineage will continue. It is natural selection, where nature can perform tiny to mass sporadic experiments on its organisms, and the results can be interesting from extinction to significant changes within a species.
With the studies that Charles Darwin obtained he published his first work, “The Origin of Species.” In this book he explained how for millions of years animals, and plants have evolved to better help their existence. Darwin reasoned that these living things had gradually changed over time to help themselves. The changes that he found seemed to have been during the process of reproduction. The traits which would help them survive became a dominant trait, while the weaker traits became recessive. A good example of what Darwin was trying to explain is shown in giraffes. Long-necked giraffes could reach the food on the trees, while the short-necked giraffes couldn’t. Since long necks helped the giraffes eat, short-necked giraffes died off from hunger. Because of this long-necks became a dominant trait in giraffes. This is what Charles Darwin would later call natural selection.
Many scientists in the past, such as Aristotle and Plato, believed that there were no changes in populations; however, other scientists, such as Darwin and Wallace, arose and argued that species inherit heritable traits from common ancestors and environmental forces drives out certain heritable traits that makes the species better suited to survive or be more “fit” for that environment. Therefore, species do change over a period of time and they were able to support their theory by showing that evolution does occur. There were four basic mechanisms of evolution in their theory: mutation, migration, genetic drift, and natural selection. Natural selection is the gradual process by which heritable traits that makes it more likely for an organism to survive and successfully reproduce increases, whereas there is a decline in those who do have those beneficial heritable traits (Natural Selection). For example, there is a decrease in rain which causes a drought in the finches’ environment. The seeds in the finches’ environment would not be soft enough for the smaller and weaker beak finches to break; therefore, they cannot compete with the larger and stronger beak finches for food. The larger and stronger beak finches has a heritable trait that helps them survive and reproduce better than others for that particular environment which makes them categorized under natural selection (Freeman, 2002).
AGenetic Drift is the variation in a population’s allele frequencies from one generation to the next as a result of chance events. Genetic Drift may cause some genes to disappear, and overall reducing the genetic variation in a certain population. There are two types of Genetic Drift: Bottleneck Effect and Founder Effect . An example of Genetic Drift would be the American Bison, which suffered a huge reduction in population numbers, after succumbing to the bottleneck effect . Due to the quick killings of the Bison, many alleles died with their carriers, and genetic variation decreased exponentially. The American Bison has been gaining numbers in the past couple decades but the genetic variation amongst the different animals is very small. Another example of Genetic Drift would be that of the Northern elephant seals. Also being the target of hunters, the N.Elephant seals population reduced to a shocking 20 individuals at the end of the 19th century . Even though their population is steadily increasing, their genes still carry the effects of the bottleneck. They N. Elephant
We can see evolution in action everywhere we look, because through natural selection, all living things have been prosperous or killed off based on their environment. That is the beauty of natural selection; a mutation occurs in an animal and if it is beneficial, the animal prospers and passes on its traits to the next generation (Green, 2012). The polar bear was just a brown bear living in a snowy environment until a mutation occurred in one bear’s DNA that caused its fur to be white. This helped the bear blend in the snow when hunting, so the trait was passed on from generation to generation, until all brown bears in the area were all killed off, and only polar bears remained. Evolution doesn’t create new features; it takes mutations that
The next type of adaptation is also genetic, but does not involve the changing of the genes themselves, but rather how they are expressed. Because humans possess a remarkable amount of ‘genetic plasticity’, developmental adjustments can occur by turning particular genes on or off to adapt to the current environmental conditions at birth and through adolescence.
Natural selection is based on the concept “survival of the fittest” where the most favourable individual best suited in the environment survive and pass on their genes for the next generation. Those individual who are less suited to the environment will die.